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nord_242_6 | Therapies of Chromosome 14 Ring | TreatmentThe treatment of Chromosome 14 Ring is directed toward the specific symptoms that are apparent in each individual. Such treatment may require the coordinated efforts of a team of medical professionals, such as pediatricians; physicians who specialize in neurological disorders (neurologists); heart specialists (cardiologists); physicians who diagnose and treat disorders of the skeleton, muscles, joints, and related tissues (orthopedists); physical therapists; and/or other health care professionals.In some cases, treatment with antiseizure (anticonvulsant) drugs may help prevent, reduce, or control seizures associated with Chromosome 14 Ring. The specific medication used may depend upon the form of seizures present and other factors. In some affected individuals, seizures may be difficult to control (refractory). In such cases, recommended treatment may include combining certain appropriate anticonvulsant drugs.The treatment of individuals with Chromosome 14 Ring may also include measures to help prevent or aggressively treat respiratory infections. In addition, orthopedic measures and physical therapy may be recommended to help prevent or correct contracture development. In individuals with congenital heart defects, treatment with certain medications, surgical intervention, and/or other measures may be required. The surgical procedures performed may depend upon the location and severity of the abnormalities, their associated symptoms, and other factors.Early intervention may also be important in ensuring that affected children reach their potential. Special services that may be beneficial include special education and other medical, social, and/or other services.Genetic counseling will also be of benefit for individuals with Chromosome 14 Ring and their families. Other treatment for this disorder is symptomatic and supportive. | Therapies of Chromosome 14 Ring. TreatmentThe treatment of Chromosome 14 Ring is directed toward the specific symptoms that are apparent in each individual. Such treatment may require the coordinated efforts of a team of medical professionals, such as pediatricians; physicians who specialize in neurological disorders (neurologists); heart specialists (cardiologists); physicians who diagnose and treat disorders of the skeleton, muscles, joints, and related tissues (orthopedists); physical therapists; and/or other health care professionals.In some cases, treatment with antiseizure (anticonvulsant) drugs may help prevent, reduce, or control seizures associated with Chromosome 14 Ring. The specific medication used may depend upon the form of seizures present and other factors. In some affected individuals, seizures may be difficult to control (refractory). In such cases, recommended treatment may include combining certain appropriate anticonvulsant drugs.The treatment of individuals with Chromosome 14 Ring may also include measures to help prevent or aggressively treat respiratory infections. In addition, orthopedic measures and physical therapy may be recommended to help prevent or correct contracture development. In individuals with congenital heart defects, treatment with certain medications, surgical intervention, and/or other measures may be required. The surgical procedures performed may depend upon the location and severity of the abnormalities, their associated symptoms, and other factors.Early intervention may also be important in ensuring that affected children reach their potential. Special services that may be beneficial include special education and other medical, social, and/or other services.Genetic counseling will also be of benefit for individuals with Chromosome 14 Ring and their families. Other treatment for this disorder is symptomatic and supportive. | 242 | Chromosome 14 Ring |
nord_243_0 | Overview of Chromosome 14, Trisomy Mosaic | Chromosome 14, Trisomy Mosaic is a rare chromosomal disorder in which chromosome 14 appears three times (trisomy) rather than twice in some cells of the body. The term “mosaic” indicates that some cells contain the extra chromosome 14, whereas others have the normal chromosomal pair.The disorder may be characterized by growth delays before birth (intrauterine growth retardation); failure to grow and gain weight at the expected rate (failure to thrive) during infancy; delays in the acquisition of skills requiring the coordination of mental and physical abilities (psychomotor delays); and mental retardation. Affected infants also have distinctive abnormalities of the head and facial (craniofacial) region, such as a prominent forehead; deeply set, widely spaced eyes; a broad nasal bridge; and low-set, malformed ears. Additional craniofacial abnormalities may include an unusually small lower jaw (micrognathia); a large mouth and thick lips; and incomplete closure or abnormally high arching of the roof of the mouth (palate). Many affected infants also have structural malformations of the heart (e.g., tetralogy of Fallot). In some cases, additional physical abnormalities may also be present. | Overview of Chromosome 14, Trisomy Mosaic. Chromosome 14, Trisomy Mosaic is a rare chromosomal disorder in which chromosome 14 appears three times (trisomy) rather than twice in some cells of the body. The term “mosaic” indicates that some cells contain the extra chromosome 14, whereas others have the normal chromosomal pair.The disorder may be characterized by growth delays before birth (intrauterine growth retardation); failure to grow and gain weight at the expected rate (failure to thrive) during infancy; delays in the acquisition of skills requiring the coordination of mental and physical abilities (psychomotor delays); and mental retardation. Affected infants also have distinctive abnormalities of the head and facial (craniofacial) region, such as a prominent forehead; deeply set, widely spaced eyes; a broad nasal bridge; and low-set, malformed ears. Additional craniofacial abnormalities may include an unusually small lower jaw (micrognathia); a large mouth and thick lips; and incomplete closure or abnormally high arching of the roof of the mouth (palate). Many affected infants also have structural malformations of the heart (e.g., tetralogy of Fallot). In some cases, additional physical abnormalities may also be present. | 243 | Chromosome 14, Trisomy Mosaic |
nord_243_1 | Symptoms of Chromosome 14, Trisomy Mosaic | The symptoms and physical findings associated with Chromosome 14, Trisomy Mosaic may depend on the percentage of cells containing the extra 14th chromosome. However, the syndrome is typically characterized by growth and developmental delays, mental retardation, distinctive craniofacial malformations, and/or other physical abnormalities.Before birth, there may be excessive fluid in the amniotic sac (polyhydramnios), which is the thin-walled membrane surrounding the developing fetus during pregnancy. In addition, some infants with Chromosome 14, Trisomy Mosaic may be born prior to 37 weeks' gestation (premature infant). (Gestation refers to the period of development from conception to birth. “Full-term” infants are born anywhere from 37 to 42 weeks of gestation.)Chromosome 14, Trisomy Mosaic may also be characterized by abnormal growth delays before birth (prenatal growth retardation) and a failure to grow and gain weight at the expected rate (failure to thrive) during infancy. In addition, affected individuals typically have psychomotor delays and mental retardation.The syndrome is also associated with characteristic craniofacial malformations, resulting in a distinctive appearance. Such features may include a prominent forehead; a broad nose; an unusually long vertical groove in the center of the upper lip (philtrum); a prominent upper jaw (maxilla); and a small, receding lower jaw (microretrognathia). Various eye (ocular) abnormalities may also be present, such as deeply set and/or widely spaced eyes (ocular hypertelorism); abnormal reduction in the size of the eyes (microphthalmia); narrow eyelid folds (palpebral fissures); mild drooping of the upper eyelids (ptosis); and/or a translucent film over the eyes. Affected infants may also have small, low-set, abnormally folded ears; a wide mouth and thick lips; incomplete closure (clefting) or unusually high arching of the roof of the mouth (palate); and/or a short, wide neck. In addition, in some cases, the face may appear relatively dissimilar from one side to the other (facial asymmetry).Many infants with Chromosome 14, Trisomy Mosaic also have structural abnormalities of the heart that are present at birth (congenital heart defects), particularly tetralogy of Fallot. This congenital defect is characterized by a combination of distinctive heart (cardiac) malformations. These include an abnormal opening in the partition (septum) that separates the two lower chambers (ventricles) of the heart; obstruction of the proper outflow of blood from the lower right ventricle due to narrowing of the opening between the ventricle and the pulmonary artery (pulmonary stenosis); displacement of the aorta, enabling oxygen-depleted blood to flow from the right ventricle to the aorta; and thickening (hypertrophy) of the heart muscle (myocardium) of the right ventricle. (The pulmonary artery transports oxygen-depleted blood from the right ventricle to the lungs, where the exchange of oxygen and carbon dioxide occurs. The aorta, the major artery of the body, arises from the left ventricle and supplies oxygen-rich blood to most arteries.) Associated symptoms and findings may include insufficient oxygen supply to body tissues (hypoxia), bluish discoloration of the skin and mucous membranes (cyanosis), shortness of breath (dyspnea), feeding difficulties, failure to thrive, and/or other abnormalities. In some instances, Chromosome 14, Trisomy Mosaic may be associated with other cardiac defects. In severe cases, congenital heart disease may lead to potentially life-threatening complications.In some individuals with the syndrome, additional physical abnormalities may also be present. For example, according to reports in the medical literature, many infants with Chromosome 14, Trisomy Mosaic have had areas of abnormally increased skin pigmentation (hyperpigmentation) that may appear in a linear, spirallike (whorl), patchy, or netlike (reticular) distribution. Additional physical findings associated with the syndrome have included genital malformations in affected males, including undescended testes (cryptorchidism) and/or an abnormally small penis; body asymmetry, such as dissimilarity in the length of the arms or the legs (limb length asymmetry); and/or other skeletal abnormalities, such as dislocation of the hips, overlapping of certain fingers or toes, and/or other features. | Symptoms of Chromosome 14, Trisomy Mosaic. The symptoms and physical findings associated with Chromosome 14, Trisomy Mosaic may depend on the percentage of cells containing the extra 14th chromosome. However, the syndrome is typically characterized by growth and developmental delays, mental retardation, distinctive craniofacial malformations, and/or other physical abnormalities.Before birth, there may be excessive fluid in the amniotic sac (polyhydramnios), which is the thin-walled membrane surrounding the developing fetus during pregnancy. In addition, some infants with Chromosome 14, Trisomy Mosaic may be born prior to 37 weeks' gestation (premature infant). (Gestation refers to the period of development from conception to birth. “Full-term” infants are born anywhere from 37 to 42 weeks of gestation.)Chromosome 14, Trisomy Mosaic may also be characterized by abnormal growth delays before birth (prenatal growth retardation) and a failure to grow and gain weight at the expected rate (failure to thrive) during infancy. In addition, affected individuals typically have psychomotor delays and mental retardation.The syndrome is also associated with characteristic craniofacial malformations, resulting in a distinctive appearance. Such features may include a prominent forehead; a broad nose; an unusually long vertical groove in the center of the upper lip (philtrum); a prominent upper jaw (maxilla); and a small, receding lower jaw (microretrognathia). Various eye (ocular) abnormalities may also be present, such as deeply set and/or widely spaced eyes (ocular hypertelorism); abnormal reduction in the size of the eyes (microphthalmia); narrow eyelid folds (palpebral fissures); mild drooping of the upper eyelids (ptosis); and/or a translucent film over the eyes. Affected infants may also have small, low-set, abnormally folded ears; a wide mouth and thick lips; incomplete closure (clefting) or unusually high arching of the roof of the mouth (palate); and/or a short, wide neck. In addition, in some cases, the face may appear relatively dissimilar from one side to the other (facial asymmetry).Many infants with Chromosome 14, Trisomy Mosaic also have structural abnormalities of the heart that are present at birth (congenital heart defects), particularly tetralogy of Fallot. This congenital defect is characterized by a combination of distinctive heart (cardiac) malformations. These include an abnormal opening in the partition (septum) that separates the two lower chambers (ventricles) of the heart; obstruction of the proper outflow of blood from the lower right ventricle due to narrowing of the opening between the ventricle and the pulmonary artery (pulmonary stenosis); displacement of the aorta, enabling oxygen-depleted blood to flow from the right ventricle to the aorta; and thickening (hypertrophy) of the heart muscle (myocardium) of the right ventricle. (The pulmonary artery transports oxygen-depleted blood from the right ventricle to the lungs, where the exchange of oxygen and carbon dioxide occurs. The aorta, the major artery of the body, arises from the left ventricle and supplies oxygen-rich blood to most arteries.) Associated symptoms and findings may include insufficient oxygen supply to body tissues (hypoxia), bluish discoloration of the skin and mucous membranes (cyanosis), shortness of breath (dyspnea), feeding difficulties, failure to thrive, and/or other abnormalities. In some instances, Chromosome 14, Trisomy Mosaic may be associated with other cardiac defects. In severe cases, congenital heart disease may lead to potentially life-threatening complications.In some individuals with the syndrome, additional physical abnormalities may also be present. For example, according to reports in the medical literature, many infants with Chromosome 14, Trisomy Mosaic have had areas of abnormally increased skin pigmentation (hyperpigmentation) that may appear in a linear, spirallike (whorl), patchy, or netlike (reticular) distribution. Additional physical findings associated with the syndrome have included genital malformations in affected males, including undescended testes (cryptorchidism) and/or an abnormally small penis; body asymmetry, such as dissimilarity in the length of the arms or the legs (limb length asymmetry); and/or other skeletal abnormalities, such as dislocation of the hips, overlapping of certain fingers or toes, and/or other features. | 243 | Chromosome 14, Trisomy Mosaic |
nord_243_2 | Causes of Chromosome 14, Trisomy Mosaic | In individuals with Chromosome 14, Trisomy Mosaic, chromosome 14 is present three times (trisomy) rather than twice in some cells of the body (mosaicism). Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p,” a long arm identified by the letter “q,” and a narrowed region at which the two arms are joined (centromere). The same chromosomal (i.e., karyotypical) makeup is usually present in all body cells. (“Karyotype” refers to the full chromosome set within the nucleus of a cell.) However, those with a mosaicism have two or more cell lines that are karyotypically distinct. In individuals with Chromosome 14, Trisomy Mosaic, there is trisomy (duplication) of chromosome 14 in a percentage of cells, while other cells have a normal chromosomal makeup. The additional chromosome is responsible for the symptoms and physical findings that characterize the syndrome. Individuals with a low percentage of affected cells (low mosaicism) may have fewer, less severe symptoms than those with a high percentage of affected cells (high mosaicism).Chromosome 14, Trisomy Mosaic appears to result from errors of chromosomal separation (nondisjunction) during the division of reproductive cells in one of the parents (parental meiosis) or during cellular division after fertilization (fetal mitosis). There have been some reports in which the syndrome has appeared to occur due to uniparental disomy or the formation of an isochromosome (14q isochromosome). Uniparental disomy is a chromosomal abnormality in which affected individuals have inherited both copies of a chromosomal pair from one parent, rather than one copy from each parent. An isochromosome is an abnormal chromosome with identical arms on each side of the centromere. | Causes of Chromosome 14, Trisomy Mosaic. In individuals with Chromosome 14, Trisomy Mosaic, chromosome 14 is present three times (trisomy) rather than twice in some cells of the body (mosaicism). Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p,” a long arm identified by the letter “q,” and a narrowed region at which the two arms are joined (centromere). The same chromosomal (i.e., karyotypical) makeup is usually present in all body cells. (“Karyotype” refers to the full chromosome set within the nucleus of a cell.) However, those with a mosaicism have two or more cell lines that are karyotypically distinct. In individuals with Chromosome 14, Trisomy Mosaic, there is trisomy (duplication) of chromosome 14 in a percentage of cells, while other cells have a normal chromosomal makeup. The additional chromosome is responsible for the symptoms and physical findings that characterize the syndrome. Individuals with a low percentage of affected cells (low mosaicism) may have fewer, less severe symptoms than those with a high percentage of affected cells (high mosaicism).Chromosome 14, Trisomy Mosaic appears to result from errors of chromosomal separation (nondisjunction) during the division of reproductive cells in one of the parents (parental meiosis) or during cellular division after fertilization (fetal mitosis). There have been some reports in which the syndrome has appeared to occur due to uniparental disomy or the formation of an isochromosome (14q isochromosome). Uniparental disomy is a chromosomal abnormality in which affected individuals have inherited both copies of a chromosomal pair from one parent, rather than one copy from each parent. An isochromosome is an abnormal chromosome with identical arms on each side of the centromere. | 243 | Chromosome 14, Trisomy Mosaic |
nord_243_3 | Affects of Chromosome 14, Trisomy Mosaic | In observed cases, Chromosome 14, Trisomy Mosaic has appeared to affect females more frequently than males. Since the chromosomal syndrome was originally described in the medical literature, over 20 cases have been reported. | Affects of Chromosome 14, Trisomy Mosaic. In observed cases, Chromosome 14, Trisomy Mosaic has appeared to affect females more frequently than males. Since the chromosomal syndrome was originally described in the medical literature, over 20 cases have been reported. | 243 | Chromosome 14, Trisomy Mosaic |
nord_243_4 | Related disorders of Chromosome 14, Trisomy Mosaic | Other chromosomal disorders may be characterized by symptoms and findings similar to those potentially associated with Chromosome 14, Trisomy Mosaic. Chromosomal testing is necessary to confirm the specific chromosomal abnormality present. (For further information on such chromosomal disorders, choose the name of the specific disorder in question or use “chromosome” as your search term in the Rare Disease Database.) | Related disorders of Chromosome 14, Trisomy Mosaic. Other chromosomal disorders may be characterized by symptoms and findings similar to those potentially associated with Chromosome 14, Trisomy Mosaic. Chromosomal testing is necessary to confirm the specific chromosomal abnormality present. (For further information on such chromosomal disorders, choose the name of the specific disorder in question or use “chromosome” as your search term in the Rare Disease Database.) | 243 | Chromosome 14, Trisomy Mosaic |
nord_243_5 | Diagnosis of Chromosome 14, Trisomy Mosaic | A diagnosis of Chromosome 14, Trisomy Mosaic may be suggested before birth (prenatally) by specialized tests such as ultrasound, amniocentesis, and/or chorionic villus sampling (CVS). During fetal ultrasonography, reflected sound waves are used to create an image of the developing fetus. Ultrasonography may reveal characteristic findings that suggest Chromosome 14, Trisomy Mosaic, such as excessive fluid in the membranous sac surrounding the developing fetus (polyhydramnios), growth retardation, and/or certain physical malformations (e.g., cleft palate). During amniocentesis, a sample of fluid that surrounds the developing fetus is removed and analyzed, whereas CVS involves the removal of tissue samples from a portion of the placenta. Chromosomal analysis performed on the fluid or tissue samples may reveal the presence of Chromosome 14, Trisomy Mosaic.The diagnosis may also be made or confirmed after birth (postnatally) based upon a thorough clinical evaluation, detection of characteristic physical findings, and chromosomal analysis. In addition, specialized testing may also be conducted to detect or characterize certain abnormalities that may be associated with the disorder, such as congenital heart defects. Cardiac evaluation may include clinical examination with a stethoscope to evaluate heart and lung sounds; x-ray studies; tests that record the electrical activities of the heart muscle (electrocardiography [EKG]); a technique in which sound waves are directed toward the heart, enabling evaluation of cardiac motion and structure (echocardiogram); or other measures (e.g., cardiac catheterization). | Diagnosis of Chromosome 14, Trisomy Mosaic. A diagnosis of Chromosome 14, Trisomy Mosaic may be suggested before birth (prenatally) by specialized tests such as ultrasound, amniocentesis, and/or chorionic villus sampling (CVS). During fetal ultrasonography, reflected sound waves are used to create an image of the developing fetus. Ultrasonography may reveal characteristic findings that suggest Chromosome 14, Trisomy Mosaic, such as excessive fluid in the membranous sac surrounding the developing fetus (polyhydramnios), growth retardation, and/or certain physical malformations (e.g., cleft palate). During amniocentesis, a sample of fluid that surrounds the developing fetus is removed and analyzed, whereas CVS involves the removal of tissue samples from a portion of the placenta. Chromosomal analysis performed on the fluid or tissue samples may reveal the presence of Chromosome 14, Trisomy Mosaic.The diagnosis may also be made or confirmed after birth (postnatally) based upon a thorough clinical evaluation, detection of characteristic physical findings, and chromosomal analysis. In addition, specialized testing may also be conducted to detect or characterize certain abnormalities that may be associated with the disorder, such as congenital heart defects. Cardiac evaluation may include clinical examination with a stethoscope to evaluate heart and lung sounds; x-ray studies; tests that record the electrical activities of the heart muscle (electrocardiography [EKG]); a technique in which sound waves are directed toward the heart, enabling evaluation of cardiac motion and structure (echocardiogram); or other measures (e.g., cardiac catheterization). | 243 | Chromosome 14, Trisomy Mosaic |
nord_243_6 | Therapies of Chromosome 14, Trisomy Mosaic | TreatmentThe treatment of Chromosome 14, Trisomy Mosaic is directed toward the specific symptoms that are apparent in each individual. Such treatment may require the coordinated efforts of a team of medical professionals, such as pediatricians; surgeons; physicians who diagnose and treat heart abnormalities (cardiologists); and/or other health care professionals.If affected infants and children with tetralogy of Fallot have episodes in which cyanosis suddenly worsens (hypoxic spells), treatment may include the administration of oxygen, morphine, sodium bicarbonate, or other therapies as required to help improve oxygen concentration. In addition, in those with tetralogy of Fallot, surgical measures may be necessary to help alleviate symptoms and correct heart malformations (e.g., palliative systemic-to-pulmonary artery shunt, corrective open-heart surgery). Because individuals with tetralogy of Fallot may be susceptible to bacterial infection of the internal lining of the heart (endocarditis), antibiotics should be prescribed before and after dental visits and surgical procedures. Respiratory infections must also be treated vigorously and early.In some infants and children with Chromosome 14, Trisomy Mosaic, treatment may also include the surgical repair of certain craniofacial, genital, or other abnormalities potentially associated with the disorder. The surgical procedures performed will depend upon the severity of the anatomical abnormalities, their associated symptoms, and other factors. Other treatment is symptomatic and supportive.Early intervention may be important in ensuring that children with Chromosome 14, Trisomy Mosaic reach their potential. Special services that may be beneficial include special education, physical therapy, and/or other medical, social, and/or vocational services. Genetic counseling will also be of benefit for affected individuals and their families. | Therapies of Chromosome 14, Trisomy Mosaic. TreatmentThe treatment of Chromosome 14, Trisomy Mosaic is directed toward the specific symptoms that are apparent in each individual. Such treatment may require the coordinated efforts of a team of medical professionals, such as pediatricians; surgeons; physicians who diagnose and treat heart abnormalities (cardiologists); and/or other health care professionals.If affected infants and children with tetralogy of Fallot have episodes in which cyanosis suddenly worsens (hypoxic spells), treatment may include the administration of oxygen, morphine, sodium bicarbonate, or other therapies as required to help improve oxygen concentration. In addition, in those with tetralogy of Fallot, surgical measures may be necessary to help alleviate symptoms and correct heart malformations (e.g., palliative systemic-to-pulmonary artery shunt, corrective open-heart surgery). Because individuals with tetralogy of Fallot may be susceptible to bacterial infection of the internal lining of the heart (endocarditis), antibiotics should be prescribed before and after dental visits and surgical procedures. Respiratory infections must also be treated vigorously and early.In some infants and children with Chromosome 14, Trisomy Mosaic, treatment may also include the surgical repair of certain craniofacial, genital, or other abnormalities potentially associated with the disorder. The surgical procedures performed will depend upon the severity of the anatomical abnormalities, their associated symptoms, and other factors. Other treatment is symptomatic and supportive.Early intervention may be important in ensuring that children with Chromosome 14, Trisomy Mosaic reach their potential. Special services that may be beneficial include special education, physical therapy, and/or other medical, social, and/or vocational services. Genetic counseling will also be of benefit for affected individuals and their families. | 243 | Chromosome 14, Trisomy Mosaic |
nord_244_0 | Overview of Chromosome 15 Ring | Chromosome 15 Ring results from loss (deletion) of genetic material from both ends of the 15th chromosome and a joining of the ends to form a ring. Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p” and a long arm identified by the letter “q”. Chromosomes are further subdivided into bands that are numbered.In individuals with Chromosome 15 Ring, the variability of associated symptoms and findings may depend upon the amount and location of genetic material lost from the 15th chromosome, the stability of the ring chromosome during subsequent cellular divisions, or other factors. Evidence suggests that the clinical features seen in Chromosome 15 Ring appear to result from deletions of genetic material from the long arm (q) of chromosome 15 (known as “monosomy 15q”), with the ring chromosome typically replacing a normal 15th chromosome. In addition, in some cases, only a certain percentage of an individual's cells may contain Chromosome 15 Ring, while other cells may have a normal chromosomal makeup (a finding known as “chromosomal mosaicism”), potentially affecting the variability of associated symptoms and findings.In most cases, Chromosome 15 Ring appears to be caused by spontaneous (de novo) errors very early in embryonic development. In such cases, the parents of the affected child usually have normal chromosomes and a relatively low risk of having another child with the chromosomal abnormality. However, there have been rare cases in which a parent of an affected individual also has Chromosome 15 Ring. In such instances, the chances are greater of having another child with the chromosomal abnormality. In addition, a few cases have been reported in which Chromosome 15 Ring has been the result of a “balanced translocation” in one of the parents. Translocations occur when regions of certain chromosomes break off and are rearranged, resulting in shifting of genetic material and an altered set of chromosomes. If a chromosomal rearrangement is balanced, meaning that it consists of an altered but balanced set of chromosomes, it is usually harmless to the carrier. However, such a chromosomal rearrangement may be associated with an increased risk of abnormal chromosomal development in the carrier's offspring.Chromosomal analysis and genetic counseling are typically recommended for parents of an affected child to help confirm or exclude the presence of Chromosome 15 Ring, potential mosaicism, or a balanced translocation in one of the parents.Many individuals with Chromosome 15 Ring have some features similar to those associated with Russell-Silver syndrome (RSS), which is a genetic disorder characterized by growth deficiency and short stature, distinctive facial abnormalities, and other features. (For further information, please see the “Related Disorders” section below.) In some of these cases, genetic analysis has indicated that the prenatal and postnatal growth retardation associated with Chromosome 15 Ring (and potentially suggestive of RSS) may result from deletion of a gene known as the insulin-like growth factor I receptor (IGF1R) gene, which has been mapped to the long arm of chromosome 15 (15q25-q26). | Overview of Chromosome 15 Ring. Chromosome 15 Ring results from loss (deletion) of genetic material from both ends of the 15th chromosome and a joining of the ends to form a ring. Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p” and a long arm identified by the letter “q”. Chromosomes are further subdivided into bands that are numbered.In individuals with Chromosome 15 Ring, the variability of associated symptoms and findings may depend upon the amount and location of genetic material lost from the 15th chromosome, the stability of the ring chromosome during subsequent cellular divisions, or other factors. Evidence suggests that the clinical features seen in Chromosome 15 Ring appear to result from deletions of genetic material from the long arm (q) of chromosome 15 (known as “monosomy 15q”), with the ring chromosome typically replacing a normal 15th chromosome. In addition, in some cases, only a certain percentage of an individual's cells may contain Chromosome 15 Ring, while other cells may have a normal chromosomal makeup (a finding known as “chromosomal mosaicism”), potentially affecting the variability of associated symptoms and findings.In most cases, Chromosome 15 Ring appears to be caused by spontaneous (de novo) errors very early in embryonic development. In such cases, the parents of the affected child usually have normal chromosomes and a relatively low risk of having another child with the chromosomal abnormality. However, there have been rare cases in which a parent of an affected individual also has Chromosome 15 Ring. In such instances, the chances are greater of having another child with the chromosomal abnormality. In addition, a few cases have been reported in which Chromosome 15 Ring has been the result of a “balanced translocation” in one of the parents. Translocations occur when regions of certain chromosomes break off and are rearranged, resulting in shifting of genetic material and an altered set of chromosomes. If a chromosomal rearrangement is balanced, meaning that it consists of an altered but balanced set of chromosomes, it is usually harmless to the carrier. However, such a chromosomal rearrangement may be associated with an increased risk of abnormal chromosomal development in the carrier's offspring.Chromosomal analysis and genetic counseling are typically recommended for parents of an affected child to help confirm or exclude the presence of Chromosome 15 Ring, potential mosaicism, or a balanced translocation in one of the parents.Many individuals with Chromosome 15 Ring have some features similar to those associated with Russell-Silver syndrome (RSS), which is a genetic disorder characterized by growth deficiency and short stature, distinctive facial abnormalities, and other features. (For further information, please see the “Related Disorders” section below.) In some of these cases, genetic analysis has indicated that the prenatal and postnatal growth retardation associated with Chromosome 15 Ring (and potentially suggestive of RSS) may result from deletion of a gene known as the insulin-like growth factor I receptor (IGF1R) gene, which has been mapped to the long arm of chromosome 15 (15q25-q26). | 244 | Chromosome 15 Ring |
nord_244_1 | Symptoms of Chromosome 15 Ring | Although associated features may be variable, Chromosome 15 Ring is commonly characterized by growth delays before and after birth, resulting in short stature (dwarfism); varying degrees of mental retardation; low muscle tone (hypotonia); craniofacial malformations; and limb abnormalities.According to reports in the medical literature, Chromosome 15 Ring is often associated with mild to moderate mental retardation. However, in some instances, severe mental retardation may become evident during adulthood. In addition, some affected infants and children may have delays in the acquisition of language and speech.In many individuals with Chromosome 15 Ring, craniofacial malformations may result in a distinctive facial appearance. Such abnormalities may include an unusually small head (microcephaly) with a prominent forehead (frontal bossing); a “triangular-shaped” face; widely spaced eyes (ocular hypertelorism); a high, broad nasal bridge; and/or malformed outer ears.Many affected individuals may also have abnormalities of the hands and feet. These may include delayed bone age; abnormal shortness of certain bones of the fingers and toes (phalanges), causing the hands and feet to appear short; abnormal deviation (clinodactyly) of the “pinkies” or fifth fingers; and/or underdevelopment (hypoplasia) of the thumbs.In many affected males, decreased functioning of the testes (hypogonadism) results in infertility. However, reports suggest that gonadal (i.e., ovarian) function, sexual development, and fertility appear to be normal in most affected females.In some cases, Chromosome 15 Ring may be associated with additional physical findings. Such abnormalities may include structural malformations of the heart that are present at birth (congenital heart defects), kidney (renal) defects, and/or congenital dislocation of the hips. In addition, some affected individuals may have light brown, pale tan, or “coffee-colored” patches on the skin (cafe-au-lait spots). | Symptoms of Chromosome 15 Ring. Although associated features may be variable, Chromosome 15 Ring is commonly characterized by growth delays before and after birth, resulting in short stature (dwarfism); varying degrees of mental retardation; low muscle tone (hypotonia); craniofacial malformations; and limb abnormalities.According to reports in the medical literature, Chromosome 15 Ring is often associated with mild to moderate mental retardation. However, in some instances, severe mental retardation may become evident during adulthood. In addition, some affected infants and children may have delays in the acquisition of language and speech.In many individuals with Chromosome 15 Ring, craniofacial malformations may result in a distinctive facial appearance. Such abnormalities may include an unusually small head (microcephaly) with a prominent forehead (frontal bossing); a “triangular-shaped” face; widely spaced eyes (ocular hypertelorism); a high, broad nasal bridge; and/or malformed outer ears.Many affected individuals may also have abnormalities of the hands and feet. These may include delayed bone age; abnormal shortness of certain bones of the fingers and toes (phalanges), causing the hands and feet to appear short; abnormal deviation (clinodactyly) of the “pinkies” or fifth fingers; and/or underdevelopment (hypoplasia) of the thumbs.In many affected males, decreased functioning of the testes (hypogonadism) results in infertility. However, reports suggest that gonadal (i.e., ovarian) function, sexual development, and fertility appear to be normal in most affected females.In some cases, Chromosome 15 Ring may be associated with additional physical findings. Such abnormalities may include structural malformations of the heart that are present at birth (congenital heart defects), kidney (renal) defects, and/or congenital dislocation of the hips. In addition, some affected individuals may have light brown, pale tan, or “coffee-colored” patches on the skin (cafe-au-lait spots). | 244 | Chromosome 15 Ring |
nord_244_2 | Causes of Chromosome 15 Ring | Chromosome 15 Ring results from loss (deletion) of genetic material from both ends of the 15th chromosome and a joining of the ends to form a ring. Chromosomes are found in the nucleus of all body cells except red blood cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p” and a long arm identified by the letter “q.” Chromosomes are further subdivided into bands that are numbered.In individuals with Chromosome 15 Ring, the variability of associated symptoms and findings may depend upon the amount and location of genetic material lost from the 15th chromosome, the stability of the ring chromosome during subsequent cellular divisions, or other factors. Evidence suggests that the clinical features seen in Chromosome 15 Ring appear to result from deletions of genetic material from the long arm (q) of chromosome 15 (known as “monosomy 15q”), with the ring chromosome typically replacing a normal 15th chromosome. In addition, in some cases, only a certain percentage of an individual's cells may contain Chromosome 15 Ring, while other cells may have a normal chromosomal makeup (a finding known as “chromosomal mosaicism”), potentially affecting the variability of associated symptoms and findings.In most cases, Chromosome 15 Ring appears to be caused by spontaneous (de novo) errors very early in embryonic development. In such cases, the parents of the affected child usually have normal chromosomes and a relatively low risk of having another child with the chromosomal abnormality. However, there have been rare cases in which a parent of an affected individual also has Chromosome 15 Ring. In such instances, the chances are greater of having another child with the chromosomal abnormality. In addition, a few cases have been reported in which Chromosome 15 Ring has been the result of a “balanced translocation” in one of the parents. Translocations occur when regions of certain chromosomes break off and are rearranged, resulting in shifting of genetic material and an altered set of chromosomes. If a chromosomal rearrangement is balanced, meaning that it consists of an altered but balanced set of chromosomes, it is usually harmless to the carrier. However, such a chromosomal rearrangement may be associated with an increased risk of unbalanced chromosome inheritance by in the carrier's offspring. Chromosomal analysis and genetic counseling are typically recommended for parents of an affected child to help confirm or exclude the presence of Chromosome 15 Ring, potential mosaicism, or a balanced translocation in one of the parents.Many individuals with Chromosome 15 Ring have some features similar to those associated with Russell-Silver syndrome (RSS), which is a genetic disorder characterized by growth deficiency and short stature, distinctive facial abnormalities, and other features. (For further information, please see the “Related Disorders” section below.) In some of these cases, genetic analysis has indicated that the prenatal and postnatal growth retardation associated with Chromosome 15 Ring (and potentially suggestive of RSS) may result from deletion of a gene known as the insulin-like growth factor I receptor (IGF1R) gene, which has been mapped to the long arm of chromosome 15 (15q25-q26). | Causes of Chromosome 15 Ring. Chromosome 15 Ring results from loss (deletion) of genetic material from both ends of the 15th chromosome and a joining of the ends to form a ring. Chromosomes are found in the nucleus of all body cells except red blood cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p” and a long arm identified by the letter “q.” Chromosomes are further subdivided into bands that are numbered.In individuals with Chromosome 15 Ring, the variability of associated symptoms and findings may depend upon the amount and location of genetic material lost from the 15th chromosome, the stability of the ring chromosome during subsequent cellular divisions, or other factors. Evidence suggests that the clinical features seen in Chromosome 15 Ring appear to result from deletions of genetic material from the long arm (q) of chromosome 15 (known as “monosomy 15q”), with the ring chromosome typically replacing a normal 15th chromosome. In addition, in some cases, only a certain percentage of an individual's cells may contain Chromosome 15 Ring, while other cells may have a normal chromosomal makeup (a finding known as “chromosomal mosaicism”), potentially affecting the variability of associated symptoms and findings.In most cases, Chromosome 15 Ring appears to be caused by spontaneous (de novo) errors very early in embryonic development. In such cases, the parents of the affected child usually have normal chromosomes and a relatively low risk of having another child with the chromosomal abnormality. However, there have been rare cases in which a parent of an affected individual also has Chromosome 15 Ring. In such instances, the chances are greater of having another child with the chromosomal abnormality. In addition, a few cases have been reported in which Chromosome 15 Ring has been the result of a “balanced translocation” in one of the parents. Translocations occur when regions of certain chromosomes break off and are rearranged, resulting in shifting of genetic material and an altered set of chromosomes. If a chromosomal rearrangement is balanced, meaning that it consists of an altered but balanced set of chromosomes, it is usually harmless to the carrier. However, such a chromosomal rearrangement may be associated with an increased risk of unbalanced chromosome inheritance by in the carrier's offspring. Chromosomal analysis and genetic counseling are typically recommended for parents of an affected child to help confirm or exclude the presence of Chromosome 15 Ring, potential mosaicism, or a balanced translocation in one of the parents.Many individuals with Chromosome 15 Ring have some features similar to those associated with Russell-Silver syndrome (RSS), which is a genetic disorder characterized by growth deficiency and short stature, distinctive facial abnormalities, and other features. (For further information, please see the “Related Disorders” section below.) In some of these cases, genetic analysis has indicated that the prenatal and postnatal growth retardation associated with Chromosome 15 Ring (and potentially suggestive of RSS) may result from deletion of a gene known as the insulin-like growth factor I receptor (IGF1R) gene, which has been mapped to the long arm of chromosome 15 (15q25-q26). | 244 | Chromosome 15 Ring |
nord_244_3 | Affects of Chromosome 15 Ring | Since Chromosome 15 Ring was originally described, at least 25 cases have been recorded in the medical literature. In such observed cases, females appear to be affected more frequently than males. | Affects of Chromosome 15 Ring. Since Chromosome 15 Ring was originally described, at least 25 cases have been recorded in the medical literature. In such observed cases, females appear to be affected more frequently than males. | 244 | Chromosome 15 Ring |
nord_244_4 | Related disorders of Chromosome 15 Ring | Symptoms of the following disorders may be similar to those of Chromosome 15 Ring. Comparisons may be useful for a differential diagnosis:Russell-Silver syndrome (RSS) is a rare genetic disorder characterized by growth delays before and after birth, leading to short stature (dwarfism); overgrowth of one side of the body (hemihypertrophy) that may affect the head, trunk, arms, and/or legs; distinctive craniofacial features; and other physical abnormalities. Characteristic craniofacial malformations may include a “triangular-shaped” face with a small, pointed chin; a prominent forehead (frontal bossing); bluish discoloration of the “whites” of the eyes (blue sclera); an unusually small, wide mouth with downwardly turned corners; and/or a small jaw (micrognathia). In some cases, additional physical abnormalities may include abnormal deviation or “incurving” (clinodactyly) of the fifth fingers; webbing or fusion (syndactyly) of certain toes; underdevelopment (hypoplasia) of bones of the fingers (phalanges); coffee-colored patches on the skin (cafe-au-lait spots); and/or abnormalities of the kidneys and urinary tract. In addition, although most affected individuals have normal intelligence, mild mental retardation may sometimes be present. In most cases, RSS is thought to result from new genetic changes (mutations) that occur randomly for unknown reasons (sporadically). Less commonly, it appears that the disorder may be inherited as an autosomal recessive trait. In addition, a rare form of RSS has been identified that is thought to be inherited as an X-linked dominant trait.As mentioned above, RSS and Chromosome 15 Ring may share several features, including growth retardation and short stature, a triangular-shaped face, finger (digital) abnormalities, cafe-au-lait spots, and other abnormalities. Reports indicate that certain features are typically more marked in those with Chromosome 15 Ring, such as mental retardation, smallness of the head (microcephaly) and other facial abnormalities, congenital heart defects, and digital malformations. Thus, experts suggest that the presence of such findings in association with RSS features should lead to chromosomal analysis to help confirm or exclude the presence of Chromosome 15 Ring. (For further information, choose “Russell Silver” as your search term in the Rare Disease Database.) Additional chromosomal disorders may have features similar to those associated with Chromosome 15 Ring. Chromosomal testing is necessary to confirm the specific chromosomal abnormality present. (For further information on such disorders, choose the name of the specific chromosomal disorder in question or use “chromosome” as your search term in the Rare Disease Database.) | Related disorders of Chromosome 15 Ring. Symptoms of the following disorders may be similar to those of Chromosome 15 Ring. Comparisons may be useful for a differential diagnosis:Russell-Silver syndrome (RSS) is a rare genetic disorder characterized by growth delays before and after birth, leading to short stature (dwarfism); overgrowth of one side of the body (hemihypertrophy) that may affect the head, trunk, arms, and/or legs; distinctive craniofacial features; and other physical abnormalities. Characteristic craniofacial malformations may include a “triangular-shaped” face with a small, pointed chin; a prominent forehead (frontal bossing); bluish discoloration of the “whites” of the eyes (blue sclera); an unusually small, wide mouth with downwardly turned corners; and/or a small jaw (micrognathia). In some cases, additional physical abnormalities may include abnormal deviation or “incurving” (clinodactyly) of the fifth fingers; webbing or fusion (syndactyly) of certain toes; underdevelopment (hypoplasia) of bones of the fingers (phalanges); coffee-colored patches on the skin (cafe-au-lait spots); and/or abnormalities of the kidneys and urinary tract. In addition, although most affected individuals have normal intelligence, mild mental retardation may sometimes be present. In most cases, RSS is thought to result from new genetic changes (mutations) that occur randomly for unknown reasons (sporadically). Less commonly, it appears that the disorder may be inherited as an autosomal recessive trait. In addition, a rare form of RSS has been identified that is thought to be inherited as an X-linked dominant trait.As mentioned above, RSS and Chromosome 15 Ring may share several features, including growth retardation and short stature, a triangular-shaped face, finger (digital) abnormalities, cafe-au-lait spots, and other abnormalities. Reports indicate that certain features are typically more marked in those with Chromosome 15 Ring, such as mental retardation, smallness of the head (microcephaly) and other facial abnormalities, congenital heart defects, and digital malformations. Thus, experts suggest that the presence of such findings in association with RSS features should lead to chromosomal analysis to help confirm or exclude the presence of Chromosome 15 Ring. (For further information, choose “Russell Silver” as your search term in the Rare Disease Database.) Additional chromosomal disorders may have features similar to those associated with Chromosome 15 Ring. Chromosomal testing is necessary to confirm the specific chromosomal abnormality present. (For further information on such disorders, choose the name of the specific chromosomal disorder in question or use “chromosome” as your search term in the Rare Disease Database.) | 244 | Chromosome 15 Ring |
nord_244_5 | Diagnosis of Chromosome 15 Ring | In some cases, a diagnosis of Chromosome 15 Ring may be suggested before birth (prenatally) by specialized tests such as ultrasound, amniocentesis, or chorionic villus sampling (CVS). During fetal ultrasonography, reflected sound waves are used to create an image of the developing fetus. Ultrasound studies may reveal characteristic findings that suggest a chromosomal disorder or other developmental abnormalities in the fetus. During amniocentesis, a sample of fluid that surrounds the developing fetus is removed and analyzed, while CVS involves the removal of tissue samples from a portion of the placenta. Chromosomal analysis performed on the fluid or tissue samples may reveal the presence of Chromosome 15 Ring.The disorder may also be diagnosed or confirmed soon after birth, during infancy, or later during childhood based upon a thorough clinical evaluation, detection of characteristic physical findings, and chromosomal analysis. Specialized tests may also be conducted to help detect and/or characterize certain abnormalities that may be associated with the disorder. Such testing may include advanced imaging techniques (e.g., to assess skeletal abnormalities, renal malformations, etc.); studies to evaluate the structure and function of the heart (e.g., x-ray imaging, electrocardiogram [EKG], echocardiogram); and/or other diagnostic studies. | Diagnosis of Chromosome 15 Ring. In some cases, a diagnosis of Chromosome 15 Ring may be suggested before birth (prenatally) by specialized tests such as ultrasound, amniocentesis, or chorionic villus sampling (CVS). During fetal ultrasonography, reflected sound waves are used to create an image of the developing fetus. Ultrasound studies may reveal characteristic findings that suggest a chromosomal disorder or other developmental abnormalities in the fetus. During amniocentesis, a sample of fluid that surrounds the developing fetus is removed and analyzed, while CVS involves the removal of tissue samples from a portion of the placenta. Chromosomal analysis performed on the fluid or tissue samples may reveal the presence of Chromosome 15 Ring.The disorder may also be diagnosed or confirmed soon after birth, during infancy, or later during childhood based upon a thorough clinical evaluation, detection of characteristic physical findings, and chromosomal analysis. Specialized tests may also be conducted to help detect and/or characterize certain abnormalities that may be associated with the disorder. Such testing may include advanced imaging techniques (e.g., to assess skeletal abnormalities, renal malformations, etc.); studies to evaluate the structure and function of the heart (e.g., x-ray imaging, electrocardiogram [EKG], echocardiogram); and/or other diagnostic studies. | 244 | Chromosome 15 Ring |
nord_244_6 | Therapies of Chromosome 15 Ring | TreatmentThe treatment of Chromosome 15 Ring is directed toward the specific symptoms that are apparent in each individual. Such treatment may require the coordinated efforts of a team of medical professionals, such as pediatricians; surgeons; physicians who specialize in disorders of the skeleton, muscles, joints, and related tissues (orthopedists); physicians who diagnose and treat heart abnormalities (cardiologists); speech-language pathologists; physical therapists; and/or other health care professionals.For some affected individuals, treatment may include surgical repair of certain craniofacial or other malformations potentially associated with the disorder. In addition, for those with congenital heart defects, treatment with certain medications, surgical intervention, and/or other measures may be necessary. The specific surgical procedures performed will depend upon the severity and location of the anatomical abnormalities, their associated symptoms, and other factors.Early intervention may be important in ensuring that affected children reach their potential. Special services that may be beneficial include special education, physical therapy, speech therapy, and/or other medical, social, and/or vocational services. Genetic counseling will also be of benefit for affected individuals and their families. Other treatment for this disorder is symptomatic and supportive. | Therapies of Chromosome 15 Ring. TreatmentThe treatment of Chromosome 15 Ring is directed toward the specific symptoms that are apparent in each individual. Such treatment may require the coordinated efforts of a team of medical professionals, such as pediatricians; surgeons; physicians who specialize in disorders of the skeleton, muscles, joints, and related tissues (orthopedists); physicians who diagnose and treat heart abnormalities (cardiologists); speech-language pathologists; physical therapists; and/or other health care professionals.For some affected individuals, treatment may include surgical repair of certain craniofacial or other malformations potentially associated with the disorder. In addition, for those with congenital heart defects, treatment with certain medications, surgical intervention, and/or other measures may be necessary. The specific surgical procedures performed will depend upon the severity and location of the anatomical abnormalities, their associated symptoms, and other factors.Early intervention may be important in ensuring that affected children reach their potential. Special services that may be beneficial include special education, physical therapy, speech therapy, and/or other medical, social, and/or vocational services. Genetic counseling will also be of benefit for affected individuals and their families. Other treatment for this disorder is symptomatic and supportive. | 244 | Chromosome 15 Ring |
nord_245_0 | Overview of Chromosome 15, Distal Trisomy 15q | Chromosome 15, Distal Trisomy 15q is an extremely rare chromosomal disorder in which the end (distal) portion of the long arm (q) of the 15th chromosome (15q) appears three times (trisomy) rather than twice in cells of the body. The disorder is characterized by growth delays before and/or after birth (prenatal and/or postnatal growth retardation); mental retardation; and/or distinctive malformations of the head and facial (craniofacial) area. Additional abnormalities typically include an unusually short neck; malformations of the fingers and/or toes; abnormal sideways curvature of the spine (scoliosis) and/or other skeletal malformations; genital abnormalities, particularly in affected males; and/or, in some cases, heart (cardiac) defects. The range and severity of symptoms and physical findings may vary from case to case, depending upon the length and location of the duplicated portion of chromosome 15q. In most cases, Chromosome 15, Distal Trisomy 15q is due to a chromosomal balanced translocation in one of the parents. | Overview of Chromosome 15, Distal Trisomy 15q. Chromosome 15, Distal Trisomy 15q is an extremely rare chromosomal disorder in which the end (distal) portion of the long arm (q) of the 15th chromosome (15q) appears three times (trisomy) rather than twice in cells of the body. The disorder is characterized by growth delays before and/or after birth (prenatal and/or postnatal growth retardation); mental retardation; and/or distinctive malformations of the head and facial (craniofacial) area. Additional abnormalities typically include an unusually short neck; malformations of the fingers and/or toes; abnormal sideways curvature of the spine (scoliosis) and/or other skeletal malformations; genital abnormalities, particularly in affected males; and/or, in some cases, heart (cardiac) defects. The range and severity of symptoms and physical findings may vary from case to case, depending upon the length and location of the duplicated portion of chromosome 15q. In most cases, Chromosome 15, Distal Trisomy 15q is due to a chromosomal balanced translocation in one of the parents. | 245 | Chromosome 15, Distal Trisomy 15q |
nord_245_1 | Symptoms of Chromosome 15, Distal Trisomy 15q | In individuals with Chromosome 15, Distal Trisomy 15q, an extremely rare chromosomal disorder, the end (distal) portion of the long arm (q) of chromosome 15 (15q) is duplicated (trisomic). Symptoms and physical characteristics associated with the disorder may vary in range and severity, depending upon the exact size and location of the duplicated portion of chromosome 15q.In some cases, Chromosome 15, Distal Trisomy 15q may be characterized by abnormally slow growth before and/or after birth (prenatal and/or postnatal growth retardation) . In addition, many affected infants experience swallowing and feeding difficulties that may be due to the presence of certain malformations of the head and facial (craniofacial) area. Such feeding and swallowing difficulties may result in or contribute to an affected infant's failure to grow or gain weight at the expected rate (failure to thrive). However, in certain rare cases (i.e., trisomy 15q25-qter), affected individuals may exhibit abnormally tall stature. (For more information on trisomy 15q25-qter, see the “Causes” section below.)Most infants with Chromosome 15, Distal Trisomy 15q also exhibit abnormally diminished muscle tone (hypotonia). In addition, most affected infants and children have severe to profound mental retardation. However, in rare cases (i.e., trisomy 15q25-qter), only mild mental retardation may be present.Many infants and children with the disorder have characteristic malformations of the head and facial (craniofacial) area. In some cases, the fibrous joints between certain bones in the skull (sagittal sutures) close prematurely (craniosynostosis), causing the head to appear abnormally long and narrow (dolichocephaly). In addition, in many cases, the head may appear abnormally small (microcephaly), with abnormal bulging (prominence) of the back of the head (occiput) and a sloping forehead. In addition, the face may appear dissimilar from one side to the other (facial asymmetry). In rare cases (i.e., trisomy 15q25-qter), affected infants may have hydrocephalus, a condition characterized by inhibition of the normal flow of cerebrospinal fluid (CSF) within and abnormal widening (dilatation) of the cerebral spaces of the brain (ventricles), causing accumulation of CSF in the skull and potentially increased pressure on brain tissue.Additional craniofacial malformations typically associated with the disorder may include downwardly slanting, short, and/or narrow eyelid folds (palpebral fissures); drooping of the upper eyelids (ptosis); an abnormally large, prominent, and/or rounded (bulbous) nose with a broad nasal bridge; and/or an unusually small, triangular mouth. In addition, many affected infants and children may have an abnormally long groove in the upper lip (philtrum), a crease in the center (midline) of the lower lip, a highly arched roof of the mouth (palate), an unusually small jaw (micrognathia), and/or abnormally round, “puffy” cheeks. In some cases, the ears may be abnormally large, low-set, and/or malformed (dysplastic). In addition, the neck may be short and/or webbed, which, in some cases, may be due to malformations of certain bones in the upper portion of the spine (cervical vertebrae). Approximately one third of affected infants and children may also experience episodes of uncontrolled electrical disturbances in the brain (seizures).In addition, most infants and children with Chromosome 15, Distal Trisomy 15q have skeletal abnormalities affecting the fingers, toes, chest (thorax), and/or spine. Affected individuals may have unusually long, thin fingers and/or toes (arachnodactyly), permanently flexed fingers (camptodactyly), and/or excessive extension (hyperextension) of the thumbs. In addition, the joints of the hands and feet may become fixed in a permanently flexed position (joint contractures). Affected individuals may also have side-to-side curvature of the spine (scoliosis) and/or abnormal depression of the sternum, the bone forming the center of the chest (“funnel chest” or pectus excavatum).In many cases, individuals with Chromosome 15, Distal Trisomy 15q also have genital abnormalities. In males, such abnormalities may include failure of the testes to descend into the scrotum (cryptorchidism) and/or low levels of testicular function (hypogonadism), resulting in delayed development of secondary sexual characteristics (i.e., deepening of the voice, characteristic hair growth patterns, sudden increase in growth and development of the testes and scrotum, etc.). Some affected females may exhibit underdevelopment of the two long folds of skin on either side of the vaginal opening (labia majora).In addition, many affected infants may have abnormalities of the heart (congenital heart defects) and/or may exhibit an increased susceptibility to recurrent respiratory tract infections. In some cases, swallowing and feeding difficulties may cause food to be inhaled (aspirated) into the lungs, which may result in severe lung infections (aspiration pneumonia). In some cases, such abnormalities may result in life-threatening complications. | Symptoms of Chromosome 15, Distal Trisomy 15q. In individuals with Chromosome 15, Distal Trisomy 15q, an extremely rare chromosomal disorder, the end (distal) portion of the long arm (q) of chromosome 15 (15q) is duplicated (trisomic). Symptoms and physical characteristics associated with the disorder may vary in range and severity, depending upon the exact size and location of the duplicated portion of chromosome 15q.In some cases, Chromosome 15, Distal Trisomy 15q may be characterized by abnormally slow growth before and/or after birth (prenatal and/or postnatal growth retardation) . In addition, many affected infants experience swallowing and feeding difficulties that may be due to the presence of certain malformations of the head and facial (craniofacial) area. Such feeding and swallowing difficulties may result in or contribute to an affected infant's failure to grow or gain weight at the expected rate (failure to thrive). However, in certain rare cases (i.e., trisomy 15q25-qter), affected individuals may exhibit abnormally tall stature. (For more information on trisomy 15q25-qter, see the “Causes” section below.)Most infants with Chromosome 15, Distal Trisomy 15q also exhibit abnormally diminished muscle tone (hypotonia). In addition, most affected infants and children have severe to profound mental retardation. However, in rare cases (i.e., trisomy 15q25-qter), only mild mental retardation may be present.Many infants and children with the disorder have characteristic malformations of the head and facial (craniofacial) area. In some cases, the fibrous joints between certain bones in the skull (sagittal sutures) close prematurely (craniosynostosis), causing the head to appear abnormally long and narrow (dolichocephaly). In addition, in many cases, the head may appear abnormally small (microcephaly), with abnormal bulging (prominence) of the back of the head (occiput) and a sloping forehead. In addition, the face may appear dissimilar from one side to the other (facial asymmetry). In rare cases (i.e., trisomy 15q25-qter), affected infants may have hydrocephalus, a condition characterized by inhibition of the normal flow of cerebrospinal fluid (CSF) within and abnormal widening (dilatation) of the cerebral spaces of the brain (ventricles), causing accumulation of CSF in the skull and potentially increased pressure on brain tissue.Additional craniofacial malformations typically associated with the disorder may include downwardly slanting, short, and/or narrow eyelid folds (palpebral fissures); drooping of the upper eyelids (ptosis); an abnormally large, prominent, and/or rounded (bulbous) nose with a broad nasal bridge; and/or an unusually small, triangular mouth. In addition, many affected infants and children may have an abnormally long groove in the upper lip (philtrum), a crease in the center (midline) of the lower lip, a highly arched roof of the mouth (palate), an unusually small jaw (micrognathia), and/or abnormally round, “puffy” cheeks. In some cases, the ears may be abnormally large, low-set, and/or malformed (dysplastic). In addition, the neck may be short and/or webbed, which, in some cases, may be due to malformations of certain bones in the upper portion of the spine (cervical vertebrae). Approximately one third of affected infants and children may also experience episodes of uncontrolled electrical disturbances in the brain (seizures).In addition, most infants and children with Chromosome 15, Distal Trisomy 15q have skeletal abnormalities affecting the fingers, toes, chest (thorax), and/or spine. Affected individuals may have unusually long, thin fingers and/or toes (arachnodactyly), permanently flexed fingers (camptodactyly), and/or excessive extension (hyperextension) of the thumbs. In addition, the joints of the hands and feet may become fixed in a permanently flexed position (joint contractures). Affected individuals may also have side-to-side curvature of the spine (scoliosis) and/or abnormal depression of the sternum, the bone forming the center of the chest (“funnel chest” or pectus excavatum).In many cases, individuals with Chromosome 15, Distal Trisomy 15q also have genital abnormalities. In males, such abnormalities may include failure of the testes to descend into the scrotum (cryptorchidism) and/or low levels of testicular function (hypogonadism), resulting in delayed development of secondary sexual characteristics (i.e., deepening of the voice, characteristic hair growth patterns, sudden increase in growth and development of the testes and scrotum, etc.). Some affected females may exhibit underdevelopment of the two long folds of skin on either side of the vaginal opening (labia majora).In addition, many affected infants may have abnormalities of the heart (congenital heart defects) and/or may exhibit an increased susceptibility to recurrent respiratory tract infections. In some cases, swallowing and feeding difficulties may cause food to be inhaled (aspirated) into the lungs, which may result in severe lung infections (aspiration pneumonia). In some cases, such abnormalities may result in life-threatening complications. | 245 | Chromosome 15, Distal Trisomy 15q |
nord_245_2 | Causes of Chromosome 15, Distal Trisomy 15q | Chromosome 15, Distal Trisomy 15q is an extremely rare chromosomal disorder in which the end (distal) portion of the long arm (q) of the 15th chromosome appears three times (trisomy) rather than twice in cells of the body. Chromosomes are found in the nucleus of all body cells except red blood cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p” and a long arm identified by the letter “q.” Chromosomes are further subdivided into bands that are numbered. For example, “15q21” refers to band 21 on the long arm of chromosome 15.The duplication of the distal portion of chromosome 15q is responsible for the symptoms and physical features that characterize this disorder. The range and severity of associated abnormalities may depend upon the exact length and location of the duplicated portion of chromosome 15q.According to investigators, in those with Chromosome 15, Distal Trisomy 15q, the duplicated portion of 15q usually begins between bands 15q21 and 15q23 (breakpoint) and extends toward the end or “terminal” portion of chromosome 15q (qter). In rare cases, the breakpoint has occurred at band 15q25. According to the medical literature, although individuals with trisomy 15q25-qter have many of the characteristic abnormalities typically associated with the disorder, there may be some differences. (For further information, please see the “Symptoms” section above.) A few families have also been described in which the breakpoint has occurred at band 15q15.In most cases, Chromosome 15, Distal Trisomy 15q is due to a chromosomal “balanced translocation” in one of the parents. Translocations occur when regions of certain chromosomes break off and are rearranged, resulting in shifting of genetic material and an altered set of chromosomes. A translocation is balanced if it consists of an altered but balanced set of chromosomes. If a chromosomal rearrangement is balanced, meaning that it consists of an altered but balanced amount of genetic material, it is usually harmless to the carrier. However, such a chromosomal rearrangement may be associated with an increased risk of unbalanced chromosome inheritance in the carrier's offspring. Chromosomal analysis and genetic counseling are typically recommended for parents of an affected child to help confirm or exclude a chromosomal rearrangement in one of the parents.According to the medical literature, in the case of parental balanced translocations that result in Distal Trisomy 15q, the second chromosome involved with chromosome 15q has varied from case to case; however, symptoms and findings characteristically associated with the disorder (clinical phenotype) appear consistent. | Causes of Chromosome 15, Distal Trisomy 15q. Chromosome 15, Distal Trisomy 15q is an extremely rare chromosomal disorder in which the end (distal) portion of the long arm (q) of the 15th chromosome appears three times (trisomy) rather than twice in cells of the body. Chromosomes are found in the nucleus of all body cells except red blood cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p” and a long arm identified by the letter “q.” Chromosomes are further subdivided into bands that are numbered. For example, “15q21” refers to band 21 on the long arm of chromosome 15.The duplication of the distal portion of chromosome 15q is responsible for the symptoms and physical features that characterize this disorder. The range and severity of associated abnormalities may depend upon the exact length and location of the duplicated portion of chromosome 15q.According to investigators, in those with Chromosome 15, Distal Trisomy 15q, the duplicated portion of 15q usually begins between bands 15q21 and 15q23 (breakpoint) and extends toward the end or “terminal” portion of chromosome 15q (qter). In rare cases, the breakpoint has occurred at band 15q25. According to the medical literature, although individuals with trisomy 15q25-qter have many of the characteristic abnormalities typically associated with the disorder, there may be some differences. (For further information, please see the “Symptoms” section above.) A few families have also been described in which the breakpoint has occurred at band 15q15.In most cases, Chromosome 15, Distal Trisomy 15q is due to a chromosomal “balanced translocation” in one of the parents. Translocations occur when regions of certain chromosomes break off and are rearranged, resulting in shifting of genetic material and an altered set of chromosomes. A translocation is balanced if it consists of an altered but balanced set of chromosomes. If a chromosomal rearrangement is balanced, meaning that it consists of an altered but balanced amount of genetic material, it is usually harmless to the carrier. However, such a chromosomal rearrangement may be associated with an increased risk of unbalanced chromosome inheritance in the carrier's offspring. Chromosomal analysis and genetic counseling are typically recommended for parents of an affected child to help confirm or exclude a chromosomal rearrangement in one of the parents.According to the medical literature, in the case of parental balanced translocations that result in Distal Trisomy 15q, the second chromosome involved with chromosome 15q has varied from case to case; however, symptoms and findings characteristically associated with the disorder (clinical phenotype) appear consistent. | 245 | Chromosome 15, Distal Trisomy 15q |
nord_245_3 | Affects of Chromosome 15, Distal Trisomy 15q | Chromosome 15, Distal Trisomy 15q is an extremely rare chromosomal disorder that is thought to affect males approximately twice as often as females. Since the disorder was originally described in the medical literature in 1974 (A. Fujimoto), more than 30 cases have been reported in the literature. The majority of symptoms and physical features associated with the disorder are apparent at birth. | Affects of Chromosome 15, Distal Trisomy 15q. Chromosome 15, Distal Trisomy 15q is an extremely rare chromosomal disorder that is thought to affect males approximately twice as often as females. Since the disorder was originally described in the medical literature in 1974 (A. Fujimoto), more than 30 cases have been reported in the literature. The majority of symptoms and physical features associated with the disorder are apparent at birth. | 245 | Chromosome 15, Distal Trisomy 15q |
nord_245_4 | Related disorders of Chromosome 15, Distal Trisomy 15q | Other chromosomal disorders may be characterized by prenatal and postnatal growth retardation, mental retardation, distinctive craniofacial abnormalities, genital malformations, congenital heart defects, and/or other abnormalities similar to those potentially associated with Chromosome 15, Distal Trisomy 15q. Chromosomal testing is necessary to confirm the specific chromosomal abnormality present. (For further information on such disorders, choose the name of the specific chromosomal disorder in question or use “chromosome” as your search term in the Rare Disease Database.) | Related disorders of Chromosome 15, Distal Trisomy 15q. Other chromosomal disorders may be characterized by prenatal and postnatal growth retardation, mental retardation, distinctive craniofacial abnormalities, genital malformations, congenital heart defects, and/or other abnormalities similar to those potentially associated with Chromosome 15, Distal Trisomy 15q. Chromosomal testing is necessary to confirm the specific chromosomal abnormality present. (For further information on such disorders, choose the name of the specific chromosomal disorder in question or use “chromosome” as your search term in the Rare Disease Database.) | 245 | Chromosome 15, Distal Trisomy 15q |
nord_245_5 | Diagnosis of Chromosome 15, Distal Trisomy 15q | In some cases, the diagnosis of Chromosome 15, Distal Trisomy 15q may be determined before birth (prenatally) by specialized tests such as ultrasound, amniocentesis, and/or chorionic villus sampling (CVS. Ultrasound studies may reveal characteristic findings that suggest a chromosomal disorder or other developmental abnormalities in the fetus. During amniocentesis, a sample of fluid that surrounds the developing fetus is removed and studied. During chorionic villus sampling, a tissue sample is removed from a portion of the placenta. Chromosomal studies performed on this fluid or tissue sample may reveal the presence of Distal Trisomy 15q.Chromosome 15, Distal Trisomy 15q may also be diagnosed and/or confirmed after birth (postnatally) based upon a thorough clinical evaluation, identification of characteristic physical findings, and chromosomal studies.Certain specific abnormalities that may occur in association with Distal Trisomy 15q may be detected and/or confirmed by specialized imaging studies and/or additional tests. For example, specialized x-ray studies may be used to confirm and/or characterize certain skeletal abnormalities potentially associated with the disorder (e.g., dolichocephaly, micrognathia, cervical vertebral abnormalities, scoliosis). Congenital heart defects potentially associated with Chromosome 15, Distal Trisomy 15q may be detected, confirmed, and/or characterized by a thorough clinical evaluation and specialized tests that allow physicians to evaluate the structure and function of the heart (e.g., x-ray studies, electrocardiogram [EKG] echocardiogram, cardiac catherization). In addition, in some cases, electroencephalography (EEG), which records the brain's electrical impulses, may reveal brain wave patterns that are characteristic of certain types of seizure activity. | Diagnosis of Chromosome 15, Distal Trisomy 15q. In some cases, the diagnosis of Chromosome 15, Distal Trisomy 15q may be determined before birth (prenatally) by specialized tests such as ultrasound, amniocentesis, and/or chorionic villus sampling (CVS. Ultrasound studies may reveal characteristic findings that suggest a chromosomal disorder or other developmental abnormalities in the fetus. During amniocentesis, a sample of fluid that surrounds the developing fetus is removed and studied. During chorionic villus sampling, a tissue sample is removed from a portion of the placenta. Chromosomal studies performed on this fluid or tissue sample may reveal the presence of Distal Trisomy 15q.Chromosome 15, Distal Trisomy 15q may also be diagnosed and/or confirmed after birth (postnatally) based upon a thorough clinical evaluation, identification of characteristic physical findings, and chromosomal studies.Certain specific abnormalities that may occur in association with Distal Trisomy 15q may be detected and/or confirmed by specialized imaging studies and/or additional tests. For example, specialized x-ray studies may be used to confirm and/or characterize certain skeletal abnormalities potentially associated with the disorder (e.g., dolichocephaly, micrognathia, cervical vertebral abnormalities, scoliosis). Congenital heart defects potentially associated with Chromosome 15, Distal Trisomy 15q may be detected, confirmed, and/or characterized by a thorough clinical evaluation and specialized tests that allow physicians to evaluate the structure and function of the heart (e.g., x-ray studies, electrocardiogram [EKG] echocardiogram, cardiac catherization). In addition, in some cases, electroencephalography (EEG), which records the brain's electrical impulses, may reveal brain wave patterns that are characteristic of certain types of seizure activity. | 245 | Chromosome 15, Distal Trisomy 15q |
nord_245_6 | Therapies of Chromosome 15, Distal Trisomy 15q | TreatmentThe treatment of Chromosome 15, Distal Trisomy 15q is directed toward the specific symptoms that are apparent in each individual. Treatment may require the coordinated efforts of a team of specialists. Pediatricians, surgeons, physicians who specialize in diagnosing and treating disorders of the skeletal system (orthopedists), and/or other health care professionals may need to systematically and comprehensively plan an affected child's treatment.The treatment of Chromosome 15, Distal Trisomy 15q may include surgical repair of certain malformations. In some cases, surgery may be performed to correct congenital heart defects, craniofacial malformations, webbing of the neck, flexion contractures, abnormalities of the hands and/or feet, genital malformations, and/or other abnormalities that may be associated with the disorder. The surgical procedures performed will depend upon the severity and location of the anatomical abnormalities and their associated symptoms.In some cases, abnormalities involving the joints, tendons, muscles, and bones (e.g., flexion contractures, malformations of the fingers and/or toes, scoliosis) may be treated with orthopedic techniques potentially in combination with surgery. Physical therapy may also be prescribed to help improve coordination of movements (mobility).In addition, physicians may recommend preventive measures for affected infants and children who may be prone to repeated respiratory infections. Physicians may also regularly monitor affected individuals for such infections to ensure early detection and appropriate, prompt treatment.Early intervention is important to ensure that children with Chromosome 15, Distal Trisomy 15q reach their potential. Special services that may be beneficial to affected children may include special remedial education, special social support, and/or other medical, social, and/or vocational services.Genetic counseling will be of benefit for families of children with Chromosome 15, Distal Trisomy 15q. Chromosomal studies are necessary to determine whether a balanced translocation is present in one of the parents. Other treatment for the disorder is symptomatic and supportive. | Therapies of Chromosome 15, Distal Trisomy 15q. TreatmentThe treatment of Chromosome 15, Distal Trisomy 15q is directed toward the specific symptoms that are apparent in each individual. Treatment may require the coordinated efforts of a team of specialists. Pediatricians, surgeons, physicians who specialize in diagnosing and treating disorders of the skeletal system (orthopedists), and/or other health care professionals may need to systematically and comprehensively plan an affected child's treatment.The treatment of Chromosome 15, Distal Trisomy 15q may include surgical repair of certain malformations. In some cases, surgery may be performed to correct congenital heart defects, craniofacial malformations, webbing of the neck, flexion contractures, abnormalities of the hands and/or feet, genital malformations, and/or other abnormalities that may be associated with the disorder. The surgical procedures performed will depend upon the severity and location of the anatomical abnormalities and their associated symptoms.In some cases, abnormalities involving the joints, tendons, muscles, and bones (e.g., flexion contractures, malformations of the fingers and/or toes, scoliosis) may be treated with orthopedic techniques potentially in combination with surgery. Physical therapy may also be prescribed to help improve coordination of movements (mobility).In addition, physicians may recommend preventive measures for affected infants and children who may be prone to repeated respiratory infections. Physicians may also regularly monitor affected individuals for such infections to ensure early detection and appropriate, prompt treatment.Early intervention is important to ensure that children with Chromosome 15, Distal Trisomy 15q reach their potential. Special services that may be beneficial to affected children may include special remedial education, special social support, and/or other medical, social, and/or vocational services.Genetic counseling will be of benefit for families of children with Chromosome 15, Distal Trisomy 15q. Chromosomal studies are necessary to determine whether a balanced translocation is present in one of the parents. Other treatment for the disorder is symptomatic and supportive. | 245 | Chromosome 15, Distal Trisomy 15q |
nord_246_0 | Overview of Chromosome 18 Ring | Chromosome 18 Ring is a rare disorder in which there is loss (deletion) of genetic material from one or both ends of the 18th chromosome and joining of the chromosomal ends to form a ring. Associated symptoms and findings may vary greatly in range and severity from case to case, depending upon the amount and location of lost genetic material and other factors. A ring may also be formed without the loss of any genetic material. However, many individuals with the disorder are affected by mental retardation; low muscle tone (hypotonia); growth retardation; repeated infections during the first years of life; and/or malformations of the skull and facial (craniofacial) region. Such craniofacial features often include an unusually small head (microcephaly), widely spaced eyes (ocular hypertelorism), and/or vertical skin folds that cover the eyes' inner corners (epicanthal folds). Chromosome 18 Ring is usually caused by spontaneous (de novo) errors very early in the development of the embryo that appear to occur randomly for unknown reasons (sporadically). | Overview of Chromosome 18 Ring. Chromosome 18 Ring is a rare disorder in which there is loss (deletion) of genetic material from one or both ends of the 18th chromosome and joining of the chromosomal ends to form a ring. Associated symptoms and findings may vary greatly in range and severity from case to case, depending upon the amount and location of lost genetic material and other factors. A ring may also be formed without the loss of any genetic material. However, many individuals with the disorder are affected by mental retardation; low muscle tone (hypotonia); growth retardation; repeated infections during the first years of life; and/or malformations of the skull and facial (craniofacial) region. Such craniofacial features often include an unusually small head (microcephaly), widely spaced eyes (ocular hypertelorism), and/or vertical skin folds that cover the eyes' inner corners (epicanthal folds). Chromosome 18 Ring is usually caused by spontaneous (de novo) errors very early in the development of the embryo that appear to occur randomly for unknown reasons (sporadically). | 246 | Chromosome 18 Ring |
nord_246_1 | Symptoms of Chromosome 18 Ring | As mentioned above, associated symptoms and physical features may be extremely variable. For example, there have been a few cases in which individuals with Chromosome 18 Ring have few or no apparent symptoms. However, others with the chromosomal abnormality may have multiple, severe features of the disorder. In most affected individuals, characteristic features include moderate to severe mental retardation; growth delays; poor muscle tone (hypotonia); craniofacial malformations; eye abnormalities; and/or an increased susceptibility to certain infections.In individuals with Chromosome 18 Ring, craniofacial abnormalities often include an unusually small head (microcephaly); a highly arched roof of the mouth (palate); and a short upper lip with an outwardly turned (everted) lower lip, producing a distinctive, “carp-shaped” mouth. Additional craniofacial features may include an unusually small or protruding lower jaw (micrognathia or prognathism) and/or an undersized tongue (microglossia). Affected individuals may also have low-set, malformed (dysplastic) ears and/or narrow (stenotic) or absent (atretic) ear canals, with associated hearing impairment.Reports indicate that over half of affected individuals also have eye (ocular) abnormalities. Such ocular defects may include widely spaced eyes (ocular hypertelorism); vertical skin folds over the inner angles of the eyes (epicanthal folds); drooping of the upper eyelids (ptosis); and/or abnormal deviation of one eye in relation to the other (strabismus). Some affected individuals may also have involuntary, rhythmic, rapid eye movements (nystagmus); abnormally small eyes (microphthalmia); and/or partial absence of the iris or the colored region of the eyes (aniridia).Investigators indicate that up to 50 percent of individuals with Chromosome 18 Ring have low levels of a particular antibody (i.e., immunoglobulin A [IgA]), resulting in an increased susceptibility to certain infections during the first years of life. Rare cases have also been reported in which affected individuals have low levels of other immunoglobulins (e.g., IgG, IgM).Chromosome 18 Ring may also be characterized by skeletal abnormalities, such as rib and/or spinal column (vertebral) defects; unusually small or short arms and legs (micromelia); abnormal deviation (clinodactyly) of the “pinkies” or fifth fingers; and/or overlying toes. Additional physical features reported in association with the disorder have included widely spaced, underdeveloped nipples; a low hair line; webbing of the neck; genital abnormalities; structural malformations of the heart (congenital heart defects); and/or kidney (renal) defects. In addition, some researchers indicate that Chromosome 18 Ring may be associated with an increased predisposition to autoimmune thyroiditis. Also known as Hashimoto's thyroiditis, this condition is characterized by inflammation of the thyroid gland (thyroiditis) due to an abnormal immune reaction in which the body produces antibodies improperly directed against the thyroid. (For further information, please choose “Hashimoto*” as your search term in the Rare Disease Database.) A few severe cases have also been reported in which Chromosome 18 Ring has been associated with holoprosencephaly. This is an extremely rare condition in which the forebrain (prosencephalon) fails to divide properly into hemispheres during embryonic development, resulting in malformations of the center (midline) of the brain and the craniofacial region. Associated findings may be extremely variable. Some affected individuals may have an abnormally small head (microcephaly), closely set eyes (hypotelorism), absence of certain front teeth (incisors), incomplete closure of the roof of the mouth (cleft palate), an abnormal groove in the upper lip (cleft lip), and/or other abnormalities. Severely affected individuals may have additional abnormalities, such as malformation or absence of the nose and/or fusion of the orbits into a single eye cavity containing one eye (cyclopia). (For further information on this condition, please choose “holoprosencephaly” as your search term in the Rare Disease Database.) | Symptoms of Chromosome 18 Ring. As mentioned above, associated symptoms and physical features may be extremely variable. For example, there have been a few cases in which individuals with Chromosome 18 Ring have few or no apparent symptoms. However, others with the chromosomal abnormality may have multiple, severe features of the disorder. In most affected individuals, characteristic features include moderate to severe mental retardation; growth delays; poor muscle tone (hypotonia); craniofacial malformations; eye abnormalities; and/or an increased susceptibility to certain infections.In individuals with Chromosome 18 Ring, craniofacial abnormalities often include an unusually small head (microcephaly); a highly arched roof of the mouth (palate); and a short upper lip with an outwardly turned (everted) lower lip, producing a distinctive, “carp-shaped” mouth. Additional craniofacial features may include an unusually small or protruding lower jaw (micrognathia or prognathism) and/or an undersized tongue (microglossia). Affected individuals may also have low-set, malformed (dysplastic) ears and/or narrow (stenotic) or absent (atretic) ear canals, with associated hearing impairment.Reports indicate that over half of affected individuals also have eye (ocular) abnormalities. Such ocular defects may include widely spaced eyes (ocular hypertelorism); vertical skin folds over the inner angles of the eyes (epicanthal folds); drooping of the upper eyelids (ptosis); and/or abnormal deviation of one eye in relation to the other (strabismus). Some affected individuals may also have involuntary, rhythmic, rapid eye movements (nystagmus); abnormally small eyes (microphthalmia); and/or partial absence of the iris or the colored region of the eyes (aniridia).Investigators indicate that up to 50 percent of individuals with Chromosome 18 Ring have low levels of a particular antibody (i.e., immunoglobulin A [IgA]), resulting in an increased susceptibility to certain infections during the first years of life. Rare cases have also been reported in which affected individuals have low levels of other immunoglobulins (e.g., IgG, IgM).Chromosome 18 Ring may also be characterized by skeletal abnormalities, such as rib and/or spinal column (vertebral) defects; unusually small or short arms and legs (micromelia); abnormal deviation (clinodactyly) of the “pinkies” or fifth fingers; and/or overlying toes. Additional physical features reported in association with the disorder have included widely spaced, underdeveloped nipples; a low hair line; webbing of the neck; genital abnormalities; structural malformations of the heart (congenital heart defects); and/or kidney (renal) defects. In addition, some researchers indicate that Chromosome 18 Ring may be associated with an increased predisposition to autoimmune thyroiditis. Also known as Hashimoto's thyroiditis, this condition is characterized by inflammation of the thyroid gland (thyroiditis) due to an abnormal immune reaction in which the body produces antibodies improperly directed against the thyroid. (For further information, please choose “Hashimoto*” as your search term in the Rare Disease Database.) A few severe cases have also been reported in which Chromosome 18 Ring has been associated with holoprosencephaly. This is an extremely rare condition in which the forebrain (prosencephalon) fails to divide properly into hemispheres during embryonic development, resulting in malformations of the center (midline) of the brain and the craniofacial region. Associated findings may be extremely variable. Some affected individuals may have an abnormally small head (microcephaly), closely set eyes (hypotelorism), absence of certain front teeth (incisors), incomplete closure of the roof of the mouth (cleft palate), an abnormal groove in the upper lip (cleft lip), and/or other abnormalities. Severely affected individuals may have additional abnormalities, such as malformation or absence of the nose and/or fusion of the orbits into a single eye cavity containing one eye (cyclopia). (For further information on this condition, please choose “holoprosencephaly” as your search term in the Rare Disease Database.) | 246 | Chromosome 18 Ring |
nord_246_2 | Causes of Chromosome 18 Ring | Chromosome 18 Ring results from loss (deletion) of genetic material from one or both ends of the 18th chromosome and a joining of the ends to form a ring. Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p” and a long arm identified by the letter “q.” Chromosomes are further subdivided into bands that are numbered.In individuals with Chromosome 18 Ring, the range and severity of associated symptoms and findings may be extremely variable, depending upon the amount and specific location of genetic material lost from the 18th chromosome, the stability of the ring chromosome during subsequent cellular divisions, or other factors. Some investigators suggest that certain characteristic features seen in Chromosome 18 Ring may result from deletions of genetic material at specific locations on the short and long arms of chromosome 18 (e.g., 18p11; 18q23), with the ring chromosome replacing a normal 18th chromosome. In addition, in some cases, only a percentage of an individual's cells may contain Chromosome 18 Ring, while other cells may have a normal chromosomal makeup (a finding known as “chromosomal mosaicism”), potentially affecting the variability of associated symptoms and findings. Most reports in which individuals have demonstrated few or minor features of the disorder have been associated with a Chromosome 18 Ring mosaicism.In most cases, Chromosome 18 Ring appears to be caused by spontaneous (de novo) errors very early in embryonic development. In such instances, the parents of the affected child usually have normal chromosomes and a relatively low risk of having another child with the chromosomal abnormality. However, there have been some cases in which a parent of an affected individual also has Chromosome 18 Ring in all or some cells. In such instances, it is believed that Chromosome 18 Ring may have been inherited and that the chances are greater of having another child with the chromosomal abnormality. Chromosomal analysis and genetic counseling are typically recommended for parents of an affected child to help confirm or exclude the presence of Chromosome 18 Ring or potential mosaicism. | Causes of Chromosome 18 Ring. Chromosome 18 Ring results from loss (deletion) of genetic material from one or both ends of the 18th chromosome and a joining of the ends to form a ring. Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p” and a long arm identified by the letter “q.” Chromosomes are further subdivided into bands that are numbered.In individuals with Chromosome 18 Ring, the range and severity of associated symptoms and findings may be extremely variable, depending upon the amount and specific location of genetic material lost from the 18th chromosome, the stability of the ring chromosome during subsequent cellular divisions, or other factors. Some investigators suggest that certain characteristic features seen in Chromosome 18 Ring may result from deletions of genetic material at specific locations on the short and long arms of chromosome 18 (e.g., 18p11; 18q23), with the ring chromosome replacing a normal 18th chromosome. In addition, in some cases, only a percentage of an individual's cells may contain Chromosome 18 Ring, while other cells may have a normal chromosomal makeup (a finding known as “chromosomal mosaicism”), potentially affecting the variability of associated symptoms and findings. Most reports in which individuals have demonstrated few or minor features of the disorder have been associated with a Chromosome 18 Ring mosaicism.In most cases, Chromosome 18 Ring appears to be caused by spontaneous (de novo) errors very early in embryonic development. In such instances, the parents of the affected child usually have normal chromosomes and a relatively low risk of having another child with the chromosomal abnormality. However, there have been some cases in which a parent of an affected individual also has Chromosome 18 Ring in all or some cells. In such instances, it is believed that Chromosome 18 Ring may have been inherited and that the chances are greater of having another child with the chromosomal abnormality. Chromosomal analysis and genetic counseling are typically recommended for parents of an affected child to help confirm or exclude the presence of Chromosome 18 Ring or potential mosaicism. | 246 | Chromosome 18 Ring |
nord_246_3 | Affects of Chromosome 18 Ring | Since Chromosome 18 Ring was originally described, more than 70 cases have been reported in the medical literature. In these observed cases, females appear to be affected slightly more often than males. The disorder is often detected at birth or during prenatal testing. | Affects of Chromosome 18 Ring. Since Chromosome 18 Ring was originally described, more than 70 cases have been reported in the medical literature. In these observed cases, females appear to be affected slightly more often than males. The disorder is often detected at birth or during prenatal testing. | 246 | Chromosome 18 Ring |
nord_246_4 | Related disorders of Chromosome 18 Ring | Symptoms of the following disorders may be similar to those of Chromosome 18 Ring. Comparisons may be useful for a differential diagnosis: Additional chromosomal disorders may have features similar to those associated with Chromosome 18 Ring. Chromosomal testing is necessary to confirm the specific chromosomal abnormality present. (For further information on such disorders, choose the name of the specific chromosomal disorder in question or use “chromosome” as your search term in the Rare Disease Database.) | Related disorders of Chromosome 18 Ring. Symptoms of the following disorders may be similar to those of Chromosome 18 Ring. Comparisons may be useful for a differential diagnosis: Additional chromosomal disorders may have features similar to those associated with Chromosome 18 Ring. Chromosomal testing is necessary to confirm the specific chromosomal abnormality present. (For further information on such disorders, choose the name of the specific chromosomal disorder in question or use “chromosome” as your search term in the Rare Disease Database.) | 246 | Chromosome 18 Ring |
nord_246_5 | Diagnosis of Chromosome 18 Ring | Ultrasound will indicate that something unusual is happening to the fetus. The diagnosis of Chromosome 18 Ring is made before birth (prenatally) by specialized tests such as amniocentesis, and/or chorionic villus sampling (CVS). During fetal ultrasonography, reflected sound waves create an image of the developing fetus, potentially revealing certain findings that suggest a chromosomal disorder or other developmental abnormalities in the fetus. During fetal blood sampling, blood is drawn with a needle that is guided via ultrasound into the umbilical vein. With amniocentesis, a sample of fluid that surrounds the developing fetus is removed and analyzed, while CVS involves the removal of tissue samples from a portion of the placenta. Chromosomal analysis performed on such fluid or tissue samples may reveal the presence of Chromosome 18 Ring.The disorder may also be diagnosed or confirmed after birth (postnatally) based upon a thorough clinical evaluation, detection of characteristic physical findings, and chromosomal analysis. Specialized tests may also be performed to help detect and/or characterize certain abnormalities that may be associated with the disorder. | Diagnosis of Chromosome 18 Ring. Ultrasound will indicate that something unusual is happening to the fetus. The diagnosis of Chromosome 18 Ring is made before birth (prenatally) by specialized tests such as amniocentesis, and/or chorionic villus sampling (CVS). During fetal ultrasonography, reflected sound waves create an image of the developing fetus, potentially revealing certain findings that suggest a chromosomal disorder or other developmental abnormalities in the fetus. During fetal blood sampling, blood is drawn with a needle that is guided via ultrasound into the umbilical vein. With amniocentesis, a sample of fluid that surrounds the developing fetus is removed and analyzed, while CVS involves the removal of tissue samples from a portion of the placenta. Chromosomal analysis performed on such fluid or tissue samples may reveal the presence of Chromosome 18 Ring.The disorder may also be diagnosed or confirmed after birth (postnatally) based upon a thorough clinical evaluation, detection of characteristic physical findings, and chromosomal analysis. Specialized tests may also be performed to help detect and/or characterize certain abnormalities that may be associated with the disorder. | 246 | Chromosome 18 Ring |
nord_246_6 | Therapies of Chromosome 18 Ring | TreatmentThe treatment of Chromosome 18 Ring is directed toward the specific symptoms that are apparent in each individual. In some cases, physicians may recommend surgical repair of certain craniofacial, skeletal, ocular, auditory, and/or other malformations potentially associated with the disorder. The specific surgical procedures performed will depend upon the severity and location of the anatomical abnormalities, their associated symptoms, and other factors.For affected individuals with hearing loss, recommended treatment may include surgical measures and/or the use of specialized hearing aids or additional supportive techniques that may aid communication. In those with ocular abnormalities, corrective lenses, surgery, and/or other measures may be used to help improve vision in some cases. In addition, for individuals with low levels of certain antibodies (e.g., IgA), disease management includes ongoing monitoring and appropriate, supportive measures to help prevent and aggressively treat infections.Early intervention may be important in ensuring that affected children reach their potential. Special services that may be beneficial include special education, physical therapy, speech therapy, and/or other medical, social, and/or vocational services. Genetic counseling will also be of benefit for affected individuals and their families. Other treatment for this disorder is symptomatic and supportive. | Therapies of Chromosome 18 Ring. TreatmentThe treatment of Chromosome 18 Ring is directed toward the specific symptoms that are apparent in each individual. In some cases, physicians may recommend surgical repair of certain craniofacial, skeletal, ocular, auditory, and/or other malformations potentially associated with the disorder. The specific surgical procedures performed will depend upon the severity and location of the anatomical abnormalities, their associated symptoms, and other factors.For affected individuals with hearing loss, recommended treatment may include surgical measures and/or the use of specialized hearing aids or additional supportive techniques that may aid communication. In those with ocular abnormalities, corrective lenses, surgery, and/or other measures may be used to help improve vision in some cases. In addition, for individuals with low levels of certain antibodies (e.g., IgA), disease management includes ongoing monitoring and appropriate, supportive measures to help prevent and aggressively treat infections.Early intervention may be important in ensuring that affected children reach their potential. Special services that may be beneficial include special education, physical therapy, speech therapy, and/or other medical, social, and/or vocational services. Genetic counseling will also be of benefit for affected individuals and their families. Other treatment for this disorder is symptomatic and supportive. | 246 | Chromosome 18 Ring |
nord_247_0 | Overview of Chromosome 18, Monosomy 18p | Chromosome 18, Monosomy 18p is a rare chromosomal disorder in which all or part of the short arm (p) of chromosome 18 is deleted (monosomic). The disorder is typically characterized by short stature, variable degrees of mental retardation, speech delays, malformations of the skull and facial (craniofacial) region, and/or additional physical abnormalities. Associated craniofacial defects may vary greatly in range and severity from case to case. However, such features commonly include an unusually small head (microcephaly); a broad, flat nose; a “carp-shaped” mouth; large, protruding ears; widely spaced eyes (ocular hypertelorism); and/or other abnormalities. Rarely (i.e., in about 10 percent of cases), Monosomy 18p may be associated with holoprosencephaly, a condition in which the forebrain (prosencephalon) fails to divide properly during embryonic development. Holoprosencephaly may result in varying degrees of mental retardation, other neurologic findings, and/or extremely variable midline facial defects, such as the presence of a single, central front tooth (maxillary incisor); closely spaced eyes (hypotelorism); an abnormal groove in the upper lip (cleft lip); incomplete closure of the roof of the mouth (cleft palate); and/or, in severe cases, absence of the nose and/or cyclopia. Cyclopia is characterized by fusion of the eye cavities (orbits) into a single cavity containing one eye.In some individuals with Monosomy 18p, additional physical abnormalities may be present. Such findings commonly include a short, webbed neck; a broad chest with widely spaced nipples; relatively small hands and feet; and/or an unusually small penis (micropenis) and/or undescended testes (cryptorchidism) in affected males.Monosomy 18p is usually caused by spontaneous (de novo) errors very early in the development of the embryo that appear to occur randomly for unknown reasons (sporadically). | Overview of Chromosome 18, Monosomy 18p. Chromosome 18, Monosomy 18p is a rare chromosomal disorder in which all or part of the short arm (p) of chromosome 18 is deleted (monosomic). The disorder is typically characterized by short stature, variable degrees of mental retardation, speech delays, malformations of the skull and facial (craniofacial) region, and/or additional physical abnormalities. Associated craniofacial defects may vary greatly in range and severity from case to case. However, such features commonly include an unusually small head (microcephaly); a broad, flat nose; a “carp-shaped” mouth; large, protruding ears; widely spaced eyes (ocular hypertelorism); and/or other abnormalities. Rarely (i.e., in about 10 percent of cases), Monosomy 18p may be associated with holoprosencephaly, a condition in which the forebrain (prosencephalon) fails to divide properly during embryonic development. Holoprosencephaly may result in varying degrees of mental retardation, other neurologic findings, and/or extremely variable midline facial defects, such as the presence of a single, central front tooth (maxillary incisor); closely spaced eyes (hypotelorism); an abnormal groove in the upper lip (cleft lip); incomplete closure of the roof of the mouth (cleft palate); and/or, in severe cases, absence of the nose and/or cyclopia. Cyclopia is characterized by fusion of the eye cavities (orbits) into a single cavity containing one eye.In some individuals with Monosomy 18p, additional physical abnormalities may be present. Such findings commonly include a short, webbed neck; a broad chest with widely spaced nipples; relatively small hands and feet; and/or an unusually small penis (micropenis) and/or undescended testes (cryptorchidism) in affected males.Monosomy 18p is usually caused by spontaneous (de novo) errors very early in the development of the embryo that appear to occur randomly for unknown reasons (sporadically). | 247 | Chromosome 18, Monosomy 18p |
nord_247_1 | Symptoms of Chromosome 18, Monosomy 18p | The symptoms and physical findings associated with Chromosome 18, Monosomy 18p may be variable from case to case. However, the syndrome is typically characterized by short stature, mental retardation, various malformations of the skull and facial (craniofacial) region, and/or additional physical abnormalities.In many cases, infants with Monosomy 18p have a low birth weight, mild to moderate growth deficiency, and poor muscle tone (hypotonia). In addition, reports indicate that mental retardation is almost always present. The degree of mental deficiency may be extremely variable, ranging from borderline to severe; however, most are affected by moderate mental retardation. Many children also have severe delays in the acquisition of speech and language skills, with many not speaking simple words or sentences before approximately age seven to nine years. Some affected children may also have behavioral or emotional abnormalities, such as difficulties concentrating, restlessness, and rapidly changing moods (emotional lability).As noted above, associated craniofacial abnormalities may be variable in range and degree. However, such malformations often include an abnormally small head (microcephaly); a distinctively round face (that may change with age to appear relatively long); a wide, “carp-shaped” mouth with downturning corners; a flattened or broad nose; and large, poorly formed, low-set ears. Many affected infants also have certain eye (ocular) abnormalities, such as widely spaced eyes (ocular hypertelorism); drooping upper eyelids (ptosis); vertical skin folds that may cover the eyes' inner corners (epicanthal folds); and/or abnormal deviation of one eye in relation to the other (strabismus). Additional abnormalities may include an unusually small, retracted lower jaw (microretrognathia) and a potentially increased risk of tooth decay (dental caries).In approximately 10 percent of individuals with Monosomy 18p, holoprosencephaly may be present. In those with this rare condition, the forebrain failed to normally divide into hemispheres during embryonic development. Holoprosencephaly may result in variable degrees of mental retardation, sudden episodes of uncontrolled electrical activity in the brain (seizures), and/or additional, variable neurologic findings; in extremely severe cases, potentially life-threatening complications may result during infancy or childhood. As noted earlier, holoprosencephaly may also result in various abnormalities of midfacial development. Reports suggest that some with the condition may have a normal or near normal facial appearance, while others may have relatively mild to extremely severe midline facial defects. In some affected individuals, associated malformations may include the presence of a single, central front tooth of the upper jaw (maxillary incisor); widely or closely set eyes (ocular hypertelorism or hypotelorism); an abnormal groove in the side or middle of the upper lip (lateral or median cleft lip); incomplete closure of the roof of the mouth (cleft palate); and/or, in extremely severe cases, fusion of the eye cavities (orbits) into a single cavity containing one eye (cyclopia). In addition, depending on the severity of defective midfacial development, nasal abnormalities may be present, such as an unusually flattened nose; a blind-ending, single-nostril nose; or absence of the nose (arhinia) and/or the presence of a tubular appendage above the orbit (proboscis). (For more information on this condition, choose “holoprosencephaly” as your search term in the Rare Disease Database.) In some instances, Monosomy 18p may be characterized by other physical findings. Some affected infants may have an abnormal accumulation of fluid in soft tissues of the hands and feet, with associated swelling (lymphedema); a short, webbed neck; and/or an unusually broad chest with widely spaced nipples. Limb malformations may also be present, such as relatively small hands and feet; short fingers; abnormal deviation of the “pinkies” or fifth fingers (clinodactyly); and/or webbing or fusion (syndactyly) of certain toes. In affected males, physical features may include an unusually small penis (micropenis) and/or undescended testes (cryptorchidism). Additional features have also been reported in association with Monosomy 18p in some cases, such as deficiency of a particular antibody (i.e., immunoglobulin A [IgA]) that helps the body to fight certain infections; abnormal absence of scalp hair (alopecia) beginning during infancy; and/or other findings. In addition, according to researchers, various structural malformations of the heart (congenital heart defects) may be present in up to five percent of cases. | Symptoms of Chromosome 18, Monosomy 18p. The symptoms and physical findings associated with Chromosome 18, Monosomy 18p may be variable from case to case. However, the syndrome is typically characterized by short stature, mental retardation, various malformations of the skull and facial (craniofacial) region, and/or additional physical abnormalities.In many cases, infants with Monosomy 18p have a low birth weight, mild to moderate growth deficiency, and poor muscle tone (hypotonia). In addition, reports indicate that mental retardation is almost always present. The degree of mental deficiency may be extremely variable, ranging from borderline to severe; however, most are affected by moderate mental retardation. Many children also have severe delays in the acquisition of speech and language skills, with many not speaking simple words or sentences before approximately age seven to nine years. Some affected children may also have behavioral or emotional abnormalities, such as difficulties concentrating, restlessness, and rapidly changing moods (emotional lability).As noted above, associated craniofacial abnormalities may be variable in range and degree. However, such malformations often include an abnormally small head (microcephaly); a distinctively round face (that may change with age to appear relatively long); a wide, “carp-shaped” mouth with downturning corners; a flattened or broad nose; and large, poorly formed, low-set ears. Many affected infants also have certain eye (ocular) abnormalities, such as widely spaced eyes (ocular hypertelorism); drooping upper eyelids (ptosis); vertical skin folds that may cover the eyes' inner corners (epicanthal folds); and/or abnormal deviation of one eye in relation to the other (strabismus). Additional abnormalities may include an unusually small, retracted lower jaw (microretrognathia) and a potentially increased risk of tooth decay (dental caries).In approximately 10 percent of individuals with Monosomy 18p, holoprosencephaly may be present. In those with this rare condition, the forebrain failed to normally divide into hemispheres during embryonic development. Holoprosencephaly may result in variable degrees of mental retardation, sudden episodes of uncontrolled electrical activity in the brain (seizures), and/or additional, variable neurologic findings; in extremely severe cases, potentially life-threatening complications may result during infancy or childhood. As noted earlier, holoprosencephaly may also result in various abnormalities of midfacial development. Reports suggest that some with the condition may have a normal or near normal facial appearance, while others may have relatively mild to extremely severe midline facial defects. In some affected individuals, associated malformations may include the presence of a single, central front tooth of the upper jaw (maxillary incisor); widely or closely set eyes (ocular hypertelorism or hypotelorism); an abnormal groove in the side or middle of the upper lip (lateral or median cleft lip); incomplete closure of the roof of the mouth (cleft palate); and/or, in extremely severe cases, fusion of the eye cavities (orbits) into a single cavity containing one eye (cyclopia). In addition, depending on the severity of defective midfacial development, nasal abnormalities may be present, such as an unusually flattened nose; a blind-ending, single-nostril nose; or absence of the nose (arhinia) and/or the presence of a tubular appendage above the orbit (proboscis). (For more information on this condition, choose “holoprosencephaly” as your search term in the Rare Disease Database.) In some instances, Monosomy 18p may be characterized by other physical findings. Some affected infants may have an abnormal accumulation of fluid in soft tissues of the hands and feet, with associated swelling (lymphedema); a short, webbed neck; and/or an unusually broad chest with widely spaced nipples. Limb malformations may also be present, such as relatively small hands and feet; short fingers; abnormal deviation of the “pinkies” or fifth fingers (clinodactyly); and/or webbing or fusion (syndactyly) of certain toes. In affected males, physical features may include an unusually small penis (micropenis) and/or undescended testes (cryptorchidism). Additional features have also been reported in association with Monosomy 18p in some cases, such as deficiency of a particular antibody (i.e., immunoglobulin A [IgA]) that helps the body to fight certain infections; abnormal absence of scalp hair (alopecia) beginning during infancy; and/or other findings. In addition, according to researchers, various structural malformations of the heart (congenital heart defects) may be present in up to five percent of cases. | 247 | Chromosome 18, Monosomy 18p |
nord_247_2 | Causes of Chromosome 18, Monosomy 18p | Chromosome 18, Monosomy 18p is a chromosomal abnormality in which there is deletion (monosomy) of all or a portion of the short arm (p) of chromosome 18. Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p” and a long arm identified by the letter “q”. Chromosomes are further subdivided into bands that are numbered.Monosomy 18p usually appears to be caused by spontaneous (de novo) errors very early in embryonic development. In such instances, the parents of the affected child usually have normal chromosomes and a relatively low risk of having another child with the chromosomal abnormality. However, other cases have been reported in which Monosomy 18p has appeared to result from a “balanced translocation” in one of the parents. Translocations occur when regions of certain chromosomes break off and are rearranged, resulting in shifting of genetic material and an altered set of chromosomes. If a chromosomal rearrangement is balanced, meaning that it consists of an altered but balanced set of chromosomes, it is usually harmless to the carrier. However, such a chromosomal rearrangement may be associated with an increased risk of abnormal chromosomal development in the carrier's offspring. In addition, in some rare cases, a parent of an affected child has also had deletion of the short arm of chromosome 18 in all or some cells. (Cases in which only a percentage of an individual's cells has the chromosomal abnormality while other cells have a normal chromosomal make-up are known as “mosaicism.”) Chromosomal analysis and genetic counseling are typically recommended for parents of an affected child to help confirm or exclude the presence of potential mosaicism or a balanced translocation in one of the parents. | Causes of Chromosome 18, Monosomy 18p. Chromosome 18, Monosomy 18p is a chromosomal abnormality in which there is deletion (monosomy) of all or a portion of the short arm (p) of chromosome 18. Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p” and a long arm identified by the letter “q”. Chromosomes are further subdivided into bands that are numbered.Monosomy 18p usually appears to be caused by spontaneous (de novo) errors very early in embryonic development. In such instances, the parents of the affected child usually have normal chromosomes and a relatively low risk of having another child with the chromosomal abnormality. However, other cases have been reported in which Monosomy 18p has appeared to result from a “balanced translocation” in one of the parents. Translocations occur when regions of certain chromosomes break off and are rearranged, resulting in shifting of genetic material and an altered set of chromosomes. If a chromosomal rearrangement is balanced, meaning that it consists of an altered but balanced set of chromosomes, it is usually harmless to the carrier. However, such a chromosomal rearrangement may be associated with an increased risk of abnormal chromosomal development in the carrier's offspring. In addition, in some rare cases, a parent of an affected child has also had deletion of the short arm of chromosome 18 in all or some cells. (Cases in which only a percentage of an individual's cells has the chromosomal abnormality while other cells have a normal chromosomal make-up are known as “mosaicism.”) Chromosomal analysis and genetic counseling are typically recommended for parents of an affected child to help confirm or exclude the presence of potential mosaicism or a balanced translocation in one of the parents. | 247 | Chromosome 18, Monosomy 18p |
nord_247_3 | Affects of Chromosome 18, Monosomy 18p | Chromosome 18, Monosomy 18p appears to affect females more frequently than males by a ratio of approximately three to two. Reports indicate that the mean parental age is older than average for the mothers and fathers of children with Monosomy 18p (i.e., age 32 years and 38 years, respectively). Since Monosomy 18p was originally described in 1963, over 120 cases have been reported in the medical literature. | Affects of Chromosome 18, Monosomy 18p. Chromosome 18, Monosomy 18p appears to affect females more frequently than males by a ratio of approximately three to two. Reports indicate that the mean parental age is older than average for the mothers and fathers of children with Monosomy 18p (i.e., age 32 years and 38 years, respectively). Since Monosomy 18p was originally described in 1963, over 120 cases have been reported in the medical literature. | 247 | Chromosome 18, Monosomy 18p |
nord_247_4 | Related disorders of Chromosome 18, Monosomy 18p | Symptoms of the following disorders may be similar to those of Chromosome 18, Monosomy 18p. Comparisons may be useful for a differential diagnosis: Chromosome 18 Ring is a rare disorder in which there is deletion of genetic material from both ends of the 18th chromosome (i.e., from the short arm and the long arm of chromosome 18) and joining of the chromosomal ends to form a ring. Associated symptoms and findings may vary greatly in range and severity, depending upon the amount and location of lost genetic material and other factors. There have been a few cases in which individuals with Chromosome 18 Ring have few or no apparent symptoms. However, others with the chromosomal abnormality may have multiple features. In many cases, those with Chromosome 18 Ring are affected by mental retardation; low muscle tone (hypotonia); growth retardation; and/or malformations of the skull and facial (craniofacial) region. Such craniofacial features often include an unusually small head (microcephaly); widely spaced eyes (ocular hypertelorism); vertical skin folds that may cover the eyes' inner corners (epicanthal folds); drooping of the upper eyelids (ptosis); a highly arched palate; a “carp-shaped” mouth; and/or low-set, malformed ears and/or narrow (stenotic) or absent (atretic) ear canals, with associated hearing impairment. The disorder may also be characterized by additional physical abnormalities, such as deficiency of a particular antibody (i.e., immunoglobulin A [IgA]) that helps to fight certain infections; rib and/or spinal column (vertebral) defects; abnormal deviation (clinodactyly) of the fifth fingers; webbing of the neck; structural malformations of the heart (congenital heart defects); and/or kidney (renal) defects. A few severe cases have also been reported in which Chromosome 18 Ring has been associated with holoprosencephaly. Chromosome 18 Ring is usually caused by spontaneous (de novo) errors very early in the development of the embryo that appear to occur randomly for unknown reasons (sporadically). (For further information on this disorder, choose “Chromosome 18 Ring” as your search term in the Rare Disease Database.)Additional chromosomal disorders may have certain features similar to those associated with Chromosome 18, Monosomy 18p. Chromosomal testing is necessary to confirm the specific chromosomal abnormality present. (For further information on such disorders, choose the name of the specific chromosomal disorder in question or use “chromosome” as your search term in the Rare Disease Database.) | Related disorders of Chromosome 18, Monosomy 18p. Symptoms of the following disorders may be similar to those of Chromosome 18, Monosomy 18p. Comparisons may be useful for a differential diagnosis: Chromosome 18 Ring is a rare disorder in which there is deletion of genetic material from both ends of the 18th chromosome (i.e., from the short arm and the long arm of chromosome 18) and joining of the chromosomal ends to form a ring. Associated symptoms and findings may vary greatly in range and severity, depending upon the amount and location of lost genetic material and other factors. There have been a few cases in which individuals with Chromosome 18 Ring have few or no apparent symptoms. However, others with the chromosomal abnormality may have multiple features. In many cases, those with Chromosome 18 Ring are affected by mental retardation; low muscle tone (hypotonia); growth retardation; and/or malformations of the skull and facial (craniofacial) region. Such craniofacial features often include an unusually small head (microcephaly); widely spaced eyes (ocular hypertelorism); vertical skin folds that may cover the eyes' inner corners (epicanthal folds); drooping of the upper eyelids (ptosis); a highly arched palate; a “carp-shaped” mouth; and/or low-set, malformed ears and/or narrow (stenotic) or absent (atretic) ear canals, with associated hearing impairment. The disorder may also be characterized by additional physical abnormalities, such as deficiency of a particular antibody (i.e., immunoglobulin A [IgA]) that helps to fight certain infections; rib and/or spinal column (vertebral) defects; abnormal deviation (clinodactyly) of the fifth fingers; webbing of the neck; structural malformations of the heart (congenital heart defects); and/or kidney (renal) defects. A few severe cases have also been reported in which Chromosome 18 Ring has been associated with holoprosencephaly. Chromosome 18 Ring is usually caused by spontaneous (de novo) errors very early in the development of the embryo that appear to occur randomly for unknown reasons (sporadically). (For further information on this disorder, choose “Chromosome 18 Ring” as your search term in the Rare Disease Database.)Additional chromosomal disorders may have certain features similar to those associated with Chromosome 18, Monosomy 18p. Chromosomal testing is necessary to confirm the specific chromosomal abnormality present. (For further information on such disorders, choose the name of the specific chromosomal disorder in question or use “chromosome” as your search term in the Rare Disease Database.) | 247 | Chromosome 18, Monosomy 18p |
nord_247_5 | Diagnosis of Chromosome 18, Monosomy 18p | In some cases, Chromosome 18, Monosomy 18p may be suggested before birth (prenatally) by specialized tests such as ultrasound, amniocentesis, and/or chorionic villus sampling (CVS). During fetal ultrasonography, reflected sound waves create an image of the developing fetus, potentially revealing certain findings that suggest a chromosomal disorder or other developmental abnormalities. With amniocentesis, a sample of fluid that surrounds the developing fetus is removed and analyzed, while CVS involves the removal of tissue samples from a portion of the placenta. Chromosomal analysis performed on such fluid or tissue samples may reveal the presence of Monosomy 18p.The disorder is usually diagnosed or confirmed after birth (postnatally) based upon a thorough clinical evaluation, detection of characteristic physical findings, and chromosomal analysis. Specialized tests may also be conducted to help detect and/or characterize certain abnormalities that may be associated with the disorder. | Diagnosis of Chromosome 18, Monosomy 18p. In some cases, Chromosome 18, Monosomy 18p may be suggested before birth (prenatally) by specialized tests such as ultrasound, amniocentesis, and/or chorionic villus sampling (CVS). During fetal ultrasonography, reflected sound waves create an image of the developing fetus, potentially revealing certain findings that suggest a chromosomal disorder or other developmental abnormalities. With amniocentesis, a sample of fluid that surrounds the developing fetus is removed and analyzed, while CVS involves the removal of tissue samples from a portion of the placenta. Chromosomal analysis performed on such fluid or tissue samples may reveal the presence of Monosomy 18p.The disorder is usually diagnosed or confirmed after birth (postnatally) based upon a thorough clinical evaluation, detection of characteristic physical findings, and chromosomal analysis. Specialized tests may also be conducted to help detect and/or characterize certain abnormalities that may be associated with the disorder. | 247 | Chromosome 18, Monosomy 18p |
nord_247_6 | Therapies of Chromosome 18, Monosomy 18p | TreatmentThe treatment of Chromosome 18, Monosomy 18p is directed toward the specific symptoms that are apparent in each individual. Such treatment may require the coordinated efforts of a team of medical professionals, such as pediatricians; surgeons; physicians who specialize in disorders of the skeleton, muscles, joints, and related tissues (orthopedists); neurologists; speech-language pathologists; and/or other health care professionals.In some cases, physicians may recommend surgical repair of certain craniofacial, skeletal, ocular, and/or other defects potentially associated with the disorder. The specific surgical procedures performed will depend upon the severity and location of the anatomical abnormalities, their associated symptoms, and other factors.Early intervention may be important in ensuring that affected children reach their potential. Special services that may be beneficial include special education, speech therapy, physical therapy, and/or other medical, social, and/or vocational services. Genetic counseling will also be of benefit for affected individuals and their families. Other treatment for this disorder is symptomatic and supportive. | Therapies of Chromosome 18, Monosomy 18p. TreatmentThe treatment of Chromosome 18, Monosomy 18p is directed toward the specific symptoms that are apparent in each individual. Such treatment may require the coordinated efforts of a team of medical professionals, such as pediatricians; surgeons; physicians who specialize in disorders of the skeleton, muscles, joints, and related tissues (orthopedists); neurologists; speech-language pathologists; and/or other health care professionals.In some cases, physicians may recommend surgical repair of certain craniofacial, skeletal, ocular, and/or other defects potentially associated with the disorder. The specific surgical procedures performed will depend upon the severity and location of the anatomical abnormalities, their associated symptoms, and other factors.Early intervention may be important in ensuring that affected children reach their potential. Special services that may be beneficial include special education, speech therapy, physical therapy, and/or other medical, social, and/or vocational services. Genetic counseling will also be of benefit for affected individuals and their families. Other treatment for this disorder is symptomatic and supportive. | 247 | Chromosome 18, Monosomy 18p |
nord_248_0 | Overview of Chromosome 18, Tetrasomy 18p | Chromosome 18, Tetrasomy 18p is a very rare chromosomal disorder in which the short arm of the 18th chromosome (18p) appears four times (tetrasomy) rather than twice in cells of the body. Individuals with a normal chromosomal make-up (karyotype) have two 18th chromosomes, both of which have a short arm (“18p”) and a long arm (“18q”). However, in individuals with Chromosome 18, Tetrasomy 18p, four short arms (18ps) are present in cells of the body rather than the normal two.The symptoms of Chromosome 18, Tetrasomy 18p may vary from case to case. Many affected individuals may have abnormalities of the head and facial (craniofacial) area; malformations of the spine, hands, and/or feet; neuromuscular abnormalities, such as increased muscle tone (hypertonia), increased reflex reactions (hyperreflexia), and difficulty coordinating movement; kidney (renal) malformations; and/or additional physical abnormalities. In addition, children and adults with Chromosome 18, Tetrasomy 18p often exhibit moderate to severe mental retardation, limitations in speech, and/or behavioral abnormalities. In most cases, Chromosome 18, Tetrasomy 18p is the result of a spontaneous (de novo) genetic change (mutation) early in embryonic development that occurs for unknown reasons (sporadic). | Overview of Chromosome 18, Tetrasomy 18p. Chromosome 18, Tetrasomy 18p is a very rare chromosomal disorder in which the short arm of the 18th chromosome (18p) appears four times (tetrasomy) rather than twice in cells of the body. Individuals with a normal chromosomal make-up (karyotype) have two 18th chromosomes, both of which have a short arm (“18p”) and a long arm (“18q”). However, in individuals with Chromosome 18, Tetrasomy 18p, four short arms (18ps) are present in cells of the body rather than the normal two.The symptoms of Chromosome 18, Tetrasomy 18p may vary from case to case. Many affected individuals may have abnormalities of the head and facial (craniofacial) area; malformations of the spine, hands, and/or feet; neuromuscular abnormalities, such as increased muscle tone (hypertonia), increased reflex reactions (hyperreflexia), and difficulty coordinating movement; kidney (renal) malformations; and/or additional physical abnormalities. In addition, children and adults with Chromosome 18, Tetrasomy 18p often exhibit moderate to severe mental retardation, limitations in speech, and/or behavioral abnormalities. In most cases, Chromosome 18, Tetrasomy 18p is the result of a spontaneous (de novo) genetic change (mutation) early in embryonic development that occurs for unknown reasons (sporadic). | 248 | Chromosome 18, Tetrasomy 18p |
nord_248_1 | Symptoms of Chromosome 18, Tetrasomy 18p | Chromosome 18, Tetrasomy 18p is a very rare chromosomal disorder in which the short arm of chromosome 18 (18p) appears four times (tetrasomy) rather than twice in cells of the body. Symptoms may vary from case to case.Many infants with Chromosome 18, Tetrasomy 18p have a low birthweight, feeding problems, and a tendency to vomit. If necessary calories and nutrients are not obtained, affected infants may fail to thrive as a result. Most infants with Chromosome 18, Tetrasomy 18p have abnormalities of the head and facial (craniofacial) area. The fibrous joint (sagittal suture) between the bones that form the sides of the skull (parietal bones) may close prematurely (dolichocephaly), causing the head to appear unusually long and narrow; the head may also be abnormally small (microcephaly), and the two sides of the face may appear to be of unequal shape and/or size (facial asymmetry). Affected infants may also have an abnormally small mouth; a highly arched roof of the mouth (palate); an unusually small jaw (micrognathia); malformed (dysplastic), low-set ears; and/or a pinched nose. In rare cases, additional craniofacial abnormalities may include vertical skin folds on either side of the nose (epicanthal folds) that may cover the eyes' inner corners; eyes that are unusually close together (ocular hypotelorism); incomplete closure of the roof of the mouth (cleft palate); and/or overgrowth of the gums (gingival hypertrophy).Individuals with Chromosome 18, Tetrasomy 18p often have several skeletal abnormalities. These may include a sideways curvative of the spine (scoliosis), sometimes occurring in association with a front-to-back curvative of the spine (kyphosis); an unusually small hipbone; and/or additional hip deformities (e.g., coxa valga). Many affected individuals exhibit malformations of the bones in the hands and/or feet, including fingers and/or toes that overlap and/or are unusually long, abnormally bent (clinodactyly), and/or webbed or fused (syndactyly). In some cases, the arches of the feet may also be flat (pes planus). Additional abnormalities of the hands may also be present, such as a single deep crease across the palms of the hands (simian crease) and/or absence of the horizontal ridges that are normally on the skin on the far end of the fingers (distal flexion ridges). Many affected individuals also tend to have a distinctive body shape, consisting of an abnormally thin build, narrow chest and shoulders, and unusually prominent bones and/or muscles (asthenic habitus). In most people with Tetrasomy 18p, clusters of nerve fibers in the spinal cord (pyramidal tract) that help to regulate voluntary and reflex muscle activity may not function appropriately. As a result, affected individuals may exhibit several neuromuscular abnormalities, such as increased muscle tone (hypertonia); increased reflex reactions (hyperreflexia), including an abnormal reflex that consists of repeated flexing and relaxing of the foot (ankle clonus); and/or muscle stiffness and awkwardness in movement (spasticity). As affected people grow older, many may have an abnormal walking style (gait). In addition, in some individuals with Tetrasomy 18p, electrical disturbances may occur in the brain, causing involuntary tightening and relaxing (clonus) of specific muscles or muscle groups (motor seizures). Many individuals with Chromosome 18, Tetrasomy 18p may also exhibit kidney (renal) abnormalities. For example, each kidney normally has a tube (ureter) that brings urine to the bladder. However, in some cases of Tetrasomy 18p, each kidney may have two such tubes (double ureter). If the double ureters fail to join together to become one tube before entering the bladder, one of the tubes may drain the urine in an inappropriate (ectopic) location. Blockage (obstruction) may result, causing an abnormal accumulation of urine in and swelling (distension) of the ureters (hydroureter) and kidneys (hydronephrosis). In addition, the other ureter may only be loosely embedded in the bladder, potentially causing backflow (reflux) of urine into the ureter, repeated bladder infections, and/or ureter blockage and hydronephrosis. Other kidney abnormalities have also occurred in association with Chromosome 18, Tetrasomy 18p. For example, during normal development, the kidneys eventually “rotate” into their proper position in the back of the abdominal cavity. However, in some individuals with Tetrasomy 18p, the kidneys may not rotate into the appropriate position. As a result, the kidneys may be compressed by other organs that are also in the abdominal cavity, potentially causing abnormal renal function. In addition, in some cases of Tetrasomy 18p, the two kidneys may be united at the base, forming a horseshoe shape (horseshoe kidney); in such cases, kidney function is usually normal. Some individuals with Tetrasomy 18p may have additional physical abnormalities. For example, at birth, some may have temporarily low levels of an antibody that helps fight infections (i.e., immunoglobulin A [IgA]). In addition, some individuals may exhibit a heart murmur and/or, in rare cases, failure of the testes to descend into the scrotum (cryptorchidism) in males. In most cases, children and adults with Chromosome 18, Tetrasomy 18p also exhibit moderate to severe mental retardation, limited speech and vocabulary, and behavioral abnormalities. | Symptoms of Chromosome 18, Tetrasomy 18p. Chromosome 18, Tetrasomy 18p is a very rare chromosomal disorder in which the short arm of chromosome 18 (18p) appears four times (tetrasomy) rather than twice in cells of the body. Symptoms may vary from case to case.Many infants with Chromosome 18, Tetrasomy 18p have a low birthweight, feeding problems, and a tendency to vomit. If necessary calories and nutrients are not obtained, affected infants may fail to thrive as a result. Most infants with Chromosome 18, Tetrasomy 18p have abnormalities of the head and facial (craniofacial) area. The fibrous joint (sagittal suture) between the bones that form the sides of the skull (parietal bones) may close prematurely (dolichocephaly), causing the head to appear unusually long and narrow; the head may also be abnormally small (microcephaly), and the two sides of the face may appear to be of unequal shape and/or size (facial asymmetry). Affected infants may also have an abnormally small mouth; a highly arched roof of the mouth (palate); an unusually small jaw (micrognathia); malformed (dysplastic), low-set ears; and/or a pinched nose. In rare cases, additional craniofacial abnormalities may include vertical skin folds on either side of the nose (epicanthal folds) that may cover the eyes' inner corners; eyes that are unusually close together (ocular hypotelorism); incomplete closure of the roof of the mouth (cleft palate); and/or overgrowth of the gums (gingival hypertrophy).Individuals with Chromosome 18, Tetrasomy 18p often have several skeletal abnormalities. These may include a sideways curvative of the spine (scoliosis), sometimes occurring in association with a front-to-back curvative of the spine (kyphosis); an unusually small hipbone; and/or additional hip deformities (e.g., coxa valga). Many affected individuals exhibit malformations of the bones in the hands and/or feet, including fingers and/or toes that overlap and/or are unusually long, abnormally bent (clinodactyly), and/or webbed or fused (syndactyly). In some cases, the arches of the feet may also be flat (pes planus). Additional abnormalities of the hands may also be present, such as a single deep crease across the palms of the hands (simian crease) and/or absence of the horizontal ridges that are normally on the skin on the far end of the fingers (distal flexion ridges). Many affected individuals also tend to have a distinctive body shape, consisting of an abnormally thin build, narrow chest and shoulders, and unusually prominent bones and/or muscles (asthenic habitus). In most people with Tetrasomy 18p, clusters of nerve fibers in the spinal cord (pyramidal tract) that help to regulate voluntary and reflex muscle activity may not function appropriately. As a result, affected individuals may exhibit several neuromuscular abnormalities, such as increased muscle tone (hypertonia); increased reflex reactions (hyperreflexia), including an abnormal reflex that consists of repeated flexing and relaxing of the foot (ankle clonus); and/or muscle stiffness and awkwardness in movement (spasticity). As affected people grow older, many may have an abnormal walking style (gait). In addition, in some individuals with Tetrasomy 18p, electrical disturbances may occur in the brain, causing involuntary tightening and relaxing (clonus) of specific muscles or muscle groups (motor seizures). Many individuals with Chromosome 18, Tetrasomy 18p may also exhibit kidney (renal) abnormalities. For example, each kidney normally has a tube (ureter) that brings urine to the bladder. However, in some cases of Tetrasomy 18p, each kidney may have two such tubes (double ureter). If the double ureters fail to join together to become one tube before entering the bladder, one of the tubes may drain the urine in an inappropriate (ectopic) location. Blockage (obstruction) may result, causing an abnormal accumulation of urine in and swelling (distension) of the ureters (hydroureter) and kidneys (hydronephrosis). In addition, the other ureter may only be loosely embedded in the bladder, potentially causing backflow (reflux) of urine into the ureter, repeated bladder infections, and/or ureter blockage and hydronephrosis. Other kidney abnormalities have also occurred in association with Chromosome 18, Tetrasomy 18p. For example, during normal development, the kidneys eventually “rotate” into their proper position in the back of the abdominal cavity. However, in some individuals with Tetrasomy 18p, the kidneys may not rotate into the appropriate position. As a result, the kidneys may be compressed by other organs that are also in the abdominal cavity, potentially causing abnormal renal function. In addition, in some cases of Tetrasomy 18p, the two kidneys may be united at the base, forming a horseshoe shape (horseshoe kidney); in such cases, kidney function is usually normal. Some individuals with Tetrasomy 18p may have additional physical abnormalities. For example, at birth, some may have temporarily low levels of an antibody that helps fight infections (i.e., immunoglobulin A [IgA]). In addition, some individuals may exhibit a heart murmur and/or, in rare cases, failure of the testes to descend into the scrotum (cryptorchidism) in males. In most cases, children and adults with Chromosome 18, Tetrasomy 18p also exhibit moderate to severe mental retardation, limited speech and vocabulary, and behavioral abnormalities. | 248 | Chromosome 18, Tetrasomy 18p |
nord_248_2 | Causes of Chromosome 18, Tetrasomy 18p | Chromosome 18, Tetrasomy 18p is a rare chromosomal disorder in which the short arm of chromosome 18 (18p) appears four times (tetrasomy) rather than twice in cells of the body. Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p” and a long arm identified by the letter “q.” Chromosomes are further subdivided into bands that are numbered.Individuals with a normal chromosomal make-up (karyotype) have two 18th chromosomes, both of which consist of a short arm (18p), a long arm (18q), and a narrowed region at which the two arms are joined (centromere). However, people with Chromosome 18, Tetrasomy 18p have an extra chromosome known as an “isochromosome” that consists of two identical short arms (18ps) and a centromere. (An isochromosome is a chromosome with identical arms on each side of the centromere.) Therefore, a total of four short arms (18ps) are present in cells of the body rather than the normal two, resulting in the symptoms and physical findings that characterize this disorder. In most affected individuals, Chromosome 18, Tetrasomy 18p has resulted from a spontaneous (de novo) change very early in embryonic development that occurred for unknown reasons (sporadically). In such cases, the parents of the affected child usually have normal chromosomes and a relatively low risk of having another child with the chromosomal abnormality. However, there have been rare cases in which a parent also has an extra 18p isochromosome in all or some cells (i.e., chromosomal mosaicism). (Chromosomal mosaicism describes cases in which only a percentage of cells contains the chromosomal abnormality while other cells have a normal chromosomal makeup.) In such instances, it is believed that Chromosome 18, Tetrasomy 18p may have been inherited and that the chances are greater of having another child with the chromosomal abnormality. Chromosomal analysis and genetic counseling are recommended for parents of an affected child. | Causes of Chromosome 18, Tetrasomy 18p. Chromosome 18, Tetrasomy 18p is a rare chromosomal disorder in which the short arm of chromosome 18 (18p) appears four times (tetrasomy) rather than twice in cells of the body. Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p” and a long arm identified by the letter “q.” Chromosomes are further subdivided into bands that are numbered.Individuals with a normal chromosomal make-up (karyotype) have two 18th chromosomes, both of which consist of a short arm (18p), a long arm (18q), and a narrowed region at which the two arms are joined (centromere). However, people with Chromosome 18, Tetrasomy 18p have an extra chromosome known as an “isochromosome” that consists of two identical short arms (18ps) and a centromere. (An isochromosome is a chromosome with identical arms on each side of the centromere.) Therefore, a total of four short arms (18ps) are present in cells of the body rather than the normal two, resulting in the symptoms and physical findings that characterize this disorder. In most affected individuals, Chromosome 18, Tetrasomy 18p has resulted from a spontaneous (de novo) change very early in embryonic development that occurred for unknown reasons (sporadically). In such cases, the parents of the affected child usually have normal chromosomes and a relatively low risk of having another child with the chromosomal abnormality. However, there have been rare cases in which a parent also has an extra 18p isochromosome in all or some cells (i.e., chromosomal mosaicism). (Chromosomal mosaicism describes cases in which only a percentage of cells contains the chromosomal abnormality while other cells have a normal chromosomal makeup.) In such instances, it is believed that Chromosome 18, Tetrasomy 18p may have been inherited and that the chances are greater of having another child with the chromosomal abnormality. Chromosomal analysis and genetic counseling are recommended for parents of an affected child. | 248 | Chromosome 18, Tetrasomy 18p |
nord_248_3 | Affects of Chromosome 18, Tetrasomy 18p | Chromosome 18, Tetrasomy 18p is a very rare chromosomal disorder that appears to affect males and females equally. Approximately 40 cases have been reported in the medical literature. | Affects of Chromosome 18, Tetrasomy 18p. Chromosome 18, Tetrasomy 18p is a very rare chromosomal disorder that appears to affect males and females equally. Approximately 40 cases have been reported in the medical literature. | 248 | Chromosome 18, Tetrasomy 18p |
nord_248_4 | Related disorders of Chromosome 18, Tetrasomy 18p | Symptoms of the following disorders may be similar to those of Chromosome 18, Tetrasomy 18p. Comparisons may be useful for a differential diagnosis: Chromosome 18, Trisomy 18 is a rare chromosomal disorder in which part or all of chromosome 18 appears three times (trisomy) rather than twice in all or some of the cells of the body. The disorder is often characterized by a low birthweight; feeding and breathing difficulties; failure to grow and gain weight at the expected rate (failure to thrive); developmental delays; and mental retardation. In addition, affected infants may have distinctive craniofacial abnormalities, such as an unusually long, narrow head (dolicocephaly) with a prominent back region (occiput); malformed, low-set ears; a small mouth; and/or a small jaw (micrognathia). Additional physical features may include structural heart defects, such as an abnormal opening in the fibrous partition that separates the two lower chambers of the heart (ventricular septal defects); kidney (renal) abnormalities, particularly horseshoe kidney and swelling of the ureters and kidneys with urine (hydroureter and hydronephrosis); undescended testes (cryptorchidism) in affected males; overlapping, flexed fingers; foot malformations; and/or other physical findings. The exact cause of Chromosome 18, Trisomy 18 is not fully understood. (For more information on this disorder, choose “Trisomy 18” as your search term in the Rare Disease Database.) Additional chromosomal disorders may have features similar to those associated with Chromosome 18, Tetrasomy 18p. Chromosomal testing is necessary to confirm the specific chromosomal abnormality present. (For further information on such disorders, choose the name of the specific chromosomal disorder in question or use “chromosome” as your search term in the Rare Disease Database.) | Related disorders of Chromosome 18, Tetrasomy 18p. Symptoms of the following disorders may be similar to those of Chromosome 18, Tetrasomy 18p. Comparisons may be useful for a differential diagnosis: Chromosome 18, Trisomy 18 is a rare chromosomal disorder in which part or all of chromosome 18 appears three times (trisomy) rather than twice in all or some of the cells of the body. The disorder is often characterized by a low birthweight; feeding and breathing difficulties; failure to grow and gain weight at the expected rate (failure to thrive); developmental delays; and mental retardation. In addition, affected infants may have distinctive craniofacial abnormalities, such as an unusually long, narrow head (dolicocephaly) with a prominent back region (occiput); malformed, low-set ears; a small mouth; and/or a small jaw (micrognathia). Additional physical features may include structural heart defects, such as an abnormal opening in the fibrous partition that separates the two lower chambers of the heart (ventricular septal defects); kidney (renal) abnormalities, particularly horseshoe kidney and swelling of the ureters and kidneys with urine (hydroureter and hydronephrosis); undescended testes (cryptorchidism) in affected males; overlapping, flexed fingers; foot malformations; and/or other physical findings. The exact cause of Chromosome 18, Trisomy 18 is not fully understood. (For more information on this disorder, choose “Trisomy 18” as your search term in the Rare Disease Database.) Additional chromosomal disorders may have features similar to those associated with Chromosome 18, Tetrasomy 18p. Chromosomal testing is necessary to confirm the specific chromosomal abnormality present. (For further information on such disorders, choose the name of the specific chromosomal disorder in question or use “chromosome” as your search term in the Rare Disease Database.) | 248 | Chromosome 18, Tetrasomy 18p |
nord_248_5 | Diagnosis of Chromosome 18, Tetrasomy 18p | The diagnosis of Chromosome 18, Tetrasomy 18p may be determined before birth (prenatally) by specialized tests such as ultrasound, fetal blood sampling, amniocentesis, and/or chorionic villus sampling (CVS). During fetal ultrasonography, reflected sound waves are used to create an image of the developing fetus. Ultrasound studies may reveal characteristic findings that suggest a chromosomal disorder or other developmental abnormalities in the fetus. During fetal blood sampling, blood is drawn with a needle that is guided via ultrasound into the umbilical vein. With amniocentesis, a sample of fluid that surrounds the developing fetus is removed and analyzed, while CVS involves the removal of tissue samples from a portion of the placenta. Chromosomal analysis performed on fluid or tissue samples (i.e., obtained via fetal blood sampling, amniocentesis, or CVS) may reveal the presence of Chromosome 18p Tetrasomy.The disorder may also be diagnosed and/or confirmed after birth (postnatally) by a thorough clinical evaluation, the detection of characteristic physical findings, and standard or specialized chromosomal studies (e.g., fluorescence in situ hybridization [FISH]). Additional diagnostic tests may also be conducted to help detect and/or characterize certain abnormalities that may be associated with the disorder. | Diagnosis of Chromosome 18, Tetrasomy 18p. The diagnosis of Chromosome 18, Tetrasomy 18p may be determined before birth (prenatally) by specialized tests such as ultrasound, fetal blood sampling, amniocentesis, and/or chorionic villus sampling (CVS). During fetal ultrasonography, reflected sound waves are used to create an image of the developing fetus. Ultrasound studies may reveal characteristic findings that suggest a chromosomal disorder or other developmental abnormalities in the fetus. During fetal blood sampling, blood is drawn with a needle that is guided via ultrasound into the umbilical vein. With amniocentesis, a sample of fluid that surrounds the developing fetus is removed and analyzed, while CVS involves the removal of tissue samples from a portion of the placenta. Chromosomal analysis performed on fluid or tissue samples (i.e., obtained via fetal blood sampling, amniocentesis, or CVS) may reveal the presence of Chromosome 18p Tetrasomy.The disorder may also be diagnosed and/or confirmed after birth (postnatally) by a thorough clinical evaluation, the detection of characteristic physical findings, and standard or specialized chromosomal studies (e.g., fluorescence in situ hybridization [FISH]). Additional diagnostic tests may also be conducted to help detect and/or characterize certain abnormalities that may be associated with the disorder. | 248 | Chromosome 18, Tetrasomy 18p |
nord_248_6 | Therapies of Chromosome 18, Tetrasomy 18p | TreatmentThe treatment of Chromosome 18, Tetrasomy 18p is directed toward the specific symptoms that are apparent in each individual. Such treatment may include surgical repair of craniofacial, skeletal, renal, and/or other malformations that may be associated with the disorder. The specific surgical procedures performed will depend upon the severity and location of the anatomical abnormalities, their associated symptoms, and other factors.Other treatment of Chromosome 18, Tetrasomy 18p is symptomatic and supportive. A team approach may be helpful in ensuring that affected individuals reach their fullest potential. Such a team approach may include special remedial education, speech therapy, physical therapy, and other medical, social, or vocational services. Genetic counseling will also be of benefit for families of children with Chromosome 18, Tetrasomy 18p. | Therapies of Chromosome 18, Tetrasomy 18p. TreatmentThe treatment of Chromosome 18, Tetrasomy 18p is directed toward the specific symptoms that are apparent in each individual. Such treatment may include surgical repair of craniofacial, skeletal, renal, and/or other malformations that may be associated with the disorder. The specific surgical procedures performed will depend upon the severity and location of the anatomical abnormalities, their associated symptoms, and other factors.Other treatment of Chromosome 18, Tetrasomy 18p is symptomatic and supportive. A team approach may be helpful in ensuring that affected individuals reach their fullest potential. Such a team approach may include special remedial education, speech therapy, physical therapy, and other medical, social, or vocational services. Genetic counseling will also be of benefit for families of children with Chromosome 18, Tetrasomy 18p. | 248 | Chromosome 18, Tetrasomy 18p |
nord_249_0 | Overview of Chromosome 18q- Syndrome | Chromosome 18q- syndrome (also known as Chromosome 18, Monosomy 18q) is a rare chromosomal disorder in which there is deletion of part of the long arm (q) of chromosome 18. Associated symptoms and findings may vary greatly in range and severity from case to case. However, characteristic features include short stature; mental retardation; poor muscle tone (hypotonia); malformations of the hands and feet; and abnormalities of the skull and facial (craniofacial) region, such as a small head (microcephaly), a “carp-shaped” mouth, deeply set eyes, prominent ears, and/or unusually flat, underdeveloped midfacial regions (midfacial hypoplasia). Some affected individuals may also have visual abnormalities, hearing impairment, genital malformations, structural heart defects, and/or other physical abnormalities. Chromosome 18q- syndrome usually appears to result from spontaneous (de novo) errors very early during embryonic development that occur for unknown reasons (sporadically). | Overview of Chromosome 18q- Syndrome. Chromosome 18q- syndrome (also known as Chromosome 18, Monosomy 18q) is a rare chromosomal disorder in which there is deletion of part of the long arm (q) of chromosome 18. Associated symptoms and findings may vary greatly in range and severity from case to case. However, characteristic features include short stature; mental retardation; poor muscle tone (hypotonia); malformations of the hands and feet; and abnormalities of the skull and facial (craniofacial) region, such as a small head (microcephaly), a “carp-shaped” mouth, deeply set eyes, prominent ears, and/or unusually flat, underdeveloped midfacial regions (midfacial hypoplasia). Some affected individuals may also have visual abnormalities, hearing impairment, genital malformations, structural heart defects, and/or other physical abnormalities. Chromosome 18q- syndrome usually appears to result from spontaneous (de novo) errors very early during embryonic development that occur for unknown reasons (sporadically). | 249 | Chromosome 18q- Syndrome |
nord_249_1 | Symptoms of Chromosome 18q- Syndrome | As noted above, associated symptoms and findings may vary from case to case. However, many infants with the disorder have a low birth weight and growth delays after birth, resulting in short stature. In addition, Chromosome 18q- syndrome is often characterized by low muscle tone (hypotonia); sudden episodes of uncontrolled electrical activity in the brain (seizures); moderate to severe delays in the acquisition of skills requiring the coordination of mental and physical activities (psychomotor retardation); and varying degrees of mental retardation. Evidence suggests that most individuals with the disorder are affected by profound, severe, or moderate mental retardation. However, mild mental deficiency has been reported in some cases. In addition, some affected children may have behavioral problems, such as abnormally increased activity (hyperactivity), aggressive behavior, and tantrums.Chromosome 18q- syndrome is also typically associated with malformations of the skull and facial (craniofacial) region. Characteristic craniofacial findings may include an unusually small head (microcephaly); flat, underdeveloped (hypoplastic) midfacial regions; deeply set eyes; a “carp-shaped” mouth; and/or relative protrusion of the lower jaw (mandibular prognathism). Some affected individuals may also have a broad nasal bridge; incomplete closure (clefting) or unusual narrowness of the roof of the mouth (palate); and/or an abnormal groove in the upper lip (cleft lip). Chromosome 18q- syndrome is also often characterized by additional eye (ocular) defects, such as vertical skin folds that may cover the eyes' inner corners (epicanthal folds); involuntary, rhythmic, rapid eye movements (nystagmus); and/or abnormal deviation of one eye in relation to the other (strabismus). Associated ocular defects may also include abnormally small eyes (microphthalmia); partial absence of ocular tissue from the colored region of the eyes (coloboma of the iris); clouding of the normally transparent front region of the eyes (corneal opacities); defects of the retinas and optic disks; and/or other ocular abnormalities. (The retina is the nerve-rich membrane upon which images are focused at the back of the eye; its specialized nerve cells convert light into nerve impulses that are transmitted to the brain via the optic nerve. The optic disk, also known as the “blind spot,” is the region where fibers of the retina become part of the optic nerve.) Such ocular defects may result in varying degrees of visual impairment. Some individuals with Chromosome 18q- syndrome may also have malformations of the ears. These may include unusually prominent ears and/or abnormally narrow (stenotic) or absent (atretic) external ear canals, with associated hearing impairment.Chromosome 18q- syndrome is also often associated with distinctive abnormalities of the hands and feet, including long, thin, tapered hands; abnormal skin ridge patterns on the fingers and palms; abnormal placement of the thumbs and certain toes; and/or deformities in which the feet are twisted out of shape or position (clubfeet). Some affected individuals may also have rib malformations, hip deformities, and/or other skeletal defects. In addition, abnormal dimples may be present in certain regions, including over the knuckles and the sides of the knees.Individuals with Chromosome 18q- syndrome may also have genital abnormalities. In affected females, there may be underdevelopment of the skin folds surrounding the vaginal opening (hypoplastic labia). In males with the disorder, genital malformations may include undescended testes (cryptorchidism); an abnormally small penis (micropenis) and scrotum; and/or abnormal placement of the urinary opening (hypospadias), such as on the underside of the penis. Additional physical abnormalities have also been reported in association with the disorder, such as widely spaced nipples; deficiency of a particular antibody (i.e., immunoglobulin A [IgA]) that helps the body to fight certain infections; kidney (renal) defects; and/or other findings. In addition, in over 30 percent of cases, congenital heart defects may be present. Such heart defects have included an abnormal opening in the fibrous partition (septum) that normally separates the upper chambers (atria) or the lower chambers (ventricles) of the heart (atrial or ventricular septal defects); abnormal narrowing (stenosis) of the opening between the pulmonary artery and the right ventricle (pulmonary stenosis); or patent ductus arteriosus (PDA). In PDA, the channel that is present between the pulmonary artery and the aorta during fetal development fails to close after birth. (The pulmonary artery transports oxygen-poor blood from the right ventricle to the lungs, where the exchange of oxygen and carbon dioxide occurs. The aorta, the major artery of the body, arises from the left ventricle and supplies oxygen-rich blood to most arteries.) In some individuals with Chromosome 18q- syndrome, additional physical abnormalities may also be present. | Symptoms of Chromosome 18q- Syndrome. As noted above, associated symptoms and findings may vary from case to case. However, many infants with the disorder have a low birth weight and growth delays after birth, resulting in short stature. In addition, Chromosome 18q- syndrome is often characterized by low muscle tone (hypotonia); sudden episodes of uncontrolled electrical activity in the brain (seizures); moderate to severe delays in the acquisition of skills requiring the coordination of mental and physical activities (psychomotor retardation); and varying degrees of mental retardation. Evidence suggests that most individuals with the disorder are affected by profound, severe, or moderate mental retardation. However, mild mental deficiency has been reported in some cases. In addition, some affected children may have behavioral problems, such as abnormally increased activity (hyperactivity), aggressive behavior, and tantrums.Chromosome 18q- syndrome is also typically associated with malformations of the skull and facial (craniofacial) region. Characteristic craniofacial findings may include an unusually small head (microcephaly); flat, underdeveloped (hypoplastic) midfacial regions; deeply set eyes; a “carp-shaped” mouth; and/or relative protrusion of the lower jaw (mandibular prognathism). Some affected individuals may also have a broad nasal bridge; incomplete closure (clefting) or unusual narrowness of the roof of the mouth (palate); and/or an abnormal groove in the upper lip (cleft lip). Chromosome 18q- syndrome is also often characterized by additional eye (ocular) defects, such as vertical skin folds that may cover the eyes' inner corners (epicanthal folds); involuntary, rhythmic, rapid eye movements (nystagmus); and/or abnormal deviation of one eye in relation to the other (strabismus). Associated ocular defects may also include abnormally small eyes (microphthalmia); partial absence of ocular tissue from the colored region of the eyes (coloboma of the iris); clouding of the normally transparent front region of the eyes (corneal opacities); defects of the retinas and optic disks; and/or other ocular abnormalities. (The retina is the nerve-rich membrane upon which images are focused at the back of the eye; its specialized nerve cells convert light into nerve impulses that are transmitted to the brain via the optic nerve. The optic disk, also known as the “blind spot,” is the region where fibers of the retina become part of the optic nerve.) Such ocular defects may result in varying degrees of visual impairment. Some individuals with Chromosome 18q- syndrome may also have malformations of the ears. These may include unusually prominent ears and/or abnormally narrow (stenotic) or absent (atretic) external ear canals, with associated hearing impairment.Chromosome 18q- syndrome is also often associated with distinctive abnormalities of the hands and feet, including long, thin, tapered hands; abnormal skin ridge patterns on the fingers and palms; abnormal placement of the thumbs and certain toes; and/or deformities in which the feet are twisted out of shape or position (clubfeet). Some affected individuals may also have rib malformations, hip deformities, and/or other skeletal defects. In addition, abnormal dimples may be present in certain regions, including over the knuckles and the sides of the knees.Individuals with Chromosome 18q- syndrome may also have genital abnormalities. In affected females, there may be underdevelopment of the skin folds surrounding the vaginal opening (hypoplastic labia). In males with the disorder, genital malformations may include undescended testes (cryptorchidism); an abnormally small penis (micropenis) and scrotum; and/or abnormal placement of the urinary opening (hypospadias), such as on the underside of the penis. Additional physical abnormalities have also been reported in association with the disorder, such as widely spaced nipples; deficiency of a particular antibody (i.e., immunoglobulin A [IgA]) that helps the body to fight certain infections; kidney (renal) defects; and/or other findings. In addition, in over 30 percent of cases, congenital heart defects may be present. Such heart defects have included an abnormal opening in the fibrous partition (septum) that normally separates the upper chambers (atria) or the lower chambers (ventricles) of the heart (atrial or ventricular septal defects); abnormal narrowing (stenosis) of the opening between the pulmonary artery and the right ventricle (pulmonary stenosis); or patent ductus arteriosus (PDA). In PDA, the channel that is present between the pulmonary artery and the aorta during fetal development fails to close after birth. (The pulmonary artery transports oxygen-poor blood from the right ventricle to the lungs, where the exchange of oxygen and carbon dioxide occurs. The aorta, the major artery of the body, arises from the left ventricle and supplies oxygen-rich blood to most arteries.) In some individuals with Chromosome 18q- syndrome, additional physical abnormalities may also be present. | 249 | Chromosome 18q- Syndrome |
nord_249_2 | Causes of Chromosome 18q- Syndrome | Chromosome 18q- syndrome is a chromosomal disorder in which there is deletion (monosomy) of part of the long arm (q) of chromosome 18. Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p” and a long arm identified by the letter “q.” Chromosomes are further subdivided into bands that are numbered. For example, “18q21” refers to band 21 of the long arm of chromosome 18.Evidence suggests that individuals with characteristic features of the disorder have deletions from within band 18q21 (e.g., 18q21.3) or 18q22 (e.g., 18q22.2) that may extend to the end (or “terminal”) of chromosome 18q (qter). In some cases, the deletion could be interstitial; that is, in the middle of the chromosome. In addition, in some cases, only a certain percentage of an affected individual's cells may have the deletion, while other cells may have a normal chromosomal makeup (a finding known as “chromosomal mosaicism”). The range and severity of symptoms may depend on the specific size of the deletion and the percentage of cells with the chromosomal abnormality. Reports suggest that those with 18q- mosaicism tend to have less severe symptoms and findings.In most cases, Chromosome 18q- syndrome appears to be caused by spontaneous (de novo) errors very early in embryonic development. In such instances, the parents of the affected child usually have normal chromosomes and a relatively low risk of having another child with the chromosomal abnormality. Less commonly, the deletion may result from a “balanced translocation” in one of the parents. Translocations occur when portions of certain chromosomes break off and are rearranged, resulting in shifting of genetic material and an altered set of chromosomes. If a chromosomal rearrangement is balanced, meaning that it consists of an altered but balanced set of chromosomes, it is usually harmless to the carrier. However, such a chromosomal rearrangement may be associated with an increased risk of abnormal chromosomal development in the carrier's offspring. Rare cases have also been reported in which the disorder has appeared to result from a parental chromosomal inversion or other chromosomal rearrangements. An inversion is characterized by breakage of a chromosome in two places and reunion of the segment in the reverse order. Chromosomal analysis and genetic counseling are typically recommended for parents of an affected child to help confirm or exclude the presence of a balanced translocation or other chromosomal rearrangement in one of the parents. | Causes of Chromosome 18q- Syndrome. Chromosome 18q- syndrome is a chromosomal disorder in which there is deletion (monosomy) of part of the long arm (q) of chromosome 18. Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p” and a long arm identified by the letter “q.” Chromosomes are further subdivided into bands that are numbered. For example, “18q21” refers to band 21 of the long arm of chromosome 18.Evidence suggests that individuals with characteristic features of the disorder have deletions from within band 18q21 (e.g., 18q21.3) or 18q22 (e.g., 18q22.2) that may extend to the end (or “terminal”) of chromosome 18q (qter). In some cases, the deletion could be interstitial; that is, in the middle of the chromosome. In addition, in some cases, only a certain percentage of an affected individual's cells may have the deletion, while other cells may have a normal chromosomal makeup (a finding known as “chromosomal mosaicism”). The range and severity of symptoms may depend on the specific size of the deletion and the percentage of cells with the chromosomal abnormality. Reports suggest that those with 18q- mosaicism tend to have less severe symptoms and findings.In most cases, Chromosome 18q- syndrome appears to be caused by spontaneous (de novo) errors very early in embryonic development. In such instances, the parents of the affected child usually have normal chromosomes and a relatively low risk of having another child with the chromosomal abnormality. Less commonly, the deletion may result from a “balanced translocation” in one of the parents. Translocations occur when portions of certain chromosomes break off and are rearranged, resulting in shifting of genetic material and an altered set of chromosomes. If a chromosomal rearrangement is balanced, meaning that it consists of an altered but balanced set of chromosomes, it is usually harmless to the carrier. However, such a chromosomal rearrangement may be associated with an increased risk of abnormal chromosomal development in the carrier's offspring. Rare cases have also been reported in which the disorder has appeared to result from a parental chromosomal inversion or other chromosomal rearrangements. An inversion is characterized by breakage of a chromosome in two places and reunion of the segment in the reverse order. Chromosomal analysis and genetic counseling are typically recommended for parents of an affected child to help confirm or exclude the presence of a balanced translocation or other chromosomal rearrangement in one of the parents. | 249 | Chromosome 18q- Syndrome |
nord_249_3 | Affects of Chromosome 18q- Syndrome | Chromosome 18q- syndrome appears to affect females more frequently than males by a ratio of approximately three to two. Since the disorder was originally reported in the medical literature in 1964, more than 80 cases have been recorded. | Affects of Chromosome 18q- Syndrome. Chromosome 18q- syndrome appears to affect females more frequently than males by a ratio of approximately three to two. Since the disorder was originally reported in the medical literature in 1964, more than 80 cases have been recorded. | 249 | Chromosome 18q- Syndrome |
nord_249_4 | Related disorders of Chromosome 18q- Syndrome | Symptoms of the following disorders may be similar to those of Chromosome 18q- syndrome. Comparisons may be useful for a differential diagnosis: Chromosome 18, Monosomy 18p is a rare chromosomal disorder in which all or part of the short arm (p) of chromosome 18 is deleted. The disorder is typically characterized by short stature, variable degrees of mental retardation, speech delays, craniofacial malformations, and/or additional physical abnormalities. Associated craniofacial defects may vary greatly in range and severity. However, such features commonly include an unusually small head (microcephaly); a broad, flat nose; a “carp-shaped” mouth; large, protruding ears; widely spaced eyes (ocular hypertelorism); and/or other abnormalities. In about 10 percent of cases, Monosomy 18p may be associated with holoprosencephaly, a condition in which the forebrain (prosencephalon) fails to divide properly during embryonic development. Holoprosencephaly may result in varying degrees of mental retardation, other neurologic findings, and/or extremely variable midline facial defects, such as the presence of a single, central front tooth (maxillary incisor); closely spaced eyes (hypotelorism); an abnormal groove in the upper lip (cleft lip); incomplete closure of the roof of the mouth (cleft palate); and/or, in severe cases, absence of the nose and/or cyclopia. Cyclopia is characterized by fusion of the eye cavities (orbits) into a single cavity containing one eye. In some individuals with Monosomy 18p, additional physical abnormalities may be present, such as a short, webbed neck; a broad chest with widely spaced nipples; relatively small hands and feet; and/or an unusually small penis (micropenis) and/or undescended testes (cryptorchidism) in affected males. Monosomy 18p is usually caused by spontaneous (de novo) errors very early in embryonic development. (For further information, please choose “monosomy 18p” as your search term in the Rare Disease Database.)Chromosome 18 Ring is a rare disorder in which there is deletion of chromosomal material from both ends of the 18th chromosome and joining of the ends to form a ring. Associated symptoms and findings may vary greatly in range and severity, depending upon the amount and location of lost genetic material and other factors. However, many individuals with the disorder are affected by mental retardation, low muscle tone (hypotonia), growth retardation, and/or craniofacial malformations. Such craniofacial features often include an unusually small head (microcephaly); widely spaced eyes (ocular hypertelorism); vertical skin folds that may cover the eyes' inner corners (epicanthal folds); a highly arched palate; a “carp-shaped” mouth; and/or low-set, malformed ears and/or narrow (stenotic) or absent (atretic) ear canals, with associated hearing impairment. The disorder may also be characterized by additional physical abnormalities, such as deficiency of a particular antibody (i.e., immunoglobulin A [IgA]) that helps to fight certain infections; rib and/or spinal column (vertebral) defects; abnormal deviation (clinodactyly) of the fifth fingers; webbing of the neck; structural malformations of the heart (congenital heart defects); and/or kidney (renal) defects. A few severe cases have also been reported in which Chromosome 18 Ring has been associated with holoprosencephaly. Chromosome 18 Ring is usually caused by spontaneous (de novo) errors very early in the development of the embryo that appear to occur randomly for unknown reasons (sporadically). (For further information, please choose “chromosome 18 ring” as your search term in the Rare Disease Database.)Additional chromosomal disorders may have features similar to those potentially associated with Chromosome 18q- syndrome. Chromosomal testing is necessary to confirm the specific chromosomal abnormality present. (For further information on such disorders, choose the name of the specific chromosomal disorder in question or use “chromosome” as your search term in the Rare Disease Database.) | Related disorders of Chromosome 18q- Syndrome. Symptoms of the following disorders may be similar to those of Chromosome 18q- syndrome. Comparisons may be useful for a differential diagnosis: Chromosome 18, Monosomy 18p is a rare chromosomal disorder in which all or part of the short arm (p) of chromosome 18 is deleted. The disorder is typically characterized by short stature, variable degrees of mental retardation, speech delays, craniofacial malformations, and/or additional physical abnormalities. Associated craniofacial defects may vary greatly in range and severity. However, such features commonly include an unusually small head (microcephaly); a broad, flat nose; a “carp-shaped” mouth; large, protruding ears; widely spaced eyes (ocular hypertelorism); and/or other abnormalities. In about 10 percent of cases, Monosomy 18p may be associated with holoprosencephaly, a condition in which the forebrain (prosencephalon) fails to divide properly during embryonic development. Holoprosencephaly may result in varying degrees of mental retardation, other neurologic findings, and/or extremely variable midline facial defects, such as the presence of a single, central front tooth (maxillary incisor); closely spaced eyes (hypotelorism); an abnormal groove in the upper lip (cleft lip); incomplete closure of the roof of the mouth (cleft palate); and/or, in severe cases, absence of the nose and/or cyclopia. Cyclopia is characterized by fusion of the eye cavities (orbits) into a single cavity containing one eye. In some individuals with Monosomy 18p, additional physical abnormalities may be present, such as a short, webbed neck; a broad chest with widely spaced nipples; relatively small hands and feet; and/or an unusually small penis (micropenis) and/or undescended testes (cryptorchidism) in affected males. Monosomy 18p is usually caused by spontaneous (de novo) errors very early in embryonic development. (For further information, please choose “monosomy 18p” as your search term in the Rare Disease Database.)Chromosome 18 Ring is a rare disorder in which there is deletion of chromosomal material from both ends of the 18th chromosome and joining of the ends to form a ring. Associated symptoms and findings may vary greatly in range and severity, depending upon the amount and location of lost genetic material and other factors. However, many individuals with the disorder are affected by mental retardation, low muscle tone (hypotonia), growth retardation, and/or craniofacial malformations. Such craniofacial features often include an unusually small head (microcephaly); widely spaced eyes (ocular hypertelorism); vertical skin folds that may cover the eyes' inner corners (epicanthal folds); a highly arched palate; a “carp-shaped” mouth; and/or low-set, malformed ears and/or narrow (stenotic) or absent (atretic) ear canals, with associated hearing impairment. The disorder may also be characterized by additional physical abnormalities, such as deficiency of a particular antibody (i.e., immunoglobulin A [IgA]) that helps to fight certain infections; rib and/or spinal column (vertebral) defects; abnormal deviation (clinodactyly) of the fifth fingers; webbing of the neck; structural malformations of the heart (congenital heart defects); and/or kidney (renal) defects. A few severe cases have also been reported in which Chromosome 18 Ring has been associated with holoprosencephaly. Chromosome 18 Ring is usually caused by spontaneous (de novo) errors very early in the development of the embryo that appear to occur randomly for unknown reasons (sporadically). (For further information, please choose “chromosome 18 ring” as your search term in the Rare Disease Database.)Additional chromosomal disorders may have features similar to those potentially associated with Chromosome 18q- syndrome. Chromosomal testing is necessary to confirm the specific chromosomal abnormality present. (For further information on such disorders, choose the name of the specific chromosomal disorder in question or use “chromosome” as your search term in the Rare Disease Database.) | 249 | Chromosome 18q- Syndrome |
nord_249_5 | Diagnosis of Chromosome 18q- Syndrome | In some cases, Chromosome 18q- syndrome may be suggested before birth (prenatally) by specialized tests such as ultrasound, amniocentesis, and/or chorionic villus sampling (CVS). During fetal ultrasonography, reflected sound waves create an image of the developing fetus, potentially revealing certain findings that suggest a chromosomal disorder or other developmental abnormalities. With amniocentesis, a sample of fluid that surrounds the developing fetus is removed and analyzed, while CVS involves the removal of tissue samples from a portion of the placenta. Chromosomal analysis performed on such fluid or tissue samples may reveal the presence of Monosomy 18q.The disorder is usually diagnosed or confirmed after birth (postnatally) based upon a thorough clinical evaluation, detection of characteristic physical findings, and chromosomal analysis. Specialized tests may also be performed to help detect and/or characterize certain abnormalities that may be associated with the disorder. | Diagnosis of Chromosome 18q- Syndrome. In some cases, Chromosome 18q- syndrome may be suggested before birth (prenatally) by specialized tests such as ultrasound, amniocentesis, and/or chorionic villus sampling (CVS). During fetal ultrasonography, reflected sound waves create an image of the developing fetus, potentially revealing certain findings that suggest a chromosomal disorder or other developmental abnormalities. With amniocentesis, a sample of fluid that surrounds the developing fetus is removed and analyzed, while CVS involves the removal of tissue samples from a portion of the placenta. Chromosomal analysis performed on such fluid or tissue samples may reveal the presence of Monosomy 18q.The disorder is usually diagnosed or confirmed after birth (postnatally) based upon a thorough clinical evaluation, detection of characteristic physical findings, and chromosomal analysis. Specialized tests may also be performed to help detect and/or characterize certain abnormalities that may be associated with the disorder. | 249 | Chromosome 18q- Syndrome |
nord_249_6 | Therapies of Chromosome 18q- Syndrome | TreatmentThe treatment of Chromosome 18q- syndrome is directed toward the specific symptoms that are apparent in each individual. Such disease management may require the coordinated efforts of a team of medical professionals, such as pediatricians; surgeons; neurologists; eye specialists; hearing specialists; physicians who diagnose and treat disorders of the skeleton, muscles, joints, and related tissues (orthopedists); heart specialists (cardiologists); and/or other health care professionals.In some cases, physicians may recommend surgical correction of certain craniofacial, skeletal, genital, and/or other malformations associated with the disorder. In addition, for those with congenital heart defects, treatment with certain medications, surgical intervention, and/or other measures may be required. The specific surgical procedures performed will depend upon the severity and location of the anatomical abnormalities, their associated symptoms, and other factors.For individuals with ocular abnormalities, corrective lenses, surgery, and/or other measures may be advised to help improve vision in some cases. In addition, in those with hearing impairment, recommended treatment may include surgical measures and/or the use of specialized hearing aids or additional supportive techniques that may aid communication.In some cases, anticonvulsant medications may be administered to help prevent, reduce, or control seizures. In addition, for individuals with low levels of certain antibodies (i.e., IgA deficiency), disease management may include regular monitoring and appropriate, supportive measures to help prevent and aggressively treat infections.Early intervention may also be important in ensuring that affected children reach their potential. Special services that may be beneficial include special education, physical therapy, and/or other medical, social, and/or vocational services. Genetic counseling will also be of benefit for affected individuals and their families. Other treatment for this disorder is symptomatic and supportive. | Therapies of Chromosome 18q- Syndrome. TreatmentThe treatment of Chromosome 18q- syndrome is directed toward the specific symptoms that are apparent in each individual. Such disease management may require the coordinated efforts of a team of medical professionals, such as pediatricians; surgeons; neurologists; eye specialists; hearing specialists; physicians who diagnose and treat disorders of the skeleton, muscles, joints, and related tissues (orthopedists); heart specialists (cardiologists); and/or other health care professionals.In some cases, physicians may recommend surgical correction of certain craniofacial, skeletal, genital, and/or other malformations associated with the disorder. In addition, for those with congenital heart defects, treatment with certain medications, surgical intervention, and/or other measures may be required. The specific surgical procedures performed will depend upon the severity and location of the anatomical abnormalities, their associated symptoms, and other factors.For individuals with ocular abnormalities, corrective lenses, surgery, and/or other measures may be advised to help improve vision in some cases. In addition, in those with hearing impairment, recommended treatment may include surgical measures and/or the use of specialized hearing aids or additional supportive techniques that may aid communication.In some cases, anticonvulsant medications may be administered to help prevent, reduce, or control seizures. In addition, for individuals with low levels of certain antibodies (i.e., IgA deficiency), disease management may include regular monitoring and appropriate, supportive measures to help prevent and aggressively treat infections.Early intervention may also be important in ensuring that affected children reach their potential. Special services that may be beneficial include special education, physical therapy, and/or other medical, social, and/or vocational services. Genetic counseling will also be of benefit for affected individuals and their families. Other treatment for this disorder is symptomatic and supportive. | 249 | Chromosome 18q- Syndrome |
nord_250_0 | Overview of Chromosome 21 Ring | Chromosome 21 Ring is a rare chromosomal disorder in which the affected infant has a breakage of chromosome 21 at both ends, and the ends of the chromosome join together to form a ring. The amount of genetic material lost at the two ends of the chromosome may vary. As a result, an infant with very little absent genetic material may have no apparent symptoms while an infant with a significant part of the chromosomal ends missing may have many symptoms. When symptoms of the disorder are present, the affected infant may have mental retardation as well as abnormalities of the face, eyes, skeleton, and/or internal organs. | Overview of Chromosome 21 Ring. Chromosome 21 Ring is a rare chromosomal disorder in which the affected infant has a breakage of chromosome 21 at both ends, and the ends of the chromosome join together to form a ring. The amount of genetic material lost at the two ends of the chromosome may vary. As a result, an infant with very little absent genetic material may have no apparent symptoms while an infant with a significant part of the chromosomal ends missing may have many symptoms. When symptoms of the disorder are present, the affected infant may have mental retardation as well as abnormalities of the face, eyes, skeleton, and/or internal organs. | 250 | Chromosome 21 Ring |
nord_250_1 | Symptoms of Chromosome 21 Ring | The symptoms and findings associated with Chromosome 21 Ring may be extremely variable, depending upon the amount and location of genetic material lost from the 21st chromosome and other factors. As a result, some individuals with Chromosome 21 Ring may have few or no associated symptoms, whereas others may have severe physical abnormalities and mental retardation.In some cases, the features associated with Chromosome 21 Ring may resemble those seen in individuals with other disorders of chromosome 21, such as Chromosome 21 Monosomy or Down Syndrome (also known as Chromosome 21 Trisomy). (For further information on these chromosomal disorders, please see the “Causes” and “Related Disorders” sections of this report below.)Additional features have also been reported in association with Chromosome 21 Ring, such as growth delays, abnormally diminished muscle tone (hypotonia), and malformations of the head and facial (craniofacial) area. For example, craniofacial abnormalities may include an unusually small head (microcephaly) or improper development of midfacial regions due to failed division of certain brain regions during embryonic development (holoprosencephaly). (For further information, please use “holoprosencephaly” as your search term in the Rare Disease Database.) Eye abnormalities may also be present, such as defective development (dysgenesis) of certain regions near the front of the eye (anterior segment); dislocation of the lens; or incomplete development (hypoplasia) of the nerve (i.e., optic nerve) that transmits impulses from the nerve-rich innermost layer of the eye (retina) to the brain. The degree of potential visual impairment depends upon the severity and combination of eye abnormalities present. Reports suggest that some individuals with Chromosome 21 Ring may also have an increased predisposition to respiratory, sinus, or other forms of infection. In addition, in some cases, other physical abnormalities may be present, such as skeletal defects or malformations of certain internal organs (visceral anomalies). Although some individuals with Chromosome 21 Ring have normal intelligence, others may have varying levels of mental retardation. The disorder may also be characterized by delays in the acquisition of skills requiring the coordination of mental and physical activities (psychomotor retardation), including impaired speech and language skills. According to reports in the medical literature, individuals with Chromosome 21 Ring, including those without any apparent symptoms, may have an increased incidence of infertility or pregnancy loss. | Symptoms of Chromosome 21 Ring. The symptoms and findings associated with Chromosome 21 Ring may be extremely variable, depending upon the amount and location of genetic material lost from the 21st chromosome and other factors. As a result, some individuals with Chromosome 21 Ring may have few or no associated symptoms, whereas others may have severe physical abnormalities and mental retardation.In some cases, the features associated with Chromosome 21 Ring may resemble those seen in individuals with other disorders of chromosome 21, such as Chromosome 21 Monosomy or Down Syndrome (also known as Chromosome 21 Trisomy). (For further information on these chromosomal disorders, please see the “Causes” and “Related Disorders” sections of this report below.)Additional features have also been reported in association with Chromosome 21 Ring, such as growth delays, abnormally diminished muscle tone (hypotonia), and malformations of the head and facial (craniofacial) area. For example, craniofacial abnormalities may include an unusually small head (microcephaly) or improper development of midfacial regions due to failed division of certain brain regions during embryonic development (holoprosencephaly). (For further information, please use “holoprosencephaly” as your search term in the Rare Disease Database.) Eye abnormalities may also be present, such as defective development (dysgenesis) of certain regions near the front of the eye (anterior segment); dislocation of the lens; or incomplete development (hypoplasia) of the nerve (i.e., optic nerve) that transmits impulses from the nerve-rich innermost layer of the eye (retina) to the brain. The degree of potential visual impairment depends upon the severity and combination of eye abnormalities present. Reports suggest that some individuals with Chromosome 21 Ring may also have an increased predisposition to respiratory, sinus, or other forms of infection. In addition, in some cases, other physical abnormalities may be present, such as skeletal defects or malformations of certain internal organs (visceral anomalies). Although some individuals with Chromosome 21 Ring have normal intelligence, others may have varying levels of mental retardation. The disorder may also be characterized by delays in the acquisition of skills requiring the coordination of mental and physical activities (psychomotor retardation), including impaired speech and language skills. According to reports in the medical literature, individuals with Chromosome 21 Ring, including those without any apparent symptoms, may have an increased incidence of infertility or pregnancy loss. | 250 | Chromosome 21 Ring |
nord_250_2 | Causes of Chromosome 21 Ring | Chromosome 21 Ring results from loss (deletion) of genetic material from both ends of the 21st chromosome and joining of the ends to form a ring. Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p” and a long arm identified by the letter “q.” Chromosomes are further subdivided into bands that are numbered.In individuals with Chromosome 21 Ring, associated symptoms and findings may be extremely variable, depending upon the amount and location of genetic material lost from the 21st chromosome and other factors. If the ring chromosome replaces a normal 21st chromosome, symptoms may resemble those associated with Chromosome 21 Monosomy, a disorder characterized by deletion of all or a portion of the 21st chromosome. If some cells contain a Chromosome 21 Ring in addition to the normal chromosomal pair (mosaic trisomy), some features may be present that resemble those associated with Down Syndrome (also known as Chromosome 21 Trisomy). (For further information on these chromosomal disorders, please see the “Related Disorders” section of this report below.) Chromosome 21 Ring is usually caused by spontaneous or “de novo” errors very early during the development of the embryo. The parents of an affected child typically have normal chromosomes, and the probability of having another child with the chromosomal abnormality is low. However, there have been a few reported cases in which Chromosome 21 Ring was inherited from a parent. In such cases, theoretically, the risk of transmitting the chromosomal abnormality from parent to offspring may be 50 percent for each pregnancy. | Causes of Chromosome 21 Ring. Chromosome 21 Ring results from loss (deletion) of genetic material from both ends of the 21st chromosome and joining of the ends to form a ring. Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p” and a long arm identified by the letter “q.” Chromosomes are further subdivided into bands that are numbered.In individuals with Chromosome 21 Ring, associated symptoms and findings may be extremely variable, depending upon the amount and location of genetic material lost from the 21st chromosome and other factors. If the ring chromosome replaces a normal 21st chromosome, symptoms may resemble those associated with Chromosome 21 Monosomy, a disorder characterized by deletion of all or a portion of the 21st chromosome. If some cells contain a Chromosome 21 Ring in addition to the normal chromosomal pair (mosaic trisomy), some features may be present that resemble those associated with Down Syndrome (also known as Chromosome 21 Trisomy). (For further information on these chromosomal disorders, please see the “Related Disorders” section of this report below.) Chromosome 21 Ring is usually caused by spontaneous or “de novo” errors very early during the development of the embryo. The parents of an affected child typically have normal chromosomes, and the probability of having another child with the chromosomal abnormality is low. However, there have been a few reported cases in which Chromosome 21 Ring was inherited from a parent. In such cases, theoretically, the risk of transmitting the chromosomal abnormality from parent to offspring may be 50 percent for each pregnancy. | 250 | Chromosome 21 Ring |
nord_250_3 | Affects of Chromosome 21 Ring | Chromosome 21 Ring is a rare chromosomal disorder that appears to affect males and females in equal numbers. | Affects of Chromosome 21 Ring. Chromosome 21 Ring is a rare chromosomal disorder that appears to affect males and females in equal numbers. | 250 | Chromosome 21 Ring |
nord_250_4 | Related disorders of Chromosome 21 Ring | Symptoms of the following disorders may be similar to those of Chromosome 21 Ring. Comparisons may be useful for a differential diagnosis:Down Syndrome is a chromosomal disorder in which all or a portion of chromosome 21 appears three times (trisomy) rather than twice in cells of the body. Associated symptoms may vary greatly, depending on the length and location of the duplicated (trisomic) portion of chromosome 21 as well as the percentage of cells containing the abnormality. However, many affected infants may have low muscle tone (hypotonia), a poor startle (Moro) reflex, excessive flexibility of the joints, and distinctive malformations of the head and facial (craniofacial) area. Craniofacial abnormalities may include a short, small head (microbrachycephaly); upwardly slanting eyelid folds (palpebral fissures); a small nose with a depressed nasal bridge; a relatively flat facial profile; and excessive skin on the back of the neck. Down Syndrome may also be characterized by abnormalities of the extremities, short stature, mental retardation, hearing impairment, and/or structural malformations of the heart. In addition, those with the disorder may have an increased susceptibility to respiratory disease (e.g., pneumonia), other infectious diseases, and malignancies in which there is an increased proliferation of certain white blood cells (leukemia). (For further information, use “Down” or “trisomy 21” as your search term in the Rare Disease Database.)Chromosome 21 Monosomy is a chromosomal abnormality characterized by absence (deletion) of all or a portion of chromosome 21. In most cases, associated symptoms and findings are thought to result from deletion of all or a portion of the long arm (q) of the 21st chromosome. Such abnormalities may be extremely variable, depending upon the specific location of the chromosomal deletion. Associated findings may include delayed growth before birth (intrauterine growth retardation), failure to grow and gain weight at the expected rate during infancy (failure to thrive), severe mental retardation, respiratory and digestive abnormalities, joint dislocations, and/or episodes of uncontrolled electrical activity in the brain (seizures). Craniofacial malformations may also be present, such as an abnormally small head (microcephaly), downwardly slanting eyelid folds (palpebral fissures), a prominent nose, a small jaw (micrognathia), incomplete closure of the roof of the mouth (cleft palate), and/or an abnormal groove in the upper lip (cleft lip). Some affected individuals may also have additional malformations, such as abnormalities of the eyes, brain, kidneys, and/or other bodily regions.Other chromosomal disorders may have features similar to those associated with Chromosome 21 Ring. Chromosomal testing is necessary to confirm the specific chromosomal abnormality present. (For further information on such disorders, choose the name of the specific chromosomal disorder in question or use “chromosome” as your search term in the Rare Disease Database.) | Related disorders of Chromosome 21 Ring. Symptoms of the following disorders may be similar to those of Chromosome 21 Ring. Comparisons may be useful for a differential diagnosis:Down Syndrome is a chromosomal disorder in which all or a portion of chromosome 21 appears three times (trisomy) rather than twice in cells of the body. Associated symptoms may vary greatly, depending on the length and location of the duplicated (trisomic) portion of chromosome 21 as well as the percentage of cells containing the abnormality. However, many affected infants may have low muscle tone (hypotonia), a poor startle (Moro) reflex, excessive flexibility of the joints, and distinctive malformations of the head and facial (craniofacial) area. Craniofacial abnormalities may include a short, small head (microbrachycephaly); upwardly slanting eyelid folds (palpebral fissures); a small nose with a depressed nasal bridge; a relatively flat facial profile; and excessive skin on the back of the neck. Down Syndrome may also be characterized by abnormalities of the extremities, short stature, mental retardation, hearing impairment, and/or structural malformations of the heart. In addition, those with the disorder may have an increased susceptibility to respiratory disease (e.g., pneumonia), other infectious diseases, and malignancies in which there is an increased proliferation of certain white blood cells (leukemia). (For further information, use “Down” or “trisomy 21” as your search term in the Rare Disease Database.)Chromosome 21 Monosomy is a chromosomal abnormality characterized by absence (deletion) of all or a portion of chromosome 21. In most cases, associated symptoms and findings are thought to result from deletion of all or a portion of the long arm (q) of the 21st chromosome. Such abnormalities may be extremely variable, depending upon the specific location of the chromosomal deletion. Associated findings may include delayed growth before birth (intrauterine growth retardation), failure to grow and gain weight at the expected rate during infancy (failure to thrive), severe mental retardation, respiratory and digestive abnormalities, joint dislocations, and/or episodes of uncontrolled electrical activity in the brain (seizures). Craniofacial malformations may also be present, such as an abnormally small head (microcephaly), downwardly slanting eyelid folds (palpebral fissures), a prominent nose, a small jaw (micrognathia), incomplete closure of the roof of the mouth (cleft palate), and/or an abnormal groove in the upper lip (cleft lip). Some affected individuals may also have additional malformations, such as abnormalities of the eyes, brain, kidneys, and/or other bodily regions.Other chromosomal disorders may have features similar to those associated with Chromosome 21 Ring. Chromosomal testing is necessary to confirm the specific chromosomal abnormality present. (For further information on such disorders, choose the name of the specific chromosomal disorder in question or use “chromosome” as your search term in the Rare Disease Database.) | 250 | Chromosome 21 Ring |
nord_250_5 | Diagnosis of Chromosome 21 Ring | In some cases, a diagnosis of Chromosome 21 Ring may be suggested before birth (prenatally) by specialized tests such as ultrasound, amniocentesis, and/or chorionic villus sampling (CVS). Ultrasound studies may reveal characteristic findings that suggest a chromosomal disorder or other developmental abnormalities in the fetus. During amniocentesis, a sample of fluid that surrounds the developing fetus is removed and analyzed, whereas CVS involves the removal of tissue samples from a portion of the placenta. Chromosomal analysis performed on the fluid or tissue samples may reveal the presence of Chromosome 21 Ring.The diagnosis of Chromosome 21 Ring may be confirmed after birth (postnatally) based upon a thorough clinical evaluation, characteristic physical findings, and chromosomal analysis. In some cases, specialized testing may also be conducted to detect certain abnormalities that may be associated with the disorder. For example, in those with symptoms resembling those of Down Syndrome, careful monitoring and testing may be conducted to ensure early detection and prompt treatment of certain conditions potentially associated with Chromosome 21 Trisomy (e.g., congenital heart defects; certain infections; particular malignancies, such as leukemia; etc.). | Diagnosis of Chromosome 21 Ring. In some cases, a diagnosis of Chromosome 21 Ring may be suggested before birth (prenatally) by specialized tests such as ultrasound, amniocentesis, and/or chorionic villus sampling (CVS). Ultrasound studies may reveal characteristic findings that suggest a chromosomal disorder or other developmental abnormalities in the fetus. During amniocentesis, a sample of fluid that surrounds the developing fetus is removed and analyzed, whereas CVS involves the removal of tissue samples from a portion of the placenta. Chromosomal analysis performed on the fluid or tissue samples may reveal the presence of Chromosome 21 Ring.The diagnosis of Chromosome 21 Ring may be confirmed after birth (postnatally) based upon a thorough clinical evaluation, characteristic physical findings, and chromosomal analysis. In some cases, specialized testing may also be conducted to detect certain abnormalities that may be associated with the disorder. For example, in those with symptoms resembling those of Down Syndrome, careful monitoring and testing may be conducted to ensure early detection and prompt treatment of certain conditions potentially associated with Chromosome 21 Trisomy (e.g., congenital heart defects; certain infections; particular malignancies, such as leukemia; etc.). | 250 | Chromosome 21 Ring |
nord_250_6 | Therapies of Chromosome 21 Ring | TreatmentThe treatment of Chromosome 21 Ring is directed toward the specific symptoms that are apparent in each individual. Such treatment may require the coordinated efforts of a team of medical professionals who may need to systematically and comprehensively plan an affected child's treatment. These professionals may include pediatricians, surgeons, certain specialists, and/or other health care professionals.In some affected individuals, treatment may include surgical repair of certain craniofacial, skeletal, visceral, or other abnormalities potentially associated with the disorder. The surgical procedures performed will depend upon the severity of the anatomical abnormalities, their associated symptoms, and other factors.Treatment may also include measures to help prevent or aggressively treat infections. Other treatment is symptomatic and supportive.Early intervention may be important in ensuring that children with Chromosome 21 Ring reach their potential. Special services that may be beneficial include special education, speech therapy, and/or other medical, social, and/or vocational services. Genetic counseling will also be of benefit for individuals with Chromosome 21 Ring and their families. | Therapies of Chromosome 21 Ring. TreatmentThe treatment of Chromosome 21 Ring is directed toward the specific symptoms that are apparent in each individual. Such treatment may require the coordinated efforts of a team of medical professionals who may need to systematically and comprehensively plan an affected child's treatment. These professionals may include pediatricians, surgeons, certain specialists, and/or other health care professionals.In some affected individuals, treatment may include surgical repair of certain craniofacial, skeletal, visceral, or other abnormalities potentially associated with the disorder. The surgical procedures performed will depend upon the severity of the anatomical abnormalities, their associated symptoms, and other factors.Treatment may also include measures to help prevent or aggressively treat infections. Other treatment is symptomatic and supportive.Early intervention may be important in ensuring that children with Chromosome 21 Ring reach their potential. Special services that may be beneficial include special education, speech therapy, and/or other medical, social, and/or vocational services. Genetic counseling will also be of benefit for individuals with Chromosome 21 Ring and their families. | 250 | Chromosome 21 Ring |
nord_251_0 | Overview of Chromosome 22 Ring | Ring chromosome 22 is a rare genetic condition resulting when one chromosome 22 forms a circular, or ring, structure. The ring forms after loss (deletion) of genetic material from both the short arm and long arm of chromosome 22. The size of the deletion is variable, ranging from less than 100kb to greater than 10Mb. The clinical features are also variable but typically include developmental delay, poor muscle tone (hypotonia), severe speech delay, and minor physical features such as large ears and bulbous nose. The ring chromosome typically occurs de novo, meaning that it is a new event in the child. Chromosome studies and genetic counseling are indicated for parents of a child with a ring chromosome to determine if the ring was inherited and to provide important information about what the ring will mean for the development and medical care of their child. A critical consideration for individuals with ring 22 is the risk of developing neurofibromatosis type 2 (NF2), as discussed in the “Signs and Symptoms” and “Related Disorders”. | Overview of Chromosome 22 Ring. Ring chromosome 22 is a rare genetic condition resulting when one chromosome 22 forms a circular, or ring, structure. The ring forms after loss (deletion) of genetic material from both the short arm and long arm of chromosome 22. The size of the deletion is variable, ranging from less than 100kb to greater than 10Mb. The clinical features are also variable but typically include developmental delay, poor muscle tone (hypotonia), severe speech delay, and minor physical features such as large ears and bulbous nose. The ring chromosome typically occurs de novo, meaning that it is a new event in the child. Chromosome studies and genetic counseling are indicated for parents of a child with a ring chromosome to determine if the ring was inherited and to provide important information about what the ring will mean for the development and medical care of their child. A critical consideration for individuals with ring 22 is the risk of developing neurofibromatosis type 2 (NF2), as discussed in the “Signs and Symptoms” and “Related Disorders”. | 251 | Chromosome 22 Ring |
nord_251_1 | Symptoms of Chromosome 22 Ring | The first indication that a child has ring chromosome 22 may be poor muscle tone (hypotonia). An infant may have trouble feeding, holding his or her head up, and staying in a sitting position. As the child grows, other motor milestones such as crawling and walking will be delayed, and the child may exhibit poor coordination, lack of balance and an unsteady gait. Moderate to profound intellectual development is common, as is severely delayed or absent speech. Autism or autistic-like behavior is frequently seen. Mood disorders and other behavioral issues including aggression and hyperactivity have also been described.Physical features of ring chromosome 22 are mild. They include bulbous nasal tip, broad nasal bridge, large ears, and long eyelashes. Small head size (microcephaly) was reported as a common feature in early reports, but larger studies have found this to occur in less than 35% of individuals with ring 22. In about 10% of individuals brain imaging studies show abnormalities of the central nervous system including dilation of the ventricals, atrophy (decrease in size) of the cerebellum and cerebrum, large cisterna magnum, meningiomas and brain tumors. Meningiomas and brain tumors may be indicative of neurofibromatosis type 2, as described below.Phelan-McDermid syndrome (PMS) is a rare genetic condition that results from deletion of the distal long arm of chromosome 22. One of the mechanisms that lead to deletion of the distal long arm of chromosome 22 is ring chromosome formation. It has been estimated that 14 to 33% of individuals with PMS have ring 22. This is likely to be an underestimate because not all individuals with ring 22 report their diagnosis as PMS. In addition, not everyone who has been diagnosed with PMS by chromosomal microarray (CMA) have follow-up chromosome studies to determine if a ring chromosome is present (see “Diagnosis”). Most individuals with ring 22 have a deletion on the long arm of chromosome 22 defined as 22q13. This is the same deletion causing PMS. As expected, ring 22 and PMS share the same features: impaired intellectual development, delayed or absent speech, hypotonia, and autism or autistic-like behavior. The other subtle physical features also overlap. One difference is that growth delay is often reported in ring 22 but is not common in PMS. The growth delay in ring 22 has been attributed to the lack of stability of the ring chromosome.Individuals with ring 22 are at risk of developing neurofibromatosis type 2 (NF2). NF2 is a genetic condition characterized by the growth of non-cancerous tumors in the nervous system. The gene for NF2 is on the long arm of chromosome 22, proximal to the segment that is deleted in ring 22. As discussed in “Causes”, an individual with ring 22 may have some cells with monosomy 22 – one copy of chromosome 22. This results from the instability of the ring during cell division (mitosis). The cells with monosomy 22 will be distributed in different tissues throughout the body. This includes cells in the nervous system. Monosomy 22 is considered the “ first hit” or first event that can lead to NF2. If a cell in the nervous system undergoes a “second hit” – a pathogenic variant of the NF2 gene – neurofibromatosis type 2 will result. In NF2 tumors may occur along the nerve that carries information from the inner ear to the brain leading to hearing loss, ringing in the ears, and loss of balance. Since many individuals with ring 22 have limited speech, they may not be able to tell their parents or caregivers that they have these symptoms. Tumors can also occur elsewhere in the brain leading to additional complications. For this reason, individuals with ring 22 should be monitored for signs of NF2 beginning at age 10-12, as discussed in “Related Disorders”. | Symptoms of Chromosome 22 Ring. The first indication that a child has ring chromosome 22 may be poor muscle tone (hypotonia). An infant may have trouble feeding, holding his or her head up, and staying in a sitting position. As the child grows, other motor milestones such as crawling and walking will be delayed, and the child may exhibit poor coordination, lack of balance and an unsteady gait. Moderate to profound intellectual development is common, as is severely delayed or absent speech. Autism or autistic-like behavior is frequently seen. Mood disorders and other behavioral issues including aggression and hyperactivity have also been described.Physical features of ring chromosome 22 are mild. They include bulbous nasal tip, broad nasal bridge, large ears, and long eyelashes. Small head size (microcephaly) was reported as a common feature in early reports, but larger studies have found this to occur in less than 35% of individuals with ring 22. In about 10% of individuals brain imaging studies show abnormalities of the central nervous system including dilation of the ventricals, atrophy (decrease in size) of the cerebellum and cerebrum, large cisterna magnum, meningiomas and brain tumors. Meningiomas and brain tumors may be indicative of neurofibromatosis type 2, as described below.Phelan-McDermid syndrome (PMS) is a rare genetic condition that results from deletion of the distal long arm of chromosome 22. One of the mechanisms that lead to deletion of the distal long arm of chromosome 22 is ring chromosome formation. It has been estimated that 14 to 33% of individuals with PMS have ring 22. This is likely to be an underestimate because not all individuals with ring 22 report their diagnosis as PMS. In addition, not everyone who has been diagnosed with PMS by chromosomal microarray (CMA) have follow-up chromosome studies to determine if a ring chromosome is present (see “Diagnosis”). Most individuals with ring 22 have a deletion on the long arm of chromosome 22 defined as 22q13. This is the same deletion causing PMS. As expected, ring 22 and PMS share the same features: impaired intellectual development, delayed or absent speech, hypotonia, and autism or autistic-like behavior. The other subtle physical features also overlap. One difference is that growth delay is often reported in ring 22 but is not common in PMS. The growth delay in ring 22 has been attributed to the lack of stability of the ring chromosome.Individuals with ring 22 are at risk of developing neurofibromatosis type 2 (NF2). NF2 is a genetic condition characterized by the growth of non-cancerous tumors in the nervous system. The gene for NF2 is on the long arm of chromosome 22, proximal to the segment that is deleted in ring 22. As discussed in “Causes”, an individual with ring 22 may have some cells with monosomy 22 – one copy of chromosome 22. This results from the instability of the ring during cell division (mitosis). The cells with monosomy 22 will be distributed in different tissues throughout the body. This includes cells in the nervous system. Monosomy 22 is considered the “ first hit” or first event that can lead to NF2. If a cell in the nervous system undergoes a “second hit” – a pathogenic variant of the NF2 gene – neurofibromatosis type 2 will result. In NF2 tumors may occur along the nerve that carries information from the inner ear to the brain leading to hearing loss, ringing in the ears, and loss of balance. Since many individuals with ring 22 have limited speech, they may not be able to tell their parents or caregivers that they have these symptoms. Tumors can also occur elsewhere in the brain leading to additional complications. For this reason, individuals with ring 22 should be monitored for signs of NF2 beginning at age 10-12, as discussed in “Related Disorders”. | 251 | Chromosome 22 Ring |
nord_251_2 | Causes of Chromosome 22 Ring | Ring chromosome 22 is formed when genetic material is lost (deleted) from both ends of chromosome 22 and the broken ends fuse to form a circular chromosome, or ring. Chromosomes typically are rod-like structures that are found in the nucleus of our body cells. They are composed of genetic material (DNA) and proteins, and their function is to transmit genetic information from generation to generation. The normal chromosome number is 46, or 23 pairs of chromosomes, with one member of each pair inherited from our mother and the other from our father. The chromosomes numbered from 1 to 22, according to length from longest to shortest, are called autosomes. The remaining pair of chromosomes are the sex chromosomes which are XX in females and XY in males.Structurally, chromosomes have a long arm (q) and a short arm (p) which are separated by a constriction known as the centromere. The long arm is below the centromere and the short arm is above the centromere. Depending on the length of the chromosome arm, it is divided into regions, bands, and sub-bands. A class of chromosomes referred to as ‘acrocentric’ chromosomes have the centromere very near the top of the chromosome, making the short arms very short. Chromosome 22 is an acrocentric chromosome. Structures known as ‘satellites’ are attached to the short arms of acrocentric chromosomes by narrow ‘stalks’. The short arms, stalks and satellites are comprised of repetitive genetic material. Deletion of the repetitive material is not clinically significant when the ring chromosome forms because this material is present on the other acrocentric chromosomes (chromosomes 13, 14, 15, 21, and the second copy of chromosome 22). It is the loss of the distal long arm of chromosome 22 that leads to the clinical features of ring 22. In ring 22, the most common breakpoint for the deletion on the long arm (q) of chromosome 22 is in region 1, band 3 – written as 22q13.The clinical features associated with ring chromosome 22 are variable for numerous reasons. The amount of material deleted from the long arm of 22 is inconsistent from individual to individual, causing the features to vary. In addition, the ring 22 is unstable during the division of our body cells, called mitosis. At the beginning of mitosis, each chromosome consists of a single strand of chromatin which subsequently replicates to form two sister chromatids. Initially, the sister chromatids are paired and joined at the centromere. As mitosis proceeds, the sister chromatids separate. Mitosis ultimately results in the formation of two identical daughter cells. However, the ring chromosome is unstable during mitosis and may be excluded from the daughter cells. This results in daughter cells with only one copy of chromosome 22, called monosomy 22. Another feature of mitosis is sister chromatid exchange. While the sister chromatids are paired, they can exchange genetic material. In normally formed chromosomes, the sister chromatids are exchanging genetically identical sequences. With ring chromosomes, however, sister chromatid exchange can result in double rings, rings with two centromeres (dicentric), interlocked rings, or other structural anomalies. Partial duplication or triplication of the ring may resemble a genetic condition known as “cat-eye syndrome”. (Please see “Related Disorders” for more information on the cat-eye syndrome.)Ring 22 usually occurs as a novel, or de novo, event that is not inherited from one of the parents. Both parents have normal chromosomes and their risk of having a second child with ring 22 is no greater than the general population. In rare cases, one of the parents carries the ring chromosome in a small population of cells while most of the cells have a normal chromosome constitution. This phenomenon of having two genetically different populations of cells is called ‘chromosome mosaicism’. Because most of the parental cells do not carry the ring, the parent does not show features of ring 22. However, the parent has a risk of having a subsequent child with ring 22. Genetic counseling and chromosome analysis are recommended for the parents of a child with ring 22 to determine if one of the parents carries the ring and to provide accurate risk information.There have also been exceptional cases in which a parent carries a ring chromosome in all their cells. In these cases, the deletion of chromosome 22 is very small and the parent often shows mild features or no features of ring 22. Because of the instability of the ring as discussed previously in this section, the child may show more features of ring 22 than the parent. A parent with a ring 22 has a theoretical risk of 50% for passing the ring to the offspring. Genetic counseling is needed to discuss this risk. | Causes of Chromosome 22 Ring. Ring chromosome 22 is formed when genetic material is lost (deleted) from both ends of chromosome 22 and the broken ends fuse to form a circular chromosome, or ring. Chromosomes typically are rod-like structures that are found in the nucleus of our body cells. They are composed of genetic material (DNA) and proteins, and their function is to transmit genetic information from generation to generation. The normal chromosome number is 46, or 23 pairs of chromosomes, with one member of each pair inherited from our mother and the other from our father. The chromosomes numbered from 1 to 22, according to length from longest to shortest, are called autosomes. The remaining pair of chromosomes are the sex chromosomes which are XX in females and XY in males.Structurally, chromosomes have a long arm (q) and a short arm (p) which are separated by a constriction known as the centromere. The long arm is below the centromere and the short arm is above the centromere. Depending on the length of the chromosome arm, it is divided into regions, bands, and sub-bands. A class of chromosomes referred to as ‘acrocentric’ chromosomes have the centromere very near the top of the chromosome, making the short arms very short. Chromosome 22 is an acrocentric chromosome. Structures known as ‘satellites’ are attached to the short arms of acrocentric chromosomes by narrow ‘stalks’. The short arms, stalks and satellites are comprised of repetitive genetic material. Deletion of the repetitive material is not clinically significant when the ring chromosome forms because this material is present on the other acrocentric chromosomes (chromosomes 13, 14, 15, 21, and the second copy of chromosome 22). It is the loss of the distal long arm of chromosome 22 that leads to the clinical features of ring 22. In ring 22, the most common breakpoint for the deletion on the long arm (q) of chromosome 22 is in region 1, band 3 – written as 22q13.The clinical features associated with ring chromosome 22 are variable for numerous reasons. The amount of material deleted from the long arm of 22 is inconsistent from individual to individual, causing the features to vary. In addition, the ring 22 is unstable during the division of our body cells, called mitosis. At the beginning of mitosis, each chromosome consists of a single strand of chromatin which subsequently replicates to form two sister chromatids. Initially, the sister chromatids are paired and joined at the centromere. As mitosis proceeds, the sister chromatids separate. Mitosis ultimately results in the formation of two identical daughter cells. However, the ring chromosome is unstable during mitosis and may be excluded from the daughter cells. This results in daughter cells with only one copy of chromosome 22, called monosomy 22. Another feature of mitosis is sister chromatid exchange. While the sister chromatids are paired, they can exchange genetic material. In normally formed chromosomes, the sister chromatids are exchanging genetically identical sequences. With ring chromosomes, however, sister chromatid exchange can result in double rings, rings with two centromeres (dicentric), interlocked rings, or other structural anomalies. Partial duplication or triplication of the ring may resemble a genetic condition known as “cat-eye syndrome”. (Please see “Related Disorders” for more information on the cat-eye syndrome.)Ring 22 usually occurs as a novel, or de novo, event that is not inherited from one of the parents. Both parents have normal chromosomes and their risk of having a second child with ring 22 is no greater than the general population. In rare cases, one of the parents carries the ring chromosome in a small population of cells while most of the cells have a normal chromosome constitution. This phenomenon of having two genetically different populations of cells is called ‘chromosome mosaicism’. Because most of the parental cells do not carry the ring, the parent does not show features of ring 22. However, the parent has a risk of having a subsequent child with ring 22. Genetic counseling and chromosome analysis are recommended for the parents of a child with ring 22 to determine if one of the parents carries the ring and to provide accurate risk information.There have also been exceptional cases in which a parent carries a ring chromosome in all their cells. In these cases, the deletion of chromosome 22 is very small and the parent often shows mild features or no features of ring 22. Because of the instability of the ring as discussed previously in this section, the child may show more features of ring 22 than the parent. A parent with a ring 22 has a theoretical risk of 50% for passing the ring to the offspring. Genetic counseling is needed to discuss this risk. | 251 | Chromosome 22 Ring |
nord_251_3 | Affects of Chromosome 22 Ring | Ring chromosome 22 is a rare genetic condition with over 60 cases in the medical literature since 1968. Males and females are equally likely to be affected. | Affects of Chromosome 22 Ring. Ring chromosome 22 is a rare genetic condition with over 60 cases in the medical literature since 1968. Males and females are equally likely to be affected. | 251 | Chromosome 22 Ring |
nord_251_4 | Related disorders of Chromosome 22 Ring | Phelan-McDermid syndrome (PMS) is a rare genetic disorder resulting from a deletion of the distal long arm of chromosome 22 or from a pathogenic variant of the SHANK3 gene located at 22q13. PMS is characterized by mild to profound intellectual impairment, motor delay, absent to severely delayed speech, neonatal hypotonia, autism or autistic-like features, and mild physical features.PMS was initially known as 22q13 deletion syndrome. Most individuals with ring 22 also have a deletion of 22q13. Most deletions in both ring 22 and PMS result in loss of the SHANK3 gene. Sharing the same genetic loss (deletion of 22q13) means that most individuals with ring 22 have PMS. The converse is not true – most individuals with PMS have a simple deletion of chromosome 22. There is just one break on the long arm of chromosome 22 and the segment distal to the break is deleted. The chromosome does not form a ring in most people with PMS. Unbalanced translocations in which a segment of a different partner chromosome replaced the distal region of chromosome 22 also leads to PMS, as do other structural anomalies. As mentioned in “Signs and Symptoms”, about 14% of individuals with PMS report having a ring chromosome. This is likely to be an underestimate because some individuals with ring 22 do not report having PMS. The PMS DataHub (https://pmsf.org/datahub) is a site where families affected by ring 22 can share their medical, genetic, and medication history in a confidential manner. This allows them to compare their history with other families so they can make informed decisions about their child’s care. The site is also used by researchers, pharmaceutical companies, and others who are studying different aspects of deletion 22q13 and loss of the SHANK3 gene.Neurofibromatosis Type 2 (NF2) is a genetic disorder associated with the growth of noncancerous tumors in the nervous system. The gene for NF2 is on chromosome 22. In most cases, NF2 has an autosomal dominant inheritance pattern. This means that an individual is born with a pathogenic variant (mutation) of the NF2 gene in each cell. A second mutation occurs on the other copy of the NF2 gene sometime during that person’s lifetime. This is different from most autosomal dominant conditions in which a person born with a pathogenic variant of a gene will have the associated disorder. In NF2 the person is born with the first variant and almost always develops the second variant during their life. In about 50% of patients, the first variant present at birth is inherited from one parent and in the other 50% it is a de novo event.As discussed in “Signs and Symptoms”, individuals with ring 22 are at risk of developing NF2. Surveillance for symptoms of NF2 should begin between the ages of 10 and 12. A cranial MRI should be performed and continued annually until at least the fourth decade of life. A spinal MRI should be considered every 3 to 5 years, or as indicated if symptoms occur. Hearing evaluations, including brain stem auditory evoked response (BAER) testing, complete eye exams, and skin examinations should be performed annually. If a diagnosis of NF2 is made, the extent of the disease should be established by cranial MRI, hearing evaluation including BAER testing, eye evaluation, skin examination, and consideration of spinal MRI. The evaluation and treatment of individuals with NF2 may be best undertaken at an NF2 center experienced at managing this condition.Cat-eye syndrome is a rare genetic condition that typically results from the presence of 4 copies of the short arm and proximal long arm of chromosome 22 (partial tetrasomy). In exceptional cases, three copies of the proximal long arm of chromosome 22 (partial trisomy) have resulted in cat-eye syndrome. One of the features of cat-eye syndrome is a coloboma of the iris – a cleft in the iris below the pupil so that the elongated pupil looks like a cat’s eye. Other features include down-slanting eyes, small eyes (sometimes only one eye is affected), skin tag or pit in front of the outer ear (preauricular), abnormally placed anus, kidney (renal) defects, and heart defects.As mentioned in “Causes”, ring chromosomes are unstable in cell division and can undergo sister chromatid exchange leading to dicentric ring and to duplication or triplication of material. A unique case of a mosaic double dicentric ring has been described in a child with some features of cat-eye syndrome, which included right iris coloboma, right preauricular pit, broad nasal root, a heart defect, and a renal defect.Monosomy 22 is a non-viable condition that is diagnosed prenatally in rare cases. Mosaic monosomy 22 in the absence of ring chromosome is also extremely uncommon. Only four cases of live borns with mosaic monosomy 2 have been described. In these individuals monosomy 22 was present in less than 25% of cells from peripheral blood and/or skin samples. The children with mosaic monosomy were three years of age or younger. One infant who died at two days of age had an accompanying deletion of 22q13, consistent with PMS. The features of monosomy 22 overlap the features of ring 22 and PMS, as expected. None of the mosaic monsomies were confirmed by molecular genetic testing (See “Diagnosis”). Without confirmation, it is possible that full monosomies actual represent partial monosomies resulting from cryptic translocations that are too subtle to be detected by chromosome studies. | Related disorders of Chromosome 22 Ring. Phelan-McDermid syndrome (PMS) is a rare genetic disorder resulting from a deletion of the distal long arm of chromosome 22 or from a pathogenic variant of the SHANK3 gene located at 22q13. PMS is characterized by mild to profound intellectual impairment, motor delay, absent to severely delayed speech, neonatal hypotonia, autism or autistic-like features, and mild physical features.PMS was initially known as 22q13 deletion syndrome. Most individuals with ring 22 also have a deletion of 22q13. Most deletions in both ring 22 and PMS result in loss of the SHANK3 gene. Sharing the same genetic loss (deletion of 22q13) means that most individuals with ring 22 have PMS. The converse is not true – most individuals with PMS have a simple deletion of chromosome 22. There is just one break on the long arm of chromosome 22 and the segment distal to the break is deleted. The chromosome does not form a ring in most people with PMS. Unbalanced translocations in which a segment of a different partner chromosome replaced the distal region of chromosome 22 also leads to PMS, as do other structural anomalies. As mentioned in “Signs and Symptoms”, about 14% of individuals with PMS report having a ring chromosome. This is likely to be an underestimate because some individuals with ring 22 do not report having PMS. The PMS DataHub (https://pmsf.org/datahub) is a site where families affected by ring 22 can share their medical, genetic, and medication history in a confidential manner. This allows them to compare their history with other families so they can make informed decisions about their child’s care. The site is also used by researchers, pharmaceutical companies, and others who are studying different aspects of deletion 22q13 and loss of the SHANK3 gene.Neurofibromatosis Type 2 (NF2) is a genetic disorder associated with the growth of noncancerous tumors in the nervous system. The gene for NF2 is on chromosome 22. In most cases, NF2 has an autosomal dominant inheritance pattern. This means that an individual is born with a pathogenic variant (mutation) of the NF2 gene in each cell. A second mutation occurs on the other copy of the NF2 gene sometime during that person’s lifetime. This is different from most autosomal dominant conditions in which a person born with a pathogenic variant of a gene will have the associated disorder. In NF2 the person is born with the first variant and almost always develops the second variant during their life. In about 50% of patients, the first variant present at birth is inherited from one parent and in the other 50% it is a de novo event.As discussed in “Signs and Symptoms”, individuals with ring 22 are at risk of developing NF2. Surveillance for symptoms of NF2 should begin between the ages of 10 and 12. A cranial MRI should be performed and continued annually until at least the fourth decade of life. A spinal MRI should be considered every 3 to 5 years, or as indicated if symptoms occur. Hearing evaluations, including brain stem auditory evoked response (BAER) testing, complete eye exams, and skin examinations should be performed annually. If a diagnosis of NF2 is made, the extent of the disease should be established by cranial MRI, hearing evaluation including BAER testing, eye evaluation, skin examination, and consideration of spinal MRI. The evaluation and treatment of individuals with NF2 may be best undertaken at an NF2 center experienced at managing this condition.Cat-eye syndrome is a rare genetic condition that typically results from the presence of 4 copies of the short arm and proximal long arm of chromosome 22 (partial tetrasomy). In exceptional cases, three copies of the proximal long arm of chromosome 22 (partial trisomy) have resulted in cat-eye syndrome. One of the features of cat-eye syndrome is a coloboma of the iris – a cleft in the iris below the pupil so that the elongated pupil looks like a cat’s eye. Other features include down-slanting eyes, small eyes (sometimes only one eye is affected), skin tag or pit in front of the outer ear (preauricular), abnormally placed anus, kidney (renal) defects, and heart defects.As mentioned in “Causes”, ring chromosomes are unstable in cell division and can undergo sister chromatid exchange leading to dicentric ring and to duplication or triplication of material. A unique case of a mosaic double dicentric ring has been described in a child with some features of cat-eye syndrome, which included right iris coloboma, right preauricular pit, broad nasal root, a heart defect, and a renal defect.Monosomy 22 is a non-viable condition that is diagnosed prenatally in rare cases. Mosaic monosomy 22 in the absence of ring chromosome is also extremely uncommon. Only four cases of live borns with mosaic monosomy 2 have been described. In these individuals monosomy 22 was present in less than 25% of cells from peripheral blood and/or skin samples. The children with mosaic monosomy were three years of age or younger. One infant who died at two days of age had an accompanying deletion of 22q13, consistent with PMS. The features of monosomy 22 overlap the features of ring 22 and PMS, as expected. None of the mosaic monsomies were confirmed by molecular genetic testing (See “Diagnosis”). Without confirmation, it is possible that full monosomies actual represent partial monosomies resulting from cryptic translocations that are too subtle to be detected by chromosome studies. | 251 | Chromosome 22 Ring |
nord_251_5 | Diagnosis of Chromosome 22 Ring | There are two common methods now used when a chromosome disorder is suspected. One is chromosomal microarray (CMA) and the other is next-generation sequencing (NGS). These are called molecular genetic tests because they diagnose conditions at the level of the DNA molecule. Two techniques are sometimes used to confirm the results of CMA and NGS. One is FISH (fluorescence in situ hybridization) which is a targeted method to determine if a segment of DNA is present or absent. FISH can be performed on uncultured cells or on chromosomes derived from cultured cells. The other technique is chromosome analysis which relies on counting the number of chromosomes in a subset of cells and examining chromosome structure to determine if an abnormality is present. Chromosome analysis (sometimes called karyotyping) is the only method that permits visualization of the ring chromosome at the microscope.Both CMA and NGS can show deletions at a much higher resolution than chromosome analysis. They are not targeted techniques like FISH and can look at all the genetic material simultaneously. Both techniques can determine how much genetic material has been lost. While CMA and NGS will detect that a segment of chromosome 22 is deleted, they will not show that a ring chromosome is present. This is critical information because individuals with ring 22 are at increased risk of developing NF2 while individuals with a simple deletion of chromosome 22 are not. It is important that anyone diagnosed with a deletion of 22q13 by CMA or NGS have a follow-up chromosome study to determine if a ring chromosome is present.It is a frequent misunderstanding that if NGS does not show a pathogenic variant of the NF2 gene, an individual with ring 22 is not at risk for NF2. This is wrong. The mechanism for developing NF2 in ring 22 does not rely on the presence of a pathogenic variant of NF2. It is a two-hit phenomenon as described in “Signs and Symptoms”. The presence of the ring is the first hit. An individual with ring 22 is at an increased risk of NF2 despite the absence of a pathogenic variant of the NF2 gene. The second hit could develop at any time during the lifetime of an individual with ring 22. In a survey of individuals with PMS and ring 22, the average age for diagnosis of NF2 was 25 years. Surveillance for symptoms of NF2 is essential in people with ring 22. Recommended surveillance is described in “Related Disorders”.CMA, NGS, and chromosome analysis can be performed before birth or after birth. Before birth (prenatally), a fetal ultrasound showing intrauterine growth delay, decreased fetal movements, or fetal structural anomalies may prompt genetic studies. The studies can be performed on chorionic villi or cells from amniotic fluid. Chorionic villus sampling tests a sample of placental tissue between 10 to 12 weeks of pregnancy. Amniocentesis is performed between 16 and 18 weeks of pregnancy by obtaining a sample of the fluid that surrounds the fetus. Fetal cells floating in the amniotic fluid are studied. After birth (postnatally), genetic studies can be performed on a blood sample from an individual suspected of having a genetic condition. | Diagnosis of Chromosome 22 Ring. There are two common methods now used when a chromosome disorder is suspected. One is chromosomal microarray (CMA) and the other is next-generation sequencing (NGS). These are called molecular genetic tests because they diagnose conditions at the level of the DNA molecule. Two techniques are sometimes used to confirm the results of CMA and NGS. One is FISH (fluorescence in situ hybridization) which is a targeted method to determine if a segment of DNA is present or absent. FISH can be performed on uncultured cells or on chromosomes derived from cultured cells. The other technique is chromosome analysis which relies on counting the number of chromosomes in a subset of cells and examining chromosome structure to determine if an abnormality is present. Chromosome analysis (sometimes called karyotyping) is the only method that permits visualization of the ring chromosome at the microscope.Both CMA and NGS can show deletions at a much higher resolution than chromosome analysis. They are not targeted techniques like FISH and can look at all the genetic material simultaneously. Both techniques can determine how much genetic material has been lost. While CMA and NGS will detect that a segment of chromosome 22 is deleted, they will not show that a ring chromosome is present. This is critical information because individuals with ring 22 are at increased risk of developing NF2 while individuals with a simple deletion of chromosome 22 are not. It is important that anyone diagnosed with a deletion of 22q13 by CMA or NGS have a follow-up chromosome study to determine if a ring chromosome is present.It is a frequent misunderstanding that if NGS does not show a pathogenic variant of the NF2 gene, an individual with ring 22 is not at risk for NF2. This is wrong. The mechanism for developing NF2 in ring 22 does not rely on the presence of a pathogenic variant of NF2. It is a two-hit phenomenon as described in “Signs and Symptoms”. The presence of the ring is the first hit. An individual with ring 22 is at an increased risk of NF2 despite the absence of a pathogenic variant of the NF2 gene. The second hit could develop at any time during the lifetime of an individual with ring 22. In a survey of individuals with PMS and ring 22, the average age for diagnosis of NF2 was 25 years. Surveillance for symptoms of NF2 is essential in people with ring 22. Recommended surveillance is described in “Related Disorders”.CMA, NGS, and chromosome analysis can be performed before birth or after birth. Before birth (prenatally), a fetal ultrasound showing intrauterine growth delay, decreased fetal movements, or fetal structural anomalies may prompt genetic studies. The studies can be performed on chorionic villi or cells from amniotic fluid. Chorionic villus sampling tests a sample of placental tissue between 10 to 12 weeks of pregnancy. Amniocentesis is performed between 16 and 18 weeks of pregnancy by obtaining a sample of the fluid that surrounds the fetus. Fetal cells floating in the amniotic fluid are studied. After birth (postnatally), genetic studies can be performed on a blood sample from an individual suspected of having a genetic condition. | 251 | Chromosome 22 Ring |
nord_251_6 | Therapies of Chromosome 22 Ring | Therapies should be designed to address the needs of each individual. Early intervention programs are available for babies and young children with developmental delay and should be accessed by their families. These may include physical therapy, occupational therapy, speech therapy, and other therapies as the child develops. Behavior therapies may be more intense in children with autism or autistic-like features. Adaptive sports, such as swimming and horseback riding, may help improve muscle tone, coordination, and balance.Treatments should also be directed to the child’s needs. Since most of the children have restricted communication skills, the parents and caregivers must be particularly vigilant to determine if there are any changes in the individual’s behavior or appearance that could indicate a developing health issue. In children with known medical problems, specialists should be consulted to address the problem. For example, a pediatric cardiologist for a child with a heart defect or a neurologist for a child with persistent hypotonia.A clinical geneticist and a genetic counselor should be consulted by a family affected by the presence of a ring chromosome. The continued care of the individual will require a team approach. In addition to routine pediatric or primary care visits, hearing and eye evaluations, skin examinations, neurologic assessments will be needed. Other specialists and health care professionals may be required depending on the medical requirement of the individual with ring 22. In those diagnosed with NF2, consultation at a center experienced in treating NF2 is recommended. | Therapies of Chromosome 22 Ring. Therapies should be designed to address the needs of each individual. Early intervention programs are available for babies and young children with developmental delay and should be accessed by their families. These may include physical therapy, occupational therapy, speech therapy, and other therapies as the child develops. Behavior therapies may be more intense in children with autism or autistic-like features. Adaptive sports, such as swimming and horseback riding, may help improve muscle tone, coordination, and balance.Treatments should also be directed to the child’s needs. Since most of the children have restricted communication skills, the parents and caregivers must be particularly vigilant to determine if there are any changes in the individual’s behavior or appearance that could indicate a developing health issue. In children with known medical problems, specialists should be consulted to address the problem. For example, a pediatric cardiologist for a child with a heart defect or a neurologist for a child with persistent hypotonia.A clinical geneticist and a genetic counselor should be consulted by a family affected by the presence of a ring chromosome. The continued care of the individual will require a team approach. In addition to routine pediatric or primary care visits, hearing and eye evaluations, skin examinations, neurologic assessments will be needed. Other specialists and health care professionals may be required depending on the medical requirement of the individual with ring 22. In those diagnosed with NF2, consultation at a center experienced in treating NF2 is recommended. | 251 | Chromosome 22 Ring |
nord_252_0 | Overview of Chromosome 22q11.2 Deletion Syndrome | SummaryChromosome 22q11.2 deletion syndrome (22q11.2DS) is a disorder caused by a small piece of chromosome 22 missing. 22q11.2DS is associated with a range of problems including: congenital heart disease, palate abnormalities, immune system dysfunction including autoimmune disease, low calcium (hypocalcemia) and other endocrine abnormalities such as thyroid problems and growth hormone deficiency, gastrointestinal problems, feeding difficulties, kidney abnormalities, hearing loss, seizures, skeletal abnormalities, minor facial differences, and learning and behavioral differences. The symptoms of this condition are extremely variable, even among members of the same family.IntroductionA number of separately described diagnoses including DiGeorge syndrome (DGS), velocardiofacial syndrome (VCFS), conotruncal anomaly face syndrome (CTAF), autosomal dominant OpitzG/BBB syndrome and Cayler Cardiofacial syndrome were all originally thought to be separate disorders before a deletion on chromosome 22q was identified in individuals affected with all of these conditions. | Overview of Chromosome 22q11.2 Deletion Syndrome. SummaryChromosome 22q11.2 deletion syndrome (22q11.2DS) is a disorder caused by a small piece of chromosome 22 missing. 22q11.2DS is associated with a range of problems including: congenital heart disease, palate abnormalities, immune system dysfunction including autoimmune disease, low calcium (hypocalcemia) and other endocrine abnormalities such as thyroid problems and growth hormone deficiency, gastrointestinal problems, feeding difficulties, kidney abnormalities, hearing loss, seizures, skeletal abnormalities, minor facial differences, and learning and behavioral differences. The symptoms of this condition are extremely variable, even among members of the same family.IntroductionA number of separately described diagnoses including DiGeorge syndrome (DGS), velocardiofacial syndrome (VCFS), conotruncal anomaly face syndrome (CTAF), autosomal dominant OpitzG/BBB syndrome and Cayler Cardiofacial syndrome were all originally thought to be separate disorders before a deletion on chromosome 22q was identified in individuals affected with all of these conditions. | 252 | Chromosome 22q11.2 Deletion Syndrome |
nord_252_1 | Symptoms of Chromosome 22q11.2 Deletion Syndrome | Disorders with more than one identifying feature are called syndromes. 22q11.2DS has numerous features associated with it, not all of which will be present in every affected individual.Some of the common features associated with this syndrome include cleft palate, abnormalities of the heart, developmental delays and learning disabilities, psychiatric disorders, and distinct physical features.Individuals with 22q11.2DS typically have a mild form of cleft palate. The lobe in the middle of the back of the soft palate (uvula) is split and there is a thin union of the two halves of the palate in the middle with a mucous covering on the rear portion of the mouth. The muscles under the soft palate do not fuse together and a notch can be felt where the hard and soft palates meet. This notch replaces the back spine of the palate. Abnormalities of the heart associated with this syndrome often include conotruncal heart defects, or malformations of the cardiac outflow tract. These may include the following:• Tetralogy of Fallot, a congenital abnormality in which there is obstruction in the outflow from the right ventricle of the heart to the lungs, with an enlarged right ventricle and a displaced aorta that receives blood from both the right and left ventricles. (For more information on this disorder choose “Tetralogy of Fallot” as your search term in the Rare Disease Database).• Truncus arteriosus, in which there is only a single outflow vessel instead of the typical two outflow vessels (pulmonary artery and aorta)• Interrupted aortic arch type B, a heart defect in which the aorta does not completely develop, thus resulting in an incomplete, or “interrupted” aortic arch• Ventricular septal defect, when the wall that separates the right and left chambers of the heart which receive blood and then force it back into the arteries does not form properlyAdditional heart abnormalities may include differences in the structure of the aortic arch (right aortic arch, vascular ring).Developmental delays are common among children with 22q11.2DS. While difficulties with gross and fine motor skills are not unusual, the majority of children will demonstrate a significant delay in the development of language (70% will have minimal words by 24 months of age). Mild intellectual delay or learning disability is present in the majority of individuals with 22q11.2DS, with the average IQ around 70. The majority of individuals with 22q11.2DS will have an IQ in the range of 55-85 (general population average is 100). Problems with abstraction and comprehension in reading and math are usually apparent at school age. Severe intellectual disability is less frequent but may also be present with this syndrome.Psychiatric disorders in individuals with 22q11.2DS include a higher prevalence of anxiety, attention-deficit disorder, and autism spectrum disorders. About one quarter of patients with 22q11.2DS are diagnosed with schizophrenia, which typically presents in late-adolescence. Clinical studies have shown that individuals with 22q11.2DS are about 25 times more likely than the general population to develop schizophrenic symptoms. However, the manifestation of schizophrenia in individuals with 22q11.2DS does not differ from that of the general population in regard to signs, symptoms, and treatment.Distinct physical features sometimes associated with the syndrome include loss of muscle tone (hypotonia), small slender stature, tapered hands and fingers, small head circumference (microcephaly), recessed jaw (retrognathia), tubular nose, flat cheeks, long upper jaw, long vertical groove in the middle of the upper lip (philtrum), blue coloring under the eyes, small outer ears, thick outer rims of the ear, two different sized ears and nasal sounding speech secondary to cleft palate.Some (but not all) of the following additional symptoms may be present in patients with 22q11.2DS:• An absent or underdeveloped thymus causing an insufficient production of antibodies• Deficiency of calcium in the blood (hypocalcemia)• Problems with thyroid function and growth hormone deficiency• Gastrointestinal difficulties including gastroesophageal reflux, chronic constipation, feeding difficulties, and dysmotility• Curvature of the spine (scoliosis)• Seizures and differences in the structure of the brain• Hearing loss• Eye abnormalities such as clouding of the lens of the eye or its surrounding membrane obstructing the passage of light (cataract), abnormal smallness of one or both eyeballs (microphthalmia), and twisted vessels in the optic disc• Rupture or protrusion in the groin or central abdominal region (inguinal or umbilical hernia)• Failure of the testes to descend into the scrotum in males (cryptorchidism)• Differences in the structure of the kidneys• Absent or small adenoids and absent or small tonsils.In addition, newborn children may have obstructed breathing due to the recessed jaw and loss of muscle tone in the throat area. | Symptoms of Chromosome 22q11.2 Deletion Syndrome. Disorders with more than one identifying feature are called syndromes. 22q11.2DS has numerous features associated with it, not all of which will be present in every affected individual.Some of the common features associated with this syndrome include cleft palate, abnormalities of the heart, developmental delays and learning disabilities, psychiatric disorders, and distinct physical features.Individuals with 22q11.2DS typically have a mild form of cleft palate. The lobe in the middle of the back of the soft palate (uvula) is split and there is a thin union of the two halves of the palate in the middle with a mucous covering on the rear portion of the mouth. The muscles under the soft palate do not fuse together and a notch can be felt where the hard and soft palates meet. This notch replaces the back spine of the palate. Abnormalities of the heart associated with this syndrome often include conotruncal heart defects, or malformations of the cardiac outflow tract. These may include the following:• Tetralogy of Fallot, a congenital abnormality in which there is obstruction in the outflow from the right ventricle of the heart to the lungs, with an enlarged right ventricle and a displaced aorta that receives blood from both the right and left ventricles. (For more information on this disorder choose “Tetralogy of Fallot” as your search term in the Rare Disease Database).• Truncus arteriosus, in which there is only a single outflow vessel instead of the typical two outflow vessels (pulmonary artery and aorta)• Interrupted aortic arch type B, a heart defect in which the aorta does not completely develop, thus resulting in an incomplete, or “interrupted” aortic arch• Ventricular septal defect, when the wall that separates the right and left chambers of the heart which receive blood and then force it back into the arteries does not form properlyAdditional heart abnormalities may include differences in the structure of the aortic arch (right aortic arch, vascular ring).Developmental delays are common among children with 22q11.2DS. While difficulties with gross and fine motor skills are not unusual, the majority of children will demonstrate a significant delay in the development of language (70% will have minimal words by 24 months of age). Mild intellectual delay or learning disability is present in the majority of individuals with 22q11.2DS, with the average IQ around 70. The majority of individuals with 22q11.2DS will have an IQ in the range of 55-85 (general population average is 100). Problems with abstraction and comprehension in reading and math are usually apparent at school age. Severe intellectual disability is less frequent but may also be present with this syndrome.Psychiatric disorders in individuals with 22q11.2DS include a higher prevalence of anxiety, attention-deficit disorder, and autism spectrum disorders. About one quarter of patients with 22q11.2DS are diagnosed with schizophrenia, which typically presents in late-adolescence. Clinical studies have shown that individuals with 22q11.2DS are about 25 times more likely than the general population to develop schizophrenic symptoms. However, the manifestation of schizophrenia in individuals with 22q11.2DS does not differ from that of the general population in regard to signs, symptoms, and treatment.Distinct physical features sometimes associated with the syndrome include loss of muscle tone (hypotonia), small slender stature, tapered hands and fingers, small head circumference (microcephaly), recessed jaw (retrognathia), tubular nose, flat cheeks, long upper jaw, long vertical groove in the middle of the upper lip (philtrum), blue coloring under the eyes, small outer ears, thick outer rims of the ear, two different sized ears and nasal sounding speech secondary to cleft palate.Some (but not all) of the following additional symptoms may be present in patients with 22q11.2DS:• An absent or underdeveloped thymus causing an insufficient production of antibodies• Deficiency of calcium in the blood (hypocalcemia)• Problems with thyroid function and growth hormone deficiency• Gastrointestinal difficulties including gastroesophageal reflux, chronic constipation, feeding difficulties, and dysmotility• Curvature of the spine (scoliosis)• Seizures and differences in the structure of the brain• Hearing loss• Eye abnormalities such as clouding of the lens of the eye or its surrounding membrane obstructing the passage of light (cataract), abnormal smallness of one or both eyeballs (microphthalmia), and twisted vessels in the optic disc• Rupture or protrusion in the groin or central abdominal region (inguinal or umbilical hernia)• Failure of the testes to descend into the scrotum in males (cryptorchidism)• Differences in the structure of the kidneys• Absent or small adenoids and absent or small tonsils.In addition, newborn children may have obstructed breathing due to the recessed jaw and loss of muscle tone in the throat area. | 252 | Chromosome 22q11.2 Deletion Syndrome |
nord_252_2 | Causes of Chromosome 22q11.2 Deletion Syndrome | Individuals with 22q11.2DS are missing a small part of chromosome 22. The deletion occurs at a specific location on the long arm (q arm) of chromosome 22 (region 22q11) and often includes a deletion of genes in the DiGeorge chromosomal region (DGCR). The majority of individuals (85%) have a common, standard-size deletion of approximately 3 megabases (Mb). However, 15% of individuals with 22q11.2DS have a deletion of a smaller size, often referred to as “nested” or “distal” deletions. These individuals present with nearly the same spectrum of findings as those individuals with the standard deletion.Chromosomes, which are present in the nucleus of human cells, carry the genetic information for each individual. Human body cells normally have 46 chromosomes. Pairs of human chromosomes are numbered from 1 through 22 (from the largest to the smallest) and the sex chromosomes are designated X and Y. Males have one X and one Y chromosome and females have two X chromosomes. Each chromosome has a short arm designated “p” and a long arm designated “q”. Chromosomes are further sub-divided into many bands that are numbered. For example, “chromosome 22q11” refers to band 11 on the long arm of chromosome 22. The numbered bands specify the location of the thousands of genes that are present on each chromosome.22q11.2DS is considered a contiguous deletion syndrome where many genes are missing on one chromosome and where a person with the deletion can pass it on to his or her children. The deletion occurs as a new abnormality in 93% of those affected and is inherited from a parent in 7% of those affected. The risk of passing the deletion from an affected individual to offspring is 50% for each pregnancy. The risk is the same for males and females. | Causes of Chromosome 22q11.2 Deletion Syndrome. Individuals with 22q11.2DS are missing a small part of chromosome 22. The deletion occurs at a specific location on the long arm (q arm) of chromosome 22 (region 22q11) and often includes a deletion of genes in the DiGeorge chromosomal region (DGCR). The majority of individuals (85%) have a common, standard-size deletion of approximately 3 megabases (Mb). However, 15% of individuals with 22q11.2DS have a deletion of a smaller size, often referred to as “nested” or “distal” deletions. These individuals present with nearly the same spectrum of findings as those individuals with the standard deletion.Chromosomes, which are present in the nucleus of human cells, carry the genetic information for each individual. Human body cells normally have 46 chromosomes. Pairs of human chromosomes are numbered from 1 through 22 (from the largest to the smallest) and the sex chromosomes are designated X and Y. Males have one X and one Y chromosome and females have two X chromosomes. Each chromosome has a short arm designated “p” and a long arm designated “q”. Chromosomes are further sub-divided into many bands that are numbered. For example, “chromosome 22q11” refers to band 11 on the long arm of chromosome 22. The numbered bands specify the location of the thousands of genes that are present on each chromosome.22q11.2DS is considered a contiguous deletion syndrome where many genes are missing on one chromosome and where a person with the deletion can pass it on to his or her children. The deletion occurs as a new abnormality in 93% of those affected and is inherited from a parent in 7% of those affected. The risk of passing the deletion from an affected individual to offspring is 50% for each pregnancy. The risk is the same for males and females. | 252 | Chromosome 22q11.2 Deletion Syndrome |
nord_252_3 | Affects of Chromosome 22q11.2 Deletion Syndrome | The prevalence of 22q11.2DS has been estimated to be approximately 1/3000 to 1/6,000 live births. These numbers may well be higher due to the variability of the condition, difficulty in properly diagnosing, and lack of newborn screening. | Affects of Chromosome 22q11.2 Deletion Syndrome. The prevalence of 22q11.2DS has been estimated to be approximately 1/3000 to 1/6,000 live births. These numbers may well be higher due to the variability of the condition, difficulty in properly diagnosing, and lack of newborn screening. | 252 | Chromosome 22q11.2 Deletion Syndrome |
nord_252_4 | Related disorders of Chromosome 22q11.2 Deletion Syndrome | Symptoms of the following disorders can be similar to those of 22q11.2DS. Comparisons may be useful for a differential diagnosis:Smith-Lemli-Opitz syndrome (SLOS) is a variable genetic disorder that is characterized by slow growth before and after birth, small head (microcephaly), mild to moderate intellectual disability and multiple birth defects including cleft palate, heart defects, fused second and third toes, extra fingers and toes and underdeveloped external genitals in males. The severity of SLOS varies greatly in affected individuals, even in the same family, and some have normal development and only minor birth defects. SLOS is caused by a deficiency in the enzyme 7-dehydrocholesterol reductase that results in an abnormality in cholesterol metabolism. SLOS is inherited as an autosomal recessive genetic disorder. (For more information on this disorder choose “SLOS” as your search term in the Rare Disease Database.)Alagille syndrome is a genetic liver disorder usually present at birth. It is characterized by insufficient passage of bile due to a lower than normal number of bile ducts inside the liver. In some cases, the child may be born with no bile ducts. Major symptoms include prolonged yellow skin discoloration (jaundice), eye and heart structure anomalies, abnormally shaped vertebrae of the spine, compression of nerve space inside the lower spine, an absence of deep tendon reflexes, mental deficiency, kidney (renal) abnormalities, and pancreatic insufficiency. (For more information on this disorder choose “Alagille” as your search term in the Rare Disease Database.)VACTERL association is a nonrandom association of birth defects that affects multiple organ systems. The term VACTERL is an acronym with each letter representing the first letter of one of the more common findings seen in affected children: (V) = vertebral abnormalities; (A) = anal atresia; (C) = cardiac (heart) defects; (T) = tracheoesophageal fistula; (E) = esophageal atresia; (R) = renal (kidney) abnormalities; (L) = limb abnormalities. In addition, affected children may also exhibit growth deficiencies and failure to gain weight and grow at the expected rate (failure to thrive). In some cases, the acronym VATER association is used. Some researchers have added an (S) to the VACTERL or VATER acronym to represent a single umbilical artery instead of the normal two. Intelligence is usually normal. The cause of VACTERL association is unknown. (For more information on this disorder choose “VACTERL” as your search term in the Rare Disease Database.)Oculo-auriculo-vertebral spectrum (OAVS) refers to three rare disorders that many clinicians believe to be intimately related to one another and which represent the range of severity of the same disorder. Oculo-auriculo-vertebral disorder (OAVD) is the mildest form of the disorder, while Goldenhar syndrome is the most severe form. Hemifacial microsomia appears to be an intermediate form. The disorder is characterized by a wide spectrum of symptoms and physical features that may vary greatly in severity from person to person. However, such abnormalities tend to involve the cheekbones, jaw, mouth, ears, eyes, and/or bones of the spinal column (vertebrae). In most cases OAVS appears to occur randomly, with no apparent cause (sporadic). However, in some cases, family histories suggest autosomal dominant or recessive inheritance. In addition, some researchers suggest that the disorder may be caused by the interaction of many genes, possibly in combination with environmental factors (multifactorial inheritance). (For more information on this disorder choose “oculo-auriculo-vertebral” as your search term in the Rare Disease Database.)CHARGE syndrome is a disorder that affects many areas of the body. CHARGE is an abbreviation for several of the features common in the disorder: coloboma, heart defects, atresia choanae (also known as choanal atresia), growth delay, genital abnormalities and ear abnormalities. The pattern of malformations varies among individuals with this disorder, and the multiple health problems can be life-threatening in infancy.Kabuki syndrome is a rare, multisystem disorder characterized by multiple abnormalities including distinctive facial features, growth delays, varying degrees of intellectual disability, skeletal abnormalities and short stature. A wide variety of additional symptoms affecting multiple different organ systems can potentially occur. | Related disorders of Chromosome 22q11.2 Deletion Syndrome. Symptoms of the following disorders can be similar to those of 22q11.2DS. Comparisons may be useful for a differential diagnosis:Smith-Lemli-Opitz syndrome (SLOS) is a variable genetic disorder that is characterized by slow growth before and after birth, small head (microcephaly), mild to moderate intellectual disability and multiple birth defects including cleft palate, heart defects, fused second and third toes, extra fingers and toes and underdeveloped external genitals in males. The severity of SLOS varies greatly in affected individuals, even in the same family, and some have normal development and only minor birth defects. SLOS is caused by a deficiency in the enzyme 7-dehydrocholesterol reductase that results in an abnormality in cholesterol metabolism. SLOS is inherited as an autosomal recessive genetic disorder. (For more information on this disorder choose “SLOS” as your search term in the Rare Disease Database.)Alagille syndrome is a genetic liver disorder usually present at birth. It is characterized by insufficient passage of bile due to a lower than normal number of bile ducts inside the liver. In some cases, the child may be born with no bile ducts. Major symptoms include prolonged yellow skin discoloration (jaundice), eye and heart structure anomalies, abnormally shaped vertebrae of the spine, compression of nerve space inside the lower spine, an absence of deep tendon reflexes, mental deficiency, kidney (renal) abnormalities, and pancreatic insufficiency. (For more information on this disorder choose “Alagille” as your search term in the Rare Disease Database.)VACTERL association is a nonrandom association of birth defects that affects multiple organ systems. The term VACTERL is an acronym with each letter representing the first letter of one of the more common findings seen in affected children: (V) = vertebral abnormalities; (A) = anal atresia; (C) = cardiac (heart) defects; (T) = tracheoesophageal fistula; (E) = esophageal atresia; (R) = renal (kidney) abnormalities; (L) = limb abnormalities. In addition, affected children may also exhibit growth deficiencies and failure to gain weight and grow at the expected rate (failure to thrive). In some cases, the acronym VATER association is used. Some researchers have added an (S) to the VACTERL or VATER acronym to represent a single umbilical artery instead of the normal two. Intelligence is usually normal. The cause of VACTERL association is unknown. (For more information on this disorder choose “VACTERL” as your search term in the Rare Disease Database.)Oculo-auriculo-vertebral spectrum (OAVS) refers to three rare disorders that many clinicians believe to be intimately related to one another and which represent the range of severity of the same disorder. Oculo-auriculo-vertebral disorder (OAVD) is the mildest form of the disorder, while Goldenhar syndrome is the most severe form. Hemifacial microsomia appears to be an intermediate form. The disorder is characterized by a wide spectrum of symptoms and physical features that may vary greatly in severity from person to person. However, such abnormalities tend to involve the cheekbones, jaw, mouth, ears, eyes, and/or bones of the spinal column (vertebrae). In most cases OAVS appears to occur randomly, with no apparent cause (sporadic). However, in some cases, family histories suggest autosomal dominant or recessive inheritance. In addition, some researchers suggest that the disorder may be caused by the interaction of many genes, possibly in combination with environmental factors (multifactorial inheritance). (For more information on this disorder choose “oculo-auriculo-vertebral” as your search term in the Rare Disease Database.)CHARGE syndrome is a disorder that affects many areas of the body. CHARGE is an abbreviation for several of the features common in the disorder: coloboma, heart defects, atresia choanae (also known as choanal atresia), growth delay, genital abnormalities and ear abnormalities. The pattern of malformations varies among individuals with this disorder, and the multiple health problems can be life-threatening in infancy.Kabuki syndrome is a rare, multisystem disorder characterized by multiple abnormalities including distinctive facial features, growth delays, varying degrees of intellectual disability, skeletal abnormalities and short stature. A wide variety of additional symptoms affecting multiple different organ systems can potentially occur. | 252 | Chromosome 22q11.2 Deletion Syndrome |
nord_252_5 | Diagnosis of Chromosome 22q11.2 Deletion Syndrome | The diagnosis of 22q11.2DS is suspected when clinical symptoms are present. The diagnosis is confirmed by a blood test that can detect a microscopic chromosomal deletion on chromosome 22. There are many new tests to detect this deletion including whole genome array, SNP array, comparative genomic hybridization, and MLPA. FISH studies have also been useful in finding the deletion in most patients. Furthermore, routine chromosome (cytogenetic) testing is also performed because a small number of affected individuals have a chromosome rearrangement involving chromosome 22q which may change the recurrence risk counseling for the parents. | Diagnosis of Chromosome 22q11.2 Deletion Syndrome. The diagnosis of 22q11.2DS is suspected when clinical symptoms are present. The diagnosis is confirmed by a blood test that can detect a microscopic chromosomal deletion on chromosome 22. There are many new tests to detect this deletion including whole genome array, SNP array, comparative genomic hybridization, and MLPA. FISH studies have also been useful in finding the deletion in most patients. Furthermore, routine chromosome (cytogenetic) testing is also performed because a small number of affected individuals have a chromosome rearrangement involving chromosome 22q which may change the recurrence risk counseling for the parents. | 252 | Chromosome 22q11.2 Deletion Syndrome |
nord_252_6 | Therapies of Chromosome 22q11.2 Deletion Syndrome | TreatmentA team approach is often useful and generally recommended when making decisions about the treatment of symptoms in patients with 22q11.2DS. A geneticist, pediatrician, cardiologist, immunologist, endocrinologist, gastroenterologist, otolaryngologist, plastic surgeon, speech pathologist, audiologist, orthodontist, dentist, urologist/nephrologist, orthopedist, child development specialist, neurologist and psychologist may all be called in to consult with the parents, depending on the clinical presentation of the child.Genetic counseling is recommended for families with an affected child. | Therapies of Chromosome 22q11.2 Deletion Syndrome. TreatmentA team approach is often useful and generally recommended when making decisions about the treatment of symptoms in patients with 22q11.2DS. A geneticist, pediatrician, cardiologist, immunologist, endocrinologist, gastroenterologist, otolaryngologist, plastic surgeon, speech pathologist, audiologist, orthodontist, dentist, urologist/nephrologist, orthopedist, child development specialist, neurologist and psychologist may all be called in to consult with the parents, depending on the clinical presentation of the child.Genetic counseling is recommended for families with an affected child. | 252 | Chromosome 22q11.2 Deletion Syndrome |
nord_253_0 | Overview of Chromosome 3, Monosomy 3p | Chromosome 3, Monosomy 3p is a rare chromosomal disorder in which the end (distal) portion of the short arm (p) of chromosome 3 is missing (deleted or monosomic). The range and severity of symptoms and findings may be variable. However, associated features often include growth delays before and after birth (prenatal and postnatal growth deficiency); severe to profound mental retardation; distinctive malformations of the skull and facial (craniofacial) region; eyebrows that grow together (synophrys); and/or excessive hair growth (hypertrichosis). Additional physical abnormalities may also be present. In many cases, Chromosome 3, Monosomy 3p appears to occur spontaneously (de novo) for unknown reasons. | Overview of Chromosome 3, Monosomy 3p. Chromosome 3, Monosomy 3p is a rare chromosomal disorder in which the end (distal) portion of the short arm (p) of chromosome 3 is missing (deleted or monosomic). The range and severity of symptoms and findings may be variable. However, associated features often include growth delays before and after birth (prenatal and postnatal growth deficiency); severe to profound mental retardation; distinctive malformations of the skull and facial (craniofacial) region; eyebrows that grow together (synophrys); and/or excessive hair growth (hypertrichosis). Additional physical abnormalities may also be present. In many cases, Chromosome 3, Monosomy 3p appears to occur spontaneously (de novo) for unknown reasons. | 253 | Chromosome 3, Monosomy 3p |
nord_253_1 | Symptoms of Chromosome 3, Monosomy 3p | As noted above, the symptoms and physical findings associated with Chromosome 3, Monosomy 3p may vary in range and severity from case to case. However, according to reports in the medical literature, many affected individuals have a low birthweight; marked growth delays after birth (postnatal growth retardation); severe to profound mental retardation; severe delays in the acquisition of skills requiring the coordination of mental and motor activities (psychomotor retardation); excessive hair growth (hypertrichosis); and/or distinctive malformations of the skull and facial (craniofacial) region.Many affected infants have an abnormally small head (microcephaly) that may appear unusually short and broad (brachycephaly); a flat back region of the head (occiput); and/or an abnormally high, narrow, prominent forehead. Additional craniofacial abnormalities may include a triangular face; arched eyebrows that grow together (synophrys); a broad, flat nose; an unusually long vertical groove in the middle of the upper lip (philtrum); thin lips; and/or an abnormally small lower jaw (mandible). Affected individuals may also have a downwardly turned mouth; widely spaced eyes (ocular hypertelorism); vertical skin folds that cover the eyes' inner corners (epicanthal folds); upwardly slanting eyelid folds (palpebral fissures); drooping of the upper eyelids (ptosis); and/or low-set, malformed ears. Chromosome 3, Monosomy 3p is also commonly associated with more than the normal number of fingers and/or toes (polydactyly). In many cases, there may be additional fingers, particularly duplication of the “pinkies” or fifth fingers (postaxial polydactyly). In addition, in some instances, affected infants may have duplication of certain toes, particularly the fifth toes.Reports indicate that some affected individuals may also have hearing loss and/or visual impairment. In addition, the disorder may be associated with additional physical features, such as abnormal forward (anterior) placement of the anus; undescended testes (cryptorchidism) in affected males; kidney (renal) defects: structural malformations of the heart (congenital heart defects); and/or other abnormalities. | Symptoms of Chromosome 3, Monosomy 3p. As noted above, the symptoms and physical findings associated with Chromosome 3, Monosomy 3p may vary in range and severity from case to case. However, according to reports in the medical literature, many affected individuals have a low birthweight; marked growth delays after birth (postnatal growth retardation); severe to profound mental retardation; severe delays in the acquisition of skills requiring the coordination of mental and motor activities (psychomotor retardation); excessive hair growth (hypertrichosis); and/or distinctive malformations of the skull and facial (craniofacial) region.Many affected infants have an abnormally small head (microcephaly) that may appear unusually short and broad (brachycephaly); a flat back region of the head (occiput); and/or an abnormally high, narrow, prominent forehead. Additional craniofacial abnormalities may include a triangular face; arched eyebrows that grow together (synophrys); a broad, flat nose; an unusually long vertical groove in the middle of the upper lip (philtrum); thin lips; and/or an abnormally small lower jaw (mandible). Affected individuals may also have a downwardly turned mouth; widely spaced eyes (ocular hypertelorism); vertical skin folds that cover the eyes' inner corners (epicanthal folds); upwardly slanting eyelid folds (palpebral fissures); drooping of the upper eyelids (ptosis); and/or low-set, malformed ears. Chromosome 3, Monosomy 3p is also commonly associated with more than the normal number of fingers and/or toes (polydactyly). In many cases, there may be additional fingers, particularly duplication of the “pinkies” or fifth fingers (postaxial polydactyly). In addition, in some instances, affected infants may have duplication of certain toes, particularly the fifth toes.Reports indicate that some affected individuals may also have hearing loss and/or visual impairment. In addition, the disorder may be associated with additional physical features, such as abnormal forward (anterior) placement of the anus; undescended testes (cryptorchidism) in affected males; kidney (renal) defects: structural malformations of the heart (congenital heart defects); and/or other abnormalities. | 253 | Chromosome 3, Monosomy 3p |
nord_253_2 | Causes of Chromosome 3, Monosomy 3p | Chromosome 3, Monosomy 3p is a rare chromosomal disorder in which there is deletion (monosomy) of the end (distal) portion of the short arm (p) of chromosome 3. Researchers indicate that symptoms and findings characteristic of the syndrome result from deletion of chromosomal material extending from band 25 on the short arm of chromosome 3 (breakpoint) to the end or “terminal” of 3p (3p25–>pter). Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p” and a long arm identified by the letter “q”. Chromosomes are further subdivided into bands that are numbered. Therefore, 3p25 refers to band 25 on the short arm of chromosome 3.In most reported cases, Chromosome 3, Monosomy 3p has appeared to result from spontaneous (de novo) errors very early in embryonic development. In such instances, the parents of the affected child usually have normal chromosomes and a relatively low risk of having another child with the chromosomal abnormality.All cases of Monosomy 3p except for one have been new chromosomal changes (de novo). In one case, the deletion was inherited from the mother who had the same deletion 3p. Potentially, monosomy 3p could result from a parental translocation or inversion.Translocations occur when regions of certain chromosomes break off and are interchanged, resulting in shifting of genetic material and an altered set of chromosomes. If such chromosomal rearrangements are “balanced”, all of the chromosomal material is present in two copies but at different locations. Balanced translocations are usually harmless to the carrier. However, such chromosomal rearrangements may be associated with an increased risk of abnormal chromosomal development in the carrier's offspring if inherited in an “unbalanced” state. An unbalanced translocation occurs when only one of the two chromosomes involved in the translocation is inherited from a carrier parent. The result is too much (duplication or trisomy) or too little (deletion or monosomy) chromosomal material. An inversion occurs when a chromosome breaks in two places within a single chromosome and the segment between the breaks rejoins the chromosome in the reverse order. Chromosomal analysis and genetic counseling are typically recommended for parents of an affected child to help confirm or exclude a chromosomal rearrangement in one of the parents. | Causes of Chromosome 3, Monosomy 3p. Chromosome 3, Monosomy 3p is a rare chromosomal disorder in which there is deletion (monosomy) of the end (distal) portion of the short arm (p) of chromosome 3. Researchers indicate that symptoms and findings characteristic of the syndrome result from deletion of chromosomal material extending from band 25 on the short arm of chromosome 3 (breakpoint) to the end or “terminal” of 3p (3p25–>pter). Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p” and a long arm identified by the letter “q”. Chromosomes are further subdivided into bands that are numbered. Therefore, 3p25 refers to band 25 on the short arm of chromosome 3.In most reported cases, Chromosome 3, Monosomy 3p has appeared to result from spontaneous (de novo) errors very early in embryonic development. In such instances, the parents of the affected child usually have normal chromosomes and a relatively low risk of having another child with the chromosomal abnormality.All cases of Monosomy 3p except for one have been new chromosomal changes (de novo). In one case, the deletion was inherited from the mother who had the same deletion 3p. Potentially, monosomy 3p could result from a parental translocation or inversion.Translocations occur when regions of certain chromosomes break off and are interchanged, resulting in shifting of genetic material and an altered set of chromosomes. If such chromosomal rearrangements are “balanced”, all of the chromosomal material is present in two copies but at different locations. Balanced translocations are usually harmless to the carrier. However, such chromosomal rearrangements may be associated with an increased risk of abnormal chromosomal development in the carrier's offspring if inherited in an “unbalanced” state. An unbalanced translocation occurs when only one of the two chromosomes involved in the translocation is inherited from a carrier parent. The result is too much (duplication or trisomy) or too little (deletion or monosomy) chromosomal material. An inversion occurs when a chromosome breaks in two places within a single chromosome and the segment between the breaks rejoins the chromosome in the reverse order. Chromosomal analysis and genetic counseling are typically recommended for parents of an affected child to help confirm or exclude a chromosomal rearrangement in one of the parents. | 253 | Chromosome 3, Monosomy 3p |
nord_253_3 | Affects of Chromosome 3, Monosomy 3p | Chromosome 3, Monosomy 3p appears to affect males and females in relatively equal numbers. Since the disorder was originally reported in 1978 (Verjaal M), approximately 34 cases have been described in the medical literature. | Affects of Chromosome 3, Monosomy 3p. Chromosome 3, Monosomy 3p appears to affect males and females in relatively equal numbers. Since the disorder was originally reported in 1978 (Verjaal M), approximately 34 cases have been described in the medical literature. | 253 | Chromosome 3, Monosomy 3p |
nord_253_4 | Related disorders of Chromosome 3, Monosomy 3p | Additional chromosomal disorders may have features similar to those associated with Chromosome 3, Monosomy 3p. Chromosomal analysis is necessary to confirm the specific chromosomal abnormality present. (For further information on such disorders, choose the name of the specific chromosomal disorder in question or use “chromosome” as your search term in the Rare Disease Database.) | Related disorders of Chromosome 3, Monosomy 3p. Additional chromosomal disorders may have features similar to those associated with Chromosome 3, Monosomy 3p. Chromosomal analysis is necessary to confirm the specific chromosomal abnormality present. (For further information on such disorders, choose the name of the specific chromosomal disorder in question or use “chromosome” as your search term in the Rare Disease Database.) | 253 | Chromosome 3, Monosomy 3p |
nord_253_5 | Diagnosis of Chromosome 3, Monosomy 3p | In some cases, Chromosome 3, Monosomy 3p may be suggested before birth (prenatally) by specialized tests such as ultrasound, amniocentesis, and/or chorionic villus sampling (CVS). During fetal ultrasonography, reflected sound waves create an image of the developing fetus, potentially revealing certain findings that suggest a chromosomal disorder or other developmental abnormalities in the fetus. With amniocentesis, a sample of fluid that surrounds the developing fetus is removed and analyzed, while CVS involves the removal of tissue samples from a portion of the placenta. Chromosomal analysis performed on such fluid or tissue samples may reveal the presence of Monosomy 3p.The disorder may also be diagnosed or confirmed after birth (postnatally) based upon a thorough clinical evaluation, detection of characteristic findings (e.g., growth delays, mental retardation, psychomotor retardation, craniofacial abnormalities, etc.), and chromosomal analysis. Specialized tests may also be conducted to help detect and/or characterize certain abnormalities that may be associated with the disorder. | Diagnosis of Chromosome 3, Monosomy 3p. In some cases, Chromosome 3, Monosomy 3p may be suggested before birth (prenatally) by specialized tests such as ultrasound, amniocentesis, and/or chorionic villus sampling (CVS). During fetal ultrasonography, reflected sound waves create an image of the developing fetus, potentially revealing certain findings that suggest a chromosomal disorder or other developmental abnormalities in the fetus. With amniocentesis, a sample of fluid that surrounds the developing fetus is removed and analyzed, while CVS involves the removal of tissue samples from a portion of the placenta. Chromosomal analysis performed on such fluid or tissue samples may reveal the presence of Monosomy 3p.The disorder may also be diagnosed or confirmed after birth (postnatally) based upon a thorough clinical evaluation, detection of characteristic findings (e.g., growth delays, mental retardation, psychomotor retardation, craniofacial abnormalities, etc.), and chromosomal analysis. Specialized tests may also be conducted to help detect and/or characterize certain abnormalities that may be associated with the disorder. | 253 | Chromosome 3, Monosomy 3p |
nord_253_6 | Therapies of Chromosome 3, Monosomy 3p | TreatmentThe treatment of Chromosome 3, Monosomy 3p is directed toward the specific symptoms that are apparent in each individual. Such treatment may require the coordinated efforts of a team of medical professionals, such as pediatricians; surgeons; neurologists; physicians who diagnose and treat heart abnormalities (cardiologists); hearing specialists; and/or other health care professionals. In some cases, physicians may recommend surgical repair of certain malformations associated with the disorder. The specific surgical procedures performed will depend upon the severity and location of the anatomical abnormalities, their associated symptoms, and other factors.Early intervention may be important in ensuring that affected children reach their potential. Special services that may be beneficial include special education, physical therapy, and/or other medical, social, and/or vocational services. Genetic counseling will also be of benefit for families of affected children. Other treatment for this disorder is symptomatic and supportive. | Therapies of Chromosome 3, Monosomy 3p. TreatmentThe treatment of Chromosome 3, Monosomy 3p is directed toward the specific symptoms that are apparent in each individual. Such treatment may require the coordinated efforts of a team of medical professionals, such as pediatricians; surgeons; neurologists; physicians who diagnose and treat heart abnormalities (cardiologists); hearing specialists; and/or other health care professionals. In some cases, physicians may recommend surgical repair of certain malformations associated with the disorder. The specific surgical procedures performed will depend upon the severity and location of the anatomical abnormalities, their associated symptoms, and other factors.Early intervention may be important in ensuring that affected children reach their potential. Special services that may be beneficial include special education, physical therapy, and/or other medical, social, and/or vocational services. Genetic counseling will also be of benefit for families of affected children. Other treatment for this disorder is symptomatic and supportive. | 253 | Chromosome 3, Monosomy 3p |
nord_254_0 | Overview of Chromosome 3, Trisomy 3q2 | Chromosome 3, Trisomy 3q2 is a rare chromosomal disorder in which a portion of the 3rd chromosome appears three times (trisomy) rather than twice in cells of the body. Associated symptoms and findings may be variable, depending upon the specific length and location of the duplicated (trisomic) portion of chromosome 3. However, many affected infants and children have developmental delays, mental retardation, and characteristic abnormalities of the head and facial (craniofacial) area, resulting in a distinctive facial appearance. Such craniofacial abnormalities may include a relatively short head (brachycephaly), widely spaced eyes (ocular hypertelorism), upwardly slanting eyelid folds (palpebral fissures), and a small nose with upturned nostrils (anteverted nares). Affected infants and children also tend to have long eyelashes; arched, bushy, well-defined eyebrows that grow together across the base of the nose (synophrys), an unusually low hairline on the forehead and the back of the neck; and generalized excessive hair growth (hirsutism). Chromosome 3, Trisomy 3q2 may also be characterized by eye (ocular) abnormalities, limb defects, structural heart malformations (congenital heart defects), or other physical features. | Overview of Chromosome 3, Trisomy 3q2. Chromosome 3, Trisomy 3q2 is a rare chromosomal disorder in which a portion of the 3rd chromosome appears three times (trisomy) rather than twice in cells of the body. Associated symptoms and findings may be variable, depending upon the specific length and location of the duplicated (trisomic) portion of chromosome 3. However, many affected infants and children have developmental delays, mental retardation, and characteristic abnormalities of the head and facial (craniofacial) area, resulting in a distinctive facial appearance. Such craniofacial abnormalities may include a relatively short head (brachycephaly), widely spaced eyes (ocular hypertelorism), upwardly slanting eyelid folds (palpebral fissures), and a small nose with upturned nostrils (anteverted nares). Affected infants and children also tend to have long eyelashes; arched, bushy, well-defined eyebrows that grow together across the base of the nose (synophrys), an unusually low hairline on the forehead and the back of the neck; and generalized excessive hair growth (hirsutism). Chromosome 3, Trisomy 3q2 may also be characterized by eye (ocular) abnormalities, limb defects, structural heart malformations (congenital heart defects), or other physical features. | 254 | Chromosome 3, Trisomy 3q2 |
nord_254_1 | Symptoms of Chromosome 3, Trisomy 3q2 | The symptoms and physical findings associated with Chromosome 3, Trisomy 3q2 may be variable. However, in many cases, the disorder is characterized by mental retardation, moderate to severe developmental delays, abnormally diminished muscle tone (hypotonia), distinctive abnormalities of the head and facial (craniofacial) area, and/or additional physical abnormalities. According to reports in the medical literature, craniofacial features and other physical abnormalities associated with Trisomy 3q2 are often very similar to those associated with a rare genetic disorder known as Cornelia de Lange syndrome. (For further information on Cornelia de Lange syndrome, please see the “Related Disorders” section of this report below.)Many infants with Trisomy 3q2 have characteristic craniofacial abnormalities. Such features may include a relatively short, wide head (brachycephaly); widely spaced eyes (ocular hypertelorism); upwardly slanting eyelid folds (palpebral fissures), and vertical skin folds covering the eyes' inner corners (epicanthal folds). Affected infants may also have a relatively small nose with upturned nostrils (anteverted nares), a thin upper lip, downwardly turning corners of the mouth, a small, receding lower jaw (microretrognathia), and an abnormally prominent vertical groove (philtrum) between the nose and the upper lip. In addition, there may be incomplete closure (clefting) or abnormally high arching of the roof of the mouth (palate). Affected infants and children may also have a low hairline on the forehead and the back of the neck, an abnormally short neck with excessive skin folds, unusually long eyelashes; arched, bushy, well-defined eyebrows that grow together across the base of the nose (synophrys), and generalized excessive hair growth (hirsutism).Many infants with Chromosome 3, Trisomy 3q2 may also have eye (ocular) abnormalities, such as increased fluid pressure within the eyes (glaucoma); loss of transparency of the lenses (cataracts), clouding of the front, usually transparent regions of the eyes (corneal opacities), or rapid, involuntary eye movements (nystagmus). Additional ocular abnormalities may include deviation of one eye in relation to the other (strabismus), absence or defects of ocular tissue (colobomata) involving the colored regions of the eyes (irides); or abnormal smallness of the eyes (microphthalmia). Due to such features, affected individuals may have varying degrees of visual impairment.Trisomy 3q2 may also be characterized by abnormalities of the fingers or toes. For example, there may be underdevelopment (hypoplasia) of certain bones within the ends of the fingers (distal phalanges), causing the hands to appear unusually short. Affected individuals may also have inward deviation or bending (clinodactyly) of certain fingers or toes (digits), permanent flexion of one or more digits (camptodactyly), or webbing or fusion (syndactyly) of certain toes.Some infants and children with Trisomy 3q2 may also have additional physical abnormalities. Genital defects may sometimes be present, such as undescended testes (cryptorchidism) in affected males and malformations of the internal genitals in females with the disorder. In some cases, additional abnormalities may include structural malformations of the heart at birth (congenital heart defects), kidney (renal) defects, or underdevelopment of certain regions of the brain. | Symptoms of Chromosome 3, Trisomy 3q2. The symptoms and physical findings associated with Chromosome 3, Trisomy 3q2 may be variable. However, in many cases, the disorder is characterized by mental retardation, moderate to severe developmental delays, abnormally diminished muscle tone (hypotonia), distinctive abnormalities of the head and facial (craniofacial) area, and/or additional physical abnormalities. According to reports in the medical literature, craniofacial features and other physical abnormalities associated with Trisomy 3q2 are often very similar to those associated with a rare genetic disorder known as Cornelia de Lange syndrome. (For further information on Cornelia de Lange syndrome, please see the “Related Disorders” section of this report below.)Many infants with Trisomy 3q2 have characteristic craniofacial abnormalities. Such features may include a relatively short, wide head (brachycephaly); widely spaced eyes (ocular hypertelorism); upwardly slanting eyelid folds (palpebral fissures), and vertical skin folds covering the eyes' inner corners (epicanthal folds). Affected infants may also have a relatively small nose with upturned nostrils (anteverted nares), a thin upper lip, downwardly turning corners of the mouth, a small, receding lower jaw (microretrognathia), and an abnormally prominent vertical groove (philtrum) between the nose and the upper lip. In addition, there may be incomplete closure (clefting) or abnormally high arching of the roof of the mouth (palate). Affected infants and children may also have a low hairline on the forehead and the back of the neck, an abnormally short neck with excessive skin folds, unusually long eyelashes; arched, bushy, well-defined eyebrows that grow together across the base of the nose (synophrys), and generalized excessive hair growth (hirsutism).Many infants with Chromosome 3, Trisomy 3q2 may also have eye (ocular) abnormalities, such as increased fluid pressure within the eyes (glaucoma); loss of transparency of the lenses (cataracts), clouding of the front, usually transparent regions of the eyes (corneal opacities), or rapid, involuntary eye movements (nystagmus). Additional ocular abnormalities may include deviation of one eye in relation to the other (strabismus), absence or defects of ocular tissue (colobomata) involving the colored regions of the eyes (irides); or abnormal smallness of the eyes (microphthalmia). Due to such features, affected individuals may have varying degrees of visual impairment.Trisomy 3q2 may also be characterized by abnormalities of the fingers or toes. For example, there may be underdevelopment (hypoplasia) of certain bones within the ends of the fingers (distal phalanges), causing the hands to appear unusually short. Affected individuals may also have inward deviation or bending (clinodactyly) of certain fingers or toes (digits), permanent flexion of one or more digits (camptodactyly), or webbing or fusion (syndactyly) of certain toes.Some infants and children with Trisomy 3q2 may also have additional physical abnormalities. Genital defects may sometimes be present, such as undescended testes (cryptorchidism) in affected males and malformations of the internal genitals in females with the disorder. In some cases, additional abnormalities may include structural malformations of the heart at birth (congenital heart defects), kidney (renal) defects, or underdevelopment of certain regions of the brain. | 254 | Chromosome 3, Trisomy 3q2 |
nord_254_2 | Causes of Chromosome 3, Trisomy 3q2 | In individuals with Chromosome 3, Trisomy 3q2, all or a portion of the end (distal) region of the long arm (q) of chromosome 3 is present three times (trisomy) rather than twice in cells of the body. (This distal region is sometimes referred to as “chromosome 3q2.”) Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p” and a long arm identified by the letter “q.” Chromosomes are further subdivided into bands that are numbered. For example, “3q26” refers to band 26 within the distal region of the long arm of chromosome 3.Trisomy (or duplication) of a certain region or regions of chromosome 3q2 is responsible for the symptoms and findings that characterize the disorder. The severity and range of symptoms may depend on the specific length and location of the duplicated portion of the chromosome. In addition, evidence suggests that individuals with features characteristic of the disorder typically have duplications involving bands 26.3-27.3 on chromosome 3q, indicating that this may be a critical region in producing the syndrome. In some affected individuals (75%), Chromosome 3, Trisomy 3q2 may be due to the presence of a “balanced” rearrangement in one of the parents. The rearrangement is often a translocation, but inversions may also be involved. Translocations occur when regions of different chromosomes break off and are interchanged, resulting in shifting of genetic material and an altered set of chromosomes. For example, a translocation is balanced if pieces or bands of two chromosomes break off and switch places, resulting in an altered but balanced set of chromosomes in which all the chromosomal material is present in two copies. Balanced translocations are usually harmless to the carrier. However, such a chromosomal rearrangement may cause an “unbalanced translocation” in the carrier's offspring. An unbalanced translocation occurs when only one of the two chromosomes involved in the translocation is inherited from a carrier parent. The result is too much (duplication or trisomy) or too little (deletion or monosomy) chromosomal material. Chromosomal testing may determine whether a parent has a balanced translocation.In some affected individuals, duplication of chromosome 3q2 has appeared to occur spontaneously for unknown reasons (de novo) during early embryonic development. The parents of a child with a “de novo” duplication usually have normal chromosomes and a relatively low risk of having another child with the chromosomal abnormality.In a few individuals with Trisomy 3q2, the disorder has resulted from a chromosomal inversion in one of the parents. Chromosomal inversions are characterized by breakage within a single chromosome at two points and “rejoining” of the chromosome with an inversion or a reversal of the affected chromosomal segment between the two breakpoints. Chromosomal testing may also determine whether a parent has a chromosomal inversion. | Causes of Chromosome 3, Trisomy 3q2. In individuals with Chromosome 3, Trisomy 3q2, all or a portion of the end (distal) region of the long arm (q) of chromosome 3 is present three times (trisomy) rather than twice in cells of the body. (This distal region is sometimes referred to as “chromosome 3q2.”) Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p” and a long arm identified by the letter “q.” Chromosomes are further subdivided into bands that are numbered. For example, “3q26” refers to band 26 within the distal region of the long arm of chromosome 3.Trisomy (or duplication) of a certain region or regions of chromosome 3q2 is responsible for the symptoms and findings that characterize the disorder. The severity and range of symptoms may depend on the specific length and location of the duplicated portion of the chromosome. In addition, evidence suggests that individuals with features characteristic of the disorder typically have duplications involving bands 26.3-27.3 on chromosome 3q, indicating that this may be a critical region in producing the syndrome. In some affected individuals (75%), Chromosome 3, Trisomy 3q2 may be due to the presence of a “balanced” rearrangement in one of the parents. The rearrangement is often a translocation, but inversions may also be involved. Translocations occur when regions of different chromosomes break off and are interchanged, resulting in shifting of genetic material and an altered set of chromosomes. For example, a translocation is balanced if pieces or bands of two chromosomes break off and switch places, resulting in an altered but balanced set of chromosomes in which all the chromosomal material is present in two copies. Balanced translocations are usually harmless to the carrier. However, such a chromosomal rearrangement may cause an “unbalanced translocation” in the carrier's offspring. An unbalanced translocation occurs when only one of the two chromosomes involved in the translocation is inherited from a carrier parent. The result is too much (duplication or trisomy) or too little (deletion or monosomy) chromosomal material. Chromosomal testing may determine whether a parent has a balanced translocation.In some affected individuals, duplication of chromosome 3q2 has appeared to occur spontaneously for unknown reasons (de novo) during early embryonic development. The parents of a child with a “de novo” duplication usually have normal chromosomes and a relatively low risk of having another child with the chromosomal abnormality.In a few individuals with Trisomy 3q2, the disorder has resulted from a chromosomal inversion in one of the parents. Chromosomal inversions are characterized by breakage within a single chromosome at two points and “rejoining” of the chromosome with an inversion or a reversal of the affected chromosomal segment between the two breakpoints. Chromosomal testing may also determine whether a parent has a chromosomal inversion. | 254 | Chromosome 3, Trisomy 3q2 |
nord_254_3 | Affects of Chromosome 3, Trisomy 3q2 | Chromosome 3, Trisomy 3q2 appears to affect males and females in equal numbers. At least 50 cases have been reported in the medical literature. In some cases, the disorder may be suspected before birth (prenatally) based upon the results of specialized tests. (For further information, please see the “Standard Therapies” section of this report below.) The disorder is usually detected or confirmed at birth or during early infancy based upon characteristic symptoms and physical findings. | Affects of Chromosome 3, Trisomy 3q2. Chromosome 3, Trisomy 3q2 appears to affect males and females in equal numbers. At least 50 cases have been reported in the medical literature. In some cases, the disorder may be suspected before birth (prenatally) based upon the results of specialized tests. (For further information, please see the “Standard Therapies” section of this report below.) The disorder is usually detected or confirmed at birth or during early infancy based upon characteristic symptoms and physical findings. | 254 | Chromosome 3, Trisomy 3q2 |
nord_254_4 | Related disorders of Chromosome 3, Trisomy 3q2 | Symptoms of the following disorders may be similar to those of Chromosome 3, Trisomy 3q2. Comparisons may be useful for a differential diagnosis.Cornelia de Lange syndrome is a rare genetic disorder that is apparent at birth (congenital). As mentioned above, many of the symptoms associated with Cornelia de Lange syndrome are similar to those associated with Trisomy 3q2. Although associated findings may be variable, Cornelia de Lange syndrome is often characterized by delays in physical development before and after birth (prenatal and postnatal growth retardation), abnormalities of the head and facial (craniofacial) area, resulting in a distinctive facial appearance; generalized excessive hair growth (hirsutism); malformations of the hands and arms (upper limbs); and mild to severe mental retardation. Many affected infants and children have an unusually small, short head (microbrachycephaly), an abnormally long vertical groove between the upper lip and nose (philtrum); a depressed nasal bridge, upturned nostrils (anteverted nares), and a protruding upper jaw (maxillary prognathism). Additional, characteristic facial abnormalities may include thin, downturned lips, low-set ears; arched, well-defined eyebrows that grow together across the base of the nose (synophrys); an unusually low hairline on the forehead and the back of the neck, and abnormally curly, long eyelashes. The disorder may also be characterized by distinctive malformations of the limbs, such as unusually small hands and feet, inward deviation (clinodactyly) of the fifth fingers, or webbing (syndactyly) of certain toes. Less commonly, there may be absence of the forearms, hands, and fingers. In most individuals with the disorder, Cornelia de Lange syndrome appears to occur randomly for unknown reasons (sporadically). However, there have been some familial cases, suggesting autosomal dominant inheritance. According to investigators, the disorder may be caused by changes (mutations) of a gene or genes on the long arm (q) of chromosome 3 (3q26.3). (For further information on this disorder, please choose “Cornelia de Lange” as your search term in the Rare Disease Database.) Many chromosomal disorders may have features similar to those associated with Chromosome 3, Trisomy 3q2. Chromosomal testing is necessary to confirm the specific chromosomal abnormality present. (For further information on such disorders, choose the name of the specific chromosomal disorder in question or use “chromosome” as your search term in the Rare Disease Database.) | Related disorders of Chromosome 3, Trisomy 3q2. Symptoms of the following disorders may be similar to those of Chromosome 3, Trisomy 3q2. Comparisons may be useful for a differential diagnosis.Cornelia de Lange syndrome is a rare genetic disorder that is apparent at birth (congenital). As mentioned above, many of the symptoms associated with Cornelia de Lange syndrome are similar to those associated with Trisomy 3q2. Although associated findings may be variable, Cornelia de Lange syndrome is often characterized by delays in physical development before and after birth (prenatal and postnatal growth retardation), abnormalities of the head and facial (craniofacial) area, resulting in a distinctive facial appearance; generalized excessive hair growth (hirsutism); malformations of the hands and arms (upper limbs); and mild to severe mental retardation. Many affected infants and children have an unusually small, short head (microbrachycephaly), an abnormally long vertical groove between the upper lip and nose (philtrum); a depressed nasal bridge, upturned nostrils (anteverted nares), and a protruding upper jaw (maxillary prognathism). Additional, characteristic facial abnormalities may include thin, downturned lips, low-set ears; arched, well-defined eyebrows that grow together across the base of the nose (synophrys); an unusually low hairline on the forehead and the back of the neck, and abnormally curly, long eyelashes. The disorder may also be characterized by distinctive malformations of the limbs, such as unusually small hands and feet, inward deviation (clinodactyly) of the fifth fingers, or webbing (syndactyly) of certain toes. Less commonly, there may be absence of the forearms, hands, and fingers. In most individuals with the disorder, Cornelia de Lange syndrome appears to occur randomly for unknown reasons (sporadically). However, there have been some familial cases, suggesting autosomal dominant inheritance. According to investigators, the disorder may be caused by changes (mutations) of a gene or genes on the long arm (q) of chromosome 3 (3q26.3). (For further information on this disorder, please choose “Cornelia de Lange” as your search term in the Rare Disease Database.) Many chromosomal disorders may have features similar to those associated with Chromosome 3, Trisomy 3q2. Chromosomal testing is necessary to confirm the specific chromosomal abnormality present. (For further information on such disorders, choose the name of the specific chromosomal disorder in question or use “chromosome” as your search term in the Rare Disease Database.) | 254 | Chromosome 3, Trisomy 3q2 |
nord_254_5 | Diagnosis of Chromosome 3, Trisomy 3q2 | In some cases, a diagnosis of Chromosome 3, Trisomy 3q2 may be suggested before birth (prenatally) by specialized tests such as ultrasound, amniocentesis, or chorionic villus sampling (CVS). During fetal ultrasonography, reflected sound waves are used to create an image of the developing fetus. Ultrasound studies may reveal characteristic findings that suggest a chromosomal disorder or other developmental abnormalities in the fetus. During amniocentesis, a sample of fluid that surrounds the developing fetus is removed and analyzed. CVS involves the removal of tissue samples from a portion of the placenta. Chromosomal analysis performed on cells from the fluid or tissue samples may reveal the presence of Trisomy 3q2.The diagnosis of Chromosome 3, Trisomy 3q2 is typically made at birth or during infancy based upon a thorough clinical evaluation, detection of characteristic physical findings, and chromosomal analysis. In some affected individuals, specialized testing may also be conducted to detect and/or characterize certain abnormalities that may be associated with the disorder (e.g., ocular abnormalities, congenital heart defects, renal malformations, etc.). | Diagnosis of Chromosome 3, Trisomy 3q2. In some cases, a diagnosis of Chromosome 3, Trisomy 3q2 may be suggested before birth (prenatally) by specialized tests such as ultrasound, amniocentesis, or chorionic villus sampling (CVS). During fetal ultrasonography, reflected sound waves are used to create an image of the developing fetus. Ultrasound studies may reveal characteristic findings that suggest a chromosomal disorder or other developmental abnormalities in the fetus. During amniocentesis, a sample of fluid that surrounds the developing fetus is removed and analyzed. CVS involves the removal of tissue samples from a portion of the placenta. Chromosomal analysis performed on cells from the fluid or tissue samples may reveal the presence of Trisomy 3q2.The diagnosis of Chromosome 3, Trisomy 3q2 is typically made at birth or during infancy based upon a thorough clinical evaluation, detection of characteristic physical findings, and chromosomal analysis. In some affected individuals, specialized testing may also be conducted to detect and/or characterize certain abnormalities that may be associated with the disorder (e.g., ocular abnormalities, congenital heart defects, renal malformations, etc.). | 254 | Chromosome 3, Trisomy 3q2 |
nord_254_6 | Therapies of Chromosome 3, Trisomy 3q2 | TreatmentThe treatment of Chromosome 3, Trisomy 3q2 is directed toward the specific symptoms and physical findings that are apparent in each individual. Such treatment may require the coordinated efforts of a team of medical professionals who may need to systematically and comprehensively plan an affected child's treatment. These professionals may include pediatricians; surgeons, specialists who diagnose and treat abnormalities of the skeleton, joints, muscles, and related tissues (orthopedists), physicians who specialize in heart abnormalities (cardiologists), eye specialists (ophthalmologists), and/or other health care professionals.In some affected individuals, treatment may include surgical repair of certain craniofacial, digital, ocular, cardiac, or other abnormalities potentially associated with the disorder. The surgical procedures performed will depend upon the severity of the anatomical abnormalities, their associated symptoms, and other factors. Other treatment is symptomatic and supportive.Early intervention may be important in ensuring that children with Chromosome 3, Trisomy 3q2 reach their potential. Special services that may be beneficial include special education, physical therapy, and/or other medical, social, and/or vocational services. Genetic counseling will also be of benefit for individuals with Chromosome 3, Trisomy 3q2 and their families. | Therapies of Chromosome 3, Trisomy 3q2. TreatmentThe treatment of Chromosome 3, Trisomy 3q2 is directed toward the specific symptoms and physical findings that are apparent in each individual. Such treatment may require the coordinated efforts of a team of medical professionals who may need to systematically and comprehensively plan an affected child's treatment. These professionals may include pediatricians; surgeons, specialists who diagnose and treat abnormalities of the skeleton, joints, muscles, and related tissues (orthopedists), physicians who specialize in heart abnormalities (cardiologists), eye specialists (ophthalmologists), and/or other health care professionals.In some affected individuals, treatment may include surgical repair of certain craniofacial, digital, ocular, cardiac, or other abnormalities potentially associated with the disorder. The surgical procedures performed will depend upon the severity of the anatomical abnormalities, their associated symptoms, and other factors. Other treatment is symptomatic and supportive.Early intervention may be important in ensuring that children with Chromosome 3, Trisomy 3q2 reach their potential. Special services that may be beneficial include special education, physical therapy, and/or other medical, social, and/or vocational services. Genetic counseling will also be of benefit for individuals with Chromosome 3, Trisomy 3q2 and their families. | 254 | Chromosome 3, Trisomy 3q2 |
nord_255_0 | Overview of Chromosome 4, Monosomy Distal 4q | Chromosome 4, Monosomy Distal 4q is a rare chromosomal disorder in which there is deletion (monosomy) of a portion of the 4th chromosome. Associated symptoms and findings may be variable, depending upon the specific length and location of the deleted portion of chromosome 4. However, characteristic features include growth deficiency after birth (postnatal growth retardation), varying degrees of mental retardation, malformations of the skull and facial (craniofacial) region, structural heart defects, abnormalities of the hands and feet, and/or other physical findings. Chromosome 4, Monosomy Distal 4q usually appears to result from spontaneous (de novo) errors very early during embryonic development that occur for unknown reasons (sporadically). | Overview of Chromosome 4, Monosomy Distal 4q. Chromosome 4, Monosomy Distal 4q is a rare chromosomal disorder in which there is deletion (monosomy) of a portion of the 4th chromosome. Associated symptoms and findings may be variable, depending upon the specific length and location of the deleted portion of chromosome 4. However, characteristic features include growth deficiency after birth (postnatal growth retardation), varying degrees of mental retardation, malformations of the skull and facial (craniofacial) region, structural heart defects, abnormalities of the hands and feet, and/or other physical findings. Chromosome 4, Monosomy Distal 4q usually appears to result from spontaneous (de novo) errors very early during embryonic development that occur for unknown reasons (sporadically). | 255 | Chromosome 4, Monosomy Distal 4q |
nord_255_1 | Symptoms of Chromosome 4, Monosomy Distal 4q | As mentioned above, the symptoms and physical findings associated with Chromosome 4, Monosomy Distal 4q may be variable. However, in many cases, the disorder is characterized by distinctive malformations of the skull and facial (craniofacial) region, structural malformations of the heart that are present at birth (congenital heart defects), abnormalities of the hands and feet, and/or other physical abnormalities. In addition, individuals with the disorder are typically affected by mild, moderate, or severe mental retardation and delays in the acquisition of skills requiring the coordination of mental and physical activities (psychomotor retardation).Although the birth weight is usually normal in those with Chromosome 4, Monosomy Distal 4q, most affected infants have growth deficiency after birth (postnatal growth retardation). Some infants also have low muscle tone (hypotonia) and/or sudden episodes of uncontrolled electrical activity in the brain (seizures).Characteristic craniofacial abnormalities associated with Monosomy Distal 4q may include a small head (microcephaly); a short nose with a low nasal bridge and upturned nostrils (anteverted nares); and/or low-set, pointed ears. In addition, many with the disorder have an abnormally small, receding lower jaw (microretrognathia) and incomplete closure of the roof of the mouth (cleft palate) that, in some cases, may be associated with downward displacement or retraction of the tongue (glossoptosis). The association of microretrognathia, cleft palate, and glossoptosis may be referred to as “Pierre-Robin syndrome” or “Robin malformation sequence.” The malformations associated with Pierre-Robin syndrome may lead to feeding and breathing difficulties in the newborn (neonatal) period. Associated abnormalities may include impaired sucking and swallowing, failure to grow and gain weight at the expected rate (failure to thrive), upper airway obstruction, sudden absence of spontaneous breathing (apnea), insufficient oxygen supply to body tissues (hypoxia), inflammation of the lungs due to entrance of food particles or other foreign matter into the lungs' air passages (aspiration pneumonia), and/or other abnormalities. Chromosome 4, Monosomy Distal 4q may also be associated with additional craniofacial malformations. These may include widely spaced eyes (ocular hypertelorism); upwardly slanting eyelid folds (palpebral fissures); vertical skin folds that may cover the eyes' inner corners (epicanthal folds); and/or an abnormal groove in the upper lip (cleft lip). In addition, in some cases, the shape of the forehead may appear dissimilar from one side to the other (forehead asymmetry).According to reports in the medical literature, over 60 percent of affected infants also have congenital heart (cardiac) defects. Most frequently, such cardiac defects include an abnormal opening in the partition (septum) that normally separates the lower chambers (ventricles) or the upper chambers (atria) of the heart (ventricular or atrial septal defects [VSDs or ASDs]). Additional cardiac defects reported in association with the disorder have included abnormal narrowing (stenosis) of the opening between the pulmonary artery and the right ventricle (pulmonary stenosis); abnormal narrowing of the aorta (aortic coarctation) or of the opening between the aorta and the left ventricle (aortic stenosis); patent ductus arteriosus (PDA); or tetralogy of Fallot. In PDA, the channel that is present between the pulmonary artery and the aorta during fetal development fails to close after birth. (The pulmonary artery transports oxygen-depleted blood from the right ventricle to the lungs, where the exchange of oxygen and carbon dioxide occurs. The aorta, the major artery of the body, arises from the left ventricle and supplies oxygen-rich blood to most arteries.) Tetralogy of Fallot refers to a combination of heart defects, including ventricular septal defect; pulmonary stenosis; displacement of the aorta, enabling oxygen-depleted blood to flow from the right ventricle to the aorta; and thickening (hypertrophy) of the heart muscle (myocardium) of the right ventricle. In those with cardiac defects, associated symptoms and findings may vary, depending upon the severity and combination of heart malformations present and other factors. For example, in some cases, such as those with small isolated VSDs, no symptoms may be apparent. However, in other instances, such as those with larger VSDs and/or other cardiac defects, associated symptoms and findings may include difficulties feeding, shortness of breath, failure to thrive, excessive sweating, irritability, bluish discoloration of the skin and mucous membranes (cyanosis), and/or other abnormalities. In some individuals with Monosomy Distal 4q, congenital heart disease and/or respiratory difficulties associated with certain craniofacial malformations (e.g., Pierre-Robin syndrome) may lead to potentially life-threatening complications during infancy or early childhood.Chromosome 4, Monosomy Distal 4q may also be associated with distinctive abnormalities of the hands and feet. Such malformations may include abnormal bending (clinodactyly) and tapering of the “pinkies” (fifth fingers), with unusually pointed or duplicated fingernails; implanted thumbs and great toes (halluces); abnormal skin ridge patterns on the palms and the fifth fingers; overlapping toes; and/or deformities in which the feet are twisted out of shape or position (clubfeet). In some cases, additional musculoskeletal defects may also be present, such as limited extension of the elbows and/or dislocated hips.In some affected individuals, the disorder may be associated with additional physical abnormalities, including genital, kidney (renal), gastrointestinal, and/or other malformations. | Symptoms of Chromosome 4, Monosomy Distal 4q. As mentioned above, the symptoms and physical findings associated with Chromosome 4, Monosomy Distal 4q may be variable. However, in many cases, the disorder is characterized by distinctive malformations of the skull and facial (craniofacial) region, structural malformations of the heart that are present at birth (congenital heart defects), abnormalities of the hands and feet, and/or other physical abnormalities. In addition, individuals with the disorder are typically affected by mild, moderate, or severe mental retardation and delays in the acquisition of skills requiring the coordination of mental and physical activities (psychomotor retardation).Although the birth weight is usually normal in those with Chromosome 4, Monosomy Distal 4q, most affected infants have growth deficiency after birth (postnatal growth retardation). Some infants also have low muscle tone (hypotonia) and/or sudden episodes of uncontrolled electrical activity in the brain (seizures).Characteristic craniofacial abnormalities associated with Monosomy Distal 4q may include a small head (microcephaly); a short nose with a low nasal bridge and upturned nostrils (anteverted nares); and/or low-set, pointed ears. In addition, many with the disorder have an abnormally small, receding lower jaw (microretrognathia) and incomplete closure of the roof of the mouth (cleft palate) that, in some cases, may be associated with downward displacement or retraction of the tongue (glossoptosis). The association of microretrognathia, cleft palate, and glossoptosis may be referred to as “Pierre-Robin syndrome” or “Robin malformation sequence.” The malformations associated with Pierre-Robin syndrome may lead to feeding and breathing difficulties in the newborn (neonatal) period. Associated abnormalities may include impaired sucking and swallowing, failure to grow and gain weight at the expected rate (failure to thrive), upper airway obstruction, sudden absence of spontaneous breathing (apnea), insufficient oxygen supply to body tissues (hypoxia), inflammation of the lungs due to entrance of food particles or other foreign matter into the lungs' air passages (aspiration pneumonia), and/or other abnormalities. Chromosome 4, Monosomy Distal 4q may also be associated with additional craniofacial malformations. These may include widely spaced eyes (ocular hypertelorism); upwardly slanting eyelid folds (palpebral fissures); vertical skin folds that may cover the eyes' inner corners (epicanthal folds); and/or an abnormal groove in the upper lip (cleft lip). In addition, in some cases, the shape of the forehead may appear dissimilar from one side to the other (forehead asymmetry).According to reports in the medical literature, over 60 percent of affected infants also have congenital heart (cardiac) defects. Most frequently, such cardiac defects include an abnormal opening in the partition (septum) that normally separates the lower chambers (ventricles) or the upper chambers (atria) of the heart (ventricular or atrial septal defects [VSDs or ASDs]). Additional cardiac defects reported in association with the disorder have included abnormal narrowing (stenosis) of the opening between the pulmonary artery and the right ventricle (pulmonary stenosis); abnormal narrowing of the aorta (aortic coarctation) or of the opening between the aorta and the left ventricle (aortic stenosis); patent ductus arteriosus (PDA); or tetralogy of Fallot. In PDA, the channel that is present between the pulmonary artery and the aorta during fetal development fails to close after birth. (The pulmonary artery transports oxygen-depleted blood from the right ventricle to the lungs, where the exchange of oxygen and carbon dioxide occurs. The aorta, the major artery of the body, arises from the left ventricle and supplies oxygen-rich blood to most arteries.) Tetralogy of Fallot refers to a combination of heart defects, including ventricular septal defect; pulmonary stenosis; displacement of the aorta, enabling oxygen-depleted blood to flow from the right ventricle to the aorta; and thickening (hypertrophy) of the heart muscle (myocardium) of the right ventricle. In those with cardiac defects, associated symptoms and findings may vary, depending upon the severity and combination of heart malformations present and other factors. For example, in some cases, such as those with small isolated VSDs, no symptoms may be apparent. However, in other instances, such as those with larger VSDs and/or other cardiac defects, associated symptoms and findings may include difficulties feeding, shortness of breath, failure to thrive, excessive sweating, irritability, bluish discoloration of the skin and mucous membranes (cyanosis), and/or other abnormalities. In some individuals with Monosomy Distal 4q, congenital heart disease and/or respiratory difficulties associated with certain craniofacial malformations (e.g., Pierre-Robin syndrome) may lead to potentially life-threatening complications during infancy or early childhood.Chromosome 4, Monosomy Distal 4q may also be associated with distinctive abnormalities of the hands and feet. Such malformations may include abnormal bending (clinodactyly) and tapering of the “pinkies” (fifth fingers), with unusually pointed or duplicated fingernails; implanted thumbs and great toes (halluces); abnormal skin ridge patterns on the palms and the fifth fingers; overlapping toes; and/or deformities in which the feet are twisted out of shape or position (clubfeet). In some cases, additional musculoskeletal defects may also be present, such as limited extension of the elbows and/or dislocated hips.In some affected individuals, the disorder may be associated with additional physical abnormalities, including genital, kidney (renal), gastrointestinal, and/or other malformations. | 255 | Chromosome 4, Monosomy Distal 4q |
nord_255_2 | Causes of Chromosome 4, Monosomy Distal 4q | In individuals with Chromosome 4, Monosomy Distal 4q, there is deletion (monosomy) of all or a portion of the end (distal) region of the long arm (q) of chromosome 4. (“Distal” indicates away or farthest from a particular point of reference, meaning the chromosome's centromere [described below].) Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p,” a long arm identified by the letter “q,” and a narrowed region at which the two arms are joined (centromere). Chromosomes are further subdivided into bands that are numbered outward from the centromere. For example, “4q31” refers to band 31 of the long arm of chromosome 4.Evidence suggests that individuals with characteristic features of Monosomy Distal 4q have deletions beginning within band 4q31 (breakpoint) that extend to the end (or “terminal”) of chromosome 4q (i.e., 4q31-qter). (The distal region of 4q is sometimes referred to as “4q3” and includes bands 4q31 through 4q35, the latter of which is the terminal band of 4q.) Patients with deletions from band 4q32-qter appear to have symptoms and findings similar to those associated with deletions of 4q31-qter. However, some researchers indicate that deletions beginning within bands 4q33 or 4q34 to qter appear to be characterized by less severe clinical features.In addition, evidence indicates that “interstitial” deletions within bands 4q31 to 4q34 that do not extend to qter may have many features typically associated with the syndrome. (Interstitial means situated between, such as between other regions of a chromosome.) According to some investigators, such findings suggest that characteristic features attributed to loss of 4q31-qter may primarily result from deletion of 4q31 to 4q33-q34.In contrast, reports indicate that the clinical features associated with interstitial deletions of 4q that are “proximal” to 4q31 are generally more variable and less specific than–and may differ greatly from–those associated with distal deletions. However, such features typically include mental retardation and relatively mild craniofacial abnormalities. (Proximal, which is the opposite of the term distal, indicates closer to or nearest a particular point of reference [i.e., the centromere].) In most cases, Chromosome 4, Monosomy Distal 4q appears to be caused by spontaneous (de novo) errors very early in embryonic development. In such instances, the parents of the affected child usually have normal chromosomes and a relatively low risk of having another child with the chromosomal abnormality. Less commonly, the deletion may result from a “balanced translocation” in one of the parents. Translocations occur when portions of certain chromosomes break off and are rearranged, resulting in shifting of genetic material and an altered set of chromosomes. If a chromosomal rearrangement is balanced, meaning that it consists of an altered but balanced set of chromosomes, it is usually harmless to the carrier. However, such a chromosomal rearrangement may be associated with an increased risk of abnormal chromosomal development in the carrier's offspring. Chromosomal analysis and genetic counseling are typically recommended for parents of an affected child to help confirm or exclude the presence of a balanced translocation or other chromosomal rearrangement in one of the parents. | Causes of Chromosome 4, Monosomy Distal 4q. In individuals with Chromosome 4, Monosomy Distal 4q, there is deletion (monosomy) of all or a portion of the end (distal) region of the long arm (q) of chromosome 4. (“Distal” indicates away or farthest from a particular point of reference, meaning the chromosome's centromere [described below].) Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p,” a long arm identified by the letter “q,” and a narrowed region at which the two arms are joined (centromere). Chromosomes are further subdivided into bands that are numbered outward from the centromere. For example, “4q31” refers to band 31 of the long arm of chromosome 4.Evidence suggests that individuals with characteristic features of Monosomy Distal 4q have deletions beginning within band 4q31 (breakpoint) that extend to the end (or “terminal”) of chromosome 4q (i.e., 4q31-qter). (The distal region of 4q is sometimes referred to as “4q3” and includes bands 4q31 through 4q35, the latter of which is the terminal band of 4q.) Patients with deletions from band 4q32-qter appear to have symptoms and findings similar to those associated with deletions of 4q31-qter. However, some researchers indicate that deletions beginning within bands 4q33 or 4q34 to qter appear to be characterized by less severe clinical features.In addition, evidence indicates that “interstitial” deletions within bands 4q31 to 4q34 that do not extend to qter may have many features typically associated with the syndrome. (Interstitial means situated between, such as between other regions of a chromosome.) According to some investigators, such findings suggest that characteristic features attributed to loss of 4q31-qter may primarily result from deletion of 4q31 to 4q33-q34.In contrast, reports indicate that the clinical features associated with interstitial deletions of 4q that are “proximal” to 4q31 are generally more variable and less specific than–and may differ greatly from–those associated with distal deletions. However, such features typically include mental retardation and relatively mild craniofacial abnormalities. (Proximal, which is the opposite of the term distal, indicates closer to or nearest a particular point of reference [i.e., the centromere].) In most cases, Chromosome 4, Monosomy Distal 4q appears to be caused by spontaneous (de novo) errors very early in embryonic development. In such instances, the parents of the affected child usually have normal chromosomes and a relatively low risk of having another child with the chromosomal abnormality. Less commonly, the deletion may result from a “balanced translocation” in one of the parents. Translocations occur when portions of certain chromosomes break off and are rearranged, resulting in shifting of genetic material and an altered set of chromosomes. If a chromosomal rearrangement is balanced, meaning that it consists of an altered but balanced set of chromosomes, it is usually harmless to the carrier. However, such a chromosomal rearrangement may be associated with an increased risk of abnormal chromosomal development in the carrier's offspring. Chromosomal analysis and genetic counseling are typically recommended for parents of an affected child to help confirm or exclude the presence of a balanced translocation or other chromosomal rearrangement in one of the parents. | 255 | Chromosome 4, Monosomy Distal 4q |
nord_255_3 | Affects of Chromosome 4, Monosomy Distal 4q | Chromosome 4, Monosomy Distal 4q appears to affect males and females in relatively equal numbers. Partial deletion of chromosome 4q was originally reported in a child in 1967. Chromosome 4, Monosomy Distal 4q was proposed as a distinct chromosomal syndrome with characteristic symptoms and findings in 1979. More than 30 patients with the syndrome have been reported in the medical literature. | Affects of Chromosome 4, Monosomy Distal 4q. Chromosome 4, Monosomy Distal 4q appears to affect males and females in relatively equal numbers. Partial deletion of chromosome 4q was originally reported in a child in 1967. Chromosome 4, Monosomy Distal 4q was proposed as a distinct chromosomal syndrome with characteristic symptoms and findings in 1979. More than 30 patients with the syndrome have been reported in the medical literature. | 255 | Chromosome 4, Monosomy Distal 4q |
nord_255_4 | Related disorders of Chromosome 4, Monosomy Distal 4q | Additional chromosomal disorders may be characterized by symptoms and findings similar to those associated with Chromosome 4, Monosomy Distal 4q. Chromosomal testing is necessary to confirm the specific chromosomal abnormality present. (For further information on such disorders, choose the name of the specific chromosomal disorder in question or use “chromosome” as your search term in the Rare Disease Database.) | Related disorders of Chromosome 4, Monosomy Distal 4q. Additional chromosomal disorders may be characterized by symptoms and findings similar to those associated with Chromosome 4, Monosomy Distal 4q. Chromosomal testing is necessary to confirm the specific chromosomal abnormality present. (For further information on such disorders, choose the name of the specific chromosomal disorder in question or use “chromosome” as your search term in the Rare Disease Database.) | 255 | Chromosome 4, Monosomy Distal 4q |
nord_255_5 | Diagnosis of Chromosome 4, Monosomy Distal 4q | In some cases, Chromosome 4, Monosomy Distal 4q may be suggested before birth (prenatally) by specialized tests such as ultrasound, amniocentesis, and/or chorionic villus sampling (CVS). During fetal ultrasonography, reflected sound waves create an image of the developing fetus, potentially revealing certain findings that suggest a chromosomal disorder or other developmental abnormalities. With amniocentesis, a sample of fluid that surrounds the developing fetus is removed and analyzed, while CVS involves the removal of tissue samples from a portion of the placenta. Chromosomal analysis performed on such fluid or tissue samples may reveal the presence of Monosomy Distal 4q.The disorder is usually diagnosed or confirmed after birth (postnatally) based upon a thorough clinical evaluation, detection of characteristic physical findings, and chromosomal analysis. Various specialized tests, including advanced imaging techniques, may also be performed to help detect and/or characterize certain abnormalities that may be associated with the disorder (e.g., microretrognathia, cleft palate, etc.). In addition, a thorough cardiac evaluation may be advised to detect any heart abnormalities that may be present. Such evaluation may include a thorough clinical examination, evaluation of heart and lung sounds through use of a stethoscope, and specialized tests that enable physicians to evaluate the structure and function of the heart (e.g., x-ray studies, electrocardiography [EKG]), echocardiography). | Diagnosis of Chromosome 4, Monosomy Distal 4q. In some cases, Chromosome 4, Monosomy Distal 4q may be suggested before birth (prenatally) by specialized tests such as ultrasound, amniocentesis, and/or chorionic villus sampling (CVS). During fetal ultrasonography, reflected sound waves create an image of the developing fetus, potentially revealing certain findings that suggest a chromosomal disorder or other developmental abnormalities. With amniocentesis, a sample of fluid that surrounds the developing fetus is removed and analyzed, while CVS involves the removal of tissue samples from a portion of the placenta. Chromosomal analysis performed on such fluid or tissue samples may reveal the presence of Monosomy Distal 4q.The disorder is usually diagnosed or confirmed after birth (postnatally) based upon a thorough clinical evaluation, detection of characteristic physical findings, and chromosomal analysis. Various specialized tests, including advanced imaging techniques, may also be performed to help detect and/or characterize certain abnormalities that may be associated with the disorder (e.g., microretrognathia, cleft palate, etc.). In addition, a thorough cardiac evaluation may be advised to detect any heart abnormalities that may be present. Such evaluation may include a thorough clinical examination, evaluation of heart and lung sounds through use of a stethoscope, and specialized tests that enable physicians to evaluate the structure and function of the heart (e.g., x-ray studies, electrocardiography [EKG]), echocardiography). | 255 | Chromosome 4, Monosomy Distal 4q |
nord_255_6 | Therapies of Chromosome 4, Monosomy Distal 4q | TreatmentThe treatment of Chromosome 4, Monosomy Distal 4q is directed toward the specific symptoms and findings that are apparent in each individual. Such disease management may require the coordinated efforts of a team of medical professionals, such as pediatricians; surgeons; heart specialists (cardiologists); physicians who diagnose and treat disorders of the skeleton, muscles, joints, and related tissues (orthopedists); neurologists; and/or other health care professionals.For newborns with feeding and respiratory difficulties, such as due to microretrognathia and cleft palate, possibly in association with downward displacement of the tongue (e.g., those with Pierre-Robin syndrome), recommended disease management may include keeping infants on their stomaches (prone positioning) and monitoring of breathing. In some cases, treatment may also require placement of a breathing tube via the nose or, if necessary, the performance of certain surgical procedures. These may include a procedure in which the tongue is temporarily joined to the lower lip (tongue-lip adhesion) to keep the tongue from blocking the airway or creation of an opening through the neck into the windpipe into which a tube is inserted (tracheostomy). Additional supportive measures may also be required to help improve feeding and ensure sufficient intake of nutrients, such as the use of modified artificial nipples or, in some cases, tube feeding (gavage feeding). In addition, surgical measures to correct cleft palate will be advised at the appropriate age during infancy or childhood in order to repair the abnormality and to help improve speech development. Physicians may also recommend surgical correction of additional, associated craniofacial malformations in some cases.For infants and children with congenital heart defects, treatment with certain medications, surgical intervention, and/or other measures may also be required. In addition, in some cases, physicians may advise surgical repair or correction of additional skeletal, genital, and/or other malformations associated with Chromosome 4, Monosomy Distal 4q. The specific surgical procedures performed will depend upon the severity and location of the anatomical abnormalities, their associated symptoms, and other factors.In individuals with seizures, anticonvulsant medications may be administered to help prevent, reduce, or control seizure episodes.Early intervention may also be important in ensuring that affected children reach their potential. Special services that may be beneficial include special education, speech therapy, physical therapy, and/or other medical, social, and/or vocational services. Genetic counseling will also be of benefit for affected individuals and their families. Other treatment for this disorder is symptomatic and supportive. | Therapies of Chromosome 4, Monosomy Distal 4q. TreatmentThe treatment of Chromosome 4, Monosomy Distal 4q is directed toward the specific symptoms and findings that are apparent in each individual. Such disease management may require the coordinated efforts of a team of medical professionals, such as pediatricians; surgeons; heart specialists (cardiologists); physicians who diagnose and treat disorders of the skeleton, muscles, joints, and related tissues (orthopedists); neurologists; and/or other health care professionals.For newborns with feeding and respiratory difficulties, such as due to microretrognathia and cleft palate, possibly in association with downward displacement of the tongue (e.g., those with Pierre-Robin syndrome), recommended disease management may include keeping infants on their stomaches (prone positioning) and monitoring of breathing. In some cases, treatment may also require placement of a breathing tube via the nose or, if necessary, the performance of certain surgical procedures. These may include a procedure in which the tongue is temporarily joined to the lower lip (tongue-lip adhesion) to keep the tongue from blocking the airway or creation of an opening through the neck into the windpipe into which a tube is inserted (tracheostomy). Additional supportive measures may also be required to help improve feeding and ensure sufficient intake of nutrients, such as the use of modified artificial nipples or, in some cases, tube feeding (gavage feeding). In addition, surgical measures to correct cleft palate will be advised at the appropriate age during infancy or childhood in order to repair the abnormality and to help improve speech development. Physicians may also recommend surgical correction of additional, associated craniofacial malformations in some cases.For infants and children with congenital heart defects, treatment with certain medications, surgical intervention, and/or other measures may also be required. In addition, in some cases, physicians may advise surgical repair or correction of additional skeletal, genital, and/or other malformations associated with Chromosome 4, Monosomy Distal 4q. The specific surgical procedures performed will depend upon the severity and location of the anatomical abnormalities, their associated symptoms, and other factors.In individuals with seizures, anticonvulsant medications may be administered to help prevent, reduce, or control seizure episodes.Early intervention may also be important in ensuring that affected children reach their potential. Special services that may be beneficial include special education, speech therapy, physical therapy, and/or other medical, social, and/or vocational services. Genetic counseling will also be of benefit for affected individuals and their families. Other treatment for this disorder is symptomatic and supportive. | 255 | Chromosome 4, Monosomy Distal 4q |
nord_256_0 | Overview of Chromosome 4, Partial Trisomy Distal 4q | Chromosome 4, Partial Trisomy Distal 4q is a rare chromosomal disorder in which a portion of the fourth chromosome appears three times (trisomy) rather than twice in cells of the body. Associated symptoms and findings may vary from case to case. However, common features include growth deficiency; mental retardation; distinctive malformations of the skull and facial (craniofacial) region, including an unusually small head (microcephaly), malformed ears, and a prominent nasal bridge; and/or defects of the hands and feet. In some cases, additional physical abnormalities may also be present, such as structural defects of the heart that are present at birth (congenital heart defects); genital abnormalities in affected males; urinary tract defects; and/or other findings. In most cases, the trisomy appears to result from a balanced chromosomal rearrangement in one of the parents; rarely, it is thought to arise from spontaneous (de novo) errors very early in embryonic development that occur for unknown reasons (sporadically). | Overview of Chromosome 4, Partial Trisomy Distal 4q. Chromosome 4, Partial Trisomy Distal 4q is a rare chromosomal disorder in which a portion of the fourth chromosome appears three times (trisomy) rather than twice in cells of the body. Associated symptoms and findings may vary from case to case. However, common features include growth deficiency; mental retardation; distinctive malformations of the skull and facial (craniofacial) region, including an unusually small head (microcephaly), malformed ears, and a prominent nasal bridge; and/or defects of the hands and feet. In some cases, additional physical abnormalities may also be present, such as structural defects of the heart that are present at birth (congenital heart defects); genital abnormalities in affected males; urinary tract defects; and/or other findings. In most cases, the trisomy appears to result from a balanced chromosomal rearrangement in one of the parents; rarely, it is thought to arise from spontaneous (de novo) errors very early in embryonic development that occur for unknown reasons (sporadically). | 256 | Chromosome 4, Partial Trisomy Distal 4q |
nord_256_1 | Symptoms of Chromosome 4, Partial Trisomy Distal 4q | Chromosome 4, Partial Trisomy Distal 4q is commonly characterized by a low birth weight and growth deficiency. In addition, many affected infants have low muscle tone (hypotonia), with unusual “floppiness” of voluntary (skeletal) muscles, or excessive muscle tone (hypertonia), with increased resistance to passive stretching. Additional characteristic features include mental retardation and delays in the acquisition of skills that require the coordination of mental and motor activities (psychomotor retardation). Partial Trisomy Distal 4q is also associated with various malformations of the skull and facial (craniofacial) region. Such features commonly include an abnormally small head (microcephaly); a narrow, sloping forehead; relatively large, low-set, malformed (dysplastic) ears; and/or a short neck. Affected individuals may also have a prominent nasal bridge; an abnormally short vertical groove in the center of the upper lip (i.e., short philtrum); downturned corners of the mouth; pursed lips; a pointed chin; and/or a small, receding jaw (microretrognathia). Various eye (ocular) abnormalities may also be present, such as widely spaced eyes (ocular hypertelorism); narrow, downslanting eyelid folds (palpebral fissures); vertical skin folds that may cover the eyes' inner corners (epicanthal folds); and/or abnormal deviation of one eye in relation to the other (strabismus). Additional ocular abnormalities have also been reported, including drooping of the upper eyelids (ptosis) and/or unusually small eyes (microphthalmia).Limb defects are also commonly associated with the syndrome. Such abnormalities may include malformed hands and feet; abnormal development of the thumbs; webbing or fusion (syndactyly) of certain toes; and/or a deformity in which the heel is turned outward from the midline of the leg (talipes valgus). In some cases, additional physical features may be present. Male infants typically have a developmental defect in which the testes have failed to descend into the pouchlike structure known as the scrotum (cryptorchidism). In addition, about 30 percent of affected infants may have an inguinal or umbilical hernia. In those with an inguinal hernia, there is protrusion (i.e., herniation) of a portion of the intestine into the canal that passes through lower muscular layers of the abdominal wall. (In males, the inguinal canal is the tubular passageway through which the testes normally descend from the abdomen into the scrotum before birth.) An umbilical hernia is a skin-covered protrusion of intestine and the fold of fatty membrane in front of the intestine (omentum) through a defect in the abdominal wall at the navel (i.e., the umbilicus, where the umbilical cord joined the fetal abdomen).Approximately half of affected infants also have various abnormalities of the kidneys and urinary tract, such as underdevelopment of the kidneys (renal hypoplasia); abnormal union of the two kidneys at the base, forming a “horseshoe” shape (horseshoe kidney); swelling (distension) of the kidneys with urine (hydronephrosis) due to narrowing or blockage of the tubes (i.e., ureters) that carry urine from the kidneys into the bladder; and/or other abnormalities. In addition, about half of those with the syndrome also have heart (cardiac) defects and blood vessel (vascular) abnormalities. According to reports in the medical literature, severe cardiac and/or renal defects may lead to potentially life-threatening complications in some cases. | Symptoms of Chromosome 4, Partial Trisomy Distal 4q. Chromosome 4, Partial Trisomy Distal 4q is commonly characterized by a low birth weight and growth deficiency. In addition, many affected infants have low muscle tone (hypotonia), with unusual “floppiness” of voluntary (skeletal) muscles, or excessive muscle tone (hypertonia), with increased resistance to passive stretching. Additional characteristic features include mental retardation and delays in the acquisition of skills that require the coordination of mental and motor activities (psychomotor retardation). Partial Trisomy Distal 4q is also associated with various malformations of the skull and facial (craniofacial) region. Such features commonly include an abnormally small head (microcephaly); a narrow, sloping forehead; relatively large, low-set, malformed (dysplastic) ears; and/or a short neck. Affected individuals may also have a prominent nasal bridge; an abnormally short vertical groove in the center of the upper lip (i.e., short philtrum); downturned corners of the mouth; pursed lips; a pointed chin; and/or a small, receding jaw (microretrognathia). Various eye (ocular) abnormalities may also be present, such as widely spaced eyes (ocular hypertelorism); narrow, downslanting eyelid folds (palpebral fissures); vertical skin folds that may cover the eyes' inner corners (epicanthal folds); and/or abnormal deviation of one eye in relation to the other (strabismus). Additional ocular abnormalities have also been reported, including drooping of the upper eyelids (ptosis) and/or unusually small eyes (microphthalmia).Limb defects are also commonly associated with the syndrome. Such abnormalities may include malformed hands and feet; abnormal development of the thumbs; webbing or fusion (syndactyly) of certain toes; and/or a deformity in which the heel is turned outward from the midline of the leg (talipes valgus). In some cases, additional physical features may be present. Male infants typically have a developmental defect in which the testes have failed to descend into the pouchlike structure known as the scrotum (cryptorchidism). In addition, about 30 percent of affected infants may have an inguinal or umbilical hernia. In those with an inguinal hernia, there is protrusion (i.e., herniation) of a portion of the intestine into the canal that passes through lower muscular layers of the abdominal wall. (In males, the inguinal canal is the tubular passageway through which the testes normally descend from the abdomen into the scrotum before birth.) An umbilical hernia is a skin-covered protrusion of intestine and the fold of fatty membrane in front of the intestine (omentum) through a defect in the abdominal wall at the navel (i.e., the umbilicus, where the umbilical cord joined the fetal abdomen).Approximately half of affected infants also have various abnormalities of the kidneys and urinary tract, such as underdevelopment of the kidneys (renal hypoplasia); abnormal union of the two kidneys at the base, forming a “horseshoe” shape (horseshoe kidney); swelling (distension) of the kidneys with urine (hydronephrosis) due to narrowing or blockage of the tubes (i.e., ureters) that carry urine from the kidneys into the bladder; and/or other abnormalities. In addition, about half of those with the syndrome also have heart (cardiac) defects and blood vessel (vascular) abnormalities. According to reports in the medical literature, severe cardiac and/or renal defects may lead to potentially life-threatening complications in some cases. | 256 | Chromosome 4, Partial Trisomy Distal 4q |
nord_256_2 | Causes of Chromosome 4, Partial Trisomy Distal 4q | In individuals with Chromosome 4, Partial Trisomy Distal 4q, an end (distal) region of the long arm (q) of the fourth chromosome appears three times (trisomy) rather than twice in cells of the body. “Distal” indicates away or farthest from a particular point of reference, meaning the chromosome's centromere (described below). Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p,” a long arm identified by the letter “q,” and a narrowed region at which the two arms are joined (centromere). Chromosomes are further subdivided into bands that are numbered outward from the centromere. For example, the long arm of chromosome 4 includes bands 4q11-q13, bands 4q21-q28, and bands 4q31-q35; the end or “terminal” of 4q is known as “4qter.” In addition, the region containing bands 4q21-q28 is sometimes referred to as “4q2,” while that containing bands 4q31-q35 is also called “4q3.”In individuals with this chromosomal syndrome, the length of the trisomic (duplicated) region of distal 4q may vary: reported cases have included trisomies ranging from 4q21-qter to 4q32-qter. According to investigators, the severity of associated symptoms and findings does not appear to directly correlate with the length of the trisomy. In addition, some affected individuals may have potentially undetectable duplications or deletions (monosomies) of another chromosome (e.g., due to a parental translocation [see below]), possibly contributing to variability of associated clinical features.In most reported cases, Chromosome 4, Partial Trisomy Distal 4q is due to a balanced translocation in one of the parents. Translocations occur when portions of certain chromosomes break off and are rearranged, resulting in shifting of genetic material and an altered set of chromosomes. If a chromosomal rearrangement is balanced, meaning that it consists of an altered but balanced set of chromosomes, it is usually harmless to the carrier. However, such a chromosomal rearrangement may be associated with an increased risk of abnormal chromosomal development in the carrier's offspring.Rare cases have also been reported that appear to result from spontaneous (de novo) errors very early in embryonic development. In such de novo cases, the parents of the affected child usually have normal chromosomes and a relatively low risk of having another child with the chromosomal abnormality.Chromosomal analysis and genetic counseling are typically recommended for the parents of an affected child to help confirm or exclude the presence of a balanced translocation or other chromosomal rearrangement involving chromosome 4 in one of the parents. | Causes of Chromosome 4, Partial Trisomy Distal 4q. In individuals with Chromosome 4, Partial Trisomy Distal 4q, an end (distal) region of the long arm (q) of the fourth chromosome appears three times (trisomy) rather than twice in cells of the body. “Distal” indicates away or farthest from a particular point of reference, meaning the chromosome's centromere (described below). Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as “p,” a long arm identified by the letter “q,” and a narrowed region at which the two arms are joined (centromere). Chromosomes are further subdivided into bands that are numbered outward from the centromere. For example, the long arm of chromosome 4 includes bands 4q11-q13, bands 4q21-q28, and bands 4q31-q35; the end or “terminal” of 4q is known as “4qter.” In addition, the region containing bands 4q21-q28 is sometimes referred to as “4q2,” while that containing bands 4q31-q35 is also called “4q3.”In individuals with this chromosomal syndrome, the length of the trisomic (duplicated) region of distal 4q may vary: reported cases have included trisomies ranging from 4q21-qter to 4q32-qter. According to investigators, the severity of associated symptoms and findings does not appear to directly correlate with the length of the trisomy. In addition, some affected individuals may have potentially undetectable duplications or deletions (monosomies) of another chromosome (e.g., due to a parental translocation [see below]), possibly contributing to variability of associated clinical features.In most reported cases, Chromosome 4, Partial Trisomy Distal 4q is due to a balanced translocation in one of the parents. Translocations occur when portions of certain chromosomes break off and are rearranged, resulting in shifting of genetic material and an altered set of chromosomes. If a chromosomal rearrangement is balanced, meaning that it consists of an altered but balanced set of chromosomes, it is usually harmless to the carrier. However, such a chromosomal rearrangement may be associated with an increased risk of abnormal chromosomal development in the carrier's offspring.Rare cases have also been reported that appear to result from spontaneous (de novo) errors very early in embryonic development. In such de novo cases, the parents of the affected child usually have normal chromosomes and a relatively low risk of having another child with the chromosomal abnormality.Chromosomal analysis and genetic counseling are typically recommended for the parents of an affected child to help confirm or exclude the presence of a balanced translocation or other chromosomal rearrangement involving chromosome 4 in one of the parents. | 256 | Chromosome 4, Partial Trisomy Distal 4q |
nord_256_3 | Affects of Chromosome 4, Partial Trisomy Distal 4q | In observed cases, Chromosome 4, Partial Trisomy Distal 4q has appeared to affect males and females in relatively equal numbers. More than 60 cases have been reported in the medical literature. | Affects of Chromosome 4, Partial Trisomy Distal 4q. In observed cases, Chromosome 4, Partial Trisomy Distal 4q has appeared to affect males and females in relatively equal numbers. More than 60 cases have been reported in the medical literature. | 256 | Chromosome 4, Partial Trisomy Distal 4q |
nord_256_4 | Related disorders of Chromosome 4, Partial Trisomy Distal 4q | Symptoms of the following disorders may be similar to those of Chromosome 4, Partial Trisomy Distal 4q. Comparisons may be useful for a differential diagnosis:Chromosome 4, Trisomy 4p is a rare chromosomal disorder in which all or a portion of the short arm (p) of chromosome 4 appears three times rather than twice in cells of the body. Associated symptoms and findings may vary in range and severity from case to case. However, features commonly include growth deficiency, severe mental retardation, psychomotor retardation, and characteristic craniofacial malformations. Such craniofacial defects may include an abnormally small head (microcephaly); large, malformed ears; a bulbous nose; widely spaced eyes (ocular hypertelorism); a prominent chin; a short neck; and/or other findings. The disorder may also be characterized by skeletal, genital, cardiac, renal, and/or additional physical abnormalities. In many cases, Chromosome 4, Partial Trisomy 4p is due to a balanced chromosomal rearrangement in one of the parents. Other cases have appeared to result from spontaneous (de novo) errors early in embryonic development. (For more information on this disorder, choose “Trisomy 4p” as your search term in the Rare Disease Database.) Additional chromosomal disorders may be characterized by symptoms and findings similar to those associated with Chromosome 4, Trisomy Distal 4q. Chromosomal testing is necessary to confirm the specific chromosomal abnormality present. (For further information on such disorders, choose the name of the specific chromosomal disorder in question or use “chromosome” as your search term in the Rare Disease Database.) | Related disorders of Chromosome 4, Partial Trisomy Distal 4q. Symptoms of the following disorders may be similar to those of Chromosome 4, Partial Trisomy Distal 4q. Comparisons may be useful for a differential diagnosis:Chromosome 4, Trisomy 4p is a rare chromosomal disorder in which all or a portion of the short arm (p) of chromosome 4 appears three times rather than twice in cells of the body. Associated symptoms and findings may vary in range and severity from case to case. However, features commonly include growth deficiency, severe mental retardation, psychomotor retardation, and characteristic craniofacial malformations. Such craniofacial defects may include an abnormally small head (microcephaly); large, malformed ears; a bulbous nose; widely spaced eyes (ocular hypertelorism); a prominent chin; a short neck; and/or other findings. The disorder may also be characterized by skeletal, genital, cardiac, renal, and/or additional physical abnormalities. In many cases, Chromosome 4, Partial Trisomy 4p is due to a balanced chromosomal rearrangement in one of the parents. Other cases have appeared to result from spontaneous (de novo) errors early in embryonic development. (For more information on this disorder, choose “Trisomy 4p” as your search term in the Rare Disease Database.) Additional chromosomal disorders may be characterized by symptoms and findings similar to those associated with Chromosome 4, Trisomy Distal 4q. Chromosomal testing is necessary to confirm the specific chromosomal abnormality present. (For further information on such disorders, choose the name of the specific chromosomal disorder in question or use “chromosome” as your search term in the Rare Disease Database.) | 256 | Chromosome 4, Partial Trisomy Distal 4q |
nord_256_5 | Diagnosis of Chromosome 4, Partial Trisomy Distal 4q | In some cases, the diagnosis of Chromosome 4, Partial Trisomy Distal 4q may be suggested before birth (prenatally) by specialized tests such as ultrasound, amniocentesis, percutaneous umbilical blood sampling, and/or chorionic villus sampling (CVS). During fetal ultrasonography, reflected sound waves create an image of the developing fetus, potentially revealing certain characteristic findings that suggest a chromosomal disorder or other abnormalities. With amniocentesis, a sample of fluid that surrounds the developing fetus is removed and analyzed, while CVS involves the removal of tissue samples from a portion of the placenta. Fetal blood samples may be obtained with a needle guided via ultrasound into a blood vessel in the umbilical cord. Chromosomal analysis performed on such fluid or tissue samples may reveal the presence of Partial Trisomy Distal 4q.Chromosome 4, Partial Trisomy Distal 4q may be diagnosed and/or confirmed after birth (postnatally) by a thorough clinical evaluation, identification of characteristic physical findings, and chromosomal analysis. In addition, diagnostic evaluation may include various studies to help detect and/or characterize certain abnormalities that may be associated with the disorder (e.g., particular craniofacial defects, other skeletal malformations, renal defects, etc.). In addition, a thorough cardiac evaluation may be advised to detect any heart abnormalities that may be present. Such evaluation may include a thorough clinical examination, evaluation of heart and lung sounds through use of a stethoscope, and specialized tests that enable physicians to evaluate the structure and function of the heart (e.g., x-ray studies, electrocardiography [EKG]), echocardiography). | Diagnosis of Chromosome 4, Partial Trisomy Distal 4q. In some cases, the diagnosis of Chromosome 4, Partial Trisomy Distal 4q may be suggested before birth (prenatally) by specialized tests such as ultrasound, amniocentesis, percutaneous umbilical blood sampling, and/or chorionic villus sampling (CVS). During fetal ultrasonography, reflected sound waves create an image of the developing fetus, potentially revealing certain characteristic findings that suggest a chromosomal disorder or other abnormalities. With amniocentesis, a sample of fluid that surrounds the developing fetus is removed and analyzed, while CVS involves the removal of tissue samples from a portion of the placenta. Fetal blood samples may be obtained with a needle guided via ultrasound into a blood vessel in the umbilical cord. Chromosomal analysis performed on such fluid or tissue samples may reveal the presence of Partial Trisomy Distal 4q.Chromosome 4, Partial Trisomy Distal 4q may be diagnosed and/or confirmed after birth (postnatally) by a thorough clinical evaluation, identification of characteristic physical findings, and chromosomal analysis. In addition, diagnostic evaluation may include various studies to help detect and/or characterize certain abnormalities that may be associated with the disorder (e.g., particular craniofacial defects, other skeletal malformations, renal defects, etc.). In addition, a thorough cardiac evaluation may be advised to detect any heart abnormalities that may be present. Such evaluation may include a thorough clinical examination, evaluation of heart and lung sounds through use of a stethoscope, and specialized tests that enable physicians to evaluate the structure and function of the heart (e.g., x-ray studies, electrocardiography [EKG]), echocardiography). | 256 | Chromosome 4, Partial Trisomy Distal 4q |
nord_256_6 | Therapies of Chromosome 4, Partial Trisomy Distal 4q | TreatmentThe treatment of Chromosome 4, Partial Trisomy Distal 4q is directed toward the specific symptoms and findings that are apparent in each individual. Such disease management may require the coordinated efforts of a team of medical professionals, such as pediatricians; surgeons; physicians who diagnose and treat disorders of the skeleton, muscles, joints, and related tissues (orthopedists); heart specialists (cardiologists); urinary tract and kidney specialists; and/or other health care professionals.For affected individuals with congenital heart defects, treatment with certain medications, surgical intervention, and/or other measures may be required. In addition, in some cases, physicians may recommend surgical repair or correction of certain craniofacial malformations, additional skeletal abnormalities, genital defects, hernias, renal and urinary tract anomalies, and/or other malformations associated with the disorder. The specific surgical procedures performed will depend upon the nature and severity of the anatomical abnormalities, their associated symptoms, and other factors.Early intervention services may also be important in ensuring that affected children reach their potential. Special services that may be beneficial include special remedial education, physical therapy, and/or other medical, social, and/or vocational services. Genetic counseling will also be of benefit for families of affected children. Other treatment for this disorder is symptomatic and supportive. | Therapies of Chromosome 4, Partial Trisomy Distal 4q. TreatmentThe treatment of Chromosome 4, Partial Trisomy Distal 4q is directed toward the specific symptoms and findings that are apparent in each individual. Such disease management may require the coordinated efforts of a team of medical professionals, such as pediatricians; surgeons; physicians who diagnose and treat disorders of the skeleton, muscles, joints, and related tissues (orthopedists); heart specialists (cardiologists); urinary tract and kidney specialists; and/or other health care professionals.For affected individuals with congenital heart defects, treatment with certain medications, surgical intervention, and/or other measures may be required. In addition, in some cases, physicians may recommend surgical repair or correction of certain craniofacial malformations, additional skeletal abnormalities, genital defects, hernias, renal and urinary tract anomalies, and/or other malformations associated with the disorder. The specific surgical procedures performed will depend upon the nature and severity of the anatomical abnormalities, their associated symptoms, and other factors.Early intervention services may also be important in ensuring that affected children reach their potential. Special services that may be beneficial include special remedial education, physical therapy, and/or other medical, social, and/or vocational services. Genetic counseling will also be of benefit for families of affected children. Other treatment for this disorder is symptomatic and supportive. | 256 | Chromosome 4, Partial Trisomy Distal 4q |
nord_257_0 | Overview of Chromosome 4, Trisomy 4p | Chromosome 4, Trisomy 4p is a rare chromosomal disorder in which all or a portion of the short arm (p) of chromosome 4 appears three times (trisomy) rather than twice in cells of the body. Associated symptoms and physical findings may vary greatly in range and severity from case to case. Such variability may depend upon the specific length and location of the duplicated (trisomic) portion of chromosome 4p as well as other factors. However, many affected infants may have feeding and breathing difficulties, characteristic malformations of the head and facial (craniofacial) area, and abnormalities of the hands and feet. Additional features may include other skeletal defects, genital abnormalities in affected males, or heart (cardiac) defects. Trisomy 4p is also characterized by severe mental retardation. | Overview of Chromosome 4, Trisomy 4p. Chromosome 4, Trisomy 4p is a rare chromosomal disorder in which all or a portion of the short arm (p) of chromosome 4 appears three times (trisomy) rather than twice in cells of the body. Associated symptoms and physical findings may vary greatly in range and severity from case to case. Such variability may depend upon the specific length and location of the duplicated (trisomic) portion of chromosome 4p as well as other factors. However, many affected infants may have feeding and breathing difficulties, characteristic malformations of the head and facial (craniofacial) area, and abnormalities of the hands and feet. Additional features may include other skeletal defects, genital abnormalities in affected males, or heart (cardiac) defects. Trisomy 4p is also characterized by severe mental retardation. | 257 | Chromosome 4, Trisomy 4p |
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