tokens: Heterozygous inactivating mutations involving the maternal GNAS exons 1 - 13 that encodes the alpha subunit of the stimulatory G protein ( Gsα ) cause inactivating parathyroid hormone ( PTH)/PTHrP signalling disorder type 2 ( iPPSD2 or PHP type 1A ) , which is characterized by Albright hereditary osteodystrophy and resistance to multiple hormones that act through the Gsα signalling pathway ( including PTH , thyroid - stimulating hormone , and α - melanocyte - stimulating hormone ) .