tokens: In order to identify common affected molecular - pathways and disease biomarkers in OI probands with different mutations and lethal or surviving phenotypes , primary fibroblasts from dominant OI patients , carrying COL1A1 or COL1A2 defects , were investigated by applying a Tandem Mass Tag labeling - Liquid Chromatography - Tandem Mass Spectrometry ( TMT LC - MS / MS ) proteomics approach and bioinformatic tools for comparative protein - abundance profiling .