Perturbations in fatty acid metabolism and collagen production infer pathogenicity of a novel MBTPS2 variant in Osteogenesis imperfecta

(i) PCR-sequencing: Chromatograms were generated by PCR-sequencing of a region within exon 4 of MBTPS2 using DNA extracted from a healthy control and the proband's fibroblasts (ii) Gene expression was quantified by qRT-PCR using RNA extracted from fibroblasts. Transcript levels of each gene of interest was calculated using the 2^-deltaCt method with normalization to the average Ct values of endogenous control genes GAPDH, IPO8 and TBP. (iii) Cellular fatty acid content was quantified by GC-MS/MS. Each table represents one technical replicate. Absolute values of each fatty acid are listed in the tables; relative ratios of various fatty acids are calculated at the bottom of each table. (iv) Immunocytochemistry images of ECM proteins (COL1 = collagen type I; COL4 = collagen type IV; COL5 = collagen type V; a2b1 = integrin a2b1) and binding of collagen-hybridising peptide (R-CHP).