COL1A1 and osteogenesis imperfecta: Up to 90% of OI cases are caused by autosomal dominant (AD) pathogenic variants in the COL1A1, COL1A2 genes and the IFITM5 (OMIM 614757) gene, with a 50% probability of transmission of the pathogenic variant to the next generation [11, 34, 36, 53, 54] (Table 2, Fig. 1).