COL1A1 and osteogenesis imperfecta: Over 1000 distinct mutations in the primary genetic sequence of COL1A1 and COL1A2 have been identified in one or different OI variants [1,2] (Dalgleish R.: Osteogenesis Imperfecta Variant Database (https://oi.gene.le.ac.uk, accessed January 21st 2013).