COL1A2 and osteogenesis imperfecta: Moreover, new OI models are being developed in different OI research groups, such as Brtl Ser (which presents the mutation G349S in the col1a1 gene), high bone-mass mice (HBM; a mutation in the col1a1 gene; type I procollagen c-propeptide cleavage defect), Tmem38b−/− and Mbtps2.