COL1A2 and osteogenesis imperfecta: Pathogenic variants were detected in 57 OI patients, 39 patients with COL1A1 mutation, 10 with COL1A2 mutation, and 8 with other rare genes mutations (IFITM5 n = 4, P3H1 n = 2, WNT1 n = 1, FKBP10 n = 1).