COL1A1 and osteogenesis imperfecta: In total, we identified 28 different variants in nine OI genes, including 10 COL1A1, five COL1A2, three BMP1, three FKBP10, two TMEM38B, two P3H1, one CRTAP, one SERPINF1, and one SERPINH1 (Table 1).