COL1A1 and osteoporosis: In this study, we enrolled 135 Chinese probands of OI with de novo or inherited COL1A1/COL1A2 mutations in the department of Osteoporosis and Bone Disease of Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, and then compared the gene mutation spectrum and phenotypic characteristics to investigate differences between de novo and inherited mutations among OI with COL1A1/COL1A2 mutations.