IFITM5 pathogenic variant causes osteogenesis imperfecta V with various phenotype severity in Ukrainian and Vietnamese patients

Background Osteogenesis imperfecta (OI) covers a spectrum of bone fragility disorders. OI is classified into five types; however, the genetic causes of OI might hide in pathogenic variants of 20 different genes. Often clinical OI types mimic each other. This sometimes makes it impossible to identify the OI type clinically, which can be a risk for patients. Up to 90% of OI types I–IV are caused by pathogenic variants in the COL1A1/2 genes. OI type V is caused by the c.-14C > T pathogenic variant in the 5′UTR of the IFITM5 gene and is characterized by hyperplastic callus formation and the ossification of interosseous membranes.