Recently, a modified classification system that categorizes OI into types 1 to 5 has been developed, adding type 5 OI to the classical classification (3); type 5 OI is characterized by calcification of interosseous membranes and hyperplastic callus caused by recurrent c.-14C > T variant in IFITM5 (4, 5). Here, IFITM5 is linked to osteogenesis imperfecta.