IFITM5 and osteogenesis imperfecta type 5: A recurrent gain-of-function mutation in the 5’‐UTR of IFITM5 (c.‐14C > T), encoding bone-restricted interferon-inducible transmembrane (IFITM5)-like protein (BRIL), is the cause of almost all instances of OI type V [39, 40].