The A subfamily is composed of the IFN-inducible and antiviral IFITM1, 2 and 3, as well as of IFITM5 and IFITM10, which are not IFN regulated and that in the case of IFITM5 are associated to Osteogenesis imperfecta type V, a bone-related genetic disease (4). Here, IFITM10 is linked to osteogenesis imperfecta type 5.