The absence of major skeletal abnormalities in Ifitm5-deficient mice leads to the possibility that OI type V may be treatable by suppressing the expression of both wild-type (WT) and c.-14C > T mutant Ifitm5, which is a similar condition to that in Ifitm5-deficient mice. This evidence concerns the gene IFITM5 and osteogenesis imperfecta type 5.