Eighty per cent of causative OI mutationswere detected in genes related to autosomal dominant OI (COL1A1,COL1A2 and IFITM5 genes) and 17% in genesinvolved in autosomal recessive OI forms (P3H1 orFKBP10 genes). The gene discussed is IFITM5; the disease is osteogenesis imperfecta.