Following this example, I propose to define osteogenesis imperfecta as syndromes resulting from mutations in either COL1A1 or COL1A2 genes, and to group all other syndromes with congenital brittle bones as "syndromes resembling OI" (SROI), pending the identification of their causal mutation. This evidence concerns the gene COL1A2 and osteogenesis imperfecta.