Osteogenesis imperfecta (OI) is a hereditary connective tissue disorder primarily characterized by fragile bones.487 The etiology of OI is mainly linked to genetic mutations, particularly those involving the COL1A1 or COL1A2 genes, which encode the alpha-1 and alpha-2 chains of type I collagen, a key component of the skeletal structure. The gene discussed is COL1A1; the disease is osteogenesis imperfecta.