Collagens are highly conserved and are characterized by an uninterrupted Glycine-X-Y triplet repeat. Col1, the fibrillar collagen found in most connective tissues, is the only component of the collagen found in cartilage. Mutations in this gene are associated with osteogenesis imperfecta, Ehlers-Danlos syndrome, and idiopathic osteoporosis. Col2, a fibrillar collagen found in cartilage and the vitreous humor of the eye. Mutations in this gene are associated with achondrogenesis, chondrodysplasia, early onset familial osteoarthritis, SED congenita, Langer-Saldino achondrogenesis, Kniest dysplasia. Col3 is a fibrillar collagen that is found in extensible connective tissues such as skin, lung, and the vascular system, frequently in association with type I collagen. Mutations in this gene are associated with Ehlers-Danlos syndrome type IV, aortic and arterial aneurysms. Col4 is a major consitiuent of the basement membranes along with laminins and enactins. It is composed of alpha 1 IV chain and alpha 2 IV chain in 2:1 ratio. Col4 antibodies are useful in detecting the loss of parts of basement membrane in carcinomas. Col5 is found in tissues containing Col1 and appears to regulate the assembly of heterotypic fibers composed of both Col1 and Col5. Col5 is closely related to type XI collagen; mutations in this gene are associated with Ehlers-Danlos syndrome.
CO4A5; Collagen alpha-5(IV) chain; collagen IV, alpha-5 polypeptide; collagen of basement membrane, alpha-5 chain; collagen type IV alpha5 chain; collagen, type IV, alpha 5; dA149D17.3; dA24A23.1; procollagen type IV alpha 5; procollagen, type IV, alpha 5