COL11A1 gene encodes pro-alpha1(XI) chain, one of the alpha chains that form type XI collagen. Type XI collagen is a trimer composed of three different chains: alpha 1(XI), alpha 2(XI) and alpha 3(XI). It may be involved in fibrillogenesis and contributes to maintaining the structure of type II collagen. COL11A1 mutations are known to cause multiple disorders, including type II Stickler syndrome, Marshall syndrome and fibrochondrogenesis.