This gene encodes one of the three alpha chains of type IX collagen, the major collagen component of hyaline cartilage. Type IX collagen, a heterotrimeric molecule, is usually found in tissues containing type II collagen, a fibrillar collagen. Mutations in this gene are associated with multiple epiphyseal dysplasia type 3. [provided by RefSeq, Jan 2010],disease:Defects in COL9A3 are the cause of multiple epiphyseal dysplasia type 3 (EDM3) [MIM:600969], also known as multiple epiphyseal dysplasia with myopathy. EDM is a generalized skeletal dysplasia associated with significant morbidity. Joint pain, joint deformity, waddling gait, and short stature are the main clinical signs and symptoms. EDM is broadly categorized into the more severe Fairbank and the milder Ribbing types.,function:Structural component of hyaline cartilage and vitreous of the eye.,PTM:Covalently linked to the telopeptides of type II collagen by lysine-derived cross-links.,PTM:Prolines at the third position of the tripeptide repeating unit (G-X-Y) are hydroxylated in some or all of the chains.,similarity:Belongs to the fibril-associated collagens with interrupted helices (FACIT) family.,subunit:Heterotrimer of an alpha 1(IX), an alpha 2(IX) and an alpha 3(IX) chain.,
