This gene encodes one of the three alpha chains of type IX collagen, a collagen component of hyaline cartilage. Type IX collagen is usually found in tissues containing type II collagen, a fibrillar collagen. Studies in knockout mice have shown that synthesis of the alpha 1 chain is essential for assembly of type IX collagen molecules, a heterotrimeric molecule, and that lack of type IX collagen is associated with early onset osteoarthritis. Mutations in this gene may be associated with multiple epiphyseal dysplasia. Two transcript variants have been identified for this gene.[6]
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Warman ML, Tiller GE, Polumbo PA, et al. (1993). "Physical and linkage mapping of the human and murine genes for the alpha 1 chain of type IX collagen (COL9A1)". Genomics. 17 (3): 694–8. doi:10.1006/geno.1993.1391. PMID8244386.
Pihlajamaa T, Vuoristo MM, Annunen S, et al. (1998). "Human COL9A1 and COL9A2 genes. Two genes of 90 and 15 kb code for similar polypeptides of the same collagen molecule". Matrix Biol. 17 (3): 237–41. doi:10.1016/S0945-053X(98)90063-4. PMID9707347.
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