Collagen alpha-1(XII) chain is a protein that in humans is encoded by the COL12A1 gene.
This gene encodes the alpha chain of type XII collagen, a member of the FACIT (fibril-associated collagens with interrupted triple helices) collagen family. Type XII collagen is a homotrimer found in association with type I collagen, an association that is thought to modify the interactions between collagen I fibrils and the surrounding matrix.
Alternatively spliced transcript variants encoding different isoforms have been identified.
Mutations in COL12A1 are known to cause the following conditions: