Collagen alpha-1(X) chain is the alpha chain of type X collagen, a short chain collagen expressed by hypertrophic chondrocytes during endochondral ossification. Unlike type VIII collagen, the other short chain collagen, type X collagen is a homotrimer. Mutations in this gene are associated with Schmid type metaphyseal chondrodysplasia (SMCD) and Japanese type spondylometaphyseal dysplasia (SMD).

During development and growth of long bones, chondrocytes pass sequentially through a proliferative, a hypertrophic and a degenerative stage, each characterized by a particular set of collagen types. Proliferative (stage I) chondrocytes synthesize type II collagen as the major collagen and types IX and XI as the minor collagens.