The invention provides isolated nucleic acids molecules, designated collagen XXII nucleic acid molecules, which encode a novel collagen. The invention also provides antisense nucleic acid molecules, recombinant expression vectors containing collagen XXII nucleic acid molecules, host cells into which the expression vectors have been introduced, and nonhuman transgenic animals in which a collagen XXII gene has been introduced or disrupted. The invention still further provides isolated collagen XXII proteins, fusion proteins, antigenic peptides and anti-collagen XXII antibodies. Diagnostic methods utilizing compositions of the invention are also provided.