Antibodies against type XI collagen, along with other collagen fibers, are detected in the sera of RA patients.[18] Thus, type XI collagen could act as an autoantigen, leading to the production of autoantibodies, and in this patient, the conformational changes induced by the variants in the COL11A2 gene may have changed the immunogenicity of type XI collagen, leading to the production of autoantibodies and arthritis. This evidence concerns the gene COL11A2 and arthritic joint disease.