Spondyloepiphyseal dysplasia tarda simulating juvenile arthritis: clinical and molecular genetic observations.

A sibship is reported in which two of three children developed a symmetrical polyarthropathy associated with a mild spondyloepiphyseal dysplasia. Although the physical findings resembled juvenile arthritis, laboratory investigations for inflammatory disease were entirely negative. Molecular studies in members of this family showed that none of them had any structural rearrangements or other major abnormality of the type II procollagen gene (COL2A1). The laboratory findings in this family with "pseudo-rheumatoid arthritis" do not exclude the possibility of a minor mutation of the type II procollagen gene or a defect in the processing of articular cartilage collagens.