A unifying concept for the spondyloarthropathies.

A group of diseases--ankylosing spondylitis, psoriatic arthritis, Reiter's disease, ulcerative colitis, Crohn's disease, juvenile chronic arthritis (Still's disease), Whipple's disease, and Behçet's syndrome, which previously were thought to be variants of rheumatoid arthritis, now appear to be distinct from that disease but linked together in a group termed "seronegative spondyloarthropathies." Detailed studies have been made of the clinical, radiologic, and serologic features of these individual diseases. Extensive family studies have been done epidemiologically and through examining pedigrees. These have demonstrated clinical interrelations and familial aggregation. Ankylosing spondylitis is a feature of all the groups. Studies in which B27 was found more frequently in each of these groups confirm the interrelation and suggest a genetic predisposition with a gene related to B27. There is other evidence for environmental factors such as infection in certain of the diseases. The findings have important implications in the management of the disorders.