Walsh & Hoyt: Seronegative (HLA-B27-Associated) Spondyloarthropathies

The seronegative spondyloarthropathies include ankylosing spondylitis, Reiters syndrome, psoriatic arthritis, and arthritis with inflammatory bowel disease. Ankylosing spondylitis, a rare disorder that affects about 0.10.2% of the population, is characterized by damage to the axial skeleton causing bony fusion (ankylosis). The cause is unknown. About 90% of patients with this condition possess HLA-B27, which is present in only 68% of the normal population. Ankylosing spondylitis affects men more often than women, and it is much more common in Caucasians than in dark-skinned races.