Table 1.

HLA-B27-associated spondyloarthritides

Disease	HLA-B27 frequency (%) (approximate)
Ankylosing spondylitis	96
Undifferentiated spondyloarthropathy	70
Reactive arthritis	30–70
Colitis-associated spondyloarthritis	33–75
Psoriatic spondyloarthritis	40–50
Juvenile enthesitis-related arthritis	70
Iritis	50
Cardiac conduction defects with aortic incompetence	Up to 88