Ankylosing spondylitis and other spondyloarthropathies.

: Ankylosing spondylitis and related spondyloarthropathies show a remarkable association with a genetic marker--HLA-B27--and also illustrate the relationship between host and environmental factors. HLA-B27 has revitalized the epidemiology of spondyloarthropathies and has helped to broaden the clinical spectrum of these diseases. These and other aspects of descriptive and genetic epidemiology are reviewed.