Ankylosing Spondylitis

Ankylosing spondylitis (AS) is a chronic, inflammatory disease of the axial spine. Chronic back pain and progressive spinal stiffness are the most common features of this disease. Involvement of the spine, sacroiliac joints, peripheral joints, digits, and entheses are characteristic.

What is the main cause of ankylosing spondylitis?

Ankylosing spondylitis has no known specific cause, though genetic factors seem to be involved. In particular, people who have a gene called HLA-B27 are at a greatly increased risk of developing ankylosing spondylitis. However, only some people with the gene develop the condition.