Ankylosing spondylitis is a chronic inflammatory disease that causes arthritis of the spine and hips. It can also affect other joints such as the knees, and it can cause inflammation of the eyes, lungs, or heart valves.

Ankylosing Spondylitis
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The cause of ankylosing spondylitis is not known. However, most people with ankylosing spondylitis share a common gene marker called HLA-B27. This finding indicates that genes play an important role in the development of this condition.