Ankylosing Spondylitis
What is ankylosing spondylitis?
Anatomy of the male pelvis
Ankylosing spondylitis (AS) is a type of arthritis that affects the spine. "Ankylosing" means stiff or rigid, "spondyl" means spine, and "itis" refers to inflammation. The disease causes inflammation of the spine and large joints, resulting in stiffness and pain. The disease may result in erosion at the joint between the spine and the hip bone (the sacroiliac joint), and the formation of bony bridges between vertebrae in the spine, fusing those bones. In addition, bones in the chest may fuse. The cause of AS is unknown, although researchers suspect genetics play a role. A gene called HLA-B27 occurs in over 95 percent of those with AS. However, some people with the HLA-B27 gene do not have AS.
Who is affected by ankylosing spondylitis?
AS is more common among young people, ages 17 to 35, but it can occur in children and older adults as well. The disease affects two to three times more young men than women and it tends to run in families.
