Ankylosing spondylitis is an inflammatory disease that, over time, can cause some of the bones in the spine (vertebrae) to fuse. This fusing makes the spine less flexible and can result in a hunched posture. If ribs are affected, it can be difficult to breathe deeply. Ankylosing spondylitis affects men more often than women. Signs and symptoms typically begin in early adulthood. Inflammation can also occur in other parts of the body — most commonly, the eyes.