Ankylosing Spondylitis is a progressive form of arthritis that targets the spine and sacroiliac joints. Over time, the condition may cause stiffening of the spine and eventually the bones in the spine (vertebrae), may fuse together. Because of this, as the disease progresses, many people develop bent posture. Ankylosing Spondylitis affects 129 out of every 100,000 people in the US and although the average patient is a male, ages 15-30, women are affected as well. Many researchers believe men are more likely to develop the disease than women, while others argue that the incidence in men in women is equal.