This is an uncommon genetic disease that causes low back pain. It is characterized by a stiffening of the spine due to a calcification of the ligaments that are responsible for movement between the bones of the neck and back. Ankylosing spondylitis can cause pain elsewhere in the body including the heel and the sacroiliac joint. There are also other organ systems that can be affected by the disease, such as the intestines. While ankylosing spondylitis is not curable, many secondary complications that result from this condition can be prevented if detected soon enough.