In addition to causing fusion of the spine, ankylosing spondylitis also can cause inflammation in the ribs, hips, hands, shoulders, and feet. This form of arthritis also can affect the eyes and occasionally the lungs and heart. While there is no known cure for ankylosing spondylitis, treatment can decrease pain and alleviate symptoms. People should see a doctor immediately if they experience pain in the low back or buttocks that begins slowly, worsens in the morning, and wakes them up in the second half of the night. It is particularly concerning if the pain improves with exercise and worsens with rest. While there is no known cause, people with the HLA-B27 gene are at a significantly higher risk for developing symptoms (although many people who have this gene never develop this condition. For people with ankylosing spondylitis, physical therapy provides pain relief and improves strength and flexibility. A physical therapist may prescribe specific range-of-motion and stretching exercises to help maintain joint flexibility and upright posture. He or she may put specific emphasis on strengthening the back and neck as well as on deep breathing training and aerobic exercises to maintain chest and rib flexibility. Aquatic therapy may also be beneficial.