Ankylosing spondylitis — also known as AS — is an inflammatory disease that primarily affects the spine. Men get this disease more often than women. Symptoms usually begin in early adulthood — between the ages of 17 and 40. The first symptom is often pain and stiffness in the lower back, buttocks, and hips. It’s caused by inflammation of the joints located where the base of your spine meets your pelvis. In a healthy spine, the bones fit together like a puzzle. They’re separated by tissue, which allows your back to be flexible. With “AS,” the inflammation affects the cushioning between the bones, and that can make you less able to move your back. Although “AS” mainly harms the spine, it can affect the tissues throughout the body. Some people have eye inflammation. And in rare cases, heart and lung problems can happen. The cause of AS is unknown. But genetics do seem to play a role. About 90% of people with it carry a gene called HLA B27. But not all people with this gene go on to develop the disease. There’s no cure for “AS” yet, but your doctor can give you options to help manage your symptoms and pain.