What is ankylosing spondylitis? Ankylosing spondylitis (AS) is a peripheral disease characterized by chronic inflammation of the sacroiliac joints and spine. The common symptoms are stiffness or pain in the lower back, which can be relieved by activity; in advanced stages, spinal ankylosis, deformity and even severe functional impairment can occur, mostly in adolescent males. There is a significant family aggregation of AS, with more than 90% of patients carrying HLA-B27, an antigen present on chromatin directly related to genetics in human leukocytes and coded at different loci. However, only 20% of the HLA-B27 positive population has AS, so it is not true that “HLA-B27 positivity means AS”. However, young men between the ages of 20 and 30 should be especially alert if they have recurrent intestinal and urinary tract infections and a family history of AS, and are also HLA-B27 positive. When there is low back pain, especially stiffness in the morning after waking up and relieved after activity, or inflexible lumbar activities and other symptoms should seek medical attention for early diagnosis and treatment. Note for AS patients: 1. Insist on functional joint exercises. 2, gradually increase the intensity of exercise, in order not to increase joint pain is moderate. 3, the active period must be combined with drug therapy.