Ankylosing spondylitis is a chronic progressive inflammatory disease of the spine, with inflammation of the sacroiliac joints and spinal attachment points as the primary lesions. Alternatively, it has been defined as a chronic inflammatory disease that primarily involves the spine, the medial skeleton, and the large joints of the extremities, and is characterized by fibrosis and ossification of the intervertebral disc rings and adjacent connective tissue, as well as joint ankylosis. Many patients with ankylosing spondylitis have ankylosing spondylitis in their immediate family. The chance of inheriting ankylosing spondylitis is relatively high among rheumatic immune diseases. The development of ankylosing spondylitis is closely related to human leukocyte-associated antigen B27, also known as HLA-B27. There is a clear tendency for this disease to cluster in families, which means that the disease has a definite genetic predisposition. Two to seven percent of healthy people can also be HLA-B27 positive. Therefore, not all HLA-B27-positive people can develop ankylosing spondylitis. However, the rate of HLA-B27 positivity in patients with ankylosing spondylitis can be as high as about 90% in our patients. So the rate of HLA-B27 positivity in patients with ankylosing spondylitis is high. People with ankylosing spondylitis have a 50% chance of having HLA-B27 in their immediate family, and up to 20% of these people can develop the disease.