Ankylosing spondylitis is a systemic autoimmune disease of unclear etiology characterized by chronic inflammation primarily affecting the axial joints, mainly involving the sacroiliac joint. The cause is unclear, and research by experts has shown that the disease tends to run in families, indicating familial clustering. It is not classified as a genetic disease, but there is both familial clustering and a genetic predisposition, meaning that if parents have the disease, their children are much more likely to develop it compared to others. Therefore, if symptoms such as lower back pain or neck stiffness occur, it is advisable to undergo thorough examinations and seek early diagnosis and treatment to delay joint deformity and control the progression of the disease.