Ankylosing spondylitis is primarily an autoimmune disease affecting the axial joints, which may also manifest with extra-articular symptoms. In severe cases, deformities and stiffening of the spine can occur. The cause of the disease is attributed to the interactive effects of genetics and environmental factors, making it a multi-gene inherited disorder. However, for some individuals, it may also be related to infections such as Ureaplasma urealyticum, Shigella, Salmonella, and Escherichia coli in the urinary and genital tracts. These pathogens trigger the body's inflammatory immune response, resulting in tissue damage and contributing to the onset and progression of the disease. There is a notable familial aggregation in the occurrence of this disease.