Ankylosing Spondylitis (AS) is a type of inflammatory arthritis that primarily affects the spine. It causes pain and stiffness in the back, which can worsen over time. In some cases, the inflammation can lead to the fusion of the vertebrae, resulting in a rigid spine. AS is more common in young men and often begins in early adulthood. The exact cause of AS is not fully understood, but it is associated with a genetic marker known as HLA-B27. Symptoms may include chronic back pain, reduced flexibility, and fatigue. Early diagnosis and treatment can help manage symptoms and improve quality of life.