What are the causes for Ankylosing Spondylitis, Radiologic Perspective?

Although the exact cause is unknown, ankylosing spondylitis is believed to be due to combination of a genetic influence and a triggering environmental factor. Most patients with ankylosing spondylitis have the tissue antigen human leukocyte antigen B27 (HLA-B27). People with ankylosing spondylitis often have a family history of the disease.

Source: http://www.emedicinehealth.com