Which genetic marker is commonly associated with Ankylosing Spondylitis?

Ankylosing Spondylitis (AS) is a type of inflammatory arthritis primarily affecting the spine and the sacroiliac joints. One of the most significant genetic markers associated with this condition is HLA-B27. This human leukocyte antigen is a protein that plays a crucial role in the immune system's ability to recognize antigens.

The association between HLA-B27 and Ankylosing Spondylitis is well established, with a substantial percentage of individuals diagnosed with the condition testing positive for this marker. In fact, studies show that about 90% of patients with Ankylosing Spondylitis are HLA-B27 positive. While the presence of the marker does not cause the disease, it significantly increases the risk of developing it.

On the other hand, HLA-DR4 is more closely associated with rheumatoid arthritis; HLA-A1 and HLA-DQ2 are linked to other autoimmune conditions such as celiac disease and type 1 diabetes. Therefore, HLA-B27 stands out as the primary and most critical genetic marker relevant to Ankylosing Spondylitis. Understanding the genetic predisposition can assist clinicians in diagnosing and managing the disease effectively.