Ankylosing spondylitis: Which genetic marker is commonly associated?

Ankylosing spondylitis: Which genetic marker is commonly associated?

• A. HLA-B27 is absent
• B. HLA-B8
• C. HLA-B27 is present
• D. HLA-DR4

Answer: (C)

Ankylosing spondylitis is strongly linked to the HLA-B27 antigen, a specific MHC class I molecule. The presence of HLA-B27 is found in a large proportion of patients with AS and supports the diagnosis when inflammatory back pain and other signs are present. It’s not exclusive, since many people carry HLA-B27 without developing AS, and a minority of AS patients are HLA-B27 negative, but overall this marker is the most commonly associated genetic finding. Other HLA types like HLA-B8 or HLA-DR4 are more associated with different autoimmune conditions, so they aren’t the characteristic marker for AS.

Ankylosing spondylitis is strongly linked to the HLA-B27 antigen, a specific MHC class I molecule. The presence of HLA-B27 is found in a large proportion of patients with AS and supports the diagnosis when inflammatory back pain and other signs are present. It’s not exclusive, since many people carry HLA-B27 without developing AS, and a minority of AS patients are HLA-B27 negative, but overall this marker is the most commonly associated genetic finding. Other HLA types like HLA-B8 or HLA-DR4 are more associated with different autoimmune conditions, so they aren’t the characteristic marker for AS.