Ankylosing Spondylitis
by Dr. Nazanin Firooz
What is Spondyloarthritis?
Who gets it?
Age: Unlike most other forms of arthritis, AS is usually seen in younger people. It usually begins in the teens or 20’s, with typical age of onset anywhere from age 17 – 45
Gender: It is likely to happen in 2 – 3 times more frequently in the males than females, unlike many other rheumatologic conditions
Genetics: Having a family member with AS puts a patient at higher risk of getting it, partly due to an inherited gene known as the HLA-B27 gene. The HLA-B27 gene is actually present in about 8% of healthy individuals in society. Of this 8% of people with a positive HLA-B27 gene, only 2% of them develop ankylosing spondylitis. If you have a first degree relative that is affected and you are HLA-B27 positive, your risk increases to 15 – 20%. Though infrequent, 90% of white AS patients and 50 – 80% of non-white AS patients have a positive HLA-B27.
Race: The highest frequency of this condition is in more northern populations, such as Scandinavians, Alaskans, Siberian Eskimos, and Native American tribes. These populations have a higher prevalence of the HLA B-27 genes, and the prevalence of the disease decreases from north to south as you near the equator. African Americans seem to be affected the least of all races.
What exactly happens in the disease?
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References