What is the cause of ankylosing spondylitis?
Although the exact cause of AS is unknown, we do know that genetics play a key role. Most individuals who have AS also have a gene that produces a “genetic marker” – in this case, a protein – called HLA-B27. This marker is found in over 95% of people of European ancestry with AS. However, scientists know that other genes, along with a triggering environmental factor, such as a bacterial infection, are needed to trigger AS in susceptible people. Back to top… What is the HLA-B27 gene? HLA-B27 is a perfectly normal gene found in 8% of the general population. Generally speaking, no more than 2% of people born with this gene will eventually get spondylitis. The gene itself does not cause spondylitis, but people with HLA-B27 are more susceptible to getting spondylitis. Back to top… If a parent, brother or sister has spondylitis, and I test positive for HLA-B27, what are my chances of getting the disease? If a family member had spondylitis and you test positive for the HLA-B27 gene, your
