Genetic breakthrough for ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic form of arthritis that attacks the spine, causing the vertebrae to fuse, resulting in loss of normal curvature, as well as affecting other joints and organs. New findings concerning the genetic basis of the disease could lead to novel therapies for the condition, which is thought to affect around one in 200 men and one in 500 women, usually developing during adolescence and young adulthood. The discovery of the genes, ARTS1 and IL23R, represent a considerable advance in our knowledge of the genetic basis of AS; until now only one gene (HLA-B27) has been known to be influential in the condition. Professor John Reveille, Director of Rheumatology and Clinical Immunogenetics at the University of Texas Medical School (TX, USA) and one of the lead researchers on the project, explains. “Now we have found two new genes. Together with HLA-B27, these genes account for roughly 70% of the overall cause. This means we’ve almost nailed this disease.” The discovery of both genes is the result of a comprehensive scan of the human genome, using a method known as genome-wide association scanning, to compare the DNA of thousands of sufferers with healthy controls to find what genetic differences there are between the two groups. Reveille is convinced that further discoveries concerning the genetics that underlie AS are soon to be made; “Within the next year, I predict we will have identified all the genes that play a role in this insidious disease. There is more exciting news to come.” Scientists believe that AS is triggered in susceptible individuals by common gut bacteria, although the exact mechanism behind this is unclear at present.