Rheumatoid arthritis is a common autoimmune disease in which the individual’s own immune system attacks the lining of the joints, causing stiffness and muscle aches. Like other autoimmune diseases, development of rheumatoid arthritis is likely caused by a complex combination of genetic and environmental factors. Recent research into the genetics of the disease has identified many of the genetic factors, and new studies continue to implicate additional variants that may influence risk.
A pair of such studies published this week in Nature Genetics found several new genetic variants associated with rheumatoid arthritis. In Japan, a team led by Yuta Kochi and Kazuhiko Yamamoto from the RIKEN Center for Genomic Medicine identified a variant, associated with rheumatoid arthritis risk in over 2,000 Japanese individuals with the disease and 3,400 individuals free of the disease. The second study, headed by Eli Stahl and Robert Plenge at Brigham and Women’s Hospital in Boston, confirmed the same association in over 10,000 people of European ancestry with rheumatoid arthritis.
One of the variants is in an area of the genome associated with a risk for Crohn’s disease and contains a gene called CCR6 that is known to be involved in the immune system. In follow-up experiments, the RIKEN team demonstrated that the different versions of the variant affect the behavior of CCR6, providing a potential biological explanation for the variant’s contribution to rheumatoid arthritis risk. Stahl and his colleagues also found several other genomic regions associated with rheumatoid arthritis in people with European ancestry, some of which had not yet been linked to autoimmune disease.
