SNPwatch: Two Studies Connect More Immune System Genes to Rheumatoid Arthritis

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, rs3093024, 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. In both studies, each copy of the A version of the variant increased an individual’s odds of the disease by about 1.1-1.2 times.

The area of the genome surrounding rs3093024 has already been connected to risk of 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 rs3093024 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.

(23andMe Complete Edition customers can see their data for rs3093024 and the variants identified by Stahl and his colleagues using the Browse Raw Data feature. See the table below for information on each variant.)

Genetic variants newly associated with rheumatoid arthritis

Variant	Risk Version	Effect on Odds	Population	Reference
rs3093024	A	1.10-1.19	Asian, European	Kochi et al., Stahl et al.
rs10065637*	C	1.18	European	Stahl et al.
rs26232	C	1.08	European	Stahl et al.
rs10517086*	A	1.18	European	Stahl et al.
rs10488631	C	1.25	European	Stahl et al.

* 23andMe does not provide data on the variant reported in the study, but does provide data on a variant that correlates perfectly with it in the population specified.

SNPwatch gives you the latest news about research linking various traits and conditions to individual genetic variations. These studies are exciting because they offer a glimpse into how genetics may affect our bodies and health; but in most cases, more work is needed before this research can provide information of value to individuals. For that reason it is important to remember that like all information we provide, the studies we describe in SNPwatch are for research and educational purposes only. SNPwatch is not intended to be a substitute for professional medical advice; you should always seek the advice of your physician or other appropriate healthcare professional with any questions you may have regarding diagnosis, cure, treatment or prevention of any disease or other medical condition.