Researchers Identify New Variant Associated With Increased Risk For Rheumatoid Arthritis

Rheumatoid Arthritis

Researchers from Brigham and Women's Hospital (BWH) and the Broad Institute of Harvard and MIT carried out a genome-wide association study of nearly 400 individuals with rheumatoid arthritis (RA) and identified a novel variant on chromosome 6 that increases the risk for developing the disease. The new variant is very close to a different variant on chromosome 6 that has also been shown to contribute to disease risk. These findings appear on the Nature Genetics website beginning November 4, 2007.

RA is the most common inflammatory arthritis, affecting up to one percent of the adult population. The cause of RA is still unknown, and although experts believe genes and the environment play a role, the inheritance of the disease remains unexplained. The newly identified variants on chromosome 6 join a very short list of confirmed genetic factors that affect susceptibility to the disease.

"RA is a devastating disease, yet we don't know the root cause," said first author Robert Plenge, MD, PhD, who is a rheumatologist at BWH. "Human genetics offers an opportunity to understand why some people get the disease and others don't. The hope is that discoveries such as ours will lead to improved prediction of who gets the disease, improved decisions on how to treat the disease and improved medications that target specific pathways in select patients."

In a separate study also appearing in Nature Genetics, researchers at the University of Manchester in the UK attempted to replicate all variants identified in a recent comprehensive report and found that the one on chromosome 6 was clearly replicated. Although these variants are not located in a gene, the authors suggest that a gene some distance from them (TNFAIP3) is a plausible candidate to explain the effects of these markers given its involvement in inflammatory processes.

"It's striking that two separate groups of researchers searched the entire human genome for variants that increase risk of RA and found very similar results. This indicates that this gene is clearly very important. The challenge now is to translate this discovery, and others to come, into improved patient care," added Plenge, who is also a post-doctoral fellow in Medical and Population Genetics at the Broad Institute.

The Foxtrot Fund, along with the Intramural Research Program of the National Institute of Arthritis and Musculoskeletal and Skin Disease and the National Institute of Allergy and Infectious Disease, both of the National Institutes of Health, funded the research conducted at BWH and the Broad Institute.