Rheumatoid arthritis (RA) is the most common inflammatory type of arthritis. It affects more than 2 million Americans and is still a leading cause of both disability as well as days lost from work. RA is more common in women than men, and typical onset for the disease is between 25 and 50 years of age. Symptoms of rheumatoid arthritis include swelling, loss of movement, stiffness, and pain in joints, most commonly, the fingers and wrists.

RA is to be feared and respected because it is a systemic autoimmune chronic condition that affects internal organs as well as joints. While the cause of RA is still not completely known, a recent study published in the New England Journal of Medicine conducted by researchers in the United States and Sweden links a genetic region to rheumatoid arthritis.

A new study indicates a new genetic association with RA.

Researchers in the U.S. compared genetic material of 908 patients with RA from the North American Rheumatoid Arthritis Consortium with the genetic material of 1,282 individuals without RA. Swedish researchers compared DNA samples from 673 individuals without RA with genetic material from 676 individuals with RA obtained from the Swedish Epidemiological Investigation of Rheumatoid Arthritis.

Both groups of researchers used the new genome-wide association approach, which allows researchers to examine 300,000 to 500,000 small discrepancies in genetic material. Researchers examined genetic material in blood samples of all individuals that were part of the study.

The researchers found two genes in chromosome 9 responsible for the inflammation associated with RA: TRAF1 and C5. TRAF 1 codes for tumor necrosis factor, a specific target for many of the new biologic drugs used to treat RA. C5 codes for complement, a protein that also plays a big role in inflammation. Other genetic predisposing factors have been identified previously. These include HLA-DRB1 and PTPN22.

Elaine F. Remmers, Ph.D. in the Genetics and Genonics Branch of the NAMS Intramural Research Program and one of the authors of this study stated in a press release, "TRAF1-C5 showed association not only in the sample that we did with the North American Rheumatoid Arthritis Consortium but also independently in the Swedish group. By combining our information, we were able to make a much stronger case. The combined evidence was pretty impressive."

The researchers are unclear as to both how these genes are connected to RA as well as to which gene is causing the condition. Remmers added, "Actually, both genes are very interesting candidates. They both control inflammatory processes that really are relevant for the disease, so we could easily envision either of them playing a role - or both."

The authors hope that future research can reveal more about how these genes are linked to RA. They also hope that by learning more about the genes' connection to the disease, they will become closer to producing more effective treatment for the condition.

Remmers went on to say, "We are hoping that we will find variants in either of the genes that will lead us to new targets for therapy. Once we understand how the RA-associated variants work, we may be able interfere with the pathways the variants are influencing and either prevent the disease or block its progression."

Author's note: While the subject seems to be pretty dry, this is actually pretty exciting stuff. Soon... or at least I hope soon, we will be able to biopsy patients with RA when they come in, identify the genetic markers they have, and put these patients immediately on the therapies that hopefully will either put them into complete remission or even cure them.