Genes Boost Risk for Rheumatoid Arthritis, Lupus

Discoveries could lead to new treatments for autoimmune diseases, scientists say.

By Steven Reinberg
HealthDay Reporter
Wednesday, September 5, 2007; 12:00 AM

Copyright © 2007 ScoutNews, LLC. All rights reserved.

WEDNESDAY, Sept. 5 (HealthDay News) -- Two genes boost the risk of painful rheumatoid arthritis, and one of them also increases the odds for lupus, according to two new reports.

In one report, a variant of the gene called STAT4 is one of the five genes now identified to increase the risk of developing rheumatoid arthritis or lupus, both of which are autoimmune disorders, where the immune system attacks healthy tissue.

STAT4 can boost a person's risk for the illnesses by 30 percent to 60 percent, depending on how many copies of the gene one has, the researchers found.

In the other study, a variant of the TRAF1-C5 gene was found to be associated with an increased risk for rheumatoid arthritis.

"There has been a huge amount of optimism about what genetics can bring," said lead researcher Dr. Peter K. Gregersen, head of the Feinstein Institute's Robert S. Boas Center for Genomics & Human Genetics in Manhasset, N.Y. "But everyone working on complex disease underestimated the size of the problem, which it is why it has taken a decade to identify genes related to these problems," he said during a Tuesday morning teleconference.

There are now five genes "that we are quite certain are involved in [rheumatoid arthritis], and I suspect there are another three to five at least that are involved," Gregersen said. "We are talking about gene variants that are fairly common in the population -- variants that are present in 5 percent or more of the population," he said.

Gregersen believes that identifying these genes will lead to new ways of predicting who is likely to develop rheumatoid arthritis. It might also lead to personalized treatments and perhaps effective prevention for those found to be at higher risk.

In the first study, Gregersen's team looked at DNA from almost 4,200 individuals with rheumatoid arthritis or lupus. Using gene mapping, the researchers identify STAT4 as a gene involved in increasing the risk for both diseases.

"Although we don't know how this gene variant changes immune function, it is clear that this finding places STAT4 pathways directly in a scheme of pathogenesis for both [rheumatoid arthritis] and lupus," Gregersen said. "This shows that a single gene can overlap autoimmune disorders."