From Our 2010 Archives

Gene Mutations Offer Clues to Autoimmune Disorders

WEDNESDAY, June 16 (HealthDay News) -- A new study finds that rare gene variations are more common in people with disorders in which the immune system attacks the body. These autoimmune disorders include rheumatoid arthritis and type 1 diabetes.

Researchers report that the findings could lead to better treatments -- although that's not guaranteed -- and pave the way for scientists to link uncommon genetic variations to other diseases.

The research is focused on mutations in the gene coding an enzyme in charge of a crucial cell in the immune system. The enzyme, called sialic acid acetylesterase, controls the immune system's B cells -- white cells that produce antibodies to fight the foreign proteins of viruses, bacteria and other invaders. If the enzyme fails to rein in the B cells, they may attack the body's healthy cells by mistake.

The study authors compared the genetic makeup of 923 people with common autoimmune disorders to a control group of 648 people without them. They found a genetic variation that interferes with the enzyme in 24 of the participants with autoimmune diseases but just two of the controls.

The gene variant accounts for only about 2 or 3% of autoimmune disease cases, but "we are actively investigating other genes in this pathway that may be defective in a larger percentage of patients," said study senior author Dr. Shiv Pillai, an associate professor of medicine at Harvard Medical School and researcher at the MGH Center for Cancer Research, in a hospital news release.

The research appears online June 16 in the journal Nature.

-- Randy Dotinga

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SOURCE: Massachusetts General Hospital, June 16, 2010, news release.