Gene studies home in on lupus cause

Yahoo! News—January 20, 2008

Four separate studies published on Sunday identify a series of genes linked with lupus, a debilitating illness that can affect various parts of the body at once.

The studies show that, as suspected, the immune system is going haywire in lupus. But it also points to some previously unsuspected causes of the once-mysterious disease.

The findings may not only help scientists find better treatments for the disease -- but may help in diagnosing it in the first place, as it is easily confused with other conditions.

Systemic lupus erythematosus, lupus for short, affects at least 1.4 million people in the United States and 50,000 in Britain, advocacy groups say.

It can damage the joints, kidneys, heart, lungs, brain and blood and is marked sometimes by a characteristic butterfly-shaped rash on the face.

Three studies in the journal Nature Genetics and a fourth in the New England Journal of Medicine identify several areas of DNA that carry mutations in people with lupus and their relatives.

One international team of researchers studied the DNA of more than 6,700 women, including people with lupus, their relatives, and unrelated people with no evidence of the disease. Among the four studies, about 10,000 people were tested and 13 different genes were implicated.

"Overall, these papers confirm what investigators have been finding over the past decades," said Dr. Mary Kuntz Crow of Hospital for Special Surgery in New York.

"They show that many aspects of the immune system are involved in the development of the disease, but they also provide a new level of detail regarding the specific molecular pathways that contribute."

MISSED GROUPS

Some of the genes also apparently contribute to blood vessel function and some have unknown roles, the researchers said.

In a commentary in the New England Journal of Medicine, Crow noted that the studies all miss the biggest group of people affected by lupus.

"In the major studies, all of the subjects were of European descent, but lupus is most severe in people with African, Asian and Hispanic backgrounds," Crow said in a statement.

"We need to confirm that these same genes are involved in all of our patient populations and identify any distinct genes that might be involved in those populations at greatest risk for poor outcomes."

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