Gene May Explain Women's Heightened Lupus Risk

THURSDAY, April 2 (HealthDay News) -- A gene on the X chromosome appears to be linked to lupus and might explain why women are much more likely to develop the disease than men, a new study suggests.

The gene IRAK1 may also hold a key to treating the disease. Tests by the researchers found that lupus-prone mice lacking the gene did not develop common disease symptoms such as kidney problems, production of autoimmune antibodies and white blood cell activation.

The findings were published in this week's online issue of the Proceedings of the National Academy of Sciences.

"The extensive involvement of IRAK1 in the regulation of the immune response renders its association with lupus a prime candidate for careful genetic and functional analysis," senior study author Chandra Mohan, a professor of internal medicine at the University of Texas Southwestern Medical Center at Dallas, said in a news release issued by the university.

Lupus causes a myriad of problems such as muscle pain, extreme fatigue and inflammation of the joints, skin, major organs and central nervous system. Females develop lupus 10 times more often than males, a fact researchers have theorized has to do with differences in hormones between the genders.

Future research is expected to compare the role of X-linked genes against hormonal differences in determining the likelihood of one gender being more prone to lupus.

"This first demonstration of an X chromosome gene as a disease susceptibility factor in human lupus raises the possibility that the gender difference in rates may in part be attributed to sex chromosome genes," Mohan said.

The international, multicultural genetic study found three variants of IRAK1 common in subjects whose developed lupus either as children or adults. The test on mice confirmed the link between lupus and IRAK, which previous genetic studies had suspected.

-- Kevin McKeever

SOURCE: University of Texas Southwestern Medical Center at Dallas, news release, March 30, 2009

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