Two variant forms of a gene that promotes the formation of nitric oxide-a molecule involved in blood vessel dynamics and nerve transmission-may be a risk factor for the rheumatic disease lupus in African American women, according to research supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases, a component of the National Institutes of Health, U.S. Department of Health and Human Services.

A study conducted by the Medical University of South Carolina's Gary Gilkeson, M.D., and his colleagues showed that the two different gene forms occurred much more frequently among female African American lupus patients than among controls matched for age, sex and race. These same gene forms have been associated with improved outcomes in some African patients with malaria, and the researchers chose to investigate them based on a hypothesis that genetic traits that benefit those living in Africa may have the opposite effect on North American residents.

Systemic lupus erythematosus (SLE), or lupus, is a chronic, inflammatory, autoimmune disease that mainly affects women of child-bearing age. Its symptoms range from unexplained fever, swollen joints, and skin rashes to severe organ damage of the kidneys, lungs, or central nervous system. Lupus is three times more common-and is frequently more severe-in African American women than in Caucasian women.

Support for this research was also provided by the National Institute of Allergy and Infectious Diseases, the National Institute of Environmental Health Sciences, the Veterans Administration and the Medical University of South Carolina.

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Oates J, Levesque M, Hobbs M, Smith E, Molano I, Page G, Hill B, Weinberg J, Cooper G, Gilkeson G. Nitric oxide synthase 2 promoter polymorphisms and systemic lupus erythematosus in African-Americans. J Rheumatology 2003;30(1):60-67.