The frequency of the AA genotype of FAS A-670G polymorphism was significantly higher in SLE patients than in controls, and the risk of SLE was 2.1-fold greater in individuals with AA genotype in comparison to GG genotype (OR, 2.1 (95% CI, 1 to 4.1); P = 0.03). The gene discussed is FAS; the disease is systemic lupus erythematosus.