An association between the FAS −670 A/G polymorphism and the risk of autoimmune diseases was observed in Asian patients with SLE (G vs. A: OR = 0.84, 95% CI 0.74–0.95, P=0.007) or AIH (G vs. A: OR = 0.55, 95% CI 0.40–0.76, P<0.001) and in Caucasian patients with SLE (G vs. A: OR = 0.80, 95% CI 0.67–0.96, P=0.015), MS (GG+GA vs. AA: OR = 0.80, 95% CI 0.66–0.96, P=0.018), or SSc (GG vs. GA: OR = 1.22, 95% CI 1.07–1.39, P=0.003). The gene discussed is FAS; the disease is autoimmune disease.