TNFAIP3 (tumor necrosis factor-α induced protein 3) gene encodes A20, an inhibitor of nuclear factor-κB (NF-κB) activation, and is a susceptibility gene for autoimmune diseases including systemic lupus erythematosus14,15 or rheumatoid arthritis16,17. The gene discussed is TNFAIP3; the disease is autoimmune disease.