The strain of C57BL/6 (B6) mice bearing the homozygous Fas-lpr/lpr mutation (B6-lpr/lpr) is an extensively studied murine model for SLE, in which mutation of the Fas apoptotic gene leads to a spontaneous autoimmune disorder that displayed similar with human SLE syndrome (21–23). The gene discussed is FAS; the disease is autoimmune disease.