The IBS/FMS group had more frequent positive ANAs than those with only IBS (28% vs. 3%; P < 0.001), and the same was true for anti-TPO antibodies (11% vs. 0%), AMAs (5% vs. 0%) and anti-tTG autoantibodies (mean serum levels = 0.4 vs. 4.7; P < 0.001). The gene discussed is TPO; the disease is irritable bowel syndrome.