Patients with moderate to severe ulcerative colitis (UC) have been reported to experience a primary non-response (PNR) rate of 13% to 49% to anti-tumor necrosis factor (anti-TNF) therapy [1,2,3,4,5], with an annual loss of response (LOR) reported to range from 10.1% to 13.6% [6]. The gene discussed is TNF; the disease is ulcerative colitis.