Given a defined role for T-bet in promoting Th1-mediated cellular immunity, the evidence for Th1-mediated pathology of H. pylori infection, and previous observation that Notch1 influences T-bet levels, we wondered whether Notch1 contributes to pathogenesis in H. pylori–associated gastrointestinal disease. The gene discussed is NOTCH1; the disease is gastrointestinal disease.