It now appears likely that these physiological processes may engage the expression and function of GPR43. Notably, mutations in the XBP1 gene locus of human patients has been associated with increased risk of inflammatory bowel disease (IBD), Crohn's disease and ulcerative colitis, while Xbp1−/− mice have increased susceptibility to colitis32. The gene discussed is XBP1; the disease is ulcerative colitis.