Stress, through its neuromediators, corticotrophin-releasing factor (CRF) and its related peptide urocortin(s), acting on their G protein coupled CRF (1 and 2) receptors located in the brain and the GI tract, increases intestinal permeability and modifies the gut microbiota (Taché et al., 2018); these two factors are involved in the pathophysiology of IBS and IBD. The gene discussed is UCN; the disease is irritable bowel syndrome.