Strikingly, we observed that the gut of Nfat5+/– mice became more permeable than that of WT mice, even in the absence of colitis, solely by raising the mice in separate cages according to their genotype (Figure 4A), indicating that a genetic defect in NFAT5 could impair the normal function of the physiological gut barrier. The gene discussed is NFAT5; the disease is colitis.