Since Dsg2 was missing at cell junctions in patients suffering from CD and a Dsg-specific tandem peptide ameliorated barrier dysfunction in response to TNF-α, which is regarded as a central cytokine in CD pathogenesis, we concluded that impaired Dsg2 may contribute to pathogenesis of inflammatory bowel diseases (IBD)19. The gene discussed is DSG1; the disease is Cowden disease.