The expression of proteins contributing to these structures is miss-regulated in IBS patients.(20) For example, surface-expressed TJ proteins such as claudins, occludin and junctional adhesion molecule (JAM)-A, as well as the scaffold protein zonula occludens (ZO)-1, which is involved in the control of intestinal permeability, have altered expression in IBS patients. This evidence concerns the gene OCLN and irritable bowel syndrome.