In addition to these effects, IL-10 can provide a protective role against TJ barrier disturbance, since IL-10 deficiency has been associated with increased intestinal permeability (114, 115) and mislocalization of ZO-1 and claudin-1 away from TJs, perhaps by the action of increased proinflammatory TNF-α, IL-1, and IL-6 (116). This evidence concerns the gene CLDN1 and hyperinsulinemic hypoglycemia, familial, 4.