Of significance, Cldn2 expression is upregulated in the distal colon of patient with inflammatory bowel disease and in the urinary bladder of patient with IC (Mankertz and Schulzke, 2007; Zeissig et al., 2007; Weber et al., 2008; Schulzke et al., 2009; Sanchez Freire et al., 2010). This evidence concerns the gene CLDN2 and inflammatory bowel disease.