Analysis of the gene expression data in OPLS-DAs revealed LYZ, IL1B, CLDN2, CCL20, TLR7, STAT3, BCL2, and CD1D to be among the most important genes for differentiation between CC vs. healthy subjects (Figure 2D); BIRC3, CLDN2 and CD1D for UC vs. healthy subjects (Figure 2E); and finally, CLDN2, IL10RA1, DSC2, BIRC3, CX3CL1, and CD1D for IBS vs. healthy subjects (Figure 2F). The gene discussed is CLDN2; the disease is irritable bowel syndrome.