Taken together, for these three pairs of genes (DUOXA2/DUOX2, REG1A/REG1B, and MUC1/MUC4), there is biologically relevant evidence in the context of IBD, and we here speculate that they also play a role in the non-inflamed ileum of UC patients, indicating the need for further studies. This evidence concerns the gene MUC4 and inflammatory bowel disease.