Chronic colitis in Winnie is caused by a primary epithelial cell defect due to a point mutation in the Muc2 gene resulting in aberrant mucin-2 biosynthesis leading to endoplasmic reticulum stress in intestinal goblet cells and reduced secretion of mucus which is very similar to active ulcerative colitis in humans42,43. This evidence concerns the gene MUC2 and Chronic colitis.