Studies have shown that MUC2 is a mucin synthesized and secreted by goblet cells to form the inner mucous layer, a thick and dense barrier between the luminal microbiome and the epithelial cells, which contributes to mucosal defense.22 Mucin secretion is known to be regulated by bacterial products such as lipopolysaccharide and flagellin and by various cytokines.23 Dysbiosis has been previously described in PSC,9 and alterations of the mucous layer, through its effect on microbial-epithelial interactions, could contribute to the pathogenesis of intestinal inflammation in these patients. This evidence concerns the gene MUC5AC and gastroenteritis.