In healthy humans, MUC2 O-glycosylation is uniform while it is altered in patients with active ulcerative colitis and associated with increased inflammation.37 38 A different profile was also observed in human colon cancer, linked to tumour metastatic potential and poor prognosis.39 40 Understanding the pattern of mucin glycosylation in patients with obesity and metabolic disorders, and how these could be modulated by nutritional treatments, could be useful in inducing the colonisation of specific bacteria associated with beneficial effects. The gene discussed is MUC2; the disease is obesity due to melanocortin 4 receptor deficiency.