GCG and diabetes mellitus: The major criteria include: i) presence of exocrine pancreatic insufficiency, ii) pathological pancreatic imaging, iii) absence of type 1 diabetes mellitus associated autoimmune markers; the minor criteria include: i) impaired beta cell function, ii) no excessive insulin resistance, iii) impaired incretin secretion, iv) low serum levels of lipid-soluble vitamins (A, D, E, and K).