GCGR-related hyperglucagonemia

A rare tumor of pancreas caused by mutations in the <i>GCGR</i> gene characterized by pancreatic alpha cell hyperplasia, pancreatic neuroendocrine tumors and markedly increased serum glucagon levels in the absence of a glucagonoma syndrome. Clinical manifestations may include abdominal pain, pancreatitis, fatigue, diarrhea, and diabetes mellitus.