Reduced pancreatic volume in hepatocyte nuclear factor 1A-maturity-onset diabetes of the young

Context: There are interplays between the endocrine and exocrine pancreas. We recently reported an increased frequency of exocrine dysfunction in HNF1A-maturity-onset diabetes of the young (MODY3) patients, compared with controls. Reduced pancreatic volume is seen in HNF1B-MODY (MODY5) and diabetes types 1 and 2. Objective: The aim of this study was to investigate whether HNF1A mutation carriers have reduced pancreatic volume or abnormal pancreatic structure and whether any changes are associated with exocrine dysfunction. Methods: Fifteen HNF1A mutation carriers recruited from the Norwegian MODY Registry, 31 subjects with type 1 diabetes, 10 subjects with type 2 diabetes, and 11 controls underwent computed tomography of the pancreas. We measured pancreatic volume and X-ray attenuation. Pancreatic volume index was defined as pancreatic volume divided by body surface area. Results: Pancreatic volume index was reduced in subjects with HNF1A-MODY(34.5 ml/m(2); P < 0.02) and type 1 diabetes (21.4 ml/m(2); P < 0.001) as compared with nondiabetic controls (45.7 ml/m(2)), and was reduced in subjects with diabetes in combination with fecal elastase deficiency (P = 0.03). Subjects with type 1 diabetes had smaller pancreatic volume index, compared with HNF1A mutation carriers (P < 0.001). Reduced pancreatic volume index was associated with increasing duration of diabetes. Pancreatic X-ray attenuation in HNF1A mutation carriers was not significantly different from that of nondiabetic controls. Conclusions: HNF1A mutation carriers have reduced pancreatic volume but less reduced than in patients with type 1 diabetes. Insulinopenia could explain both the pancreatic volume reduction and the associated pancreatic dysfunction.