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/m2; P < 0.02) and type 1 diabetes (21.4 ml/m2; P < 0.001) as compared with nondiabetic controls (45.7 ml/m2), 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.