A Case of a 10-Year-Old Boy With HNF1B-MODY and Pancreatic Body and Tail Agenesis Treated as Type 2 Diabetes

Abstract

HNF1B-MODY is sometimes associated with agenesis of the dorsal pancreas, and the phenotypes reported in adults range from cases in which endogenous insulin was depleted to cases treated as type 2 diabetes (T2D). In children, many cases are diagnosed with type 1 diabetes, and there are few reports of cases treated for T2D. The patient was a 10-year-old boy with mild obesity who was being treated for T2D. He was referred to our hospital because his HbA1c level worsened even after treatment with oral hypoglycemic agents. Pancreatic islet-related autoantibodies were negative, ketosis was not observed, and the ΔCPR value determined by glucagon loading did not suggest an obvious decrease in insulin secretion. However, he had lost weight in the past month and insulin was indispensable for blood sugar control. Imaging tests revealed a defect in the pancreatic body and tail, and a cyst in the right kidney, and genetic testing confirmed the diagnosis of HNF1B-MODY. In HNF1B-MODY, decreased insulin secretion may not be obvious; therefore, even in pediatric patients with T2D, the diagnosis must be reconsidered if the clinical course is atypical.