Challenges in the management of patients with HNF1B MODY and multisystem manifestations: the cases of two adolescent boys.

Introduction: Hepatocyte nuclear factor-1 beta (HNF1B) encodes a homeodomain-containing transcription factor, which is expressed early in embryogenesis and is involved in the development of multiple tissues and organs. HNF1B mutations cause complex multisystem disorders, with renal developmental disease and maturity onset diabetes of the young (HNF1B MODY), a rare cause of diabetes mellitus, being representative features.

Methods: We present two adolescent boys from different socioeconomic backgrounds who were diagnosed with genetically confirmed HNF1B MODY following hospitalization for diabetic ketoacidosis in the first case and after diagnostic work-up due to impaired glucose tolerance in the second case. Multisystem manifestations, including pancreatic hypoplasia and early-onset diabetes mellitus (DM), renal cysts, hypomagnesemia, hyperuricemia, liver and biliary impairment, genital tract malformations, and primary hyperparathyroidism were also present, strongly suggesting HNF1B MODY.

Results: The first patient was treated with subcutaneous insulin but was lost to follow-up due to social reasons. Conversely, early diagnosis in the second patient allowed the management of multisystem defects by a multidisciplinary team of experts. Moreover, manifestation of HNF1B MODY in the form of diabetic ketoacidosis was prevented and a structured diabetes training program has proven successful in regulating glycemic control, postponing the necessity for insulin treatment.

Conclusion: Early genetic work-up of patients with dysglycemia associated with a specific phenotype suggestive of HNF1B MODY is extremely important in the care of children and adolescents with diabetes since it ensures that early and optimal management is initiated, thereby preventing the onset of life-threatening diabetic ketoacidosis and other multisystem complications and/or comorbidities.