ESPE Abstracts

Introduction: Type 5 monogenic diabetes is an autosomal dominant disease due to a mutation in HNF1beta gene. This gene is expressed predominantly in kidney and pancreas, thus clinical manifestations are characterised by renal abnormalities and diabetes.

Objectives: To review the clinical characteristics of patients who were diagnosed with type 5 monogenic diabetes in the Pediatric Endocrinology Unit of a tertiary referral hospital.

Patients and methods: The medical history of 7 children who were diagnosed with type 5 monogenic diabetes with genetic confirmation were reviewed.

Results: A mutation in HNF1beta gene was detected in all the patients (4 male and 2 female) between 14 and 18 years old. The genetic study in their first-degree relatives was normal in all the cases. Related to prenatal history, fetal growth restriction was presented in 6 of 7 patients, and 2 had sonographic renal abnormalities. However, the initial clinical manifestations were very different: 3 presented renal alterations, 2 transaminitis and the other 2 hyperglycemia; although while 1 patient only presented hyperglycemia, the other one had a non-ketosic debut diabetes. 6 patients had renal morphological abnormalitites at the beginning of the clinical manifestations, except one. However, renal cortical cysts were found in this last patient during disease progression. 3 patients developed chronic kidney disease, leading to a renal transplant in one of them. Neither woman presented mullerian abnormalities. During disease progression some other complications appeared: exocrine pancreatic insufficiency (1 patient), hyperuricemia (1 patient), hypomagnesemia (2 patients), hypertrygliceridemia (1 patient) o transaminitis (2 patients). 4 patients met diagnostic criteria for diabetes, thus they were treated with insulin. None of them presented positive antibodies for diabetes.

Conclusion: Phenotypic variability at the onset of Type 5 monogenic diabetes implies a diagnostic challenge. The study of HNF1beta gene should be considered in any patient with hyperglucemia, negative antibodies for diabetes, family history of type 2 diabetes and renal abnormalities. While progressive disfunction of beta cells is observed, not all the patients require insulin treatment at the beginning of the disease.