Endocrine Abstracts

Introduction: Neonatal diabetes mellitus (NDM) is a rare disease diagnosed within the first months of life that is usually permanent in 50% of cases. Heterozygous mutations of KCNJ11 and ABCC8 genes encoding the two Kir6.2 and SUR1 subunits of the b-cell ATP-dependent potassium channel have been associated with NDM, which is characterized by a successful response to sulfonylureas.

Case report: We present a 32-year-old woman diagnosed with type 1 diabetes. She was born at 37 weeks (weight: 2900 g) and presented with diabetes onset at 3 months. Since onset she has been treated with insulin and has presented as poorly controlled. She began treatment with CSII for planning pregnancy and presented an acceptable metabolic control during pregnancy (HbA1c 6%), which finalized at 37 weeks by eutocic delivery. The neonate (weight: 2750 g and height: 48 cm) developed hyperglycemia from the 24th hour of life that required insulin. Genetic studies requested in both patients detected a heterozygous mutation in the KCNJ11 gene (p.Arg201His, c.602G> A). Evaluation of glycemic control (including CGMS) and assessment of pancreatic reserve before switching from insulin to sulfonylureas, and again after 6 months, were performed.

Results: We observed an improvement in both glycemic control and pancreatic reserve with sulfonylureas in the mother, although she needed high doses (0.8 mg/kg per day). In the child good glycemic control as well as improvement of pancreatic reserve were also achieved and we completely stopped insulin on the third day after start of sulfonylureas, requiring downstream dose (0.2 mg/kg per day).

Conclusions: The onset of NDM due to a mutation of KCNJ11 in the first days of life is exceptional, also the association to not low birth weight. Most patients with NDM respond to treatment with sulfonylureas, but the response may vary. It is essential to reconsider the diagnosis of type 1 diabetes in patients with disease onset before 6 months of life.