Hypoglycemia in sulfonylurea‐treated KCNJ11‐neonatal diabetes: Mild‐moderate symptomatic episodes occur infrequently but none involving unconsciousness or seizures.

Background: Neonatal diabetes mellitus (NDM) caused by mutations in <italic>KCNJ11</italic> can be successfully treated with high dose oral sulfonylureas; however, little data is available on the risk of hypoglycemia. Objective: To determine the frequency, severity, and clinical significance of hypoglycemia in <italic>KCNJ11</italic>‐related NDM. Methods: Utilizing the University of Chicago Monogenic Diabetes Registry, parents completed an online questionnaire addressing hypoglycemia. Continuous glucose monitoring (CGM) data was available for 7 subjects. Results: Thirty subjects with <italic>KCNJ11</italic>‐related permanent NDM (166 patient‐years on sulfonylurea) had median sulfonylurea dose of 0.39 mg/kg/day (0.24‐0.88 IQR, interquartile range) with median HbA1c 5.7% (39 mmol/mol) (5.5‐6.1 IQR, 37‐43 mmol/mol). Hypoglycemia (<70 mg/dL) was reported monthly once or less frequently in 89.3% of individuals, but 3 (10.7%) reported once weekly or more. Of all hypoglycemic episodes reported, none involved seizures or unconsciousness and thus did not meet the current ISPAD definition of severe hypoglycemia. Seven individuals wore a CGM for a total of 912 hours with blood sugars falling below 70 mg/dL for 5.8% of the time recorded, similar to ranges reported for people without diabetes. Conclusions: In our cohort of <italic>KCNJ11</italic>‐related permanent NDM, hypoglycemia is infrequent and mild despite the high doses of sulfonylurea used and near‐normal level of glycemic control. Long‐term follow‐up on larger numbers will be required to clarify the incidence and determinants of hypoglycemia in this unique population. [ABSTRACT FROM AUTHOR]