ESPE Abstracts

Background: Permanent neonatal diabetes mellitus is caused by mutations in the K_ATP channel subunits. DEND (Developmental delay, Epilepsy, and Neonatal Diabetes) syndrome is the most severe form of permanent neonatal diabetes. We experienced a patient with DEND syndrome, who was initially misdiagnosed as type 1 diabetes, who has been successfully switched from insulin injection to oral sulfonylurea therapy.

Case presentation: A 50-day-old male presented with fever and seizure, complicated by persistent hyperglycemia. He was born at 38 weeks of gestation with a birth weight of 2.75 kg. Laboratory findings were consistent with diabetic ketoacidosis, and insulin therapy was initiated with conventional regimen. Also, antiepileptic drug was administered to control seizure. At 10 months of age, he cannot hold his head up or make eye contact with others, and electroencephalography showed spike discharges from right central and left central area. At age 17.9 years, direct sequencing of KCNJ11 identified a heterozygous mutation of c.602G>A (p.R201H). Since then, gliclazide was initiated and the insulin dose was gradually reduced. After 3 months, insulin was discontinued with a gliclazide dose of 2.4 mg/kg. He continued to have excellent glycaemic control with HbA1c level of 5.9% at age 18.7 years. However, his psychomotor retardation was not improved. Currently, he is 18.8 years old and still not able to talk with others because of severe intellectual disability. The patient had neonatal diabetes, epilepsy, and pronounced severe developmental delay.

Conclusion: We described clinical course of a case of DEND syndrome caused by an activating mutation of KCNJ11.

Novel insights into clinical practice: This study emphasizes the necessity to screen K_ATP channel mutations in diabetes diagnosed before 6 months, especially if combined with developmental delay and epilepsy.