Novel perspectives of super-high dose sulfonylurea and high-dose oral prednisolone in an infant with DEND syndrome due to V64M heterozygote KCNJ11 mutation

Aims To report a novel mutation associated with developmental delay, epilepsy, and neonatal diabetes—DEND Syndrome, responsive to a novel management combination. Methods We describe the investigation, treatment, and genetic diagnosis of a newborn diagnosed with DEND syndrome. Results The patient was found to be de-novo heterozygous for pathogenic KCNJ11 missense variant: c.190G > A, p. (Val64Met), associated with DEND syndrome, responsive to a combination of super high doses of sulfonylurea (SU) and oral high-dose steroids. A single case was reported so far due to this mutation, presenting with severe DEND syndrome, treated by insulin only. His phenotypic description and management during 18 months, demonstrates this mutation is responsive to super-high doses of SU combined with high dose 6 weeks steroids protocol. Conclusions We have identified a heterozygous missense mutation as the etiology for severe DEND syndrome in a one-day old neonate, presenting with asymptomatic hyperglycemia, responsive to a novel management combination.