Impact of Sulphonylureas on Neurodevelopmental Outcomes in KCNJ11-related Intermediate Developmental Delay, Epilepsy and Neonatal Diabetes (iDEND) Syndrome

The goal of this observational study is to learn about the impact of the diabetes drug glibenclamide (glyburide) on neurodevelopment in individuals with iDEND (developmental delay, epilepsy and neonatal diabetes) due to the V59M mutation in the KCNJ11 gene. The main question it aims to answer is whether initiating sulphonylurea (SU) therapy in the first year of life results in better neurodevelopmental outcomes in affected individuals, in comparison to starting therapy later than 12 months of age. Participants will undergo a neurodevelopmental assessment comprising parental and teacher completion of standardised questionnaires, and where possible face to face neuropsychological testing. Researchers will compare the outcomes of these standardised tests in the individuals who started SU therapy \<12 months of age in comparison to those who started \>12 months of age.