Neonatal diabetes mellitus (NDM) due to KCNJ11 gene mutation presents with diabetes in the first 3 months of life and sometimes with neurological features like developmental delay, muscle weakness and epilepsy.
Recent studies have shown that heterozygous mutations in KCNJ11, which encodes Kir6.2, the pore-forming subunit of the ATP-sensitive potassium (K(ATP)) channel, cause permanent neonatal diabetes either alone (R201C, R201H) or in association with developmental delay, muscle weakness and epilepsy (V59G,V59M).
We report the response to sulfonylurea treatment in a boy with neonatal diabetes and marked developmental delay resulting from the KCNJ11 mutation V59M.