[Low doses of sulphonyluria as a successful replacement for insulin therapy in a patient with neonatal diabetes due to a mutation of KCNJ11 gene encoding Kir6.2].

Neonatal diabetes mellitus is a rare metabolic disorder with an estimated incidence of 1:300.000 to 400.000 newborns, and less than 50% of the neonates have permanent neonatal diabetes mellitus (PNDM). Recently, activating mutation in the KCNJ11 gene encoding Kir6.2 subunit of the adenosin triphosphate-sensitive potassium (K(ATP)) channel has been described as the most frequent cause of PNDM. Under physiological circumstances K(ATP) channel closure plays a central role in glucose-stimulated insulin secretion from pancreatic beta cells. Sulphonylurea drugs stimulate insulin secretion by binding to and closing K(ATP) channels and thus bypassing beta cell metabolism stimulate the same chain of reactions as glucose. We describe a boy diagnosed with PNDM at the age of 3 months when insulin therapy was started, and at the age of 4.5 years KCNJ11 gene was sequenced and found that the boy carried a de novo activating R201H mutation. Insulin therapy was successfully switched to low doses of oral glibenclamide. Accordingly, it is important to emphasize that every person diagnosed with diabetes before six months of life, however old they actually are, should be tested for K(ATP) mutations which is offered via the website www.diabetesgenes.org.