A Novel KCNJ11 Mutation Associated with Transient Neonatal Diabetes

Özet

Neonatal diabetes mellitus (NDM) is a rare type of monogenic diabetes that presents in the first 6 months of life. Activating mutations inthe KCNJ11 gene encoding for the Kir6.2 subunit of the ATP-sensitive potassium (KATP ) channel can lead to transient NDM (TNDM) or topermanent NDM (PNDM). A female infant presented on the 22nd day of life with severe hyperglycemia and ketoacidosis (glucose: 907mg/dL, blood gas pH: 6.84, HCO3: 6 mmol/L). She was initially managed with intravenous (IV) fluids and IV insulin. Ketoacidosis resolvedwithin 48 hours and she was started on subcutaneous insulin injections with intermediate acting insulin NPH twice daily requiring initially0.75-1.35 IU/kg/d. Pre-prandial C-peptide levels were 0.51 ng/mL (normal: 1.77-4.68). Insulin requirements were gradually reduced andinsulin administration was discontinued at the age of 10 months with subsequent normal glucose and HbA1c levels. C-peptide levelsnormalized (pre-prandial: 1.6 ng/mL, postprandial: 2 ng/mL). Genetic analysis identified a novel missense mutation (p.Pro254Gln) inthe KCNJ11 gene. We report a novel KCNJ11 mutation in a patient who presented in the first month of life with a phenotype of NDM thatsubsided at the age of 10 months. It is likely that the novel p.P254Q mutation results in mild impairment of the KATP channel function leading to TNDM.