Glibenclamide controls ketosis‐prone diabetes in a 38‐year‐old woman with Kir6.2 mutation

Monogenic forms of diabetes, where there is a single gene defect causing diabetes, are rare, accounting for about 1‐2% of all cases of diabetes in young people. Neonatal diabetes is one form of monogenic diabetes. It usually presents within six months of birth and can be permanent or transient. Several mutations in the KCNJ11 gene lead to permanent neonatal diabetes by interfering with insulin release from islet cells. These patients can be treated with sulphonylureas as they facilitate insulin secretion by acting on the mutated pancreatic potassium channel.

We report the case of a patient with KCNJ11 S3C mutation, who is the oldest patient with neonatal diabetes to have successfully transferred from insulin to sulphonylureas. She was diagnosed with diabetes at the age of four and was treated as having type 1 diabetes mellitus. Her glycaemic control was always sub‐optimal; she had had several admissions with diabetic ketoacidosis. Her daughter who developed diabetes at six weeks was found to have neonatal diabetes, which led to her genetic testing. Our patient was also diagnosed with the same KCNJ11 mutation as her daughter. At 38 years of age, after outpatient assessment, she was started on glibenclamide and in three weeks came off insulin completely, achieving good glycaemic control with glibenclamide. Her HbA1c improved from 10% pre‐transfer to 5.9% in four months. Copyright © 2009 John Wiley & Sons, Ltd.