Impact of glibenclamide therapy in a patient with neonatal diabetes and intermediate DEND syndrome with the V59M mutation in the KCNJ11 gene
A. Giestas1, T. Borges1, M. Oliveira1, A. Guimarães2 & H. Cardoso1
Introduction: Neonatal diabetes is a rare condition diagnosed within the first months of life. Activating mutation of KCNJ11, the gene encoding the Ki6.2 subunit of the ATP-sensitive potassium channel, is the most common cause of permanent neonatal diabetes, and ~20% of patients have neurological features.
Patients with the severe neurological phenotype exhibit developmental delay, motor weakness, and epilepsy in addition to diabetes (DEND syndrome). Intermediate DEND syndrome is a less severe clinical picture.
Sulfonylurea therapy is associated with metabolic and neurologic improvement in these patients.
Case report: We report the case of a boy diagnosed diabetes at the age of 6 weeks, which proved to be permanent, and who was treated with insulin from diagnosis. He immigrated and was lost in follow-up since the age of 18 months until he was 19 years. When we reviewed him, there was a past of behavioural and psychomotor disabilities since the age of 4, so DEND syndrome was suspected, and he was tested for K ATP channel defects. A heterozygous mutation p.VAL59Met (c.175G>A) was found in exon 1 of the KCNJ11gene, confirming the diagnosis of intermediate DEND syndrome.
Glibenclamide treatment was started at age 19 and increased up the dosage of 0.6 mg/kg per day, and insulin doses were gradually reduced, leading not only to improved glycaemic control (HbA(1c) fell from 11.6 to 8.9%), but also an impressive improvement in several aspects of cognitive function.
Conclusion: Although neonatal diabetes is a rare form of diabetes mellitus, genetic studies are critical in the diagnosis and treatment of these patients.
In this case neurological and glycaemic control improvement was seen after starting glibenclamide, but did not result in freedom from exogenous insulin.
Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.