# ABCC8 Mutation Causing Permanent Neonatal Diabetes Mellitus in Early Infancy: A Case Report

## TL;DR

A case report describes a rare genetic cause of neonatal diabetes and how treatment shifted from insulin to oral medication, improving the infant's health.

## Contribution

A novel ABCC8 mutation causing permanent neonatal diabetes is reported, with management adapted to low-resource settings.

## Key findings

- A heterozygous pathogenic ABCC8 missense variant was identified in an infant with neonatal diabetes.
- Switching from insulin to oral sulfonylurea achieved euglycemia in a low-resource setting.
- Genetic testing confirmed the diagnosis and guided treatment decisions.

## Abstract

Neonatal diabetes mellitus (NDM) is a rare monogenic form of diabetes presenting within the first 6 months of life. It can be transient or permanent; early diagnosis is essential to improve outcomes.

A 45-day-old male infant presented with fever, dehydration, and marked hyperglycemia. Initially misdiagnosed as meningitis, further evaluation revealed diabetic ketoacidosis, confirmed by elevated blood glucose and +4 urine ketones. He was stabilized with IV fluids and insulin, then transitioned to subcutaneous insulin. Persistent hyperglycemia and patient's age raised suspicion for NDM, warranting genetic testing, which identified a heterozygous pathogenic ABCC8 missense variant. Oral sulfonylurea was initiated using a locally compounded suspension due to limited resources. Insulin was successfully tapered, and euglycemia was achieved on sulfonylurea monotherapy.

Highlighted here is the importance of genetic testing in suspected NDM; it directly guides management. Shifting from insulin to oral agents improves glycemic control and long-term prognosis. Managing NDM in low-resource settings requires adaptive, multidisciplinary approaches. Ideally, patients should be followed into adolescence, focusing on neurodevelopment, as some variants may lead to neurological complications.

Recognizing NDM in infants with unexplained hyperglycemia is important for timely, targeted treatment. Individualized care is possible in constrained settings, offering improved overall outcome.