Background MODY is a rare type of autosomal dominant diabetes, approximately 99% of cases of MODY result from mutation in HNF4A (MODY type 1), GCK (MODY type 2), HNF1A (MODY type 3), the most common presentation of MODY is mild, asymptomatic hyperglycemia in a child, adolescent, or young adult with a family history of autosomal dominant diabetes, however children carrying HNF4A (MODY type 1) mutation, can present in early infancy with macrosomia and diazoxide- responsive hyperinsulinism.

Case Report(s) Aseel was a full-term male baby, with normal birth weight (50% percentile).

At the age of 1 day, he had a hypoglycemic jitteriness. Evaluation at the time of hypoglycemia revealed suppressed ketone production, and a positive response to glucagon.

Based on these findings a diagnosis of hyperinsuilinism was made and he was treated with diazoxide. His mother was diagnosed with diabetes at age of 17 year and treated with insulin.

Genetic mutation testing was done for the mother, she was heterozygous for a pathogenic variant in the HNF4A gene (Glu24Ter), confirming a diagnosis of MODY.

Testing for this variant has been requested for the baby who was diagnosed with diazoxied- responsive hyperinsulinism at the age of 1 day, found to have the same mutation as his mother, heterozygous for the HNF4A nonsense variant (Glu24Ter).

Conclusion(s) pathogenic mutation in HNF4A causes the maturity-onset diabetes in adolescence and adulthood. When either parents is known to have HNF4A diabetes there is a 50% chance that a baby will inherit the genetic mutation.

Babies carrying HNF4A mutations can present in early neonatal period with hypoglycemia and diazoxide-responsive hyperinsulinism.