Detection of hepatocyte nuclear factor 4A(HNF4A) gene variant as the cause for congenital hyperinsulinism leads to revision of the diagnosis of the mother.

OBJECTIVES

Congenital Hyperinsulinism (CHI) is the most common cause of persistent hypoketotic hypoglycaemia in neonates and infants. It is a genetic disorder with both familial and sporadic forms.

CASE PRESENTATION: In this study, we examined two unrelated infants of diabetic mothers (IDMs) presented with HH. DNA sequencing (Sanger and NGS panel) identified pathogenic variants of the Hepatocyte Nuclear Factor 4A (HNF4A) gene in both families. Pathogenic variants of HNF4A gene are reported to cause HH in the newborn period and Maturity Onset Diabetes of the Young (MODY) later in life. The diagnosis of MODY was made in retrospect for the two mothers, thus improving the management of their diabetes.

CONCLUSION

Genetic testing for CHI is strongly recommended if neonatal hypoglycemia persists. A family history of MODY or presumed type II diabetes can support that the affected gene is HNF4A.