Congenital Hyperinsulinism Caused by a De Novo Mutation in the ABCC8 Gene - A Case Report

Congenital hyperinsulinism (CHI) is a rare genetic disorder characterized by inappropriate insulin secretion and severe hypoglycaemia. There are two histological subtypes: diffuse and focal form. Diffuse form is most common in autosomal recessive mutations in ABCC8/KCNJ11 gene, while focal CHI is caused a paternally inherited mutation and a somatic maternal allele loss. Here we report a case of a term male infant presented with severe hyperinsulinaemic hypoglycaemia. Gene panel testing was performed to give rapid genetic diagnosis. We detected the c.4415-13G>A heterozygous mutation in the ABCC8 gene. Targeted genetic testing of the parents proved the de novo origin of the mutation. The mutation has been previously described. The infant received octreotide treatment and is prepared for 18-fluoro-dopa PET-CT examination in order to localize the lesion. Rapid genetic testing might be crucial in the clinical management strategy, with decision algorithms taking into account of the genetic status of the patient.