Molecular genetic testing (Hypoglycemia, Hyperinsulinism and Ketone Metabolism Panel, Blueprint Genetics Laboratory) identified a homozygous deletion in the ABCC8 gene, c.(2390+1_2391-1)_(3329+1_3330-1)del, which encompasses exons 20–26; the result correlating with diffuse CHI. Here, ABCC8 is linked to congenital isolated hyperinsulinism.