HNF4A and congenital isolated hyperinsulinism: Dominant forms of CHI include activating mutations in encoding glutamate dehydrogenase (GLUD1), encoding glucokinase (GCK), encoding hepatocyte nuclear factor 4a (HNF4A) and encoding monocarboxylate transporter1 (SLC16A1) (12,15,16).Histological classification includes three major subgroups: diffuse, focal, and atypical, with the diffuse form inherited as autosomal recessive or dominant manner and the focal form being sporadic in inheritance.