Hyperinsulinism due to HNF4A deficiency is a form of diazoxide-sensitive diffuse hyperinsulinism (DHI), characterized by macrosomia, transient or persistent hyperinsulinemic hypoglycemia (HH), responsiveness to diazoxide and a propensity to develop maturity-onset diabetes of the young subtype 1 (MODY-1). The disease is hyperinsulinism due to HNF4A deficiency (MONDO_0016988, a Monarch Disease Ontology id). Also known as: hyperinsulinemic hypoglycemia due to HNF4A deficiency.