Hyperinsulinemic hypoglycemia due to INSR deficiency is a very rare autosomal dominant form of familial hyperinsulinism characterized clinically in the single reported family by postprandial hypoglycemia, fasting hyperinsulinemia, and an elevated serum insulin-to-C peptide ratio, and a variable age of onset. The disease is hyperinsulinism due to INSR deficiency (Monarch Disease Ontology term MONDO_0012381). Also known as: hyperinsulinemic hypoglycemia due to INSR deficiency, hyperinsulinemic hypoglycemia due to insulin receptor deficiency, hyperinsulinemic hypoglycemia, familial, type 5.