Diagnoses included nonketotic hyperclycinemia (NKH) (n = 2), ornithine transcarbamylase deficiency (OTC) (n = 3), propionic academia (n = 1), congenital disorder of glycosylation 1a (CDG1a) (n = 1), D‐bifunctional protein deficiency (DBP) (n = 1), and GM1 Gangliosidosis (n = 1). Here, PMM2 is linked to hyperinsulinemic hypoglycemia, familial, 4.