Reduced dopamine transporter (DAT)‐binding was seen in the majority of the 39 GNDs with available dopaminergic imaging results, but not in Rett syndrome, Dravet syndrome (SCN1A), dihydropteridine reductase deficiency, and CLTC. The gene discussed is SLC6A3; the disease is hyperinsulinemic hypoglycemia, familial, 4.