SMIT1 therefore endows KCNQs with an additional capacity to distinguish between GABA and close structural orthologues that are both present endogenously in the nervous system (BHB) and altered in a therapeutically/pathologically relevant manner: BHB is the first ketone body produced during fasting or ketogenic diets, and also in diabetic ketoacidosis. The gene discussed is SLC5A3; the disease is diabetic ketoacidosis.