These neuronal projections are important routes for leptin, insulin, and ghrelin in the hypothalamus.33 Researchers have speculated that Arc NPY neurons projecting to the DMH control energy balance by stimulating food intake and inhibiting heat generation, especially in the case of energy deficiency.34 It is well known that a set of neurons distributed in the DMH is responsible for these functions (eg, cocaine‐ and amphetamine‐regulated transcript (CART) neurons and cholinergic neurons). The gene discussed is INS; the disease is hyperinsulinemic hypoglycemia, familial, 4.