Rodents treated at neonatal age with monosodium l-glutamate (MSG), which destroys 80%–90% of the ARC neurons [91,92], develop neuroendocrine and metabolic abnormalities, resulting in a phenotype of adiposity characterized by GH deficiency [93], hyperinsulinemia [94], and hyperleptinemia due to leptin resistance [95]. The gene discussed is LEP; the disease is Hyperinsulinemia.