Metreleptin (Amylin Pharmaceuticals, now AstraZeneca) was approved by the FDA in 2014, and by the European Medicines Agency (EMA) in 2018, for the treatment of lipodystrophy, and leptin supplementation largely normalizes metabolic and neuroendocrine alterations in humans with congenital leptin deficiency95,118,136,217 and in patients with anorexia nervosa218. This evidence concerns the gene LEP and lipodystrophy.