LEP and congenital secretory chloride diarrhea 1: Those actions have been identified mainly through animal models of leptin deficiency (namely, the ob/ob and the db/db mice), but also through studies carried out in humans with leptin deficiency: patients with lipodystrophy syndromes, hypothalamic amenorrhea, and congenital leptin deficiency (CLD) due to mutations in the leptin gene [2].