A mutation in the human leptin receptor gene causes obesity and pituitary dysfunction

The adipocyte-specific hormone leptin, the product of the obese (ob) gene,regulates adipose-tissue mass through hypothalamic effects on satiety and energy expenditure1,2,3,4. Leptin acts through the leptin receptor, a single-transmembrane-domain receptor of the cytokine-receptor family5,6,7. In rodents, homozygous mutations ingenes encoding leptin1 or the leptin receptor6 cause early-onsetmorbid obesity, hyperphagia and reduced energy expenditure. These rodents also show hypercortisolaemia, alterations in glucose homeostasis, dyslipidaemia, and infertility due to hypogonadotropic hypogonadism8. In humans, leptin deficiency due to a mutation in the leptin gene is associated with early-onset obesity9. Here we describe a homozygous mutation in the human leptin receptor gene that results in a truncated leptin receptor lacking both the transmembrane and the intracellular domains. In addition to their early-onset morbid obesity, patients homozygous for this mutation have no pubertal development and their secretion of growth hormone and thyrotropin is reduced. These results indicate that leptin is an important physiological regulator of several endocrine functions in humans.