The levels of leptin have been demonstrated to be strongly associated with obesity, sexual development and reproductive function, as well as the time of sexual maturity; and leptin can eliminate the inhibitory effect of neuropeptide Y on hypothalamic GnRH.14 It can regulate puberty onset and reproductive function through the hypothalamus-pituitary-gonad axis, promote the pituitary secretion of luteinizing hormone and follicle-stimulating hormone, and finally promote GnRH release, leading to early puberty initiation. The gene discussed is LEP; the disease is obesity due to melanocortin 4 receptor deficiency.