The main results of this study are 1) the increase in the number of the signs associated with breast development at CPP presentation is associated with a significantly higher BMI SDS, frequency of obesity, LH basal and peak levels, LH/FSH peak ratios, and plasma estradiol concentrations; 2) obesity is associated with a higher percentage of BA advance greater than 2 years and a higher frequency of pubic or axillary hair development but not with LH secretion, suggesting that obesity accelerates adrenarche but not the maturation of the hypothalamic-pituitary-ovarian axis. This evidence concerns the gene BRD2 and obesity due to melanocortin 4 receptor deficiency.