In women with PCOS, the abnormality in the regulation of hypothalamic GnRH secretion, with persistently rapid GnRH pulsatility, pituitary synthesis of LH over that of FSH, and increased LH concentrations and LH/FSH ratios, has been explained, at least in part, by a decreased sensitivity of the GnRH pulse generator to the progesterone suppression [18-20]. This evidence concerns the gene PLOD1 and polycystic ovary syndrome.