KISS1 and polycystic ovary syndrome: As noted previously, mutations in KISS1/KISS1R cause congenital GnRH deficiency (characterized by delayed or absent puberty and infertility) [17] or central precocious puberty [18], and aberrant kisspeptin signaling has been implicated in polycystic ovary syndrome (PCOS) [32] and hypothalamic amenorrhea [33].