GNRH1 and Gonadotropin deficiency: Gonadotropin deficiency (also known as hypogonadotropic hypogonadism) refers to sex hormone deficiency arising from either inadequate secretion or action of hypothalamic gonadotropin-releasing hormone (GnRH) or the pituitary gonadotropins follicle-stimulating hormone (FSH) and luteinising hormone (LH).