It is known that mutations in the TAC3 or TACR3 genes, respectively coding for NKB or NK3R, cause hypogonadotropic hypogonadism in humans because of disturbances in the secretion of gonadotropic hormones from the anterior pituitary gland (21, 27, 30). Here, TACR3 is linked to hypogonadotropic hypogonadism.