GNRH1 and cartilage-hair hypoplasia: These mechanisms provide a strong biological rationale for early gonadotropin therapy in infants with congenital hypogonadotropic hypogonadism (CHH), due to impaired gonadotropin-releasing hormone (GnRH) secretion or action, in whom the normal postnatal hormonal surge is absent or blunted [1,2,3,8,9].