Over 22 human GNRHR inactivating mutations, with no hotspot, were described [63] and these different genotypes result in a wide phenotypic spectrum, ranging from fertile eunuch syndrome and partial hypogonadotropic hypogonadism to the most complete form of GnRH resistance, characterized by cryptorchidism, micropenis, undetectable gonadotropins and the absence of pubertal development [1]. This evidence concerns the gene GNRH1 and hypogonadotropic hypogonadism.