In 2003, Kp was identified as a potent secretagogue of GnRH, based on mutation of its cognate receptor Kiss1R also named GPR54 (de Roux et al., 2003; Funes et al., 2003; Seminara et al., 2003), or of Kp gene itself (Kiss1;d'Anglemont de Tassigny et al., 2007; Dungan et al., 2007), resulting in hypogonadic hypogonadism and infertility. This evidence concerns the gene NPPA and hypogonadism.