Indeed, the lack of migration of GnRH-1 neurons forms the basis of the hypogonadotropic hypogonadism observed in Kallmann syndrome, a genetic disorder from either FGFR1 and/or anosmin-1 gene disruption, which also results in anosmia (Dodé et al., 2003; Dodé and Hardelin, 2009). The gene discussed is GNRH1; the disease is Kallmann syndrome.