GNRH1 and Anosmia: When the embryonic migration of gonadotropin-releasing hormone (GnRH) neurons from the nasal placode to their final destination in the hypothalamus is disrupted, the resulting phenotype is Kallmann syndrome (KS), which is defined as the association of HH with hyposmia or anosmia (Sonne and Lopez-Ojeda, 2021).