<b>Conclusion:</b> This case describes the clinical phenotype associated with a rare <i>SPRY4</i> gene allelic variant, consisting in congenital severe smell defect and adult-onset IHH; in patients with apparently isolated congenital anosmia genetic analysis can be valuable to guide follow up, since IHH can manifest later in adulthood. This evidence concerns the gene SPRY4 and Kallmann syndrome.