Olfactory Phenotypic Spectrum in Idiopathic Hypogonadotropic Hypogonadism: Pathophysiological and Genetic Implications

IHH subjects display a broad spectrum of olfactory function, with a significant hyposmic phenotype in nearly one third of subjects. The hyposmic subjects harbor mutations in genes affecting GnRH neuronal migration and its secretion, suggesting a pathophysiological overlap between Kallmann syndrome and normosmic IHH. Accurate olfactory phenotyping in IHH subjects will inform the pathophysiology of this condition and guide genetic testing.