The diagnostic value of the olfactory evaluation for congenital hypogonadotropic hypogonadism

Abstract

ObjectiveThe aim of this study was to evaluate the diagnostic accuracy of different olfactory evaluation tools in congenital hypogonadotropic hypogonadism (CHH) patients.MethodsSeventy-one CHH patients were prospectively recruited at Peking Union Medical College Hospital between November 2020 and July 2021. The Chinese Olfactory Function Test (COFT) and Self-reported Olfactory Scale (SROS) were adapted as the subjective tools for the evaluation of olfactory function, and magnetic resonance imaging of olfactory apparatus (MRI-OA) was the objective tool. The olfactory bulb volume (OBV) and the olfactory sulcus depth (OSD) were quantified.ResultsBased on the COFT, 36 patients were categorized as having normosmic CHH (nCHH), and the other 35 patients were categorized as having Kallmann syndrome (KS). Among nCHH patients, 35 patients were classified as having normal olfaction and 1 patient had abnormal olfaction by SROS. For KS patients, there were 30 patients grouped into abnormal olfaction, while 5 patients had normal olfaction by SROS. For MRI-OA, 67% (18/27) of nCHH patients showed normal olfactory apparatus, and 33% (9/27) showed bilateral or unilateral olfactory bulb aplasia or hypoplasia. Among KS patients, 96% (27/28) of patients showed bilateral olfactory bulb hypoplasia or aplasia, and 4% (1/28) of patients showed normal olfactory apparatus. All six patients with unilateral olfactory bulb aplasia and three patients with bilateral olfactory bulb aplasia showed normal olfactory function. The accuracy of the SROS in the diagnosis of nCHH and KS was 91.5%, with a sensitivity of 0.857 and a specificity of 0.972, while the accuracy of MRI-OA is 92.7%, with a sensitivity of 0.964 and a specificity of 0.889.ConclusionSROS and MRI-OA both showed high accuracy to distinguish between KS and nCHH. The abnormal structure of the olfactory apparatus was relatively common in nCHH patients. CHH patients with unilateral olfactory bulb aplasia dysplasia usually had normal olfaction. Normal olfaction without apparent olfactory bulbs is rare but occurred in male CHH patients.

Illuminating the terminal nerve: Uncovering the link between GnRH‐1 neuron and olfactory development

“…The prevailing model suggests that the migration of GnRH‐1 neurons depends on proper olfactory development, considering the developmental defects observed in the OBs, tracts, and sulci of KS patients (Knorr et al., 1993; Yu et al., 2022). However, evidence from mice indicates that GnRH‐1 neuronal migration can occur despite defective OB development (Taroc et al., 2017).…”

Illuminating the Terminal Nerve: Uncovering the Link between GnRH-1 and Olfactory Development

“…The prevailing model suggests that the migration of GnRH-1 neurons depends on proper olfactory development, considering the developmental defects observed in the olfactory bulbs, tracts, and sulci of Kallmann Syndrome (KS) patients (Knorr et al, 1993; Yu et al, 2022). However, evidence from mice indicates that GnRH-1 neuronal migration can occur despite a defective olfactory bulb development (Taroc et al, 2017).…”

Olfactory function and olfactory bulbs in patients with Kallmann syndrome

“…По результатам исследований у пациентов с синдромом Кальмана чаще выявлялась полная аплазия обеих луковиц: так, в исследовании Т. Hacquart et al [ 20 ] данные структуры головного мозга отсутствовали у 14 из 19 пациентов с синдромом Кальмана, а в исследовании Yu et al аплазия отмечалась у 27 из 28 пациентов [ 21 ]. В нашем исследовании двусторонняя аплазия отмечалась только у 3 пациентов.…”

“…У 2 из них отмечалась гипоплазия обеих луковиц, у 1 — односторонняя гипоплазия. Эти результаты согласуются с данными зарубежных исследований: по результатам исследования В. Yu et al, проведенного в 2022 г., изменения ольфакторного аппарата у пациентов с гипогонадизмом без нарушения обоняния определялись у 9 из 36 пациентов (25%) [ 21 ]. Вероятнее всего, ненарушенная обонятельная функция у пациентов с гипоплазией одной или обеих луковиц объясняется сохранным остаточным объемом другой луковицы или обеих структур.…”

“…Вероятнее всего, ненарушенная обонятельная функция у пациентов с гипоплазией одной или обеих луковиц объясняется сохранным остаточным объемом другой луковицы или обеих структур. Известно, что обонятельная функция у нормосмических пациентов с изменениями ольфакторного аппарата со временем может ухудшиться [ 21 ].…”