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Gender differences in narcolepsy: What are recent findings telling us?
Markus H Schmidt1,2, Claudio L A Bassetti1
1Department of Neurology, Inselspital, University Hospital Bern, Switzerland.
Sleep
|May 31, 2022
Summary
Female mice exhibit more narcolepsy symptoms, including cataplexy, than males. These gender differences in narcolepsy expression warrant further investigation in humans.
Area of Science:
- Neuroscience
- Sleep Medicine
- Genetics
Background:
- Narcolepsy is a chronic neurological disorder affecting sleep-wake cycles.
- Previous studies suggest potential gender differences in narcolepsy.
- Hypocretin (Hcrt) deficiency is a key factor in narcolepsy pathogenesis.
Purpose of the Study:
- To review and synthesize findings on gender differences in narcolepsy expression in mouse models.
- To explore the influence of the estrous cycle on narcolepsy symptoms in females.
- To contextualize animal findings within existing literature and suggest future research directions.
Main Methods:
- Analysis of published data from two mouse models: Hcrt-tTa;TetO diptheria toxin-A (DTA) and Hypocretin knock-out (Hcrt-KO).
- Comparison of cataplexy events and expression between male and female mice.
- Examination of cataplexy onset timing in relation to Hcrt cell loss in the DTA model.
- Assessment of cataplexy during different phases of the female estrous cycle.
Main Results:
- Female mice consistently showed higher cataplexy frequency and severity than males across models.
- In the DTA model, females exhibited an earlier onset of cataplexy during Hcrt neuron degeneration.
- Cataplexy in females doubled during the estrous phase compared to other cycle phases.
- Prior literature indicates gender differences in Hcrt expression and hormonal effects on sleep.
Conclusions:
- Animal models strongly indicate significant gender differences in narcolepsy expression, particularly concerning cataplexy.
- Hormonal fluctuations, specifically the estrous cycle, play a role in modulating narcolepsy symptoms in females.
- While human data are lacking, these findings underscore the need for systematic research into gender-specific aspects of narcolepsy in humans.
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