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Prevalence of restless legs syndrome and sleep quality in carriers of the fragile X premutation


  • S.  M. S. and R. J. H.  have participated in research on fragile X syndrome funded by Seaside Therapeutics, Roche, Novartis and Marinus Pharmaceuticals. S. D. B. has previously worked as a consultant regarding restless legs syndrome for UCB. R. J. H. has additionally received funding from Curemark and Forest for past treatment studies and she has consulted with Novartis and Genentech on treatment issues for fragile X syndrome and autism. All other authors deny a conflict of interest. No sponsor of this work was directly involved in study design, data collection, analysis, interpretation, manuscript preparation or the decision to submit the manuscript for publication.


This study examined the relationship between the fragile X premutation and restless legs syndrome (RLS). Demographic, medical history and survey responses related to sleep were collected from 213 participants (127 carriers and 86 age matched controls). Subjects were asked about the presence of the four formal diagnostic criteria for RLS. Individuals with the premutation were 1.9 times as likely to meet criteria for RLS (95% CI 1.1–3.2, p = 0.025) as controls. Premutation carriers with RLS also experienced significantly worse symptoms than matched controls with adjusted mean scores of 15.1 ± 8.8 vs 7.9 ± 4.4, respectively on the International Restless Legs Scale (IRLS). As markers for domains of sleep disturbance, all subjects completed the Epworth Sleepiness Scale (ESS), the Insomnia Severity Index (ISA) and the Pittsburgh Sleep Quality Index (PSQI). Premutation carriers demonstrated significantly more pathology on these tests except for the ESS where there was a trend towards increased daytime sleepiness in carriers. RLS joins a host of other conditions that should be carefully screened for in those carrying the fragile X premutation and sleep should be a focus for clinicians providing care to them.

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