Most patients experience sleep-related disorders: Review study

Researchers note need for guidelines for Fabry patients with sleep problems

Steve Bryson, PhD avatar

by Steve Bryson, PhD |

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A person wearing pajamas floats above his bed while his pillow and blanket float beside him. The moon can be seen through a window.

A review study revealed that those with Fabry disease have a high prevalence of a wide range of sleep problems, with excessive daytime sleepiness being the most common.

Reviewed studies also commonly reported insomnia, unrefreshing sleep, periodic limb movements, and REM sleep behavior disorder, or physically acting out dreams when sleeping.

Researchers noted, however, that there are very few studies investigating sleep problems in Fabry patients.

“The attention of clinicians caring for these patients should be drawn to the careful assessment of potential sleep disorders in patients diagnosed with this condition,” the researchers wrote. They also called for the “creation of guidelines for the treatment of sleep disorders in patients with [Fabry disease].”

The review study, “Fabry disease and sleep disorders: a systematic review,” was published in the journal Frontiers in Neurology.

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Fabry disease is a genetic disorder marked by an absent or markedly deficient alpha-galactosidase A (Gal A) enzyme. As a result, the fatty substance Gal A normally breaks down, called globotriaosylceramide (Gb3 or Gl-3), builds up to toxic levels and causes damage, particularly in the nervous system, heart, and kidneys.

Beyond these effects, sleep disorders have been reported in people with Fabry, which include sleep-disordered breathing, insomnia, and excessive daytime sleepiness.

Still, “it is important to note that there are no guidelines available for the treatment of sleep disorders in patients with [Fabry disease],” wrote researchers at Wroclaw Medical University in Poland.

To characterize sleep disorders in Fabry, the team conducted a systematic review of the medical literature focusing on the types and prevalence of sleep disorders in this patient population.

Nine studies matched their criteria, which included 330 people diagnosed with Fabry via genetic tests, with an average age of about 40 years of whom 56% were female. Among them, 219 (66.4%) were treated with enzyme replacement therapy (ERT), the standard Fabry treatment that provides a lab-made source of Gal A to patients.

213 patients had sleep problems including excessive daytime sleepiness

Overall, 213 (64.5%) patients had sleep problems, with excessive daytime sleepiness most frequently reported in six studies, as assessed by the Epworth Sleepiness Scale. In four of these studies, 43 out of 183 (23.5%) Fabry patients were diagnosed with excessive daytime sleepiness.

Generally, sleep problems appeared 4-5 years after Fabry onset, which was delayed in some patients for up to 10-11 years. Poor sleep quality was diagnosed in 42 out of 72 individuals (58.3%) using the patient-reported Pittsburgh Sleep Quality Index questionnaire.

REM sleep behavior disorder was reported in 29 of 110 participants (26.4%), as measured by the REM Sleep Behavior Disorder Screening questionnaire. In one study that conducted patient interviews, 26 out of 56 (46.4%) said they experienced insomnia or unrefreshing sleep.

Sleep problems also were caused by sleep apnea, or when breathing repeatedly stops and starts. A total of 32 of 147 (20.4%) patients were diagnosed with obstructive sleep apnea (OSA), caused by relaxed throat muscles blocking the airways. Five of 52 (11.8%) were diagnosed with central sleep apnea (CSA), or when signals from the brain that control breathing are impaired. Among these, two had both OSA and CSA.

According to researchers, in Fabry patients, “the prevalence of OSA and CSA was within the ranges observed in the general population.”

No association between organ involvement and either OSA or CSA was not found in the studies examined, nor was ERT effective at treating sleep disorders.

Periodic limb movement, or uncontrolled movement of arms and legs, was diagnosed in 19 of 20 (95%) Fabry males who participated in one study, the review showed.

Using the National Institute of Health guidelines, the overall quality of the majority of studies reviewed was deemed as either fair or poor.

“This review has revealed the presence of many sleep-related conditions that significantly affect the quality of life of [Fabry disease] patients,” the research team concluded. “Despite sleep disorders being more prevalent in the general population than in patients with FD, only a few studies on this subject are available in the literature.

“The authors would also like to emphasize the need for further research on this topic involving a larger group of subjects.”