Fabry Disease and Sleep
What is Fabry disease?
Fabry disease is a rare metabolic disease caused by mutations in the GLA gene located on the X chromosome. This gene provides cells with directions necessary to make the alpha-galactosidase A enzyme that helps to break down a specific type of fat called globotriaosylceramide (GL-3 or Gb3).
Because of these mutations, cells cannot make enough functional alpha-galactosidase A enzyme. Its lack leads to Gb3 accumulation in cells, causing the many symptoms of Fabry disease.
How common are sleep issues in patients?
Researchers have reported a number of sleep disorders in Fabry patients, including restless leg syndrome, sleep-disordered breathing, insomnia, and excessive daytime sleepiness.
A study in 49 patients with mild to moderate disease on average found excessive daytime sleepiness a problem for 68% of them. In fact, such sleepiness and fatigue were these patients’ “most common clinical symptoms.”
Another study reported finding central sleep apnea in five of its 23 Fabry patients, for 22% repeatedly stopping then restarting breathing during sleep. (Central sleep apnea is similar to obstructive sleep apnea, also fairly common to Fabry patients, but the two have distinct causes.)
A study in Argentina found restless leg syndrome in four of 11 patients, which its researchers associated with neuropathy and its symptoms of burning and painful feet.
A study that looked at 20 men with Fabry disease examined in a sleep laboratory found almost 95% had abnormal periodic leg movement (excessive leg movement during sleep), and 50% had sleep-disordered breathing, particularly obstructive sleep apnea. Most of those with excessive leg movement — 15 of these 19 people — had symptoms consistent with restless leg syndrome.
Insomnia and/or sleep that fails to refresh was reported by 45.9% of Fabry patients (17 of 32)in a study in Brazil.
A study of Fabry patients with mild disease showed a prevalence toward obstructive sleep apnea in patients compared with healthy individuals serving as controls: apnea affected 19.2% of its 52 patients and 9% of its 104 controls.
How may Fabry disease affect sleep?
Researchers don’t fully understand how exactly Fabry disease causes sleep disturbances. The authors of one study — finding a “high prevalence” of breathing disorders like obstructive sleep apnea — suggested that the accumulation of glycosphingolipids (such as Gb3) in the upper airway muscles contribute to apnea by weakening these muscle. They also suggested that glycosphingolipid buildup in respiratory muscles, particularly the diaphragm, might depress respiration (nocturnal hypoventilation). But these researchers stressed that their study was not “powered” for conclusions, and these suggestions are educated guesses at best.
Restless leg syndrome, as described in some of the above-mentioned studies, appeared to be related to peripheral neuropathy symptoms of pain and burning sensations. Peripheral neuropathy has been previously reported as a symptom of Fabry disease.
Breathing-related disorders, such as hypopneas and apneas, may lead to excessive daytime sleepiness by affecting the amount of oxygen taken in during sleep. Fatigue and daytime sleepiness can also be due to restless sleep and insomnia, studies suggested.
Several options are available that might help people with Fabry disease get a better night’s sleep. You should consult with your physician if you are experiencing sleep issues, as they may be able to prescribe treatments to help.
Continuous positive airway pressure (CPAP) machines may be an option for some sleep-related breathing disorders, although their use with Fabry patients does not appear to be topic of study.
General recommendations for insomnia include setting nighttime routines that promote good sleep. These can include stopping “screen time” — time spent watching TV, doing computer work, or playing online games — in the immediate hours before going to bed, avoiding caffeinated drinks later in the day, reading a book before bed, and taking a relaxing bath in the evening.
Last updated: Nov. 13, 2020
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