Prevalence and Phenotype of Sleep Disorders in 60 Adults With Prader-Willi Syndrome

Excessive sleepiness is a common symptom in Prader-Willi syndrome (PWS), and it negatively impacts the quality of life. Obstructive sleep apnea and narcolepsy phenotypes have been reported in PWS. We characterized sleep disorders in a large cohort of adults with PWS.

All consecutive patients with genetically confirmed PWS unselected for sleep-related symptoms, underwent a clinical interview, polysomnography, and multiple sleep latency tests (MSLT, n = 60), followed by long-term (24 hours) polysomnography (n = 22/60).

Among 60 adults evaluated (57% female, aged 25 ± 10 years, body mass index: 39 ± 12 kg/m2), 67% reported excessive sleepiness. According to the sleep study results, 43% had a previously unrecognized hypersomnia disorder, 15% had an isolated sleep breathing disorder, 12% had combined hypersomnia disorder and untreated breathing sleep disorder, and only 30% had normal sleep. Isolated hypersomnia disorder included narcolepsy in 35% (type 1, n = 1, and type 2, n = 8), hypersomnia in 12% (total sleep time >11 hours, n = 2, and MSLT <8 minutes, n = 1), and borderline phenotype in 53% (≥2 sleep onset in REM periods and MSLT >8 minutes, n = 10, and 8 minutes < MSLT < 10 minutes, n = 4). Sleep breathing disorders, isolated and combined, included obstructive sleep apnea (n = 14, already treated in seven), sleep hypoxemia (n = 1) and previously undiagnosed hypoventilation (n = 5). Modafinil was taken by 16 patients (well tolerated in 10), resulting in improved sleepiness over a mean 5-year follow-up period.

Sleepiness affects more than half of adult patients with PWS, with a variety of hypersomnia disorder (narcolepsy, hypersomnia, and borderline phenotypes) and breathing sleep disorders. Earlier diagnosis and management of sleep disorders may improve sleepiness, cognition, and behavior in these patients.