Prader-Willi Syndrome and Sleep: Unraveling the Connection

Prader-Willi Syndrome and Sleep: Unraveling the Connection

Did you know that people with Prader-Willi Syndrome (PWS) often experience sleep issues? Indeed, about 57% of individuals with PWS have some type of sleep-disordered breathing before starting their growth hormone therapy. The most common issue is excessive daytime sleepiness, often caused by sleep apnea which is a sleep disorder characterized by breathing interruptions during sleep that disturb the quality and efficiency of sleep.

Prader-Willi Syndrome


Prader-Willi syndrome is a rare genetic disorder that occurs in approximately one out of every 15,000 births. This disorder affects a child’s metabolism. And, it results in body and behavior changes and can also cause delays in childhood milestones and puberty

Children with PWS have extremely low muscle tone and poor feeding during early infancy, but then, between 2 and 6 years of age, they develop an immense appetite and don’t feel full after meals. As a result, these children develop severe obesity if their excessive eating isn’t managed.


Although PWS affects every individual differently, there are some common symptoms that appear in infancy, including:

  • Weak cry
  • Tiredness
  • Poor feeding
  • Weak muscle tone

Other symptoms might affect the body of a child which can be present at birth but become more noticeable later on as the child grows. These might include:

  • Long and narrow head
  • Almond-shaped eyes
  • Triangular mouth
  • Small hands
  • Small feet
  • Short height
  • Underdeveloped genitals

Plus, some symptoms might affect a child’s behavior and development can also occur, including:

  • Temper tantrums
  • Intellectual disability
  • Obsessive or compulsive behaviors
  • Sleep disorders
  • Eating challenges


A majority of PWS cases, nearly 70%, are caused by a deletion in one region of the father’s chromosome 15. As a result, several genes lose their function which cannot be made up for by the corresponding mother’s genes on chromosome 15 as they are always inactive.

Furthermore, another cause of this change to chromosome 15 gene might be maternal uniparental disomy which makes up about 25% of PWS cases. This occurs when a child inherits two maternal copies of chromosome 15, and none from their father.

Thirdly, translocation is responsible for less than 1% of PWS cases. This happens when a piece of chromosome 15 relocates to another chromosome. Hence, the chromosome produces genes that work ineffectively since they aren’t in the right place.

Prader-Willi Syndrome and Sleep

As already mentioned, PWS patients frequently experience sleep issues and they most commonly experience excessive daytime sleepiness. For example, sleep apnea leads to fatigue and daytime sleepiness as a result of poor sleep quality and quantity. Similarly, obstructive sleep apnea leads to increased body mass index, i.e. obesity.

In addition, many PWS patients experience oxygen desaturations caused by these apneas, i.e. breathing interruptions. Therefore, people with this genetic syndrome typically undergo sleep studies to check the occurrence of apnea and measure oxygen desaturation.

Moreover, as a result of hypothalamic dysfunction, PWS patients have inherited sleep/wake cycle abnormalities. Namely, they go through more sleep cycles and more REM periods per night, yet the overall amount of REM sleep is decreased which also leads to extreme daytime sleepiness.

Finally, apart from sleep apnea, narcolepsy is yet another sleep disorder affecting individuals with PWS. This disorder affects the cycles of sleep and results in fragmented sleep and intrusion of REM sleep into wakefulness.

Last but not least, no matter the sleep issue PWS patients experience, seeking professional help from a sleep specialist is of utmost importance. They will be able to provide the right treatment for your sleep issue so that you can finally get a good night’s sleep and feel well-rested after waking up.