Prader-Willi Syndrome Caitlin Campbell

Also referred to as: Prader-Labhart-Willi Syndrome, Willi-Prader Syndrome, Prader-Willi-Fanconi Syndrome, or PWS

Signs and Symptoms

  • Weak muscle tone (hypotonia)
  • Insatiable appetite
  • Hyperphagia (chronic over-eating) which can lead to obesity
  • Mild to moderate intellectual impairment
  • Underdeveloped genitals
  • Short stature
  • Small hands
  • Extremely fair skin and light colored hair
  • Temper outbursts, stubbornness and compulsive behavior
  • Sleep abnormalities
  • Often have a narrow temples, long faces, and almond shaped eyes
  • High tolerance of pain
  • Myopia (shortsightedness)

Genetic Differences

There are three ways in which Prader-Willi can occur, but all three deal with chromosome 15.

The most common case of Prader-Willi Syndrome occurs when there is a deletion of the paternal chromosome 15.

These patients only inherit their mother's chromosome and, because it is missing the father's, it is inactivated.

Prader-Willi Syndrome can also be caused by maternal uniparental disomy. This is when the offspring receives two of chromosome 15 from his mother.

Lastly, the most rare genetic abnormality that can cause Prader-Willi is when there is a translocation or a mutation on chromosome 15 which deactivates the paternal gene.


PWS affects somewhere between 1 in 8,000 to 1 in 25,000 people. It affects both women and men equally.

It is very rare for Prader-Willi to be inherited or passed down, because the deletion of the paternal chromosome 15 and the maternal uniparental disomy are randomized events.


"It is possible for a genetic change that abnormally inactivates genes on the paternal chromosome 15 to be passed from one generation to the next."

Diagnosis and Treatment

A genetic test called methylation can be performed to test for PWS. It can detect 99% of PWS cases.

An early diagnosis is very important in minimizing the symptoms. There is no cure since PWS is a genetic abnormality, however, the symptoms can be treated through therapy.

Nutrition therapy is essential for these patients because they must stay on a very strict diet in order to maintain their weight at a healthy level.

Growth Hormone treatments can also help patients reduce body weight and increase in height.

Occupational therapy, physical therapy, speech therapy, and even psychiatric therapy are often also helpful in letting PWS patients live a more normal life.

Quality of Life

A study was done in 2011 which proved that the quality of life for patients with PWS over the age of 14 was greatly impaired. The two main influences of this are the patient's weight and their facial characteristics.

It has also been proven that those with PWS have a lower self-esteem.

"PWS is the most common genetic cause of morbid obesity in children."

Patients with PWS are also never able to reproduce as their sex organs never fully develop.

Life expectancy is near normal if the patients symptoms can be kept under control and their weight managed.


Caliandro, P., Grugni, G., Taruscio, D., Kodra, Y., & Padua, L. (1970, January 01). Quality of Life Assessment in Prader–Willi Syndrome. Retrieved March 01, 2017, from

Nordqvist, C. (n.d.). What is Prader-Willi Syndrome? Retrieved March 01, 2017, from

Prader-Willi Syndrome. (2017, February 28). Retrieved March 01, 2017, from

Prader-Willi Syndrome. (n.d.). Retrieved March 01, 2017, from

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