What is Prader-Willi syndrome?

Prader-Willi syndrome (PWS) is a rare genetic condition that affects your child’s appetite, growth, metabolism (how their body uses food for energy). and behavior. Babies with PWS are very weak and have trouble feeding. Later in infancy and during childhood, they often do not feel full after a meal. This can cause unhealthy weight gain and behavior challenges.

What causes PWS?

PWS is caused in several ways:

  • When a small amount of genetic material on chromosome 15 is not inherited from the father
  • A missing piece of chromosome 15
  • A gene that is changed on chromosome 15

In most cases, PWS happens at random. It is not anyone’s fault. These genetic changes usually lead to changes in the hypothalamus (part of the brain that controls the release of hormones). When the hypothalamus does not work properly, it can affect your child’s appetite, growth, development, mood and sleep.

Rev. 4/2018. Reviewed by the MGHfC Family Advisory Council.