Prader-Willi Syndrome (PWS)

PWS is a genetic disorder that affects many parts of the body. It is the leading genetic cause of life-threatening obesity.

After infancy, symptoms of PWS include uncontrolled eating and delays in reaching physical activity milestones, such as standing and walking.

PWS is caused by genetic changes on an "unstable" region of chromosome 15 that affects the regulation of gene expression, or how genes turn on and off.

If a newborn is unable to suck or feed for a few days and has a "floppy" body and weak muscle tone, a healthcare provider may conduct genetic testing for PWS.

No, but early diagnosis and treatment may help prevent or reduce the number of challenges that individuals with PWS may experience.

Parents can enroll infants with PWS in early intervention programs. The types of treatment depend on the individual’s symptoms.

NICHD conducts and supports research on PWS and on many disorders associated with it.

NICHD conducts and supports a variety of clinical research projects related to PWS.

Find answers to other common questions about PWS, such as diseases and conditions associated with PWS and how it affects fertility and pregnancy.

Links to websites of groups that study or provide information about Prader-Willi Syndrome.