Prader-Willi syndrome (pronounced PRAH-der WILL-ee) is a complex, rare genetic disorder that results from an abnormality on the 15th chromosome. Identified in 1956, it occurs in about one in 15,000 live births, in both males and females equally, and in all races.
Though Prader-Willi syndrome is a rare disease, it is one of the ten most common conditions seen in genetics clinics and is the most common genetic cause of obesity that has been identified.
PWS affects growth, metabolism, appetite, behavior, and overall development. Persons with PWS typically have weaker muscles, short stature if not treated with growth hormone, incomplete sexual development, and a chronic feeling of hunger that, coupled with a metabolism that utilizes drastically fewer calories than normal, can lead to excessive eating and life-threatening obesity. The drive to eat is never satisfied no matter how much food is consumed, necessitating constant and continuous supervision.
PWS is a lifelong, life-threatening condition. There is no known cause of PWS, nor is there a cure — yet.