I would like to know about prater-willies syndrome? how common is this? how can it be treated?

Prader-Willi syndrom: It is a rare genetic disorder, affecting seven genes on chromosome 15 . People with prader-willi syndrome usually have narrow temples, elongated face, thin upper lip, prominent nose. They also might have low muscle tone, short stature, incomplete sexual development, cognitive disabilities, problem behaviors, and a chronic feeling of hunger that can lead to excessive eating and severe obesity.