PWS stands for Prader-Willi Syndrome, which is a rare genetic disorder that affects approximately one out of every 15,000 births. It affects males and females with equal frequency and all races and ethnicities. PWS is recognized as the most common genetic cause of life-threatening childhood obesity. The disorder was first described by Swiss doctors Andrea Prader, Alexis Labhart, and Heinrich Willi in 1956 based on the clinical characteristics of nine children they examined. The common characteristics defined in the initial report included small hands and feet, abnormal growth and body composition, hypotonia (weak muscles) at birth, insatiable hunger, extreme obesity, and intellectual disability. PWS is caused by a lack of active genetic material in a particular region of chromosome 15 (15q11-q13) . Symptoms of PWS include poor muscle tone, low levels of sex hormones, a constant feeling of hunger, short stature, poor motor skills, weight gain, underdeveloped sex organs, and mild intellectual and learning disabilities. There is no cure for PWS, but growth hormone, exercise, and dietary supervision can help build muscle mass and control weight. Other treatments may include sex hormones and behavior therapy.