Prader-Willi Syndrome Center France / A state-of-the-art residential center for children and adults with Prader-Willi Syndrome PraderWilli Syndrome Center France ABOUT PWS PraderWilli Syndrome PWS is a complex rare and random genetic disorder that affects one in twelve to fifteen thousand people. First discovered in 1956 by Swiss researchers Andrea Prader Heinrich Willi Alexis Labhart Andrew Ziegler and Guido Fanconi PWS is the leading genetic cause of morbid obesity. There is no known cause or cure. Like many syndromes PraderWilli presents a litany of difficult problems that may happen to varying degrees failuretothrive at birth obsessivecompulsive behavior mild to severe mental retardation scoliosis strabismus skinpicking learning disorders and such but the defining characteristics of PWS are hypotonia lifelong low muscle tone and hyperphagia the inability to feel sated when eating leading to a never ending feeling of great hunger that drives those with PWS to constantly seek food often in a most disastrous way.