Obesity, however, is not the only symptom to Prader-Willi Syndrome. According to Pediatrichealth.com, last updated on April 1, 2007, other symptoms can include learning and speech difficulties, poor muscle tone which results in a short stature and an inability to exercise normally, and underdeveloped genital organs. Also, children with Prader-Willi Syndrome often suffer from behavioral problems and an obsessive compulsive personality.