Age at diagnosis. Body Mass Index and physical morbidity in children and adults with the Prader-Willi syndrome: The medical findings of a population of 54 Prader-Willi patients with a molecular confirmed diagnosis are discussed. In the age group aged 18 or younger. a reasonably good control of weight as measured by Body Mass Index (BMI) is found. This is probably due to the fact that diagnosis was made at an early age and intensive diet management was started early. Despite their relatively low BMI these children remain at high risk for developing scoliosis requiring active treatment (28% of the children). Adults (older than 18) diagnosed at the age of 10 or later have a high risk for developing obesity and obesity related health problems Such as hypertension (38%). non-insulin dependant diabetes mellitus (11%) and cardio respiratory failure (16%).