Prader-Willi Syndrome (PWS) is a rare syndrome with a prevalence of 15 to 20 000 at birth. PWS represents a large fraction of mental retardation syndromes due to a genetic cause and the most frequent cause of genetic obesity. The majority of the patients are seen by paediatricians. This syndrome is responsible for severe physical, psychological and social impairments.

The diversity and the severity of the manifestations of this disease explain the requirement of multidisciplinary care which deserve specific evaluation. Today the follow-up and management of a great proportion of these patients are greatly insufficient if not absent.

Teams strongly lack information on the natural history of this severe disease and on the factors involved in its evolution and the outcome of these patients throughout life. The present project is to implement a register in the whole country for children and adult patients

Inclusion Criteria:

• all subjects with a Prader-Willi Syndrome

Exclusion Criteria:

-

Patients will be included by the paediatric endocrinologists or the endocrinologists for adults of each region based on their own recruitment