Follow-up of Prader Willi Syndrome Infants Treated by Oxytocin and Comparison With Not-treated Infants.

Long Term Evaluation of Infants Aged From 3 to 4 Years Old Included in the Ancient Study (Repeated Administrations of Oxytocin in Infants With Prader Willi Syndrome Aged From 0 to 6 Months) and Comparison With Not Treated and Age-matched Prader Willi Syndrome Infants (OT2SUITE)

The objective of this study is to collect data on tolerance and effects of early treatment with oxytocin in children with Prader Willi Syndrome aged from 3 to 4 years and to compare these infants with not treated age-matched infants with Prader Willi Syndrome.

In accordance with recommendations of regulatory authorities, we want to collect long term data of patients treated with oxytocin before the age of 6 months. Moreover clinical observations of these infants support long term effects on communication skills, global development and behaviour.

Inclusion Criteria:

• Infants with Prader Willi Syndrome (genetic diagnosis confirmed)
• For treated group : infant included in the ancient study
• For not treated group: infant never treated with oxytocin

Exclusion Criteria:

• Subject involved in another search including an exclusion period still in progress at the time of inclusion.
• Impossibility to give parents or legal guardian informed information
• No coverage by a Social Security scheme
• Refusal of parents or legal representative to sign consent.

If a patient has a contraindication to Magnetic resonance imaging, it may be included in the study but Magnetic resonance imaging will not be performed.