ESPE Abstracts

Background: Prader-Willi syndrome (PWS) is a rare and complex genetic disorder characterised in neonates by hypotonia and feeding problems. French birth incidence has never been reported.

Objective and hypotheses: To evaluate incidence of PWS at birth in France.

Method: Identification of patients with a molecular diagnosis of PWS born between January 1^st, 2013 and December 31^st, 2013 was obtained by combining various approaches in order to try to reach exhaustive results: e-mailing to members of the Pediatric Endocrinology French Society and Neonatology French Society, to genetics laboratory involved in the molecular prenatal and neonatal molecular diagnosis of PWS and to the French PWS patients association. In addition, number of live births with PWS was obtained from the annual report of the National Statistic Institute.

Results: 37 newborns with molecular diagnosis of PWS were identified in France in 2013. Three prenatal diagnoses were made during this period whose outcome was a pregnancy interruption, giving the number of 40 diagnoses per year. There were 781621 live births in 2013, birth incidence of SPW was therefore 1/19540. Molecular mechanism was known for 35 patients (95%). We found 54% of neonates having deletions and 40% maternal uniparental disomy (mUPD) with 6% of cases yet unknown.

Conclusion: Birth incidence of Prader-Willi syndrome in France in 2013 was close to 1/20 000 live births. We confirmed the increasing proportion of mUDP.