Institutional Review Board Statement
DER
The project was accepted by the corresponding ethics committees responsible in each study centre: Ethik-Kommission der Bayerishen Landersäzrtekammer from Munich, Comité d’Ethique d’Hopital Universitarie des Enfants Reine Fabiola from Brussels, Comité d’Ethique du Clinique Saint Vincent from Liege, Comitato Etico Azienda Ospedaliera San Paolo Polo Universitario from Milano, Komiscja Bioetyczna Pomnik-Centrum Zdrowia Dziecka from Warsaw, and Comitè d’Ètica d’Investigació Clínica de l’Hospital Universitari Sant Joan de Reus i Comitè d’Ètica d’Investigació Clínica de l’Hospital Universitari de Tarragona Joan XXIII. Written informed consent was obtained from parents or caregivers. All research was performed following the Declaration of Helsinki.