Department of Pediatrics, Vittore Buzzi Children's Hospital, Università degli Studi di Milano, 20154 Milan, Italy. Department of Medical and Surgical Sciences, University of Foggia, 71100 Foggia, Italy. European Paediatric Association/Union of National European Paediatric Societies and Associations, 10115 Berlin, Germany. Pediatric and Adolescent Unit, Department of Internal Medicine, University of Pavia, 27100 Pavia, Italy. Second Paediatric Clinic, Department of Mother and Child, University of Medicine and Pharmacy Iuliu Hatieganu, 400177 Cluj-Napoca, Romania. Paediatric Gastroenterology, Hepatology and Nutrition, Cerrahpasa Medical Faculty, Istanbul University, Istanbul 34000, Turkey. Department of Pediatrics, Scientific Institute 'Casa Sollievo della Sofferenza', University of Foggia, 71122 Foggia, Italy. Association pour l'Activité et la Recherche Scìentifiques, EPA-UNEPSA/ARS, 2000 Neuchâtel, Switzerland. Department of Paediatric Gastroenterology, and Nutrition, Intestinal Failure Rehabilitation Centre, National Reference Centre for Rare Digestive Diseases, Necker-Enfants Malades Hospital, Paris Centre University and Paris-Descartes School of Medicine, 75000 Paris, France.