1. Gastroenterology‐Nutrition and Hepatology Units, Hôpital Universitaire Necker‐Enfants Malades Paris France
2. Hepatology, Gastroenterology and Transplantation Unit, Hospital Papa Giovanni XXIII Bergamo Italy
3. Department of Gastroenterology, Hepatology, Nutrition Disturbances and Pediatrics The Children's Memorial Health Institute Warsaw Poland
4. Paediatric Gastroenterology Unit, Paediatric Hospital Dona Estefânia, Centro hospitalar de Lisboa Central Lisbon Portugal
5. Department of Paediatrics Dr. von Hauner Children's Hospital, LMU University Hospital Munich Munich Germany
6. Department of Pediatrics, Gastroenterology and Nutrition School of Medicine Collegium Medicum University of Warmia and Mazury Olsztyn Poland