1. Department of Genetics, Maria Sklodowska-Curie Institute – Oncology Centre, Warsaw, Poland
2. Department of Gastroenterology and Hepatology, Medical Center for Postgraduate Education, Warsaw, Poland
3. Department of Pediatric Gastroenterology and Nutrition, Medical University of Warsaw, Warsaw, Poland
4. Department of Gastroenterology, Hepatology and Feeding Disorders, Children’s Memorial Health Institute, Warsaw, Poland
5. Department of Internal Medicine and Gastroenterology with IBD Subdivision, Central Clinical Hospital of the Ministry of the Interior, Warsaw, Poland
6. Vascular Diseases and Internal Medicine, Nicolaus Copernicus University in Torun, Collegium Medicum, Bydgoszcz, Poland
7. Department of Pediatrics, Gastroenterology and Nutrition, Wroclaw Medical University, Wroclaw, Poland
8. Department of Pediatrics, School of Medicine with the Division of Dentistry in Zabrze, Medical University of Silesia, Katowice, Poland
9. Department of Pediatric Gastroenterology & Metabolic Diseases, Poznan University of Medical Sciences, Poznan, Poland
10. Department of Gastroenterology, Medical University of Lublin, Lublin, Poland
11. Department of Pediatrics, School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland
12. Medical College, University of Rzeszow, Rzeszow, Poland
13. Department of Gastroenterology, Pomeranian Medical University, Szczecin, Poland