1. Faculty of Medicine, Medical University of Warsaw, 61 Zwirki i Wigury Street, 02-091 Warsaw, Poland
2. Department of Gastroenterology with Endoscopy Unit, Medical University of Lublin, 8 Jaczewski Street, 20-954 Lublin, Poland
3. Department of Clinical Genetics, Medical University of Lublin, 11 Radziwillowska Street, 20-080 Lublin, Poland