1. Department of Internal Medicine and Institute of Gastroenterology; Yonsei University College of Medicine; Seoul Korea
2. Digestive disease center, CHA Bundang Medical Center; CHA University School of Medicine; Seongnam Korea
3. Severance Biomedical Science Institute; Yonsei University College of Medicine; Seoul Korea
4. Brain Korea 21 PLUS Project for Medical Science; Yonsei University College of Medicine; Seoul Korea