1. Department of Pediatrics, West China Second University Hospital, Key Laboratory of Obstetric & Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education, Sichuan University, Chengdu, People's Republic of China
2. Department of Gastroenterology, West China Hospital, Sichuan University, No. 37, Guo Xue Alley, Wu Hou District, Chengdu 610041, Sichuan, People's Republic of China