Ethics Statement
Our study has been conducted in accordance with the principles expressed in the Declaration of Helsinki, and was approved by the ethics committee of Zhongnan Hospital of Wuhan University (2014037). Informed consent has been obtained.
Patients and samples collection
Lithium sulfate anti-coagulated peripheral blood samples were obtained from 378 IBD patients (185 CD, 193 UC) and 509 healthy controls. All patients were recruited from the Department of Gastroenterology, Zhongnan Hospital of Wuhan University (Wuhan, China) from September 2014 to January 2016. The patients were sub-genotyped according to Montreal classification criteria. Healthy controls were selected among volunteers from January to November 2015. The demographic and sub-phenotype data for the patients and controls are shown in Supplementary Table 1. Total genomic DNA was extracted from blood using the QIAamp DNA blood midi kit (Qiagen, Shanghai, Germany). Inflamed ileal and/or colonic tissues were collected from 36 CD patients and 52 UC patients who underwent endoscopy at Zhongnan Hospital. All biopsies were taken from inflammatory sites adjacent to ulcerations. Non-inflamed colonic mucosa samples were collected from 14 healthy volunteers; another 20 normal biopsies (Zhongnan Hospital from September 2014 to June 2015) obtained from uninfected sites 20 centimeters from polyps or neoplasms served as controls. All patients and controls were of the Han population from Central China. Diagnosis of CD and UC was based on a combination of clinical symptoms, laboratory and radiological examinations and endoscopy with histology.