1 Department of Gastroenterology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK; Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge CB2 0QQ, UK.
2 Genetic Mechanisms of Disease Laboratory, The Francis Crick Institute, London, UK; Department of Gastroenterology, UCL Institute of Liver and Digestive Diseases, Royal Free Hospital, London, UK.
3 Cambridge Clinical Trials Unit, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.
4 Department of Gastroenterology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK; Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge CB2 0QQ, UK. Electronic address: mp372@cam.ac.uk.