1 Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK; Department of Gastroenterology, Imperial College Healthcare NHS Trust, London, UK.
2 Department of Gastroenterology, Royal Devon and Exeter NHS Foundation Trust, Exeter, UK; Exeter Inflammatory Bowel Disease and Pharmacogenetics Research Group, University of Exeter, Exeter, UK.
3 Institute of Genetic and Molecular Medicine, University of Edinburgh, Edinburgh, UK; Department of Gastroenterology, Western General Hospital, Edinburgh, UK.
4 Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK; Department of Gastroenterology, Imperial College Healthcare NHS Trust, London, UK. Electronic address: nicholas.powell@imperial.ac.uk.