Thiopurine-S-methyltransferase genotype and the response to azathioprine in inflammatory bowel disease

^*Gastroenterology Unit, Glasgow Royal Infirmary, 84 Castle Street, Glasgow G4 OSF; †Purine Research Laboratory, 5th Floor Thomas Guy House, Guy's Hospital, London; ‡Department of Gastroenterology, St Thomas' Hospital, London; ¶Gastroenterology Unit, Gartnavel General Hospital, Glasgow, UK. E-mail: [email protected]