Thiopurine methyltransferase genotype and thiopurine S-methyltransferase activity in Greek children with inflammatory bowel disease.

Background: Azathioprine (AZA) and 6-mercaptopurine (6MP) are used in the treatment of pediatric inflammatory bowel disease (IBD). Genetic variations in thiopurine S-methyltranfarase (TPMT) gene have been correlated with enzyme activity and with the occurrence of adverse events to AZA and 6MP. The aim of the present study was to examine the sensitivity and specificity of genotyping for TPMT enzymatic activity, reducing harm from thiopurine by pretesting, and the association of thiopurine toxicity with TPMT status in children with IBD.