Background: Inflammatory Bowel Disease (IBD) is a common disease affecting many patients. This
disease is treated by azathioprine and TPMT genetic polymorphism affecting the patient’s tolerance. The aim of this
study is to investigate the importance of TMPT genotyping in reducing the incidence of adverse effects of azathioprine.
Methods: One hundred and forty-one IBD patients were followed for azathioprine Adverse Drug Reaction (ADR).
Patients were genotyped for TPMT*2, TPMT*3A, TPMT*3B, TPMT*3C.
Results: The frequency of Azathioprine adverse effect was about 35.5%. An association between TPMT genotypes
1/3A and 3B/3B and azathioprine related bone marrow suppression was found (P value ≤ 0.05).
Conclusion: The findings suggest that there was a significant association between TPMT genotypes 1/3A and 3B/3B
and azathioprine related bone marrow suppression.