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Genetic and Rare Diseases Information Center (GARD)

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Thiopurine S methyltranferase deficiency

Other Names for this Disease
  • 6-mercaptopurine sensitivity
  • Thiopurine methyltransferase deficiency
  • Thiopurines, poor metabolism of
  • TPMT deficiency
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Your Question

My daughter has been diagnosed with this condition and her doctors do not know how to treat her. They do not understand that she cannot be exposed to toxins of any kind. How should she be treated?

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

How might an individual with thiopurine S-methyltransferase deficiency be treated?

The National Institutes of Health Clinical Pharmacogenomics Implementation Consortium isssued recommendations on how to manage patients with TPMT deficiency. They recommend that patients with one TPMT gene change reduce thiopurine doses by about 30-70%. Patients with two TPMT gene changes should reduce thiopurine doses by at least 10-fold. The frequency of doses should also be reduced from daily to three times per week.[1]
Last updated: 8/29/2012

  • Relling MV, Gardner EE, Sandborn WJ et al. Clinical Pharmacogenetics Implementation Consortium guidelines for thiopurine methyltransferase genotype and thiopurine dosing. Clin Pharmacol Ther. March 2011; 3:387-391. Accessed 8/29/2012.