thiopurine S-methyltransferase deficiency

(redirected from PMT deficiency)

thiopurine S-methyltransferase deficiency

A condition (OMIM:610460) caused by a lack of TPMT, an enzyme involved in the normal metabolic inactivation of thiopurine drugs used as immunosupressants or cytotoxic drugs for leukemia, autoimmune disease and organ transplantation. Patients with low or no TPMT activity are at risk of toxicity at standard doses of thiopurine drugs; inter-individual differences in response to thiopurines are largely determined by genetic variation at the TPMT locus.