Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.1.1.67 (thiopurine methyltransferase)
 551 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pharmacogenetics deals with inherited differences in the response to drugs. The best-recognized examples are genetic polymorphisms of drug-metabolizing enzymes, which affect about 30% of all drugs. Loss of function of thiopurine S-methyltransferase (TPMT) results in severe and life-threatening hematopoietic toxicity if patients receive standard doses of mercaptopurine and azathioprine. Gene duplication of cytochrome P4502D6 (CYP2D6), which metabolizes many antidepressants, has been identified as a mechanism of poor response in the treatment of depression. There is also a growing list of genetic polymorphisms in drug targets that have been shown to influence drug response. A major limitation that has heretofore moderated the use of pharmacogenetic testing in the clinical setting is the lack of prospective clinical trials demonstrating that such testing can improve the benefit/risk ratio of drug therapy.
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PMID:Pharmacogenomics and individualized drug therapy. 1640 40

Drug management can be a difficult task in certain situations because of the variable response observed from one patient to another. Genetic factors affecting the pharmacokinetics and pharmacodynamics of drug reactions could explain the interindividual variability in drug response. Pharmacogenetic analysis provides insight into the molecular mechanisms involved in drug response, with the ultimate goal of achieving optimal drug efficacy and safety. Numerous polymorphisms have been described in genes encoding drug-metabolising enzymes, transporters, and receptors. For some drugs, the impact on drug bioavailability and effect has been elucidated. We review here the molecular basis of interindividual variation in drug response and the methods used to identify individual risk of drug failure or toxicity. Clinical applications, concerning enzymes metabolising drugs (cytochrome P4502D6, thiopurine S-methyltransferase and N-acetyltransferase) provide an illustrative demonstration of the usefulness of pharmacogenetic tests in improving patient management. Clinical validation of these tests and new technologies (real-time PCR, DNA chips) should, in the future promote pharmacogenetics in clinical practice and may be lead to more individualized drug therapy.
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PMID:[Therapeutic failure: importance of genes?]. 1711 71