Aim Of The Study: Thiopurines are effective drugs in treating neuromyelitis optica spectrum disorders and other diseases. Thiopurines' toxicity is mainly imputed to thiopurine S-methyltransferase activity. In Chinese population, the most common and important variation of thiopurine S-methyltransferase is TPMT*3C (rs1142345). This study aims to reveal the association between thiopurine S-methyltransferase activity and genetic polymorphisms of thiopurine S-methyltransferase in patients with neuromyelitis optica spectrum disorders in China.
Material And Methods: A liquid chromatography tandem mass/mass method was used to evaluate the thiopurine S-methyltransferase activity by using 6-mercapthioprine as the substrate in human erythrocyte haemolysate via 1 h incubation at 37 °C to form its methylated product 6-methylmercaptopurine. The amount of 6-methylmercaptopurine was adjusted by haematocrit and normalized to 8 × 10 erythrocytes. The selected polymorphisms of thiopurine S-methyltransferase were identified using MassARRAY system (Sequenom) and multiple SNaPshot technique.
Results: In 69 patients with neuromyelitis optica spectrum disorders, thiopurine S-methyltransferase activity was 80.29-154.53 (127.51 ± 16.83) pmol/h/8 × 10 erythrocytes. TPMT*3C (rs1142345) was associated with lower thiopurine S-methyltransferase activity (BETA = -25.37, P = 0.011). Other selected variants were not associated with thiopurine S-methyltransferase activity.
Conclusions: TPMT*3C affects TPMT activity in Chinese patients with neuromyelitis optica spectrum disorders. Further studies are warranted to confirm the results.
Abbreviations: TPRs = thiopurines; NMOSD = neuromyelitis optica spectrum disorders; TPMT = thiopurine S-methyltransferase; LC-MS/MS = liquid chromatography tandem mass/mass; 6-MMP = 6-methylmercaptopurine; IS = internal standard; SNP = single nucleotide polymorphism; MAF = minor allele frequency; HWE = Hardy-Weinberg equilibrium; BETA = regression coefficients; UTR-3 = untranslated region 3.
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http://dx.doi.org/10.1080/00207454.2017.1401621 | DOI Listing |
Metabolites
December 2024
Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195, USA.
Background: Thiopurine methyltransferase (TPMT) plays a crucial role in the detoxification of thiopurine drugs, including the antimetabolites azathioprine and 6-mercaptopurine (6-MP) used to treat autoimmune diseases and various cancers. These drugs interfere with DNA synthesis by inhibiting the production of purine-containing nucleotides, leading to the death of rapidly dividing cells. TPMT inactivates thiopurine drugs by methylating at the thiol group.
View Article and Find Full Text PDFClin Pharmacol Ther
December 2024
Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee, USA.
Nudix hydrolase 15 (NUDT15) deficiency is strongly associated with thiopurine-induced myelosuppression. Currently, testing for NUDT15 deficiency is based on the genotyping of the most frequent and clinically characterized no-function variants, that is, *2, *3 and *9. The Hispanic/Latino-predominant variant NUDT15 *4 (p.
View Article and Find Full Text PDFPharmacotherapy
November 2024
The University of Sydney School of Pharmacy, Camperdown, New South Wales, Australia.
Introduction: Thiopurine drugs are metabolized by thiopurine methyltransferase (TPMT) and low TPMT activity can result in severe adverse drug reactions. Therefore, TPMT testing is recommended for individuals receiving thiopurines to reduce the risk of toxicity.
Objectives: The objectives of this study were to assess the rate of TPMT testing among individuals receiving thiopurines and explore factors associated with undergoing TPMT testing in Australia.
Naunyn Schmiedebergs Arch Pharmacol
November 2024
Department of Pharmacy Practice, Dr. D.Y. Patil Institute of Pharmaceutical Sciences and Research Pimpri, Pune, Maharashtra, India.
Pharmacogenet Genomics
February 2025
Division of Neonatology, Department of Pediatrics, Fetal and Neonatal Institute, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, California, USA.
Background: Pharmacogenomic testing identifies gene polymorphisms impacting drug metabolism, aiding in optimizing treatment efficacy and minimizing toxicity, thus potentially reducing healthcare utilization. 6-Mercaptopurine metabolism is affected by thiopurine methyltransferase ( TPMT ) and nudix hydrolase 15 ( NUDT15 ) polymorphisms. We sought to estimate the budget impact of preemptive pharmacogenomic testing for these genes in pediatric acute lymphoblastic leukemia (ALL) patients from an institutional perspective.
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