Background: The presence of polymorphisms in the TPMT gene is associated with adverse effects in patients treated with standard doses of thiopurine drugs. Scientific evidence recognizes significant ethnic differences in their frequencies and how their early identification can prevent clinical complications. Methods: 150 healthy residents of Aragua, Venezuela were enrolled. The SNPs c.460G>A and c.719A>G were detected by PCR-restriction fragment length polymorphism assay and c.238G>C by allele-specific PCR. Results: All genotype polymorphisms were heterozygous. TPMT*1/*3A, TPMT*1/*3C and TPMT*1/*2 genotypes were found in 4.0, 2.0 and 0.7%, respectively. Conclusion: 6.7% of individuals have an intermediate TPMT activity. These findings support the importance of prior genotyping of TPMT in Venezuelan patients who require thiopurine drug therapy.
Keywords: TPMT alleles; Venezuela; cancer; chemotherapy; pharmacogenetics; population genetics; thiopurines.