Thiopurine S-methyltransferase genetic polymorphism in the Tunisian population

BackgroundDetermine the incidence of four thiopurine S-methyltransferase (TPMT) mutant alleles, TPMT∗2, ∗3A, ∗3B and ∗3C in the Tunisian population involved in adverse drug reactions.Genomic DNAs were isolated from peripheral blood leucocytes of 119 healthy Tunisian volunteers. The frequencies of four allelic variants of the TPMT gene, TPMT∗2, ∗3A, ∗3B, ∗3C were determined using allele specific polymerase chain reaction (PCR) or PCR-restriction fragment length polymorphism technique.ResultsOf the 119 Tunisian subjects participating in this study, 117 subjects (98.3%) were homozygous for TPMT∗1 and only two subjects (1.68%) were heterozygous for TPMT∗1/∗3A. The frequency of TPMT∗3A mutant allele was 0.009.ConclusionsOur study provides the first data on the frequency of common TPMT variants in the Tunisian population. TPMT∗3A, which causes the largest decrease in enzyme activity, seemed to be a unique variant allele found in this our population.