XRCC1 and XPD Gene Polymorphisms in a South Indian Population


DNA repair systems play an important role in maintaining the integrity of the human genome. Deficiency inthe repair capacity due to either mutations or inherited polymorphisms in DNA repair genes may contribute tovariations in the DNA repair capacity and subsequently susceptibility to cancer. The interindividual variabilityas well as ethnic differences in DNA repair polymorphisms, stress the importance to establish genotype profilesunique to a population. Hence the present study aimed to determine the frequencies of XRCC1 and XPD genepolymorphisms in 255 healthy random unrelated individuals from South India. DNA was isolated from theperipheral blood sample of these individuals and the XRCC1 and XPD genotypes were determined by PCRRFLPwith Msp1 and Pst1 enzymes respectively. The XRCC1 genotype frequencies revealed 36% Arg/Arg,47% Arg/Gln and 17% Gln/Gln with Gln allele frequency of 0.41. Analysis of XPD genotypes revealed 51% Lys/Lys, 41% Lys/Gln and 8% Gln/Gln with Gln allele frequency of 0.29. No significant difference in the distributionof genotypes was seen based on gender. Comparison of the frequencies of XRCC1 and XPD polymorphismsobserved in the present study with other populations revealed a distinctive nature of the South Indian population.An understanding of DNA repair gene polymorphisms might not only enable risk assessment of humans exposedto environmental carcinogens but also response to therapy, which target the DNA repair pathway.