ABSTRACT
DNA repair systems play an important role in maintaining the integrity of the human genome. Deficiency in the repair capacity due to either mutations or inherited polymorphisms in DNA repair genes may contribute to variations in the DNA repair capacity and subsequently susceptibility to cancer. The interindividual variability as well as ethnic differences in DNA repair polymorphisms, stress the importance to establish genotype profiles unique to a population. Hence the present study aimed to determine the frequencies of XRCC1 and XPD gene polymorphisms in 255 healthy random unrelated individuals from South India. DNA was isolated from the peripheral blood sample of these individuals and the XRCC1 and XPD genotypes were determined by PCR- RFLP with 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 distribution of genotypes was seen based on gender. Comparison of the frequencies of XRCC1 and XPD polymorphisms observed 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 exposed to environmental carcinogens but also response to therapy, which target the DNA repair pathway.