NER and BER repair gene polymorphisms in a healthy north Indian cohort and comparison with different ethnic groups worldwide.

Background: Polymorphisms in DNA repair genes are associated with ability to remove DNA lesions, and therefore may contribute to an individual's susceptibility to different types of cancer. Base excision repair (BER), and nucleotide excision repair (NER) are the main DNA repair pathways. The present study was conducted to determine the frequency distribution of single nucleotide polymorphisms (SNPs) selected for genes in these two pathways i.e. OGG1 Exon 7 (C1245G), XPC Intron 9 (PAT), and Exon 15 (A33512C) in a North Indian population in comparison with global populations.

Methods: Genotyping was achieved by PCR-based analysis in 224 normal healthy, unrelated individuals of similar ethnicity.

Results: Allelic frequencies in wild type of OGG1 Exon 7 C>G were 73% (C); XPC PAT D>I 75% (D); and XPC Exon 15 A>C 60.71.9% A. On the other hand, the variant allele frequency were 27% (G) in OGG1 Exon 7 C>G; 25% (I) in XPC PAT; and 28.1% (C) in XPC Exon 15 A>C. Major differences from other ethnic populations were observed.

Conclusions: Our results suggest that frequency distribution in these DNA repair genes exhibited a distinctive pattern in our population which could be attributed to ethnic variation. This could assist in high-risk screening of humans exposed to environmental carcinogens and cancer predisposition in different ethnic groups.