Worldwide Distribution of Four SNPs in X-Ray and Repair and Cross-Complementing Group 1 (XRCC1)

X-ray repair cross-complementing group 1 (XRCC1) repairs single-strand breaks in DNA. Several reports have shown the association of single nucleotide polymorphisms (SNPs) (Arg194Trp, Pro206Pro, Arg280His, Arg399Gln) in XRCC1 to diseases. Limited population data are available regarding SNPs in XRCC1, especially in African populations. In this study, genotype distributions of four SNPs in worldwide populations were examined and compared with those reported previously.

Four SNPs (Arg194Trp, Pro206Pro, Arg280His, Arg399Gln) in XRCC1 from genomic DNA samples of 10 populations were evaluated by using polymerase chain reaction followed by restriction fragment length polymorphism analysis.

The frequency of the minor allele corresponding to the Trp allele of XRCC1Arg194Trp was higher in Asian populations than in African and Caucasian populations. As for XRCC1Pro206Pro, Africans showed higher minor allele frequencies than did Asian populations, except for Tamils and Sinhalese. XRCC1 Arg280His frequencies were similar among Africans and Caucasians but differed among Asian populations. Similarly, lower mutant XRCC1 Arg399Gln frequencies were observed in Africans.

This study is the first to show the existence of a certain genetic heterogeneity in the worldwide distribution of four SNPs in XRCC1.