Carriage of 2R allele at VNTR polymorphous site of <Emphasis Type="Italic">XRCC5</Emphasis> gene increases risk of multiple sclerosis in an Iranian population

The DNA damage has considerably raised in active MS lesions compared to normal brains, indicating the possible role of DNA repairing genes in MS. In the current study, we sought to highlight the association between genetic polymorphisms of XRCC5 and XRCC6 genes, involved in Double Strand Breaks (DSBs) repair, and MS susceptibility. A total of 235 Iranian individuals; including 113 MS patients and 122 healthy controls were participated in this study. They were genotyped for the XRCC5 VNTR polymorphism by polymerase chain reaction (PCR). The genotype analysis of the XRCC6–61C>G polymorphism was performed using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. The genotypic frequency of 2R/2R in the XRCC5 VNTR polymorphism was significantly higher in MS patients than controls (p = 0.048). The frequency of individuals with 2R allele was statistically significant in MS patients compared to controls (p = 0.041). Moreover, the frequency of 2R allele of the XRCC5 VNTR polymorphism was found to be significantly difference between MS patients and healthy groups (p = 0.003). The present study suggests that the presence of 2R allele in XRCC5 VNTR gene polymorphism may be a genetic risk factor for MS susceptibility in Iranian population.