Background: Approximately, 50% of male infertility causes have remained unknown. It seems that genetic disorders may lead to many cases of idiopathic infertility. XRCC1 ( X-ray Repair Cross Complementing group 1) acts as a scaffolding protein in the base excision repair (BER) and single strand break repair (SSBR). Single nucleotide polymorphisms (SNP) of XRCC1 may influence DNA repair capacity. Thus, they had been considered as a risk factor for infertility. XRCC1 Arg399Gln polymorphism was located on p rotected domain , BRCT1 . The aim of this study was to explore the p ossibility of association between XRCC1 Arg399Gln polymorphism and susceptibility to idiopathic male infertility.

  Materials and Methods: In this case-control study, the genotype and allele frequencies of Arg399Gln polymorphism were examined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) on a Guilanian population consisting of 144 men with idiopathic infertility and 166 healthy men. Statistical analysis was performed using the MedCalc 12 software.

  Results: According to our results, compared with Arg/Arg genotype, the Arg/Gln , Gln/Gln and Arg/Gln + Gln/Gln genotypes showed a significant association with an increased risk of idiopathic male infertility ( OR=4.19 95%CI 2.37-7.41, p<0.0001 ), (OR=3.42 95%CI 1.50-7.81, p<0.0034), (OR=4.06 95%CI 2.32-7.09, P<0.0001) , respectively. In addition, the Gln allele frequency in patients was significantly higher than that in controls(p=0.0004).

  Conclusion: In total, Arg399Gln polymorphism of XRCC1 gene can be associated with male infertility and Gln allele might be a risk factor of idiopathic male infertility in in this sample population. Larger population and different ethnicities should be studied to achieve a definitive conclusion.