The DNA non-homologous end-joining repair gene XRCC6 (Ku70) plays an essential role in the DNA double-strand break (DSB) repairs. Defects in the DSB repair pathway results in genomic instability. Varicocele is characterized by high pressure and stasis in the veins of the testis. There is little knowledge about the molecular mechanisms underlying varicocele. One of the reasons for increased spermatozoa DNA damage is high concentrations of reactive oxygen species (ROS), which leads to DNA-DSBs. We assumed that a promoter T-991C (rs5751129) polymorphism in the XRCC6 gene was associated with susceptibility to varicocele in infertile men. Therefore, 63 infertile varicocele men and 150 healthy controls were recruited in our study. The healthy controls had no history of varicocele, and they were matched with patients by age. Our results showed that infertile varicocele patients and control groups had significant differences in the distribution of their genotypic and allelic frequency (p = 0.00) in the XRCC6 promoter T-991C polymorphism. Men who carried CC genotype had a 5.22-fold increased odds ratio of developing infertile varicocele compared to those who carried the wild-type TT genotype (95% CI 2.31–11.81, P < 0.001). Our results suggested that the CC genotype and the C allele in the promoter region of XRCC6 gene might play an important role in developing infertility in the varicocele men. Further research is needed to provide the effect of this polymorphism.

中文翻译：

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XRCC6 T-991C基因多态性与精索静脉曲张风险的相关性

DNA 非同源末端连接修复基因 XRCC6 (Ku70) 在 DNA 双链断裂 (DSB) 修复中起着至关重要的作用。DSB 修复途径中的缺陷导致基因组不稳定。精索静脉曲张的特点是睾丸静脉高压和淤滞。关于精索静脉曲张的分子机制知之甚少。精子 DNA 损伤增加的原因之一是高浓度的活性氧 (ROS)，这会导致 DNA-DSB。我们假设 XRCC6 基因中的启动子 T-991C (rs5751129) 多态性与不育男性对精索静脉曲张的易感性有关。因此，我们的研究招募了 63 名不育精索静脉曲张男性和 150 名健康对照。健康对照组无精索静脉曲张病史，与患者年龄相匹配。我们的结果表明，不育精索静脉曲张患者和对照组在 XRCC6 启动子 T-991C 多态性中的基因型和等位基因频率分布（p = 0.00）有显着差异。与携带野生型 TT 基因型的男性相比，携带 CC 基因型的男性患不育性精索静脉曲张的几率增加了 5.22 倍（95% CI 2.31–11.81，P < 0.001）。我们的研究结果表明，XRCC6 基因启动子区的 CC 基因型和 C 等位基因可能在精索静脉曲张男性的不育发展中起重要作用。需要进一步研究以提供这种多态性的影响。与携带野生型 TT 基因型的男性相比，携带 CC 基因型的男性患不育性精索静脉曲张的几率增加了 5.22 倍（95% CI 2.31–11.81，P < 0.001）。我们的研究结果表明，XRCC6 基因启动子区的 CC 基因型和 C 等位基因可能在精索静脉曲张男性的不育发展中起重要作用。需要进一步研究以提供这种多态性的影响。与携带野生型 TT 基因型的男性相比，携带 CC 基因型的男性患不育性精索静脉曲张的几率增加了 5.22 倍（95% CI 2.31–11.81，P < 0.001）。我们的研究结果表明，XRCC6 基因启动子区的 CC 基因型和 C 等位基因可能在精索静脉曲张男性的不育发展中起重要作用。需要进一步研究以提供这种多态性的影响。