Department of Medical Genetics, Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming 650118, China.
Asian J Androl. 2011 Mar;13(2):298-304. doi: 10.1038/aja.2010.91. Epub 2010 Nov 22.
Several studies have reported a relationship between the length of the CAG-repeat in the polymerase γ (POLG) gene and male infertility. However, other studies have not reproduced this result. In our study, the POLG-CAG-repeat length was analyzed in 535 healthy individuals from six Chinese Han populations living in different provinces. The frequencies of 10-CAG alleles and genotypes were high (97.38 and 94.13%, respectively), with no significant difference among the six Chinese Han populations. Furthermore, we determined the distribution of the POLG-CAG-repeat in 150 infertile men and 126 fertile men. Our study suggested that the distributions of POLG-CAG-repeat alleles and genotypes were not significantly different between infertile (95.67 and 92.67%, respectively) and fertile men (97.22 and 94.44%, respectively). In a subsequent meta-analysis, combining our data with data from previous studies, a comparison of the CAG-repeat alleles in fertile versus infertile men showed no obvious risk for male infertility associated with any particular allele (pooled odds ratio (OR)=0.94; 95% confidence interval (CI): 0.60-1.48). The significance level was not attained with any of the following genetic models: homozygote comparison (not 10/not 10 versus 10/10: OR=1.34; 95% CI: 0.66-2.72), heterozygote comparison (10/not 10 versus 10/10: OR=1.04; 95% CI: 0.78-1.38), dominant model comparison (not 10/not 10+10/not 10 versus 10/10: OR=1.08; 95% CI: 0.79-1.47) and recessive genetic comparison (not 10/not 10 versus 10/not 10+10/10: OR=1.31; 95% CI: 0.68-2.55). In conclusion, there is no significant difference of the frequencies of POLG-CAG-repeat variants among six Chinese Han populations, and this polymorphism may not be associated with Chinese male infertility. On the basis of a meta-analysis, there is no obvious association between CAG-repeat variants of the POLG gene and male infertility.
一些研究报道了聚合酶γ（POLG）基因中的 CAG 重复序列长度与男性不育之间存在关系。然而，其他研究并未复制这一结果。在我们的研究中，分析了来自生活在不同省份的六个中国汉族人群的 535 名健康个体的 POLG-CAG 重复序列长度。10-CAG 等位基因和基因型的频率很高（分别为 97.38%和 94.13%），在这六个汉族人群中没有显著差异。此外，我们还确定了 150 名不育男性和 126 名生育男性的 POLG-CAG 重复序列分布。我们的研究表明，不育男性（分别为 95.67%和 92.67%）和生育男性（分别为 97.22%和 94.44%）的 POLG-CAG 重复序列等位基因和基因型分布没有显著差异。在随后的荟萃分析中，将我们的数据与之前研究的数据相结合，对生育男性和不育男性的 CAG 重复等位基因进行比较，没有发现任何特定等位基因与男性不育明显相关的风险（合并优势比（OR）=0.94；95%置信区间（CI）：0.60-1.48）。在任何以下遗传模型中均未达到显著水平：纯合子比较（非 10/非 10 与 10/10 相比：OR=1.34；95%CI：0.66-2.72）、杂合子比较（10/非 10 与 10/10 相比：OR=1.04；95%CI：0.78-1.38）、显性模型比较（非 10/非 10+10/非 10 与 10/10 相比：OR=1.08；95%CI：0.79-1.47）和隐性遗传比较（非 10/非 10 与 10/非 10+10/10 相比：OR=1.31；95%CI：0.68-2.55）。总之，六个中国汉族人群中 POLG-CAG 重复序列变体的频率没有显著差异，这种多态性可能与中国男性不育无关。基于荟萃分析，POLG 基因的 CAG 重复序列变体与男性不育之间没有明显关联。
