Rani Deepa Selvi, Carlus S Justin, Poongothai J, Jyothi Amara, Pavani Kadupa, Gupta Nalini J, Reddy Alla G, Rajan M Mamtha, Rao Kamini, Chakravarty Baidyanath, Singh Lalji, Thangaraj Kumarasamy
Centre for Cellular and Molecular Biology, Hyderabad, India.
Int J Androl. 2009 Dec;32(6):647-55. doi: 10.1111/j.1365-2605.2008.00919.x. Epub 2008 Sep 16.
Variations in the trinucleotide-CAG repeat number of the catalytic subunit of the mitochondrial DNA polymerase gamma (POLG) have been speculated to be associated with male infertility. The ten CAG repeats (10/10) were found to be the most common allele (88%), absence of which was found to be associated with male infertility. As no study on Indian population was conducted so far to support this view, we investigated the distribution of the POLG-CAG repeats in 509 oligoasthenozoospermic and 241 normozoospermic control Indian men from the same ethnic background. Our study suggested that the distribution of common allele (10/10) was almost similar in both infertile (75%) and normozoospermic (75.5%) men. Further, we had analysed the CAG repeat number in as many as 1306 Indian men belonging to different ethnic, geographical and linguistic backgrounds and found the common allele 10/10 at a frequency of 78.4%. Our study, therefore, suggests that the 10-CAG repeat is the most common allele present in Indian populations, but its absence and the occurrence of the other mutant homozygous (non 10/non 10) genotype should not be understood as being specific to infertility. It, thus, suggests that the POLG-CAG repeat variation is not associated with male infertility in Indian populations, and hence is not a useful marker for screening infertile men.
线粒体DNA聚合酶γ（POLG）催化亚基的三核苷酸CAG重复序列数量的变化被推测与男性不育有关。发现十个CAG重复序列（10/10）是最常见的等位基因（88%），发现缺乏该等位基因与男性不育有关。由于迄今为止尚未对印度人群进行研究来支持这一观点，我们调查了509名少弱精子症印度男性和241名同种族背景的正常精子症对照男性中POLG - CAG重复序列的分布情况。我们的研究表明，常见等位基因（10/10）在不育男性（75%）和正常精子症男性（75.5%）中的分布几乎相似。此外，我们分析了多达1306名来自不同种族、地理和语言背景的印度男性的CAG重复序列数量，发现常见等位基因10/10的频率为78.4%。因此，我们的研究表明，10 - CAG重复序列是印度人群中最常见的等位基因，但其缺失以及其他突变纯合子（非10/非10）基因型的出现不应被理解为不育所特有的。因此，这表明POLG - CAG重复序列变异与印度人群中的男性不育无关，因此不是筛查不育男性的有用标志物。
