Sharestani Shiva, Kalantar Seyed Mehdi, Ghasemi Nasrin, Farashahi Yazd Ehsan
Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
Abortion Research Centre, Yazd Reproductive Sciences Institute, Shahid Sadoughi University of Medical Science, Yazd, Iran.
Int J Reprod Biomed. 2021 Oct 10;19(9):845-851. doi: 10.18502/ijrm.v19i9.9717. eCollection 2021 Sep.
Androgens play a role in the development of male phenotype and spermatogenesis during puberty, the function of which is regulated by the androgen receptor () gene. There is a polymorphism site in exon 1 of the gene encoding this receptor that can have different frequencies of CAG trinucleotide repeats and leads to the formation of polyglutamine chains of different lengths in the N-terminal domain of the AR protein and reduced sperm production by affecting spermatogenesis.
To investigate whether the cause of a group of unexplained infertilities could be the increased frequency of CAG repeats in the gene of patients with oligozoospermia and azoospermia.
In this case-control study, 84 men including 42 with unexplained infertility As a case group and 42 fertile men as a control group were selected. The frequency of CAG repeats was determined by the polymerase chain reaction method and then the difference in the frequency of these repeats was determined based on the difference in band size on the agarose gel.
The mean CAG repeat length in the azoospermia and oligozoospermia group was 17.5 0.63 and in the fertile group it was 16.11 0.75 (p = 0.46). In addition, most men (88.1% in the case group and 71.41% in the control group) had 13-23 repeats.
No significant correlation was found between CAG repeat length and the risk of male factor infertility in an ethnically defined population of Iranian men. The role of regulatory factors and epigenetic changes should be taken into account too.
雄激素在青春期男性表型发育和精子发生过程中发挥作用，其功能受雄激素受体（AR）基因调控。该受体编码基因的外显子1存在一个多态性位点，可出现不同频率的CAG三核苷酸重复序列，导致AR蛋白N端结构域形成不同长度的聚谷氨酰胺链，并通过影响精子发生降低精子产量。
探讨少精子症和无精子症患者AR基因中CAG重复序列频率增加是否为一组不明原因不育症的病因。
在这项病例对照研究中，选取84名男性，其中42名不明原因不育男性作为病例组，42名有生育能力的男性作为对照组。采用聚合酶链反应法测定CAG重复序列的频率，然后根据琼脂糖凝胶上条带大小的差异确定这些重复序列频率的差异。
无精子症和少精子症组CAG重复序列的平均长度为17.5±0.63，有生育能力组为16.11±0.75（p = 0.46）。此外，大多数男性（病例组为88.1%，对照组为71.41%）的重复序列为13 - 23次。
在伊朗男性这一特定种族人群中，未发现CAG重复序列长度与男性因素不育风险之间存在显著相关性。还应考虑调控因子和表观遗传变化的作用。
