Guo Rui, Ding Biao, Hu Kaiqin, Wang Kai, Tang Dongdong, Wang Xuegu, Sun Junpei, Li KuoKuo, Cheng Huiru, Xu Chuan, Sun Miao, Lu Likui, Liu Mingxi, Cao Yunxia, Yang Xiaoyu, He Xiaojin
NHC Key Laboratory of Study on Abnormal Gametes and Reproductive Tract, Anhui Medical University, Hefei, Anhui, China.
Department of Obstetrics and Gynecology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China.
Andrology. 2025 Jul;13(5):1270-1284. doi: 10.1111/andr.13676. Epub 2024 Jun 7.
PiRNA pathway factors, including evolutionarily conserved Tudor domain-containing proteins, play crucial roles in suppressing transposons and regulating post-meiotic gene expression. TDRD5 is essential for retrotransposon silencing and pachytene piRNA biogenesis; however, a causal link between TDRD5 variants and human infertility has not yet been established.
To identify the likely pathogenic variants of TDRD5 in infertile men, characterised by azoospermia or severe oligozoospermia.
Potential candidate variants were identified and confirmed using whole-exome and Sanger sequencing. Haematoxylin and eosin staining, immunofluorescence, and ultrastructural analyses were performed to investigate the structural and functional abnormalities of spermatozoa. The pathogenicity of the identified TDRD5 variants was verified using in vitro experiments. Functional effects of the C-terminal nonsense variant were assessed via histology, immunofluorescence staining, and small-RNA sequencing. Intracytoplasmic sperm injection (ICSI) was also performed to evaluate the efficacy of the clinical treatment.
We identified a homozygous missense variant (c.3043G > A, p.A1015T) and a homozygous nonsense variant (c.2293G > T, p.E765*) of TDRD5 in two unrelated infertile men. Both patients exhibited severe oligoasthenoteratozoospermia, characterised by the presence of spermatozoa with multiple heads and/or flagella, as well as acrosomal hypoplasia. In vitro experiments revealed that the p.A1015T variant caused a diffuse distribution of TDRD5 granules, whereas the p.E765* variant led to the production of a C-terminal truncated protein with nuclear localisation, instead of the typical cytoplasmic localisation observed for the wild-type protein. Functional investigations also revealed that truncation of the C-terminal region of TDRD5 could potentially lead to a decline in the expression levels of intermitochondrial cement and chromatoid body components, such as MIWI (PIWIL1) and UPF1, and a slight decrease in the abundance of pachytene piRNA, ultimately resulting in compromised spermiogenesis. ICSI may be an effective treatment for these deficiencies.
This study implicates TDRD5 as a novel candidate gene in the pathogenesis of human male infertility, emphasising the contribution of piRNA pathway genes to male infertility. In addition, our data suggest that ICSI could be a promising treatment for infertile men harbouring TDRD5 variants.
PiRNA 通路因子，包括进化上保守的含 Tudor 结构域蛋白，在抑制转座子和调节减数分裂后基因表达中起关键作用。TDRD5 对于逆转座子沉默和粗线期 piRNA 生物合成至关重要；然而，TDRD5 变异与人类不育之间的因果关系尚未确立。
鉴定以无精子症或严重少精子症为特征的不育男性中 TDRD5 可能的致病变异。
使用全外显子组测序和 Sanger 测序鉴定并确认潜在的候选变异。进行苏木精-伊红染色、免疫荧光和超微结构分析以研究精子的结构和功能异常。使用体外实验验证所鉴定的 TDRD5 变异的致病性。通过组织学、免疫荧光染色和小 RNA 测序评估 C 末端无义变异的功能效应。还进行了卵胞浆内单精子注射（ICSI）以评估临床治疗的疗效。
我们在两名无亲缘关系的不育男性中鉴定出 TDRD5 的一个纯合错义变异（c.3043G＞A，p.A1015T）和一个纯合无义变异（c.2293G＞T，p.E765*）。两名患者均表现出严重的少弱畸精子症，其特征为存在多头和/或多鞭毛精子以及顶体发育不全。体外实验显示，p.A1015T 变异导致 TDRD5 颗粒的弥漫性分布，而 p.E765*变异导致产生一种具有核定位的 C 末端截短蛋白，而非野生型蛋白典型的胞质定位。功能研究还表明，TDRD5 C 末端区域的截短可能会导致线粒体间黏合物质和类染色质体成分（如 MIWI（PIWIL1）和 UPF1）的表达水平下降，以及粗线期 piRNA 的丰度略有降低，最终导致精子发生受损。ICSI 可能是治疗这些缺陷的有效方法。
本研究表明 TDRD5 是人类男性不育发病机制中的一个新候选基因，强调了 piRNA 通路基因对男性不育的作用。此外，我们的数据表明 ICSI 可能是治疗携带 TDRD5 变异的不育男性的一种有前景的方法。
