BACKGROUND The most common sex chromosomal aneuploidy in males is Klinefelter syndrome, which is characterized by at least one supernumerary X chromosome. While these men have long been considered infertile, focal spermatogenesis can be observed in some patients, and sperm can be surgically retrieved and used for artificial reproductive techniques. Although these gametes can be used for fertility treatments, little is known about the molecular biology of the germline in Klinefelter men. Specifically, it is unclear if germ cells in Klinefelter syndrome correctly establish the androgenetic DNA methylation profile and transcriptome. This is due to the low number of germ cells in the Klinefelter testes available for analysis. RESULTS Here, we overcame these difficulties and successfully investigated the epigenetic and transcriptional profiles of germ cells in Klinefelter patients employing deep bisulfite sequencing and single-cell RNA sequencing. On the transcriptional level, the germ cells from Klinefelter men clustered together with the differentiation stages of normal spermatogenesis. Klinefelter germ cells showed a normal DNA methylation profile of selected germ cell-specific markers compared with spermatogonia and sperm from men with normal spermatogenesis. However, germ cells from Klinefelter patients showed variations in the DNA methylation of imprinted regions. CONCLUSIONS These data indicate that Klinefelter germ cells have a normal transcriptome but might present aberrant imprinting, showing impairment in germ cell development that goes beyond mere germ cell loss.

中文翻译：

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对具有性染色体非整倍性的男性生殖细胞进行的高分辨率分析显示，转录组正常，但印迹受损。

背景技术男性中最常见的性染色体非整倍性是克氏综合征，其特征在于至少一个多余的X染色体。尽管这些人长期以来一直被认为是不育症，但在某些患者中可以观察到局灶性精子发生，并且可以通过手术取回精子并将其用于人工生殖技术。尽管这些配子可用于生育治疗，但对于克氏父子的种系的分子生物学知之甚少。具体而言，尚不清楚克氏综合征中的生殖细胞是否正确建立了雄激素性DNA甲基化谱和转录组。这是由于Klinefelter睾丸中可用于分析的生殖细胞数量少所致。结果在这里，我们克服了这些困难，并通过深度亚硫酸氢盐测序和单细胞RNA测序成功研究了Klinefelter患者生殖细胞的表观遗传和转录谱。在转录水平上，来自克氏病男性的生殖细胞与正常精子发生的分化阶段聚集在一起。与精子发生正常的精子和精子相比，Klinefelter生殖细胞显示出所选生殖细胞特异性标志物的正常DNA甲基化谱。但是，来自克氏病患者的生殖细胞在印迹区域的DNA甲基化方面表现出差异。结论这些数据表明Klinefelter生殖细胞具有正常的转录组，但可能表现出异常的印迹，表明生殖细胞发育的损害不仅限于生殖细胞的丧失。