Background X chromosome inactivation (XCI) is an indispensable process in the development of human female embryos. Reportedly, XCI occurs when a blastocyst contains 10–12 embryonic progenitor cells. To date, it remains unclear whether XCI ratios are normally preserved in Klinefelter syndrome (KS) patients with 47,XXY karyotype. Methods We examined XCI ratios in 18 KS patients through DNA methylation analysis for the polymorphic trinucleotide locus in the AR gene. The results of the KS patients were compared to previous data from healthy young women. Results XCI ratios in KS patients followed a normal distribution. Skewed XCI was observed in two patients, one of whom exhibited extremely skewed XCI. The frequencies of skewed and extremely skewed XCI in the KS cohort were comparable to those in healthy women. Conclusion This study confirmed the rarity of skewed XCI in KS patients. These results indicate that the presence of a supernumerary X chromosome during the cleavage and early blastocyst stages does not affect the developmental tempo of embryos. Our data deserve further validation.

中文翻译：

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Klinefelter 综合征患者随机 X 染色体失活

背景 X 染色体失活 (XCI) 是人类女性胚胎发育中不可或缺的过程。据报道，当囊胚含有 10-12 个胚胎祖细胞时，就会发生 XCI。迄今为止，尚不清楚 XCI 比率是否在具有 47,XXY 核型的 Klinefelter 综合征 (KS) 患者中正常保留。方法 我们通过 AR 基因中多态性三核苷酸位点的 DNA 甲基化分析检查了 18 名 KS 患者的 XCI 比率。KS 患者的结果与健康年轻女性之前的数据进行了比较。结果 KS 患者的 XCI 比率遵循正态分布。在两名患者中观察到偏斜的 XCI，其中一名患者表现出极度偏斜的 XCI。KS 队列中偏斜和极度偏斜的 XCI 频率与健康女性的频率相当。结论 本研究证实了 KS 患者中偏斜 XCI 的罕见性。这些结果表明在卵裂和早期囊胚阶段存在多余的 X 染色体不会影响胚胎的发育速度。我们的数据值得进一步验证。