Trophectoderm (TE) biopsy and next generation sequencing (NGS) are currently the preferred techniques for preimplantation genetic testing for aneuploidies (PGT-A). Although this approach delivered important improvements over previous testing strategies, increased sensitivity has also prompted a rise in diagnoses of uncertain clinical significance. This includes reports of chromosomal mosaicism, suggesting the presence of karyotypically distinct cells within a single TE biopsy. Given that PGT-A relies on the chromosomal constitution of the biopsied cells being representative of the entire embryo, the prevalence and clinical implications of blastocyst mosaicism continue to generate considerable controversy.

中文翻译：

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人类胚泡中的染色体镶嵌：最终的诊断难题

滋养外胚层（TE）活检和下一代测序（NGS）是目前用于非整倍性（PGT-A）的植入前基因测试的首选技术。尽管这种方法比以前的测试策略有了重要的改进，但灵敏度的提高也促使不确定临床意义的诊断上升。这包括有关染色体镶嵌的报道，表明在一次TE活检中存在核型不同的细胞。鉴于PGT-A依赖于代表整个胚胎的活检细胞的染色体构成，因此囊胚镶嵌症的患病率和临床意义继续引起相当大的争议。