Non-invasive prenatal testing (NIPT) is a rapidly developing and widely used method in the prenatal screening. Recently, the widespread use of the NIPT caused a neglecting of the limitations of this technology. The 38-year-old woman underwent amniocentesis because of a high risk of trisomy 2 revealed by the genome-wide Non-Invasive Prenatal Test (NIPT). The invasive prenatal diagnosis revealed the mosaicism for a small supernumerary marker chromosome sSMC derived from chromosome 2. Interphase fluorescence in situ hybridization (FISH) on uncultured amniocytes revealed three signals of centromere 2 in 30% of the cells. GTG-banded metaphases revealed abnormal karyotype (47,XX,+mar[21]/46,XX[19]) and was confirmed by array comparative genomic hybridization (aCGH). Cytogenetic analyses (FISH, aCGH, karyotype) on fetal skin biopsies were performed and confirmed the genomic gain of the centromeric region of chromosome 2. In the placenta, three cell lines were detected: a normal cell line, a cell line with trisomy 2 and a third one with only the sSMC. Whole-genome Non-Invasive Prenatal Testing allows not only the identification of common fetal trisomies but also diagnosis of rare chromosomal abnormalities. Especially in such cases, it is extremely important to perform not only NIPT verification on a sample of material other than trophoblast, but also to apply appropriate research methods. Such conduct allows detailed analysis of the detected aberration, thus appropriate clinical validity.

中文翻译：

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通过NIPT检测到的胎盘三体2在胎儿小的超数字标记染色体（sSMC）中进化

非侵入性产前检查（NIPT）是一种快速发展且在产前筛查中广泛使用的方法。最近，NIPT的广泛使用导致人们忽略了该技术的局限性。这位38岁的妇女因全基因组非侵入性产前检查（NIPT）揭示了三体2的高风险而接受了羊膜穿刺术。产前的侵入性诊断揭示了一个来源于染色体2的小数字标记染色体sSMC的镶嵌性。未培养的羊细胞上的相间荧光原位杂交（FISH）在30％的细胞中显示了着丝粒2的三个信号。GTG带中期显示异常核型（47，XX，+ mar [21] / 46，XX [19]），并已通过阵列比较基因组杂交（aCGH）得以证实。细胞遗传学分析（FISH，aCGH，进行了胎儿皮肤活检的核型分析，并证实了2号染色体着丝粒区的基因组增益。在胎盘中，检测到三种细胞系：正常细胞系，三体性2细胞系和仅具有sSMC的第三种细胞系。 。全基因组无创产前检测不仅可以鉴定常见的胎儿三体性，还可以诊断罕见的染色体异常。特别是在这种情况下，不仅要对滋养层细胞以外的其他物质进行NIPT验证，而且要采用适当的研究方法，这一点极为重要。这种行为可以对检测到的像差进行详细分析，从而具有适当的临床有效性。具有三体性2的细胞系和仅具有sSMC的第三种细胞系。全基因组无创产前检测不仅可以鉴定常见的胎儿三体性，还可以诊断罕见的染色体异常。特别是在这种情况下，不仅要对滋养层细胞以外的其他物质进行NIPT验证，而且要采用适当的研究方法，这一点极为重要。这种行为可以对检测到的像差进行详细分析，从而具有适当的临床有效性。具有三体性2的细胞系和仅具有sSMC的第三种细胞系。全基因组无创产前检测不仅可以鉴定常见的胎儿三体性，还可以诊断罕见的染色体异常。特别是在这种情况下，不仅要对滋养层细胞以外的其他物质进行NIPT验证，而且要采用适当的研究方法，这一点极为重要。这种行为可以对检测到的像差进行详细分析，从而具有适当的临床有效性。而且要应用适当的研究方法。这种行为可以对检测到的像差进行详细分析，从而具有适当的临床有效性。而且要应用适当的研究方法。这种行为可以对检测到的像差进行详细分析，从而具有适当的临床有效性。