PDF(Pubmed)
Abstract：
We aimed to identify the causes of inconsistent results between non-invasive prenatal testing (NIPT) and invasive testing methods for trisomy 21. In the first case, NIPT was performed at 11 weeks of pregnancy, and the result showed a high risk of trisomy 21 [fetal fraction (FF) = 6.98%, 21 chromosome Z-score = 3.6]. The patient underwent quantitative fluorescent (QF)-PCR and karyotyping at 14 + 0 weeks of pregnancy through CVS showing mosaicism of 47, XX, + 21[11] and 46, XX [39] in karyotyping. The patient underwent amniocentesis at 15 + 6 weeks, showing a normal pattern in QF-PCR and 46, XX karyotyping in long term culture. The second case underwent NIPT at 16 + 5 weeks of pregnancy (FF = 7.52%, 21 chromosome Z-score = 2.503). She underwent an invasive test at 19 weeks through amniotic fluid sampling. As a result, trisomy 21 was detected by QF-PCR, and mosaicism of XX, +21[22]/46, XX [4] was identified by karyotyping. Despite significant advances in fetal chromosome analysis using NIPT, invasive testing is still needed as placenta-derived DNA does not reflect 100% fetal genetic information. Placental mosaicism can be detected by NIPT, but more research is needed to increase its sensitivity. Therefore, if the NIPT result is positive, an invasive test can confirm the result, and continuous monitoring is required even if the NIPT result is negative.
摘要：
我们旨在确定非侵入性产前检测（NIPT）和21三体侵入性检测方法之间结果不一致的原因。在第一种情况下,NIPT在怀孕11周时进行，结果显示21三体的风险很高[胎儿分数（FF）=6.98％，21染色体Z评分=3.6]。患者在妊娠14+0周通过CVS进行定量荧光（QF）-PCR和核型分析，显示镶嵌性47，XX，核型分析中+21[11]和46，XX[39]。患者在15+6周时接受了羊膜穿刺术，在QF-PCR中显示正常模式，在长期培养中显示46，XX核型。第二例在妊娠16+5周时行NIPT(FF=7.52%,21号染色体Z评分=2.503)。她在19周时通过羊水采样进行了侵入性测试。因此,通过QF-PCR检测21三体，和XX的马赛克，+21[22]/46，XX[4]通过核型分析鉴定。尽管使用NIPT进行胎儿染色体分析取得了重大进展，由于胎盘来源的DNA不能反映100%的胎儿遗传信息,因此仍需要进行侵入性检测.胎盘镶嵌可以通过NIPT检测到，但是需要更多的研究来提高其灵敏度。因此,如果NIPT结果是肯定的，侵入性测试可以确认结果，即使NIPT结果为阴性，也需要持续监测。
