Department of Prenatal Medicine and Fetal Therapy, Justus-Liebig University, Giessen, Germany.
Prenatal Medicine and Genetics München, Duesseldorf, Germany.
Prenat Diagn. 2023 Feb;43(2):192-206. doi: 10.1002/pd.6320. Epub 2023 Feb 9.
We aimed to investigate how the presence of fetal anomalies and different X chromosome variants influences Cell-free DNA (cfDNA) screening results for monosomy X.
From a multicenter retrospective survey on 673 pregnancies with prenatally suspected or confirmed Turner syndrome, we analyzed the subgroup for which prenatal cfDNA screening and karyotype results were available. A cfDNA screening result was defined as true positive (TP) when confirmatory testing showed 45,X or an X-chromosome variant.
We had cfDNA results, karyotype, and phenotype data for 55 pregnancies. cfDNA results were high risk for monosomy X in 48/55, of which 23 were TP and 25 were false positive (FP). 32/48 high-risk cfDNA cases did not show fetal anomalies. Of these, 7 were TP. All were X-chromosome variants. All 16 fetuses with high-risk cfDNA result and ultrasound anomalies were TP. Of fetuses with abnormalities, those with 45,X more often had fetal hydrops/cystic hygroma, whereas those with "variant" karyotypes had different anomalies.
Both, 45,X or X-chromosome variants can be detected after a high-risk cfDNA result for monosomy X. When there are fetal anomalies, the result is more likely a TP. In the absence of fetal anomalies, it is most often an FP or X-chromosome variant.
本研究旨在探讨胎儿异常和不同 X 染色体变异体的存在如何影响 X 单体型无创产前 DNA 筛查结果。
本研究对 673 例产前疑似或确诊特纳综合征的孕妇进行了多中心回顾性调查，分析了其中具有产前 cfDNA 筛查和核型结果的亚组。当确认性检测显示 45,X 或 X 染色体变异体时，cfDNA 筛查结果被定义为真阳性（TP）。
我们共纳入了 55 例具有 cfDNA 结果、核型和表型数据的妊娠。在 55 例妊娠中，cfDNA 结果显示 X 单体型高风险的有 48 例，其中 23 例为 TP，25 例为假阳性（FP）。在 48 例高风险 cfDNA 病例中，32 例未显示胎儿异常。其中，7 例为 TP，均为 X 染色体变异体。所有高风险 cfDNA 结果且超声异常的胎儿均为 TP。在存在异常的胎儿中，45,X 型更常伴有胎儿水肿/囊状水瘤，而“变异”核型则具有不同的异常。
在 X 单体型高风险 cfDNA 结果后，均可检测到 45,X 或 X 染色体变异体。当存在胎儿异常时，结果更可能为 TP。在不存在胎儿异常的情况下，通常为 FP 或 X 染色体变异体。
