Can cell-free DNA testing be used in pregnancies with increased nuchal translucency?
Authors of this article are:
Miranda J, Paz Y Miño F, Borobio V, Badenas C, Rodriguez-Revenga L, Pauta M, Borrell A.
A summary of the article is shown below:
OBJECTIVE: To assess the frequency of atypical chromosomal and submicroscopic anomalies [both undetectable using standard cell-free DNA (cfDNA) testing], as well as fetal structural abnormalities observed at the first-trimester scan, in fetuses with an increased nuchal translucency (NT).METHODS: From January 2013 to December 2017, 226 fetuses with an NT ≥ 99th centile at 11-13 weeks’ gestation underwent genetic testing by means of quantitative fluorescence polymerase chain reaction (QF-PCR) and chromosomal microarray analysis (CMA) mainly in chorionic villi, in a clinical setting in which more than 95% of pregnant women receive first-trimester combined screening. Two different cfDNA models were assessed: targeted cfDNA (including chromosomes 21, 18 and 13) and extended cfDNA (also sex chromosomes).RESULTS: Genetic testing revealed 84 (37%) anomalies, including 68 typical aneuploidies (involving chromosomes 13, 18 or 21), six sex aneuploidies (four monosomies X and two trisomies X), three clinically relevant atypical chromosomal anomalies (one trisomy 22, one trisomy 21 mosaicism and one unbalanced translocation), five submicroscopic pathogenic variants and two Noonan syndromes. Hence, targeted and extended cfDNA testing would miss at least 12-19% of genetic anomalies, accounting for 4.4-8.4% of the fetuses with an increased NT, respectively. Finally, among fetuses with no identified genetic anomaly, a major fetal malformation was observed in 15 (6.6%) fetuses at the early anomaly scan, and in 19 (8.4%) in the second or third trimester.CONCLUSION: cfDNA does not appear to be the appropriate genetic test in fetuses with a NT above the 99th centile, given that 12-19% of the genetic anomalies were undetectable with the current tests. Additionally, 6.6% of fetuses will have a major structural abnormality identifiable using first-trimester ultrasound. This article is protected by copyright. All rights reserved.This article is protected by copyright. All rights reserved.
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This article is a good source of information and a good way to become familiar with topics such as: Aneuploidy;first-trimester ultrasound;non-invasive screening;pregnancy;prenatal diagnosis;screening.