Non-Invasive Prenatal Testing by Cell-Free DNA (cfNIPT) for Detecting Turner Syndrome With Mosaicism and Structural
Ivonne Bedei1,2, Johanna Bruder1, Ida C B Lund3,4,5
1Department of Prenatal Diagnosis and Fetal Therapy, Justus-Liebig University, Gießen, Germany.
Summary
Non-invasive prenatal testing using cell-free DNA (cfNIPT) effectively identifies fetuses with Turner Syndrome (TS) variants. While valuable for early detection, a high false-positive rate necessitates careful genetic counseling for Turner Syndrome diagnosis.
Area of Science:
- Genetics and Genomics
- Prenatal Diagnostics
- Fetal Medicine
Background:
- Turner Syndrome (TS) is a sex chromosomal disorder with diverse karyotypes.
- Many TS fetuses lack overt prenatal phenotypes, leading to delayed diagnosis.
- Accurate prenatal detection of TS variants is crucial for timely management.
Purpose of the Study:
- To evaluate the efficacy of cell-free DNA (cfNIPT) in detecting TS karyotype variants.
- To analyze phenotypic variations and clinical outcomes in fetuses with TS.
- To assess the diagnostic accuracy of cfNIPT for different TS karyotypes.
Main Methods:
- Retrospective data collection from 2000-2024 on pregnancies with suspected TS.
- Inclusion of cfNIPT results, karyotypes, prenatal ultrasound findings, and pregnancy outcomes.
- Analysis of true positives, false positives, and false negatives for cfNIPT in TS detection.
Main Results:
- Out of 114 cases, 87.7% had high-risk cfNIPT for monosomy X; 46.5% were true positives, 41.2% false positives.
- The 45, X karyotype showed higher prevalence of congenital malformations and increased nuchal translucency.
- Live birth rates were higher for mosaicism or structural variants compared to the 45, X karyotype.
Conclusions:
- cfNIPT is a valuable tool for early identification of fetuses with TS karyotype variants.
- Timely intervention and targeted management can be facilitated by cfNIPT results.
- The high false-positive rate of cfNIPT emphasizes the need for thorough genetic counseling.
