THE SIGNIFICANCE OF PLACENTAL CHROMOSOMAL COMPOSITION IN THE OCCURRENCE OF FALSE POSITIVE RESULT IN NON- INVASIVE PRENATAL TESTING: A CASE REPORT HIGHLIGHTING POSITIVE RESULT FOR TRISOMY 21
Keywords:
non-invasive prenatal test, NIPT, pregnant woman, false positive result, fetus, placentaAbstract
Introductioion: The article presents a case report of a false-positive result (FPR) for Trisomy 21 (T21) identified through a non-invasive prenatal test (NIPT) during pregnancy, which may arise from biological factors that lead to discrepancies between NIPT outcomes and the actual condition of the fetus.
T21 is the most frequently detected chromosomal anomaly, constituting 30% of findings obtained through NIPT. This study investigated the clinical application of NIPT following a positive T21 result.
Material and methods: Two distinct prenatal tests were conducted for the same pregnancy. The initial NIPT employed Harmony reagents with Ariosa cell-free DNA System, and was followed with confirmatory amniocentesis which involved quantitative florescent PCR analysis. Second NIPT utilized the VeriSeq NIPT Solution V2 from Illumina and was followed with confirmatory amniocentesis analysis and placental tissue analysis post-delivery both using quantitative fluorescent PCR and an oligonucleotide array.
Results: This study demonstrated that both NIPT tests produced consistent results, thereby clarifying the notion of a ‘false positive’ result attributed to Confined Placental Mosaicism (CPM).
Conclusion: Understanding the implications of FPR for T21 regardless of the lowest risk of CPM is essential when considering diagnostic options.
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