Confirmation rate of cell free DNA screening for sex chromosomal abnormalities according to the method of confirmatory testing. (2nd September 2020)

• Record Type: Journal Article
• Authors: Lüthgens, Kai; Grati, Francesca Romana; Sinzel, Monika; Häbig, Karina; Kagan, Karl Oliver
• Is Part Of: Prenatal diagnosis. Volume 41:Number 10(2021)
• Page Start: 1258
• Page End: 1263
• Publication Date: 2020-09-02
• Subjects: Prenatal diagnosis -- Periodicals; Fetus -- Diseases -- Diagnosis -- Periodicals; Electronic journals; 618.32075
• DOI: 10.1002/pd.5814
• Languages: English
• ISSNs: 0197-3851

Abstract

Abstract: Objective: To examine the positive predictive value (PPV) of cfDNA screening for sex chromosome aneuploidies (SCA) in a large series of over 90 000 patients. Methods: Retrospective study based on samples that were sent to Cenata, a private laboratory which uses the Harmony Prenatal Test. The SCA high‐risk results were stratified according to the method of diagnostic testing and according to karyotype result. Results: The study population consisted of 144 cases. The CfDNA test indicated monosomy X, XXX, XXY, and XYY in 62, 37, 40, and 5 cases, respectively. The overall PPV was 38.9% (30.9‐47.4), 29.0% (18.2‐42.9) for monosomy X, 29.7% (15.9‐47.9) for 47, XXX, 57.5% (40.9‐73.0) for 47, XXY, and 80.0% (28.4‐99.5) for 47, XYY). A total of 112 (77.8%) women with a high‐risk result for SCAs opted for prenatal karyotyping. In this group, there were significant differences in the PPV if the karyotype was assessed by amniocentesis or by CVS: 29.5% vs 50.0%. This significant difference was driven by the monosomy X result which shows a significantly higher PPV in CVS (54.6% (23.4‐83.3) vs 17.1% (6.6‐33.6)). For the other SCAs, the differences were not significant. Conclusion: PPV of an abnormal cfDNA test for SCAs is low, particularly for monosomy X. The confirmation rate depends on the type of confirmatory test.