Abstract | OBJECTIVE: To describe the clinical experience with noninvasive prenatal testing for fetal sex chromosomes using sequencing of maternal plasma cell-free DNA in a commercial laboratory. METHODS: A noninvasive prenatal testing laboratory data set was examined for samples in which fetal sex chromosomes were reported. Available clinical outcomes were reviewed. RESULTS: Of 18,161 samples with sex chromosome results, no sex chromosome aneuploidy was detected in 98.9% and the fetal sex was reported as XY (9,236) or XX (8,721). In 4 of 32 cases in which the fetal sex was reportedly discordant between noninvasive prenatal testing and karyotype or ultrasonogram, a potential biological reason for the discordance exists, including two cases of documented co-twin demise, one case of a maternal kidney transplant from a male donor, and one case of fetal ambiguous genitalia. In the remaining 204 samples (1.1%), one of four sex chromosome aneuploidies ( monosomy X, XXX, XXY, or XYY) was detected. The frequency of false positive results for sex chromosome aneuploidies is a minimum of 0.26% and a maximum of 1.05%. All but one of the discordant sex chromosome aneuploidy results involved the X chromosome. In two putative false-positive XXX cases, maternal XXX was confirmed by karyotype. For the false-positive cases, mean maternal age was significantly higher in monosomy X (P<.001) and lower in XXX (P=.008). CONCLUSION: Noninvasive prenatal testing results for sex chromosome aneuploidy can be confounded by maternal or fetal biological phenomena. When a discordant noninvasive prenatal testing result is encountered, resolution requires additional maternal history, detailed fetal ultrasonography, and determination of fetal and possibly maternal karyotypes.
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Authors | Diana W Bianchi, Saba Parsa, Sucheta Bhatt, Meredith Halks-Miller, Kathryn Kurtzman, Amy J Sehnert, Amy Swanson |
Journal | Obstetrics and gynecology
(Obstet Gynecol)
Vol. 125
Issue 2
Pg. 375-382
(Feb 2015)
ISSN: 1873-233X [Electronic] United States |
PMID | 25568992
(Publication Type: Journal Article, Observational Study, Research Support, Non-U.S. Gov't)
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Topics |
- Female
- Humans
- Maternal Serum Screening Tests
(statistics & numerical data)
- Pregnancy
- Sequence Analysis, DNA
- Sex Chromosome Aberrations
- Sex Chromosomes
- Sex Determination Analysis
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