Detection of triploid, molar, and vanishing twin pregnancies by a single-nucleotide polymorphism–based noninvasive prenatal test - 15/11/14
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Abstract |
Objective |
We sought to determine the ability of single-nucleotide polymorphism–based noninvasive prenatal testing (NIPT) to identify triploid, unrecognized twin, and vanishing twin pregnancies.
Study Design |
The study included 30,795 consecutive reported clinical cases received for NIPT for fetal whole-chromosome aneuploidies; known multiple gestations were excluded. Cell-free DNA was isolated from maternal blood samples, amplified via 19,488-plex polymerase chain reaction, and sequenced. Sequencing results were analyzed to determine fetal chromosome copy number and to identify the presence of additional fetal haplotypes.
Results |
Additional fetal haplotypes, indicative of fetal triploidy, vanishing twin, or undetected twin pregnancy, were identified in 130 (0.42%) cases. Clinical confirmation (karyotype for singleton pregnancies, ultrasound for multifetal pregnancies) was available for 58.5% (76/130) of cases. Of the 76 cases with confirmation, 42.1% were vanishing twin, 48.7% were viable twin, 5.3% were diandric triploids, and 3.9% were nontriploid pregnancies that lacked evidence of co-twin demise. One pregnancy had other indications suggesting triploidy but lacked karyotype confirmation. Of the 5 vanishing twin cases with a known date of demise, 100% of losses occurred in the first trimester; up to 8 weeks elapsed between loss and detection by NIPT.
Conclusion |
This single-nucleotide polymorphism–based NIPT successfully identified vanished twin, previously unrecognized twin, and triploid pregnancies. As vanishing twins are more likely to be aneuploid, and undetected residual cell-free DNA could bias NIPT results, the ability of this method to identify additional fetal haplotypes is expected to result in fewer false-positive calls and prevent incorrect fetal sex calls.
Le texte complet de cet article est disponible en PDF.Key words : noninvasive prenatal testing, single-nucleotide polymorphism, triploidy, vanishing twin
Plan
☆ | This is an open access article under the CC BY-NC-ND license (3.0/). |
This study was supported by Natera. |
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K.J.C., A.R., E.K., M.S., M.P.H., S.S., Z.D., M.R., and S.J.G. are or were employees of Natera and hold stock or options to hold stock in the company. L.W-H. participated in multicenter clinical trials sponsored by Ariosa and Sequenom and received partial grant support, but did not personally receive any funding. |
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Cite this article as: Curnow KJ, Wilkins-Haug L, Ryan A, et al. Detection of triploid, molar, and vanishing twin pregnancies by a single-nucleotide polymorphism–based noninvasive prenatal test. Am J Obstet Gynecol 2014;211:x.ex-x.ex. |
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