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Cite this article
A discordant case in which T21 positive and 47,XXY negative non-invasive prenatal testing result was associated with a 47,XXY mosaic fetus
1 United Diagnostic and Research Center for Clinical Genetics, School of Public Health of Xiamen University & Xiamen Maternal and Child Health Hospital. Xiamen, Fujian, China
2 BGI, Shenzhen, Guangdong, China
† These authors contributed equally to this work.
Clin. Exp. Obstet. Gynecol. 2018, 45(6), 963–964; https://doi.org/10.12891/ceog4528.2018
Published: 10 December 2018
The authors report a discordant case in which T21 positive and 47,XXY negative non-invasive prenatal testing (NIPT) result was associated with a 47,XXY mosaic fetus confirmed by karyotyping. By investigating the genetic cause, the initial evidence for T21 was demonstrated to be induced by the confined placental mosaicism; the initial lack of evidence for 47,XXY could be attributed to the relatively low effective fetal fraction. This case supported that confined placental mosaicism and low effective fetal fraction are major biological risk factors associated with discordant NIPT results, and provided an unusual case for pre- and post-test NIPT counseling.
Non-invasive prenatal testing