Chinese Journal of Medical Genetics 2014;31(6):778-781

doi:10.3760/cma.j.issn.1003-9406.2014.06.022

Analysis of two false positive cases from noninvasive prenatal testing.

Xuejiao CHEN 1 ; Meizhen DAI ; Weiwu SHI ; Yingqiu PAN ; Weiguo ZHANG ; Yang ZHANG ; Zhiqiang WU

Affiliations

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Country

China

Language

Chinese

Abstract

OBJECTIVETo track and analyze two false positive cases from non-invasive prenatal testing for potential fetal aneuploidy.

METHODSThe two cases, respectively reported to have XO (+++) and T18 (1/20) XO(+), were analyzed with conventional karyotyping, fluorescence in situ hybridization (FISH) and massively parallel genomic sequencing (MPS).

RESULTSThe first fetus, who was suspected for XO(+++), was verified to have super female syndrome (47,XXX/46,XX) due to confined placental mosaicism by karyotyping of amniotic fluid cells, FISH analysis of placenta and massively parallel sequencing (MPS) of fetal tissue. The second fetus, suspected to have trisomy 18 (1/20) XO(+), was verified to have Turner syndrome by karyotyping, FISH and MPS analyses of umbilical cord blood cells. And the karyotype was 45,X[48]/46, X, der(X) del(X) (p11.21) del(X) (q13.3)[62].

CONCLUSIONNon-invasive prenatal testing carries a risk for false positive diagnosis of fetal sex chromosome and trisomy 18. Combined cytogenetic and molecular techniques are required to ensure an accurate diagnosis.