ObjectiveTo explore the feasibility of high-throughput massively parallel genomic DNA sequencing technology for the noninvasive prenatal detection of fetal sex chromosome aneuploidies (SCAs).MethodsThe study enrolled pregnant women who were prepared to undergo noninvasive prenatal testing (NIPT) in the second trimester. Cell-free fetal DNA (cffDNA) was extracted from the mother’s peripheral venous blood and a high-throughput sequencing procedure was undertaken. Patients identified as having pregnancies associated with SCAs were offered prenatal fetal chromosomal karyotyping.ResultsThe study enrolled 10 275 pregnant women who were prepared to undergo NIPT. Of these, 57 pregnant women (0.55%) showed fetal SCA, including 27 with Turner syndrome (45,X), eight with Triple X syndrome (47,XXX), 12 with Klinefelter syndrome (47,XXY) and three with 47,XYY. Thirty-three pregnant women agreed to undergo fetal karyotyping and 18 had results consistent with NIPT, while 15 patients received a normal karyotype result. The overall positive predictive value of NIPT for detecting SCAs was 54.54% (18/33) and for detecting Turner syndrome (45,X) was 29.41% (5/17).ConclusionNIPT can be used to identify fetal SCAs by analysing cffDNA using massively parallel genomic sequencing, although the accuracy needs to be improved particularly for Turner syndrome (45,X).

A total of 70 pregnant women were recruited for this study, including 35 early onset preeclampsia (PE) and 35 normal pregnant women. By RNA sequencing, the circular RNA (circRNAs) in placenta were identified. Differentially expressed circRNAs were bioinformatics analyzed with gene ontology, Kyoto Encyclopedia of Genes and Genomes, and circRNA–miRNA interaction prediction. Quantitative real time polymerase chain reaction(qRT-PCR) assay was used to verify the results. Compared with the normal pregnant women, there were 49 circRNAs differentially expressed in the placental tissue of PE women, including two circRNAs were up-regulated and 47 were down-regulated. Ten differentially expressed circRNAs were selected for validation by qRT-PCR, among which results of three circRNAs, circRNA_3286, circRNA_5593, and circRNA_3800, were consistent with the sequencing. According to the bioinformatic prediction, we speculate that these circRNAs may be involved in some cellular regulatory functions in PE through their targeted miRNAs. We also evaluated the expression of circRNA_3286 in plasma to be used as a potential biomarker for PE; in vitro Transwell assay shown transfected with si-circ-3286 significantly reduced invasion in HTR8/Svneo cells. In conclusion, we displayed a preliminary landscape of circRNA differential expression in PE and discussed their possible regulatory mechanisms. This study revealed a new insight into the molecular mechanism of PE. Impact statement The abnormal expression of many regulatory factors may be involved in the development of PE. circRNAs are proved to have a series of important biological functions; however, reports about circRNA and PE are rare. In this work, we evaluated the profile analysis of circRNAs in human placenta of PE by RNA-seq and found some newly differentially expressed circRNAs which might be involved in PE. Combined with bioinformatics analysis, their possible functions were preliminarily discussed.

Objective To explore the impact of maternal sex chromosome aneuploidies (SCAs) and copy number variation (CNV) on false‐positive results of non‐invasive prenatal screening (NIPS) for predicting foetal SCAs. Methods In total, 22 844 pregnant women were recruited to undergo NIPS. Pregnant women with high‐risk of SCAs underwent prenatal diagnosis and maternal copy number variation sequencing (CNV‐seq). Results Among 117 women with high‐risk of SCAs, 72 accepted prenatal diagnosis, 86 accepted maternal CNV‐seq, and 21 had maternal sex chromosome abnormalities. The abnormality rate was significantly higher than women at low‐risk of SCAs (24.42% vs 3.51%). Using a novel parameter cffDNA (ChrX)/cffDNA, when the ratio was greater than 2, all foetuses had normal karyotype, and 75.0% (6/8) had abnormal maternal chromosome X. If the ratio was less than or equal to 2, only 10% (4/40) of the mothers had chromosome X CNV alterations, while 33.3% (13/40) of their foetuses had sex chromosomes CNV abnormalities. Conclusions Approximately 25% of pregnant women with SCAs predicted by NIPS had sex chromosome abnormalities as determined by CNV‐seq. The ratio of cffDNA (ChrX)/cffDNA can tentatively distinguish the maternal or foetal origin of abnormal cell‐free DNA. In a reanalysis of previous NIPS data, false‐positive results caused by maternal CNV might be elucidated.

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