[Prenatal diagnosis of fetal chromosome aneuploidy by massively parallel genomic sequencing]

Abstract

Objective: To perform non-invasive prenatal diagnosis (NIPD) of chromosome aneuploidy by detecting free DNA in maternal peripheral plasma by massively parallel genomic sequencing and determine the feasibility of detecting cell-free fetal DNA in chromosomal copy.

Methods: The plasma samples from 1 264 gravidas were collected from February 2012 to July 2013 at our center. Those pregnant women with a gestational age of 13 to 33 weeks having high risks in serological screening or aged over 35 years or abnormal fetus on ultrasonography. The peripheral venous blood samples were drawn from pregnant women and plasma DNA was extracted for preparing a sequencing library. By using Illumina HiSeq2000, high-throughput sequencing was performed. Amnocentesis and karyotypic analysis were conducted for positive cases and those with negative results were followed up.

Results: By massively parallel genomic sequencing, 20 of them showed positive results. By the standard of chromosomal karyotypic analysis, there were 21 positive cases of 13 trisomy and the diagnostic accordance rate was 100%. Among 18 positive cases of 6 trisomy, there were amniocentesis (n = 5, except for one dead fetus), trisomy 18 (n = 4) and normal karyotype with placenta chimera (n = 1). One positive case of 13 trisomy was in accordance with karyotypic analysis.

Conclusion: Massively parallel sequencing for NIPD may be used as further screening for pregnant women with high risks of serological screening. And this technology is highly consistent with karyotypic analysis in terms of sensitivity and specificity.