Prenatal diagnosis of trisomy 21, 18 and 13 by quantitative pyrosequencing of segmental duplications

Abstract

Chromosomal aberration mostly occurs in chromosomes 21, 18 and 13, with an incidence approximately 1 out of 160 live births in humans, therefore making prenatal diagnosis necessary in clinics. Current methods have drawbacks such as time consuming, high cost, complicated operations and low sensitivity. In this paper, a novel method for rapid and accurate prenatal diagnosis of aneuploidy is proposed based on pyrosequencing, which quantitatively detects the peak height ratio (PHR) of different bases of segmental duplication. A direct polymerase chain reaction (PCR) approach was undertaken, where a small volume of amniotic fluid was used as the starting material without DNA extraction. Single-stranded DNA was prepared from PCR products and subsequently analyzed using pyrosequencing. The PHR between target and reference chromosome of 2.2 for euploid and 3:2 for a trisomy fetus were used as reference. The reference intervals and z scores were calculated for discrimination of aneuploidy. A total of 132 samples were collected, within trisomy 21 (n = 11), trisomy 18 (n = 3), trisomy 13 (n = 2), and unaffected controls (n = 116). A set of six segmental duplications were chosen for analysis. This method had consistent results with karyotyping analysis, a correct diagnosis with 100% sensitivity and 99.9% specificity.

The accuracy and feasibility of noninvasive prenatal testing in a consecutive series of 20,626 pregnancies with different clinical characteristics

“…In recent years, chromosomal microdeletion/microduplication, sex chromosome abnormalities may be the main causes of birth defects 22 . With the discovery of cffDNA in pregnant women, NIPT has been widely used in the screening of prenatal genetic diseases, with high diagnostic accuracy for T21, T18, and T13, and the ability to screen transgenation 23–27 . In this study, the accuracy and feasibility of NIPT in 20,626 pregnant women were analyzed for providing more data support for the application of NIPT.…”

Application value of NIPT for uncommon fetal chromosomal abnormalities

“…In addition, there have been reports that chromosomal deletions, chromosomal duplications, and sex chromosome abnormalities can be the causes of neonatal birth defects, mostly consisting of new mutations [12]. Compared to traditional serological screening, NIPT has been increasingly used for its advantages, such as its noninvasiveness, high detection rate, low false positive rate, wide range of pregnancy, lower clinical information, and relatively easy method of quality control [13]. Not only does NIPT have a higher detection rate for trisomy 21, trisomy 18, and trisomy 13, it also has a better detection rate for other chromosomal abnormalities.…”

Chromosomal abnormalities: subgroup analysis by maternal age and perinatal features in zhejiang province of China, 2011–2015

“…There were notable differences based on rural versus urban populations and maternal age groups. Most studies in China have focused primarily on vulnerable populations or the relation to prenatal diagnosis [6, 10, 17, 18]. Few studies have provide a comprehensive report on the epidemiology of chromosomal abnormalities based on normal population.…”