scholarly journals Noninvasive Prenatal Detection of Fetal Trisomy 18 by Epigenetic Allelic Ratio Analysis in Maternal Plasma: Theoretical and Empirical Considerations

2006 ◽  
Vol 52 (12) ◽  
pp. 2194-2202 ◽  
Author(s):  
Yu K Tong ◽  
Chunming Ding ◽  
Rossa WK Chiu ◽  
Ageliki Gerovassili ◽  
Stephen SC Chim ◽  
...  
Keyword(s):  
Prenatal Diagnosis ◽  
Maternal Plasma ◽  
Trisomy 18 ◽  
Ratio Analysis ◽  
Dna Mixtures ◽  
Allelic Ratio ◽  
Fetal Dna ◽  
Noninvasive Prenatal Diagnosis ◽  
Cell Free Fetal Dna ◽  
Chromosomal Aneuploidies

Abstract Background: The discovery of cell-free fetal DNA in maternal plasma has opened up new possibilities for noninvasive prenatal diagnosis. However, the use of maternal plasma fetal DNA for the direct detection of fetal chromosomal aneuploidies has not been reported. We postulate that the aneuploidy status of a fetus could be revealed by an epigenetic allelic ratio approach, i.e., by analyzing the allelic ratio of a single-base variation present within DNA molecules exhibiting a placental-specific epigenetic signature in maternal plasma. Methods: Placental-derived fetal-specific unmethylated maspin (SERPINB5) promoter sequences on human chromosome 18 were detectable in placental–maternal DNA mixtures and in maternal plasma by bisulfite modification followed by methylation-specific PCR (MSP) and primer extension. The ratios between the extension products of the 2 alleles were calculated for heterozygous placentas, placental–maternal blood cell DNA mixtures, and maternal plasma samples. The allelic ratios were compared between pregnancies carrying trisomy 18 and euploid fetuses. Results: The epigenetic allelic ratios of all tested trisomy 18 samples deviated from the reference range obtained from euploid samples (placental DNA, 1.135 to 2.052; placental–maternal DNA mixtures, 1.170 to 1.985; maternal plasma, 0.330 to 3.044; without skew correction on the raw mass spectrometric data). A theoretical model was established and validated that predicted that a minimum of 200 copies of genomic DNA after bisulfite conversion were required for distinguishing euploid and aneuploid fetuses with confidence. Conclusion: Epigenetic allelic ratio analysis of maternal plasma DNA represents a promising approach for noninvasive prenatal diagnosis of fetal chromosomal aneuploidies.

scholarly journals Microsystem for Isolation of Fetal DNA from Maternal Plasma by Preparative Size Separation

2009 ◽  
Vol 55 (12) ◽  
pp. 2144-2152 ◽  
Author(s):  
Thomas Hahn ◽  
Klaus S Drese ◽  
Ciara K O'Sullivan
Keyword(s):  
Prenatal Diagnosis ◽  
High Volume ◽  
Maternal Plasma ◽  
Chromosomal Anomalies ◽  
Size Separation ◽  
Large Samples ◽  
Fetal Dna ◽  
Noninvasive Prenatal Diagnosis ◽  
Cell Free Fetal Dna ◽  
Invasive Techniques

Abstract Background: Routine prenatal diagnosis of chromosomal anomalies is based on invasive procedures, which carry a risk of approximately 1%–2% for loss of pregnancy. An alternative to these inherently invasive techniques is to isolate fetal DNA circulating in the pregnant mother’s plasma. Free fetal DNA circulates in maternal plasma primarily as fragments of lengths <500 bp, with a majority being <300 bp. Separating these fragments by size facilitates an increase in the ratio of fetal to maternal DNA. Methods: We describe our development of a microsystem for the enrichment and isolation of cell-free fetal DNA from maternal plasma. The first step involves a high-volume extraction from large samples of maternal plasma. The resulting 80-μL eluate is introduced into a polymeric microsystem within which DNA is trapped and preconcentrated. This step is followed by a transient isotachophoresis step in which the sample stacks within a neighboring channel for subsequent size separation and is recovered via an outlet at the end of the channel. Results: Recovered fractions of fetal DNA were concentrated 4–8 times over those in preconcentration samples. With plasma samples from pregnant women, we detected the fetal SRY gene (sex determining region Y) exclusively in the fragment fraction of <500 bp, whereas a LEP gene (leptin) fragment was detected in both the shorter and longer recovery fractions. Conclusions: The microdevice we have described has the potential to open new perspectives in noninvasive prenatal diagnosis by facilitating the isolation of fetal DNA from maternal plasma in an integrated, inexpensive, and easy-to-use microsystem.

scholarly journals Noninvasive Prenatal Diagnosis of Fetal Chromosomal Aneuploidies by Maternal Plasma Nucleic Acid Analysis

2008 ◽  
Vol 54 (3) ◽  
pp. 461-466 ◽  
Author(s):  
Y M Dennis Lo ◽  
Rossa W K Chiu
Keyword(s):  
Prenatal Diagnosis ◽  
Nucleic Acid ◽  
Nucleic Acids ◽  
Maternal Plasma ◽  
Small Sample ◽  
Routine Practice ◽  
Allelic Ratio ◽  
Noninvasive Prenatal Diagnosis ◽  
Nucleic Acid Analysis ◽  
Chromosomal Aneuploidies

Abstract Background: The discovery of circulating cell-free fetal nucleic acids in maternal plasma has opened up new possibilities for noninvasive prenatal diagnosis. The potential application of this technology for the noninvasive prenatal detection of fetal chromosomal aneuploidies is an aspect of this field that is being actively investigated. The main challenge of work in this area is the fact that cell-free fetal nucleic acids represent only a minor fraction of the total nucleic acids in maternal plasma. Methods and Results: We performed a review of the literature, which revealed that investigators have applied methods based on the physical and molecular enrichment of fetal nucleic acid targets from maternal plasma. The former includes the use of size fractionation of plasma DNA and the use of the controversial formaldehyde treatment method. The latter has been achieved through the development of fetal epigenetic and fetal RNA markers. The aneuploidy status of the fetus has been explored through the use of allelic ratio analysis of plasma fetal epigenetic and RNA markers. Digital PCR has been shown to offer high precision for allelic ratio and relative chromosome dosage analyses. Conclusions: After a decade of work, the theoretical and practical feasibility of prenatal fetal chromosomal aneuploidy detection by plasma nucleic acid analysis has been demonstrated in studies using small sample sets. Larger scale independent studies will be needed to validate these initial observations. If these larger scale studies prove successful, it is expected that with further development of new fetal DNA/RNA markers and new analytical methods, molecular noninvasive prenatal diagnosis of the major chromosomal aneuploidies could become a routine practice in the near future.

scholarly journals Recent Advances in Fetal Nucleic Acids in Maternal Plasma

2005 ◽  
Vol 53 (3) ◽  
pp. 293-296 ◽  
Author(s):  
Y.M. Dennis Lo
Keyword(s):  
Prenatal Diagnosis ◽  
First Trimester ◽  
Thalassemia Major ◽  
Maternal Plasma ◽  
Fetal Dna ◽  
Noninvasive Prenatal Diagnosis ◽  
Cell Free Fetal Dna ◽  
Circulating Fetal Dna ◽  
Circulating Rna ◽  
Near Future

The discovery of cell-free fetal DNA in maternal plasma in 1997 has opened up new possibilities for noninvasive prenatal diagnosis. Circulating fetal DNA molecules have been detected in maternal plasma from the first trimester onwards and can be robustly detected using a variety of molecular methods. This approach has been used for the prenatal investigation of sex-linked diseases, fetal RhD status, and prenatal exclusion of β-thalassemia major. Recently, fetal RNA has also been found in maternal plasma. Such fetal RNA has been shown to originate from the placenta and to be remarkably stable. The use of microarray-based approaches has made it feasible to rapidly generate new circulating RNA markers. It is hoped that further developments in this field will make the routine and widespread practice of noninvasive nucleic acid-based prenatal diagnosis for common pregnancy-associated disorders feasible in the near future.

scholarly journals Noninvasive prenatal diagnosis for Hemophilia A by haplotype-based approach using cell-free fetal DNA in maternal plasma

2019 ◽  
Author(s):  
Zhihui He ◽  
Chao Chen ◽  
Fengyu Guo ◽  
Lu Jiang ◽  
Yaping Zhu ◽  
...  
Keyword(s):  
Prenatal Diagnosis ◽  
Hemophilia A ◽  
Pathogenic Mutation ◽  
Maternal Plasma ◽  
Long Distance ◽  
High Coverage ◽  
Fetal Dna ◽  
Noninvasive Prenatal Diagnosis ◽  
Cell Free Fetal Dna ◽  
Haplotype A

AbstractObjectivesThis study was used to demonstrate the feasibility of haplotype-based noninvasive prenatal diagnosis for Hemophilia A.MethodsTwo families affected by Hemophilia A participated in our study. Maternal haplotypes associated with pathogenic mutation was built using targeted region genotypes of mother and the proband. Combined with maternal pathogenic haplotype, a Hidden Markov Model was constructed to deduce fetal haplotype using high-coverage targeted sequencing of maternal plasma. The presence of pathogenic haplotype in male indicated affected fetus, in female indicated carrier. Prenatal diagnosis was confirmed with amniocentesis by long distance PCR.ResultsThe haplotype-based noninvasive prenatal diagnosis was successfully performed in Hemophilia A. One fetus was identified to be normal, another fetus was identified as carrier, and the results were confirmed by amniocentesis .ConclusionOur research demonstrated the feasibility of noninvasive prenatal diagnosis for Hemophilia A by haplotype-based approach.

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