scholarly journals Noninvasive Prenatal Detection of Trisomy 21 by an Epigenetic–Genetic Chromosome-Dosage Approach

2010 ◽  
Vol 56 (1) ◽  
pp. 90-98 ◽  
Author(s):  
Yu K Tong ◽  
Shengnan Jin ◽  
Rossa WK Chiu ◽  
Chunming Ding ◽  
KC Allen Chan ◽  
...  
Keyword(s):  
Prenatal Diagnosis ◽  
Genetic Markers ◽  
Blood Cells ◽  
Trisomy 21 ◽  
Maternal Blood ◽  
Maternal Plasma ◽  
Plasma Samples ◽  
Prenatal Detection ◽  
Fetal Dna ◽  
Noninvasive Prenatal Diagnosis

Abstract Background: The use of fetal DNA in maternal plasma for noninvasive prenatal diagnosis of trisomy 21 (T21) is an actively researched area. We propose a novel method of T21 detection that combines fetal-specific epigenetic and genetic markers. Methods: We used combined bisulfite restriction analysis to search for fetal DNA markers on chromosome 21 that were differentially methylated in the placenta and maternal blood cells and confirmed any target locus with bisulfite sequencing. We then used methylation-sensitive restriction endonuclease digestion followed by microfluidics digital PCR analysis to investigate the identified marker. Chromosome-dosage analysis was performed by comparing the dosage of this epigenetic marker with that of the ZFY (zinc finger protein, Y-linked) gene on chromosome Y. Results: The putative promoter of the HLCS (holocarboxylase synthetase) gene was hypermethylated in the placenta and hypomethylated in maternal blood cells. A chromosome-dosage comparison of the hypermethylated HLCS and ZFY loci could distinguish samples of T21 and euploid placental DNA. Twenty-four maternal plasma samples from euploid pregnancies and 5 maternal plasma samples from T21 pregnancies were analyzed. All but 1 of the euploid samples were correctly classified. Conclusions: The epigenetic–genetic chromosome-dosage approach is a new method for noninvasive prenatal detection of T21. The epigenetic part of the analysis can be applied to all pregnancies. Because the genetic part of the analysis uses paternally inherited, fetal-specific genetic markers that are abundant in the genome, broad population coverage should be readily achievable. This approach has the potential to become a generally usable technique for noninvasive prenatal diagnosis.

scholarly journals Systematic Search for Placental DNA-Methylation Markers on Chromosome 21: Toward a Maternal Plasma-Based Epigenetic Test for Fetal Trisomy 21

2008 ◽  
Vol 54 (3) ◽  
pp. 500-511 ◽  
Author(s):  
Stephen S C Chim ◽  
Shengnan Jin ◽  
Tracy Y H Lee ◽  
Fiona M F Lun ◽  
Wing S Lee ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Blood Cells ◽  
Trisomy 21 ◽  
Maternal Blood ◽  
Maternal Plasma ◽  
Chromosome 21 ◽  
Noninvasive Detection ◽  
Fetal Dna ◽  
Noninvasive Prenatal Diagnosis ◽  
Methylation Patterns

Abstract Background: The presence of fetal DNA in maternal plasma represents a source of fetal genetic material for noninvasive prenatal diagnosis; however, the coexisting background maternal DNA complicates the analysis of aneuploidy in such fetal DNA. Recently, the SERPINB5 gene on chromosome 18 was shown to exhibit different DNA-methylation patterns in the placenta and maternal blood cells, and the allelic ratio for placenta-derived hypomethylated SERPINB5 in maternal plasma was further shown to be useful for noninvasive detection of fetal trisomy 18. Methods: To develop a similar method for the noninvasive detection of trisomy 21, we used methylation-sensitive single nucleotide primer extension and/or bisulfite sequencing to systematically search 114 CpG islands (CGIs)—76% of the 149 CGIs on chromosome 21 identified by bioinformatic criteria—for differentially methylated DNA patterns. The methylation index (MI) of a CpG site was estimated as the proportion of molecules methylated at that site. Results: We identified 22 CGIs which were shown to contain CpG sites that were either completely unmethylated (MI = 0.00) in maternal blood cells and methylated in the placenta (MI range, 0.22–0.65), or completely methylated (MI = 1.00) in maternal blood cells and hypomethylated in the placenta (MI range, 0.00–0.75). We detected, for the first time, placental DNA-methylation patterns on chromosome 21 in maternal plasma during pregnancy and observed their postpartum clearance. Conclusion: Twenty-two (19%) of the 114 studied CGIs on chromosome 21 showed epigenetic differences between samples of placenta and maternal blood cells; these CGIs may provide a rich source of markers for noninvasive prenatal diagnosis.

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 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 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 Maternal Plasma DNA Analysis with Massively Parallel Sequencing by Ligation for Noninvasive Prenatal Diagnosis of Trisomy 21

2010 ◽  
Vol 56 (3) ◽  
pp. 459-463 ◽  
Author(s):  
Rossa WK Chiu ◽  
Hao Sun ◽  
Ranjit Akolekar ◽  
Christopher Clouser ◽  
Clarence Lee ◽  
...  
Keyword(s):  
Prenatal Diagnosis ◽  
Trisomy 21 ◽  
Massively Parallel Sequencing ◽  
Maternal Plasma ◽  
Chromosome 21 ◽  
Massively Parallel ◽  
Plasma Dna ◽  
Parallel Sequencing ◽  
Noninvasive Prenatal Diagnosis ◽  
Sequencing By Synthesis

Abstract Background: Noninvasive prenatal diagnosis of trisomy 21 (T21) has recently been shown to be achievable by massively parallel sequencing of maternal plasma on a sequencing-by-synthesis platform. The quantification of several other human chromosomes, including chromosomes 18 and 13, has been shown to be less precise, however, with quantitative biases related to the chromosomal GC content. Methods: Maternal plasma DNA from 10 euploid and 5 T21 pregnancies was sequenced with a sequencing-by-ligation approach. We calculated the genomic representations (GRs) of sequenced reads from each chromosome and their associated measurement CVs and compared the GRs of chromosome 21 (chr21) for the euploid and T21 pregnancies. Results: We obtained a median of 12 × 106 unique reads (21% of the total reads) per sample. The GRs deviated from those expected for some chromosomes but in a manner different from that previously reported for the sequencing-by-synthesis approach. Measurements of the GRs for chromosomes 18 and 13 were less precise than for chr21. z Scores of the GR of chr21 were increased in the T21 pregnancies, compared with the euploid pregnancies. Conclusions: Massively parallel sequencing-by-ligation of maternal plasma DNA was effective in identifying T21 fetuses noninvasively. The quantitative biases observed among the GRs of certain chromosomes were more likely based on analytical factors than biological factors. Further research is needed to enhance the precision for measuring for the representations of chromosomes 18 and 13.

scholarly journals Fetal DNA in Maternal Plasma: Biology and Diagnostic Applications

2000 ◽  
Vol 46 (12) ◽  
pp. 1903-1906 ◽  
Author(s):  
Y M Dennis Lo
Keyword(s):  
Prenatal Diagnosis ◽  
Genetic Disorders ◽  
Maternal Blood ◽  
Maternal Plasma ◽  
Published Data ◽  
Plasma Dna ◽  
Fetal Dna ◽  
Cell Clearance ◽  
Clearance Kinetics ◽  
Diagnostic Applications

Abstract Background: Molecular analysis of plasma DNA during human pregnancy has led to the discovery that maternal plasma contains both fetal and maternal DNA. This valuable source of fetal DNA opens up new possibilities for noninvasive prenatal diagnosis. Approach: Published data from the last 3 years demonstrating the feasibility and utility of analyzing fetal DNA in maternal plasma are reviewed. Content: The detection of fetal DNA in maternal plasma is much simpler and more robust than detecting fetal nucleated cells in maternal blood, and does not require prior enrichment. This approach has been shown to have application in the prenatal diagnosis of fetal rhesus D status, sex-linked disorders, and other paternally inherited genetic disorders. Abnormal fetal DNA concentrations in maternal plasma and serum have been found in common pregnancy-associated disorders, including preterm labor and preeclampsia, as well as in pregnancies complicated by fetal trisomy 21. After delivery, fetal DNA is cleared rapidly from maternal plasma, with a half-life in the order of minutes. These clearance kinetics exhibit an important difference from fetal cell clearance, where long-term persistence has been demonstrated. Summary: It has been only 3 years since fetal DNA was first detected in maternal plasma, and much remains to be learned about the biology of this phenomenon. In addition, additional diagnostic applications beyond those discussed here can be expected in the near future.

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