Project description:Noninvasive prenatal diagnosis currently used does not achieve desirable levels of sensitivity and specificity. Recently, fetal methylated DNA biomarkers in maternal whole blood have been explored for noninvasive prenatal detection. However, such efforts cover only chromosomal aneuploidy; fetal methylated DNA biomarkers for detecting single-gene disease remain to be discovered. To address this issue, we systematically screened significantly hypermethylated genes in fetal tissues compared with maternal blood for noninvasive prenatal diagnosis of various inherited diseases. First, Methylated-CpG island recovery assay combined with CpG island array was performed in four maternal peripheral bloods and their corresponding placental tissues. Subsequently, direct bisulfite sequencing and combined bisulfite restriction analysis (COBRA) were carried out to validate the reliability of methylation microarray analysis. As results, 310 significantly hypermethylated genes in fetal tissues were detected by microarray. Two of five randomly selected hypermethylated genes detected by microarray were confirmed to be hypermethylated in fetal tissue samples by direct bisulfite sequencing. All four randomly selected hypermethylated genes detected by microarray were confirmed to be hypermethylated in five independent amniotic fluid samples and five independent chorionic villus samples from 10 pregnant women by CORBA. In conclusions, We found a lot of hypermethylated genes and methylation sites in fetal tissues, some of which have great potential to be developed into molecular markers for noninvasive prenatal diagnosis of monogenic disorders. Further clinical study is warranted to confirm these findings. Paired experiments, placental tissues vs. maternal peripheral bloods. Biological replicates: 4 placental tissues and 4 correspoding maternal peripheral bloods.
Project description:Noninvasive prenatal diagnosis currently used does not achieve desirable levels of sensitivity and specificity. Recently, fetal methylated DNA biomarkers in maternal whole blood have been explored for noninvasive prenatal detection. However, such efforts cover only chromosomal aneuploidy; fetal methylated DNA biomarkers for detecting single-gene disease remain to be discovered. To address this issue, we systematically screened significantly hypermethylated genes in fetal tissues compared with maternal blood for noninvasive prenatal diagnosis of various inherited diseases. First, Methylated-CpG island recovery assay combined with CpG island array was performed in four maternal peripheral bloods and their corresponding placental tissues. Subsequently, direct bisulfite sequencing and combined bisulfite restriction analysis (COBRA) were carried out to validate the reliability of methylation microarray analysis. As results, 310 significantly hypermethylated genes in fetal tissues were detected by microarray. Two of five randomly selected hypermethylated genes detected by microarray were confirmed to be hypermethylated in fetal tissue samples by direct bisulfite sequencing. All four randomly selected hypermethylated genes detected by microarray were confirmed to be hypermethylated in five independent amniotic fluid samples and five independent chorionic villus samples from 10 pregnant women by CORBA. In conclusions, We found a lot of hypermethylated genes and methylation sites in fetal tissues, some of which have great potential to be developed into molecular markers for noninvasive prenatal diagnosis of monogenic disorders. Further clinical study is warranted to confirm these findings.
Project description:The uploaded results of two samples were SNParray results in our research of which fetal CNVs were detected by noninvasive prenatal test (NIPT) and confirmed by microarray results. Sample ZNY162 received prenatal diagnosis because at 17 gestational week the pregnant woman received NIPT showing 23Mb microdeletion in Chr18. Later ultrasound examination showed developmental anomalies of feet and the 13th ribs. The pregnant woman received amniocentesis and SNParray at the 21st gestational week, which confirmed the existence of the microdeletion in Chr18. DNA was extracted from 10ml amniotic fluid and tested by Affymetrix CytoScan HD array to detect CNVs in whole genome, showing arr 18q22.3q23(69,461,933-78,014,123) Ã1. Sample LMQ155 received prenatal diagnosis because of advanced maternal age and NIPT result of a 2.29Mb microduplication in Chr13 at 15 gestational week. Amniocentesis was performed at the 17th gestational week. Affymetrix CytoScan HD array were used to detect fetal CNVs in whole genome, which showed arr 13q21.2(60,399,612-61,730,194) Ã3 that was consistent with NIPT result.
Project description:In order to evaluate the performance of CNV detection in next-generation sequencing platform in varied sample types, we employed chromosomal microarray analysis (CMA) for validation of the samples with NGS-based detection results (NCBI Sequence Read Archive with accession number SRA296708). Besides array Comparative Genomics Hybridization (aCGH, Agilent) , we used a commerical SNP-array (Illumina) including early abortus, induced termination, prenatal samples and postnatal samples. CMA results were compared with NGS-based detection results. 100% consistency was obtained between NGS-based approach and CMA in pathogenic or likely pathogenic CNVs detection.
Project description:In order to evaluate the performance of CNV detection in next-generation sequencing platform in varied sample types, we employed chromosomal microarray analysis (CMA) for validation of the samples with NGS-based detection results (NCBI Sequence Read Archive with accession number SRA296708). Besides snp-array, we used a customized array Comparative Genomics Hybridization (aCGH, Agilent) approach for a cohort of clinical samples including early abortus, induced termination, prenatal samples and postnatal samples. CMA results were compared with NGS-based detection results. 100% consistency was obtained between NGS-based approach and CMA in pathogenic or likely pathogenic CNVs detection.
Project description:BACs-on-Beads (BoBs) assay and Copy Number Variation Sequencing (CNV-Seq) are two frequently used methods in today’s prenatal diagnosis. Several researches studies were conducted to investigate the performance of each approach, but they were never compared side by side. This dataset is intended to be used as the 'gold standard dataset' for the validation of BoBs/CNV-seq test reasults on 10 amniotic fluid samples with pathogenic fetal CNVs.
Project description:Fetal DNA is present in the plasma of pregnant women. Massively parallel sequencing of maternal plasma DNA has been used to detect fetal trisomies 21, 18, 13 and selected sex chromosomal aneuploidies noninvasively. Case reports describing the detection of fetal microdeletions from maternal plasma using massively parallel sequencing have been reported. However, these previous reports were either polymorphism-dependent or used statistical analyses which were confined to one or a small number of selected parts of the genome. In this report, we reported a procedure for performing noninvasive prenatal karyotyping at 3 Mb resolution across the whole genome through the massively parallel sequencing of maternal plasma DNA. This method has been used to analyze the plasma obtained from 6 cases. In 5 cases, fetal microduplications or microdeletions have been detected successfully from maternal plasma. The two cases with fetal microduplications represented the first noninvasive prenatal detection of such changes from maternal plasma. In the remaining case, the plasma DNA sequencing result was consistent with the pregnant mother being a carrier of a microduplication. Simulation analyses were performed for determining the number of plasma DNA molecules that would need to be sequenced and aligned for enhancing the diagnostic resolution of noninvasive prenatal karyotyping to 2 Mb and 1 Mb. In conclusion, noninvasive prenatal molecular karyotyping from maternal plasma by massively parallel sequencing is feasible and would enhance the diagnostic spectrum of noninvasive prenatal testing.
Project description:<p>In the last decade, non-invasive prenatal diagnosis (NIPD) has emerged as an effective procedure for early detection of inherited diseases during pregnancy. This technique is based on using cell-free DNA (cfDNA) and fetal cfDNA (cffDNA) in maternal blood, and hence, has minimal risk for the mother and fetus compared with invasive techniques. NIPD is used today for identifying chromosomal abnormalities (in some instances) and for single-gene disorders (SGDs) of paternal origin. However, for SGDs of maternal origin, sensitivity poses a challenge that limits the testing to one genetic disorder at a time. Here we present a Bayesian method for the NIPD of monogenic diseases that is independent of the mode of inheritance and parental origin. Furthermore, we show that accounting for differences in the fragment length distribution of fetal- and maternal-derived cfDNA results in increased accuracy. Our model is the first to predict inherited insertions-deletions (indels). The method described can serve as a general framework for the NIPD of SGDs; this will facilitate easy integration of further improvements. One such improvement that is presented in the current study is a machine learning model that corrects errors based on patterns found in previously processed data. Overall, we show that next generation sequencing (NGS) can be used for the NIPD of a wide range of monogenic diseases, simultaneously. We believe that our study will lead to the achievement of a comprehensive NIPD for monogenic diseases.</p> <p>(Reprinted from Bayesian-based noninvasive prenatal diagnosis of single-gene disorders, with permission from Genome Research) </p>
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.