Unknown,Transcriptomics,Genomics,Proteomics

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Chromosomal analysis of products of conception

ABSTRACT: Results of an unbiased series of 2833 fresh products of conception samples (in conjunction with maternal blood samples for comparison) that were tested using a 300K Illumina SNP array. we report on the rate and type of whole aneuploidies, UPD, partial aneuploidies, copy number variants found in our series as well as the rate of maternal cell contamination vs. true fetal results. 2833 consecutive fresh products of conception samples and corresponding maternal and/or paternal blood samples were analyzed using a SNP array plus informatics algorithms for the purpose of detecting causal chromosome abnormalities. Hypothesized advantages of using SNP microarray with Parental SupportTM informatics over the traditional standard G-banded karyotyping include: direct testing without need for cell culture, faster turn-around time, low failure rate, the ability to detect or rule out maternal cell contamination (MCC), and the detection of small segmental changes, uniparental disomy (UPD) and parent of origin of any aneuploidies. Results showed a 22% MCC rate. In the 78% of samples with true fetal results, 60% had abnormalities with single aneuploidy being the most common. Separate evaluation of the samples to determine the resolution of the SNP array with informatics showed the ability to detect copy number variations (CNVs) as small as 1 MB or less, with 1.4% of samples revealing a clinically relevant microdeletion or duplication. 2833 fresh products of conception samples were analyze using no controls, no replicates, and no reference samples.

ORGANISM(S): Homo sapiens

SUBMITTER: Jennifer Dikan

PROVIDER: E-GEOD-39332 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:Myelodysplastic syndromes (MDS) are clonal disorders of hematopoietic progenitors characterized by ineffective hematopoiesis and high propensity to leukemias. Although a number of gene targets have been identified, in many MDS cases, particular genetic targets are unknown. In this study, we performed genome-wide profiling of copy number (CN) abnormalities and allelic imbalances in MDS genomes in order to clarify the distribution of LOH (loss of heterozygosity) and identify their target genes. We analyzed a total of 171MDS and MDS/MPD specimens, including 7 RA/RARS, 23 RCMD/RCMD-RS, 6 5q-syndrome, 30 RAEB-1, 40 RAEB-2, 4 therapy related-MDS/AML, 5 MDSu, 17 CMML-1, 16 CMML-2, 24 overt AML, using high-density SNP arrays. The data were analyzed by CNAG/AsCNAR software we specifically developed for allele-specific CN analysis and sensitive LOH detection. MDS showed characteristic CN profiles in SNP array analysis. Of particular interest is the finding of high frequency of CN-neutral LOH (Uniparental disomy,UPD), which were observed in 51 of 171 (30%) MDS cases. They preferentially involved 1p, 1q, 4q, 7q, 11q, 17p and other chromosomal segments, which were associated with homozygous mutations of both loss-of-function mutations and gain-of function mutations of tumor suppressor genes and cellular oncogenes, including TP53 (17p UPD), AML1/RUNX1 (21q UPD), Nras and cMPL (1p UPD), JAK-2 (9p UPD), and FLT3 (13q UPD). Next we tried to identify a new gene target in 11q UPD, which was most common UPD region in this study and many of these cases were CMML with a normal karyotype. The minimum 11q UPD segment is about 2Mb which existed in 11q23. We sequenced coding exons of c-cbl and detected homozygous mutations in 8 of 9 MDS cases with 11q UPD (CMML= 5, RAEB= 3, overt leukemia= 1), but very rare in cases without 11q UPD (1/162), demonstrating that the mutation is tightly linked to 11q UPD. These mutations were 8 point mutations and 1 micro-deletion, they were accumulated in the linker or RING domain. These c-cbl mutants can transform NIH3T3 in a dominant manner and these mutants are phosphorylated and activate PI3K-Akt pathway. To investigate the functions of these mutants in hematopoietic cells, we introduced these mutants into c-kit(+)Sca1(+)Lin(-) murine bone marrow cells, it prolonged replating capacity of these hematopoietic progenitors. Keywords: SNP-chip To identify oncogenic lesions in MDS, we performed a genome-wide analysis of primary MDS samples using high-density SNP arrays (Affymetrix GeneChip).

Project description:Genomic imprinting is a mechanism in which the expression of genes varies depending on their parent-of-origin. Imprinting occurs through differential DNA methylation and histone modifications on the two parental alleles, with most imprinted genes marked by CpG-rich differentially methylated regions (DMRs). DNA methylation profiling in cases of uniparental disomy (UPD) provides a unique system permitting the study of DNA derived from a single parent (PMID: 20631049). Approximately 70 human imprinted genes have been described, and imprinted loci have been associated with diseases such as diabetes and cancer. We profiled parent of origin DNA methylation marks to find novel imprinted loci. Methods: We have an unprecedented collection of whole blood DNA from XX patients with UPD covering 18 different chromosomes, allowing for the efficient detection of DMRs associated with imprinted genes for 84% of the human genome. Our study is complimented with Ovarian Teratoma DNA (maternal DNA) and Complete hydatidiform Mole (paternal DNA). DNA methylation was profiled using Illumina Infinium 450K Methylation BeadArrays. Imprinted DMRs were defined by sites at which the maternal and paternal methylation levels diverged significantly from the biparental average. We confirmed novel DMRs by bisulfite sequencing of informative trios and SequenomEpiTYPER assays. Allelic specific gene expression studies were also performed by RNA sequencing in independent biparental controls. Findings: Our results provide for the first comprehensive map of the human imprintome, doubling the number of known imprinted regions. We identified a total of 71 DMRs, 41 of which were novel. 27 novel DMRs were maternally methylated and 14 were paternally methylated. We identified DMRs on chromosomes 5, 21 and 22 previously considered devoid of imprinting, highlighting potential parent-of-origin effects in chromosomal aneuploidies such as Down syndrome. We also found DMRs in genes associated with Schizophrenia and epilepsy. Interpretation: Our data provide the first comprehensive genome-wide map of imprinted sites in the human genome, and provide novel insights into potential parent-of-origin effects in human disorders. 66 UPD samples analyzed in total, From each individual, whole bllod DNA was extracted and global DNA methylation levels were assessed using Illumina Infinium HumanMethylation450 BeadChip.

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Chromosomal analysis of products of conception

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