Project description:Discovery of common Asian copy number variants using a novel integrated high-resolution array CGH and massively parallel DNA sequencing. We attempted to discover common Asian copy number variants (CNVs) from the DNA of 30 Asian women (10 Korean, 10 CHB (HapMap), 10 JPT (HapMap)) using a custom-designed 24M-oligonucleotide Agilent platform (1.1M X 24 slides). The reference sample for aCGH was NA10851 (HapMap CEPH). In addition to the 30 women, 3 more individuals were analyzed as controls (AK1 (Kim, J.I. et al., 2009 Nature), NA12878 and NA19240).
Project description:The discovery of copy number variation in healthy individuals is far from complete, and due to the resolution of detection systems used, the majority of loci reported so far are relatively large (~65% > 10kb). Applying a two-stage high-resolution array CGH approach to analyse 50 healthy Caucasian males from northern France, we discovered 2208 copy number variants (CNVs) detected by more than one consecutive probe. These clustered into 1469 copy number variant regions (CNVRs), of which 721 are thought to be novel. The majority of these are small (median size 4.4kb) and most have common boundaries, with a coefficient of variation less than 0.1 for 83% of end-points in those observed in multiple samples. Only 6% of the CNVRs analysed showed evidence of both copy number losses and gains at the same site. A further 6089 variants were detected by single probes: 48% of these were observed in more than one individual. In total, 2570 genes were seen to intersect variants: 1284 in novel loci. Genes involved in differentiation and development were significantly overrepresented, and approximately half the genes identified feature in the OMIM database. The biological importance of many of the genes affected, along with the well-conserved nature of the majority of the copy number variants, suggests they could have important implications for phenotype and, thus, be useful for association studies of complex diseases. Keywords: comparative genomic hybridization
Project description:Autism and mental retardation (MR) are often associated, suggesting that these conditions are etiologically related. Recently, array-based comparative genomic hybridization (array CGH) has identified submicroscopic deletions and duplications as a common cause of MR. This prompted us to search for such genomic imbalances in autism and related disorders. Here we describe a 1.5 Mb duplication on chromosome 16p13.1, found in four autistic male patients from three families and several variably affected and unaffected relatives. A deletion of the same interval was identified in three unrelated patients with MR and other clinical abnormalities. Duplications and deletions of this interval have not been described before, neither as copy number variants in the Database of Genomic Variants nor in >600 individuals from other cohorts examined by high resolution array CGH in our laboratory. Thus, this is the first description of a recurrent genomic imbalance predisposing to autism and/or MR. Keywords: array CGH
Project description:To determine the involvement of Copy Number Variants (CNVs) in the origin of male infertility, patients with idiopathic severe oligozoospermia, Sertoli-cell-only syndrome and controls with normozoospermia were analysed by array CGH using the 244A/400K array sets (Agilent Technologies).
Project description:In our clinical practice, we perform genome-wide high-resolution SNP-array analysis as an adjunct to the histopathologic diagnosis for diagnostically challenging melanocytic tumors. The concept of using array-based DNA copy number analysis to screen for gene fusions associated with unbalanced genomic aberrations flanking the fusion points was applied in the diagnostic setting, and intragenic copy number changes involving common receptor kinase genes are typically further analyzed and, if necessary, studied by alternative methods. Here we present the discovery of recurrent NTRK3 gene rearrangements in childhood melanocytic neoplasms based on genome-wide high-resolution SNP-array analysis.
Project description:Gene amplifications and deletions frequently contribute to tumorigenesis. Characterization of these DNA copy-number changes is important for both the basic understanding of cancer and its diagnosis. Comparative genomic hybridization (CGH) was developed to survey DNA copy-number variations across a whole genome. With CGH, differentially labelled test and reference genomic DNAs are co-hybridized to normal metaphase chromosomes, and fluorescence ratios along the length of chromosomes provide a cytogenetic representation of DNA copy-number variation. CGH, however, has a limited ( approximately 20 Mb) mapping resolution, and higher-resolution techniques, such as fluorescence in situ hybridization (FISH), are prohibitively labour-intensive on a genomic scale. Array-based CGH, in which fluorescence ratios at arrayed DNA elements provide a locus-by-locus measure of DNA copy-number variation, represents another means of achieving increased mapping resolution. Published array CGH methods have relied on large genomic clone (for example BAC) array targets and have covered only a small fraction of the human genome. cDNAs representing over 30,000 radiation-hybrid (RH)-mapped human genes provide an alternative and readily available genomic resource for mapping DNA copy-number changes. Although cDNA microarrays have been used extensively to characterize variation in human gene expression, human genomic DNA is a far more complex mixture than the mRNA representation of human cells. Therefore, analysis of DNA copy-number variation using cDNA microarrays would require a sensitivity of detection an order of magnitude greater than has been routinely reported. We describe here a cDNA microarray-based CGH method, and its application to DNA copy-number variation analysis in breast cancer cell lines and tumours. This study is described more fully in Pollack JR et al.(1999) Nat Genet 23:41-6 Keywords: other
Project description:East-Asian (EA) patients with Non Small Cell Lung Cancer (NSCLC) are associated with a high proportion of non-smoking women, EGFR activating somatic mutations, and clinical responses to tyrosine kinase inhibitors. We identify copy number alterations specific to EA and Western European (WE) NSCLCs and conducted an integrative analysis using transcritomic data for identifying copy-number-driven candidate genes. Samples were hybridized to Affymetrix Genome-Wide Human SNP 6.0 arrays according to the manufacturer’s specifications in the same center. 226 lung adenocarcinomas (90 East-Asian and 136 Western-European) were analyzed for copy-number aberrations (CNAs) using a common high resolution SNP microarray platform.
Project description:This study used the NimbleGen dog whole genome CGH 2.1M tiling array to assay copy number variants in the dog genome in multiple breeds and wolf.
Project description:Comparison of whole genome exome array CGH to a commercial SNP array for detection of de novo and homozygous copy number variants in 99 autism simplex trios. Will update once manuscript is prepared.
Project description:Background/Aims: Microarray-based comparative genomic hybridisation (CGH) has allowed high-resolution analysis of DNA copy number alterations across the entire cancer genome. Recent advances in bioinformatics tools enable us to perform a robust and highly sensitive analysis of array CGH data and facilitate the discovery of novel cancer-related genes. Methods: We analysed a total of 29 pancreatic ductal adenocarcinoma (PDAC) samples (six cell lines and 23 microdissected tissue specimens) using 1 Mb-spaced CGH arrays. The transcript levels of all genes within the identified regions of genetic alterations were then screened using our Pancreatic Expression Database. Results: In addition to 238 high-level amplifications and 35 homozygous deletions, we identified 315 minimal common regions of “non-random” genetic alterations (115 gains and 200 losses) which were consistently observed across our tumour samples. The small size of these aberrations (median size of 880 kb) contributed to the reduced number of candidate genes included (on average 12 Ensembl-annotated genes). The database has further specified the genes whose expression levels are consistent with their copy number status. Such genes were UQCRB, SQLE, DDEF1, SLA, ERICH1 and DLC1, indicating that these may be potential target candidates within regions of aberrations. Conclusion: This study has revealed multiple novel regions that may indicate the locations of oncogenes or tumour suppressor genes in PDAC. Using the database, we provide a list of novel target genes whose altered DNA copy numbers could lead to significant changes in transcript levels in PDAC. (Harada et al. Pancreatology) Keywords: pancreatic ductal adenocarcinima, tissue microdissection, array CGH, genetic alterations