Project description:Copy Number Variations (CNVs) were identified performing Comparative Genomic Hybridization (CGH) on 225 patients after whole-genome amplification, using Agilent SurePrint G3 4x180K microarrays. CNVs were further integrated with gene expression (Affymetrix U133+2 arrays) and mutations (targeted DNA resequencing). Complete description of the methods, array quality checks and called segments are available as supplemental material in the corresponding publication.
Project description:Copy number analysis can be useful for assessing prognosis in diffuse large B cell lymphoma (DLBCL). We analyzed copy number data from tumor samples of 60 patients diagnosed with DLBCL de novo and their matched normal samples. We detected a total of 63 recurrent copy number alterations (CNAs), including 33 gains, 30 losses, and nine recurrent acquired copy number neutral loss of heterozygosity (CNN-LOH). Interestingly, 20% of cases acquired CNN-LOH of 6p21 locus, which involves the HLA region. In normal cells there were no CNAs but we observed CNN-LOH involving some key lymphoma regions such as 6p21 and 9p24.1 (5%) and 17p13.1 (2.5%) in DLBCL patients. Furthermore, a model with some specific CNA was able to predict the subtype of DLBCL, 1p36.32 and 10q23.31 losses being restricted to germinal center B cell-like (GCB) DLBCL. In contrast, 8p23.3 losses and 11q24.3 gains were strongly associated with the non-GCB subtype. A poor prognosis was associated with biallelic inactivation of TP53 or 18p11.32 losses, while prognosis was better in cases carrying 11q24.3 gains, which includes ETS1 and FLI1 genes. In summary, CNA abnormalities identify specific DLBCL groups, and we describe CN-LOH in germline cells from DLBCL patients that are associated with genes that probably play a key role in DLBCL development.
Project description:Copy number analysis can be useful for assessing prognosis in diffuse large B cell lymphoma (DLBCL). We analyzed copy number data from tumor samples of 60 patients diagnosed with DLBCL de novo and their matched normal samples. We detected a total of 63 recurrent copy number alterations (CNAs), including 33 gains, 30 losses, and nine recurrent acquired copy number neutral loss of heterozygosity (CNN-LOH). Interestingly, 20% of cases acquired CNN-LOH of 6p21 locus, which involves the HLA region. In normal cells there were no CNAs but we observed CNN-LOH involving some key lymphoma regions such as 6p21 and 9p24.1 (5%) and 17p13.1 (2.5%) in DLBCL patients. Furthermore, a model with some specific CNA was able to predict the subtype of DLBCL, 1p36.32 and 10q23.31 losses being restricted to germinal center B cell-like (GCB) DLBCL. In contrast, 8p23.3 losses and 11q24.3 gains were strongly associated with the non-GCB subtype. A poor prognosis was associated with biallelic inactivation of TP53 or 18p11.32 losses, while prognosis was better in cases carrying 11q24.3 gains, which includes ETS1 and FLI1 genes. In summary, CNA abnormalities identify specific DLBCL groups, and we describe CN-LOH in germline cells from DLBCL patients that are associated with genes that probably play a key role in DLBCL development.
Project description:BackgroundCopy number variations (CNVs) are deletions, insertions, duplications, and more complex variations ranging from 1 kb to sub-microscopic sizes. Recent advances in array technologies have enabled researchers to identify a number of CNVs from normal individuals. However, the identification of new CNVs has not yet reached saturation, and more CNVs from diverse populations remain to be discovered.ResultsWe identified 65 copy number variation regions (CNVRs) in 116 normal Korean individuals by analyzing Affymetrix 250 K Nsp whole-genome SNP data. Ten of these CNVRs were novel and not present in the Database of Genomic Variants (DGV). To increase the specificity of CNV detection, three algorithms, CNAG, dChip and GEMCA, were applied to the data set, and only those regions recognized at least by two algorithms were identified as CNVs. Most CNVRs identified in the Korean population were rare (<1%), occurring just once among the 116 individuals. When CNVs from the Korean population were compared with CNVs from the three HapMap ethnic groups, African, European, and Asian; our Korean population showed the highest degree of overlap with the Asian population, as expected. However, the overlap was less than 40%, implying that more CNVs remain to be discovered from the Asian population as well as from other populations. Genes in the novel CNVRs from the Korean population were enriched for genes involved in regulation and development processes.ConclusionCNVs are recently-recognized structural variations among individuals, and more CNVs need to be identified from diverse populations. Until now, CNVs from Asian populations have been studied less than those from European or American populations. In this regard, our study of CNVs from the Korean population will contribute to the full cataloguing of structural variation among diverse human populations.
Project description:Thousands of genomic segments appear to be present in widely varying copy numbers in different human genomes. We developed ways to use increasingly abundant whole-genome sequence data to identify the copy numbers, alleles and haplotypes present at most large multiallelic CNVs (mCNVs). We analyzed 849 genomes sequenced by the 1000 Genomes Project to identify most large (>5-kb) mCNVs, including 3,878 duplications, of which 1,356 appear to have 3 or more segregating alleles. We find that mCNVs give rise to most human variation in gene dosage-seven times the combined contribution of deletions and biallelic duplications-and that this variation in gene dosage generates abundant variation in gene expression. We describe 'runaway duplication haplotypes' in which genes, including HPR and ORM1, have mutated to high copy number on specific haplotypes. We also describe partially successful initial strategies for analyzing mCNVs via imputation and provide an initial data resource to support such analyses.
Project description:Although germline de novo copy number variants (CNVs) are known causes of autism spectrum disorder (ASD), the contribution of mosaic (early-developmental) copy number variants (mCNVs) has not been explored. In this study, we assessed the contribution of mCNVs to ASD by ascertaining mCNVs in genotype array intensity data from 12,077 probands with ASD and 5,500 unaffected siblings. We detected 46 mCNVs in probands and 19 mCNVs in siblings, affecting 2.8-73.8% of cells. Probands carried a significant burden of large (>4-Mb) mCNVs, which were detected in 25 probands but only one sibling (odds ratio = 11.4, 95% confidence interval = 1.5-84.2, P = 7.4 × 10-4). Event size positively correlated with severity of ASD symptoms (P = 0.016). Surprisingly, we did not observe mosaic analogues of the short de novo CNVs recurrently observed in ASD (eg, 16p11.2). We further experimentally validated two mCNVs in postmortem brain tissue from 59 additional probands. These results indicate that mCNVs contribute a previously unexplained component of ASD risk.