Global patterns of large copy number variations in the human genome reveal complexity in chromosome organization

SummaryGlobal patterns of copy number variations (CNVs) in chromosomes are required to understand the dynamics of genome organization and complexity. For this study, analysis was performed using the Affymetrix Genome-Wide Human SNP Array 6.0 chip and CytoScan High-Density arrays. We identified a total of 44 109 CNVs from 1715 genomes with a mean of 25 CNVs in an individual, which established the first drafts of population-specific CNV maps providing a rationale for prioritizing chromosomal regions. About 19 905 ancient CNVs were identified across all chromosomes and populations at varying frequencies. CNV count, and sometimes CNV size, contributed to the bulk CNV size of the chromosome. Population specific lengthening and shortening of chromosomal length was observed. Sex bias for CNV presence was largely dependent on ethnicity. Lower CNV inheritance rate was observed for India, compared to YRI and CEU. A total of 33 candidate CNV hotspots from 5382 copy number (CN) variable region (CNVR) clusters were identified. Population specific CNV distribution patterns in p and q arms disturbed the assumption that CNV counts in the p arm are less common compared to long arms, and the CNV occurrence and distribution in chromosomes is length independent. This study unraveled the force of independent evolutionary dynamics on genome organization and complexity across chromosomes and populations.

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Copy number variation analysis in Chinese children with complete atrioventricular canal and single ventricle

BMC Medical Genomics ◽

10.1186/s12920-021-01090-y ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Xingyu Zhang ◽

Bo Wang ◽

Guoling You ◽

Ying Xiang ◽

Qihua Fu ◽

...

Keyword(s):

Copy Number ◽

Trisomy 21 ◽

Single Ventricle ◽

Snp Array ◽

Copy Number Variations ◽

Chinese Children ◽

Atrioventricular Canal ◽

Genome Wide ◽

Number Variation ◽

Complete Atrioventricular

Abstract Background Congenital heart disease (CHD) is one of the most common birth defects. Copy number variations (CNVs) have been proved to be important genetic factors that contribute to CHD. Here we screened genome-wide CNVs in Chinese children with complete atrioventricular canal (CAVC) and single ventricle (SV), since there were scarce researches dedicated to these two types of CHD. Methods We screened CNVs in 262 sporadic CAVC cases and 259 sporadic SV cases respectively, using a customized SNP array. The detected CNVs were annotated and filtered using available databases. Results Among 262 CAVC patients, we identified 6 potentially-causative CNVs in 43 individuals (16.41%, 43/262), including 2 syndrome-related CNVs (7q11.23 and 8q24.3 deletion). Surprisingly, 90.70% CAVC patients with detected CNVs (39/43) were found to carry duplications of 21q11.2–21q22.3, which were recognized as trisomy 21 (Down syndrome, DS). In CAVC with DS patients, the female to male ratio was 1.6:1.0 (24:15), and the rate of pulmonary hypertension (PH) was 41.03% (16/39). Additionally, 6 potentially-causative CNVs were identified in the SV patients (2.32%, 6/259), and none of them was trisomy 21. Most CNVs identified in our cohort were classified as rare (< 1%), occurring just once among CAVC or SV individuals except the 21q11.2–21q22.3 duplication (14.89%) in CAVC cohort. Conclusions Our study identified 12 potentially-causative CNVs in 262 CAVC and 259 SV patients, representing the largest cohort of these two CHD types in Chinese population. The results provided strong correlation between CAVC and DS, which also showed sex difference and high incidence of PH. The presence of potentially-causative CNVs suggests the etiology of complex CHD is incredibly diverse, and CHD candidate genes remain to be discovered.

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Rapid Diagnosis of Imprinting Disorders Involving Copy Number Variation and Uniparental Disomy Using Genome-Wide SNP Microarrays

Cytogenetic and Genome Research ◽

10.1159/000435847 ◽

2015 ◽

Vol 146 (1) ◽

pp. 9-18 ◽

Cited By ~ 10

Author(s):

Weiqiang Liu ◽

Rui Zhang ◽

Jun Wei ◽

Huimin Zhang ◽

Guojiu Yu ◽

...

Keyword(s):

Copy Number ◽

Snp Array ◽

Uniparental Disomy ◽

Copy Number Variations ◽

Chromosomal Microarray ◽

Chromosomal Microarray Analysis ◽

Imprinting Disorders ◽

Genome Wide ◽

Number Variation ◽

Efficient Alternative

Imprinting disorders, such as Beckwith-Wiedemann syndrome (BWS), Prader-Willi syndrome (PWS) and Angelman syndrome (AS), can be detected via methylation analysis, methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA), or other methods. In this study, we applied single nucleotide polymorphism (SNP)-based chromosomal microarray analysis to detect copy number variations (CNVs) and uniparental disomy (UPD) events in patients with suspected imprinting disorders. Of 4 patients, 2 had a 5.25-Mb microdeletion in the 15q11.2q13.2 region, 1 had a 38.4-Mb mosaic UPD in the 11p15.4 region, and 1 had a 60-Mb detectable UPD between regions 14q13.2 and 14q32.13. Although the 14q32.2 region was classified as normal by SNP array for the 14q13 UPD patient, it turned out to be a heterodisomic UPD by short tandem repeat marker analysis. MS-MLPA analysis was performed to validate the variations. In conclusion, SNP-based microarray is an efficient alternative method for quickly and precisely diagnosing PWS, AS, BWS, and other imprinted gene-associated disorders when considering aberrations due to CNVs and most types of UPD.

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Copy Number Variation of UGT 2B Genes in Indian Families Using Whole Genome Scans

Journal of Nucleic Acids ◽

10.1155/2016/1648527 ◽

2016 ◽

Vol 2016 ◽

pp. 1-7

Author(s):

Avinash M. Veerappa ◽

Prakash Padakannaya ◽

Nallur B. Ramachandra

Keyword(s):

Copy Number ◽

Gene Deletion ◽

Indian Population ◽

Snp Array ◽

Copy Number Variations ◽

Genome Scans ◽

Genome Wide ◽

Disease Associations ◽

Number Variation

Background and Objectives. Uridine diphospho-glucuronosyltransferase 2B (UGT2B) is a family of genes involved in metabolizing steroid hormones and several other xenobiotics. These UGT2B genes are highly polymorphic in nature and have distinct polymorphisms associated with specific regions around the globe. Copy number variations (CNVs) status of UGT2B17 in Indian population is not known and their disease associations have been inconclusive. It was therefore of interest to investigate the CNV profile of UGT2B genes.Methods. We investigated the presence of CNVs in UGT2B genes in 31 members from eight Indian families using Affymetrix Genome-Wide Human SNP Array 6.0 chip.Results. Our data revealed >50% of the study members carried CNVs in UGT2B genes, of which 76% showed deletion polymorphism. CNVs were observed more in UGT2B17 (76.4%) than in UGT2B15 (17.6%). Molecular network and pathway analysis found enrichment related to steroid metabolic process, carboxylesterase activity, and sequence specific DNA binding.Interpretation and Conclusion. We report the presence of UGT2B gene deletion and duplication polymorphisms in Indian families. Network analysis indicates the substitutive role of other possible genes in the UGT activity. The CNVs of UGT2B genes are very common in individuals indicating that the effect is neutral in causing any suspected diseases.

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Impact of copy number variations burden on coding genome in humans using integrated high resolution arrays

Genetics Research ◽

10.1017/s0016672314000202 ◽

2014 ◽

Vol 96 ◽

Cited By ~ 2

Author(s):

AVINASH M. VEERAPPA ◽

KUSUMA LINGAIAH ◽

SANGEETHA VISHWESWARAIAH ◽

MEGHA N. MURTHY ◽

RAVIRAJ V. SURESH ◽

...

Keyword(s):

Copy Number ◽

Protein Complexes ◽

Snp Array ◽

Copy Number Variations ◽

Single Individual ◽

Coding Region ◽

Genome Wide ◽

Phenotypic Variations ◽

And Function ◽

Relationship Of

SummaryCopy number variations (CNVs) alter the transcriptional and translational levels of genes by disrupting the coding structure and this burden of CNVs seems to be a significant contributor to phenotypic variations. Therefore it was necessary to assess the complexities of CNV burden on the coding genome. A total of 1715 individuals from 12 populations were used for CNV analysis in the present investigation. Analysis was performed using Affymetrix Genome-Wide Human SNP Array 6·0 chip and CytoScan High-Density arrays. CNVs were more frequently observed in the coding region than in the non-coding region. CNVs were observed vastly more frequently in the coding region than the non-coding region. CNVs were found to be enriched in the regions containing functional genes (83–96%) compared with the regions containing pseudogenes (4–17%). CNVs across the genome of an individual showed multiple hits across many genes, whose proteins interact physically and function under the same pathway. We identified varying numbers of proteins and degrees of interactions within protein complexes of single individual genomes. This study represents the first draft of a population-specific CNV genes map as well as a cross-populational map. The complex relationship of CNVs on genes and their physically interacting partners unravels many complexities involved in phenotype expression. This study identifies four mechanisms contributing to the complexities caused by the presence of multiple CNVs across many genes in the coding part of the genome.

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Genome-Wide Analysis of Copy Number Variations in Normal Population Identified by SNP Arrays

The Open Biology Journal ◽

10.2174/1874196700902010054 ◽

2009 ◽

Vol 2 (1) ◽

pp. 54-65 ◽

Cited By ~ 2

Author(s):

Jian Wang ◽

Tsz-Kwong Man ◽

Kwong Kwok Wong ◽

Pulivarthi H. Rao ◽

Hon-Chiu Eastwood Leung ◽

...

Keyword(s):

Copy Number Variation ◽

Human Genome ◽

Copy Number ◽

Repetitive Sequences ◽

Snp Array ◽

Copy Number Variations ◽

Gene Copy ◽

Chemical Stimulus ◽

Genome Wide ◽

Number Variation

Gene copy number change is an essential characteristic of many types of cancer. However, it is important to distinguish copy number variation (CNV) in the human genome of normal individuals from bona fide abnormal copy number changes of genes specific to cancers. Based on Affymetrix 50K single nucleotide polymorphism (SNP) array data, we identified genome-wide copy number variations among 104 normal subjects from three ethnic groups that were used in the HapMap project. Our analysis revealed 155 CNV regions, of which 37% were gains and 63% were losses. About 21% (30) of the CNV regions are concordant with earlier reports. These 155 CNV regions are located on more than 100 cytobands across all 23 chromosomes. The CNVs range from 68bp to 18 Mb in length, with a median length of 86 Kb. Eight CNV regions were selected for validation by quantitative PCR. Analysis of genomic sequences within and adjacent to CNVs suggests that repetitive sequences such as long interspersed nuclear elements (LINEs) and long terminal repeats (LTRs) may play a role in the origin of CNVs by facilitating non-allelic homologous recombination. Thirty-two percent of the CNVs identified in this study are associated with segmental duplications. CNVs were not preferentially enriched in gene-encoding regions. Among the 364 genes that are completely encompassed by these 155 CNVs, genes related to olfactory sensory, chemical stimulus, and other physiological responses are significantly enriched. A statistical analysis of CNVs by ethnic group revealed distinct patterns regarding the CNV location and gain-to-loss ratio. The CNVs reported here will help build a more comprehensive map of genomic variations in the human genome and facilitate the differentiation between copy number variation and somatic changes in cancers. The potential roles of certain repeat elements in CNV formation, as corroborated by other studies, shed light on the origin of CNVs and will improve our understanding of the mechanisms of genomic rearrangements in the human genome.

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Combination of Genome-Wide Polymorphisms and Copy Number Variations of Pharmacogenes in Koreans

Journal of Personalized Medicine ◽

10.3390/jpm11010033 ◽

2021 ◽

Vol 11 (1) ◽

pp. 33

Author(s):

Nayoung Han ◽

Jung Mi Oh ◽

In-Wha Kim

Keyword(s):

Copy Number ◽

Genome Wide Association Study ◽

Copy Number Gain ◽

Copy Number Variations ◽

Gene Gain ◽

Single Nucleotide Variants ◽

Single Nucleotide ◽

Haplotype Blocks ◽

Genome Wide ◽

Control And Prevention

For predicting phenotypes and executing precision medicine, combination analysis of single nucleotide variants (SNVs) genotyping with copy number variations (CNVs) is required. The aim of this study was to discover SNVs or common copy CNVs and examine the combined frequencies of SNVs and CNVs in pharmacogenes using the Korean genome and epidemiology study (KoGES), a consortium project. The genotypes (N = 72,299) and CNV data (N = 1000) were provided by the Korean National Institute of Health, Korea Centers for Disease Control and Prevention. The allele frequencies of SNVs, CNVs, and combined SNVs with CNVs were calculated and haplotype analysis was performed. CYP2D6 rs1065852 (c.100C>T, p.P34S) was the most common variant allele (48.23%). A total of 8454 haplotype blocks in 18 pharmacogenes were estimated. DMD ranked the highest in frequency for gene gain (64.52%), while TPMT ranked the highest in frequency for gene loss (51.80%). Copy number gain of CYP4F2 was observed in 22 subjects; 13 of those subjects were carriers with CYP4F2*3 gain. In the case of TPMT, approximately one-half of the participants (N = 308) had loss of the TPMT*1*1 diplotype. The frequencies of SNVs and CNVs in pharmacogenes were determined using the Korean cohort-based genome-wide association study.

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Genome-wide copy number variations as molecular diagnostic tool for cutaneous intermediate melanocytic lesions: a systematic review and individual patient data meta-analysis

Virchows Archiv ◽

10.1007/s00428-021-03095-5 ◽

2021 ◽

Author(s):

Chiel F. Ebbelaar ◽

Anne M. L. Jansen ◽

Lourens T. Bloem ◽

Willeke A. M. Blokx

Keyword(s):

Systematic Review ◽

Sensitivity And Specificity ◽

Copy Number ◽

Individual Patient Data ◽

Meta Analysis ◽

Copy Number Variations ◽

Patient Data ◽

Melanocytic Lesions ◽

Genome Wide ◽

Malignant Lesions

AbstractCutaneous intermediate melanocytic neoplasms with ambiguous histopathological features are diagnostically challenging. Ancillary cytogenetic techniques to detect genome-wide copy number variations (CNVs) might provide a valuable tool to allow accurate classification as benign (nevus) or malignant (melanoma). However, the CNV cut-off value to distinguish intermediate lesions from melanoma is not well defined. We performed a systematic review and individual patient data meta-analysis to evaluate the use of CNVs to classify intermediate melanocytic lesions. A total of 31 studies and 431 individual lesions were included. The CNV number in intermediate lesions (median 1, interquartile range [IQR] 0–2) was significantly higher (p<0.001) compared to that in benign lesions (median 0, IQR 0–1) and lower (p<0.001) compared to that in malignant lesions (median 6, IQR 4–11). The CNV number displayed excellent ability to differentiate between intermediate and malignant lesions (0.90, 95% CI 0.86–0.94, p<0.001). Two CNV cut-off points demonstrated a sensitivity and specificity higher than 80%. A cut-off of ≥3 CNVs corresponded to 85% sensitivity and 84% specificity, and a cut-off of ≥4 CNVs corresponded to 81% sensitivity and 91% specificity, respectively. This individual patient data meta-analysis provides a comprehensive overview of CNVs in cutaneous intermediate melanocytic lesions, based on the largest pooled cohort of ambiguous melanocytic neoplasms to date. Our meta-analysis suggests that a cut-off of ≥3 CNVs might represent the optimal trade-off between sensitivity and specificity in clinical practice to differentiate intermediate lesions from melanoma.

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