@article {782, title = {CNVs cause autosomal recessive genetic diseases with or without involvement of SNV/indels.}, journal = {Genet Med}, volume = {22}, year = {2020}, month = {2020 10}, pages = {1633-1641}, abstract = {

PURPOSE: Improved resolution of molecular diagnostic technologies enabled detection of smaller sized exonic level copy-number variants (CNVs). The contribution of CNVs to autosomal recessive (AR) conditions may be better recognized using a large clinical cohort.

METHODS: We retrospectively investigated the CNVs{\textquoteright} contribution to AR conditions in cases subjected to chromosomal microarray analysis (CMA, N = ~70,000) and/or clinical exome sequencing (ES, N = ~12,000) at Baylor Genetics; most had pediatric onset neurodevelopmental disorders.

RESULTS: CNVs contributed to biallelic variations in 87 cases, including 81 singletons and three affected sibling pairs. Seventy cases had CNVs affecting both alleles, and 17 had a CNV and a single-nucleotide variant (SNV)/indel in trans. In total, 94.3\% of AR-CNVs affected one gene; among these 41.4\% were single-exon and 35.0\% were multiexon partial-gene events. Sixty-nine percent of homozygous AR-CNVs were embedded in homozygous genomic intervals. Five cases had large deletions unmasking an SNV/indel on the intact allele for a recessive condition, resulting in multiple molecular diagnoses.

CONCLUSIONS: AR-CNVs are often smaller in size, transmitted through generations, and underrecognized due to limitations in clinical CNV detection methods. Our findings from a large clinical cohort emphasized integrated CNV and SNV/indel analyses for precise clinical and molecular diagnosis especially in the context of genomic disorders.

}, keywords = {Child, DNA Copy Number Variations, Exons, Humans, INDEL Mutation, Retrospective Studies, Whole Exome Sequencing}, issn = {1530-0366}, doi = {10.1038/s41436-020-0864-8}, author = {Yuan, Bo and Wang, Lei and Liu, Pengfei and Shaw, Chad and Dai, Hongzheng and Cooper, Lance and Zhu, Wenmiao and Anderson, Stephanie A and Meng, Linyan and Wang, Xia and Wang, Yue and Xia, Fan and Xiao, Rui and Braxton, Alicia and Peacock, Sandra and Schmitt, Eric and Ward, Patricia A and Vetrini, Francesco and He, Weimin and Chiang, Theodore and Muzny, Donna and Gibbs, Richard A and Beaudet, Arthur L and Breman, Amy M and Smith, Janice and Cheung, Sau Wai and Bacino, Carlos A and Eng, Christine M and Yang, Yaping and Lupski, James R and Bi, Weimin} } @article {526, title = {The coexistence of copy number variations (CNVs) and single nucleotide polymorphisms (SNPs) at a locus can result in distorted calculations of the significance in associating SNPs to disease.}, journal = {Hum Genet}, volume = {137}, year = {2018}, month = {2018 Jul}, pages = {553-567}, abstract = {

With the recent advance in genome-wide association studies (GWAS), disease-associated single nucleotide polymorphisms (SNPs) and copy number variants (CNVs) have been extensively reported. Accordingly, the issue of incorrect identification of recombination events that can induce the distortion of multi-allelic or hemizygous variants has received more attention. However, the potential distorted calculation bias or significance of a detected association in a GWAS due to the coexistence of CNVs and SNPs in the same genomic region may remain under-recognized. Here we performed the association study within a congenital scoliosis (CS) cohort whose genetic etiology was recently elucidated as a compound inheritance model, including mostly one rare variant deletion CNV null allele and one common variant non-coding hypomorphic haplotype of the TBX6 gene. We demonstrated that the existence of a deletion in TBX6 led to an overestimation of the contribution of the SNPs on the hypomorphic allele. Furthermore, we generalized a model to explain the calculation bias, or distorted significance calculation for an association study, that can be {\textquoteright}induced{\textquoteright} by CNVs at a locus. Meanwhile, overlapping between the disease-associated SNPs from published GWAS and common CNVs (overlap 10\%) and pathogenic/likely pathogenic CNVs (overlap 99.69\%) was significantly higher than the random distribution (p < 1 {\texttimes} 10 and p = 0.034, respectively), indicating that such co-existence of CNV and SNV alleles might generally influence data interpretation and potential outcomes of a GWAS. We also verified and assessed the influence of colocalizing CNVs to the detection sensitivity of disease-associated SNP variant alleles in another adolescent idiopathic scoliosis (AIS) genome-wide association study. We proposed that detecting co-existent CNVs when evaluating the association signals between SNPs and disease traits could improve genetic model analyses and better integrate GWAS with robust Mendelian principles.

}, keywords = {Adolescent, Congenital Abnormalities, DNA Copy Number Variations, Female, Genetic Predisposition to Disease, Genome, Human, Genome-Wide Association Study, Genomics, Genotype, Haplotypes, Humans, Phenotype, Polymorphism, Single Nucleotide, Scoliosis}, issn = {1432-1203}, doi = {10.1007/s00439-018-1910-3}, author = {Liu, Jiaqi and Zhou, Yangzhong and Liu, Sen and Song, Xiaofei and Yang, Xin-Zhuang and Fan, Yanhui and Chen, Weisheng and Akdemir, Zeynep Coban and Yan, Zihui and Zuo, Yuzhi and Du, Renqian and Liu, Zhenlei and Yuan, Bo and Zhao, Sen and Liu, Gang and Chen, Yixin and Zhao, Yanxue and Lin, Mao and Zhu, Qiankun and Niu, Yuchen and Liu, Pengfei and Ikegawa, Shiro and Song, You-Qiang and Posey, Jennifer E and Qiu, Guixing and Zhang, Feng and Wu, Zhihong and Lupski, James R and Wu, Nan} } @article {376, title = {Identification of novel candidate disease genes from de novo exonic copy number variants.}, journal = {Genome Med}, volume = {9}, year = {2017}, month = {2017 09 21}, pages = {83}, abstract = {

BACKGROUND: Exon-targeted microarrays can detect small (<1000~bp) intragenic copy number variants (CNVs), including those that affect only a single exon. This genome-wide high-sensitivity approach increases the molecular diagnosis for conditions with known disease-associated genes, enables better genotype-phenotype correlations, and facilitates variant allele detection allowing novel disease gene discovery.

METHODS: We retrospectively analyzed data from 63,127 patients referred for clinical chromosomal microarray analysis (CMA) at Baylor Genetics laboratories, including 46,755 individuals tested using exon-targeted arrays, from 2007 to 2017. Small CNVs harboring a single gene or two to five non-disease-associated genes were identified; the genes involved were evaluated for a potential disease association.

RESULTS: In this clinical population, among rare CNVs involving any single gene reported in 7200 patients (11\%), we identified 145 de novo autosomal CNVs (117 losses and 28 intragenic gains), 257 X-linked deletion CNVs in males, and 1049 inherited autosomal CNVs (878 losses and 171 intragenic gains); 111 known disease genes were potentially disrupted by de novo autosomal or X-linked (in males) single-gene CNVs. Ninety-one genes, either recently proposed as candidate disease genes or not yet associated with diseases, were disrupted by 147 single-gene CNVs, including 37 de novo deletions and ten de novo intragenic duplications on autosomes and 100 X-linked CNVs in males. Clinical features in individuals with de novo or X-linked CNVs encompassing at most five genes (224~bp to 1.6~Mb in size) were compared to those in individuals with larger-sized deletions (up to 5~Mb in size) in the internal CMA database or loss-of-function single nucleotide variants (SNVs) detected by clinical or research whole-exome sequencing (WES). This enabled the identification of recently published genes (BPTF, NONO, PSMD12, TANGO2, and TRIP12), novel candidate disease genes (ARGLU1 and STK3), and further confirmation of disease association for two recently proposed disease genes (MEIS2 and PTCHD1). Notably, exon-targeted CMA detected several pathogenic single-exon CNVs missed by clinical WES analyses.

CONCLUSIONS: Together, these data document the efficacy of exon-targeted CMA for detection of genic and exonic CNVs, complementing and extending WES in clinical diagnostics, and the potential for discovery of novel disease genes by genome-wide assay.

}, keywords = {Cohort Studies, DNA Copy Number Variations, Exons, Genetic Diseases, Inborn, Genome, Human, Homeodomain Proteins, Humans, Intracellular Signaling Peptides and Proteins, Membrane Proteins, Neurodevelopmental Disorders, Protein-Serine-Threonine Kinases, Retrospective Studies, Transcription Factors, Whole Genome Sequencing}, issn = {1756-994X}, doi = {10.1186/s13073-017-0472-7}, author = {Gambin, Tomasz and Yuan, Bo and Bi, Weimin and Liu, Pengfei and Rosenfeld, Jill A and Coban-Akdemir, Zeynep and Pursley, Amber N and Nagamani, Sandesh C S and Marom, Ronit and Golla, Sailaja and Dengle, Lauren and Petrie, Heather G and Matalon, Reuben and Emrick, Lisa and Proud, Monica B and Treadwell-Deering, Diane and Chao, Hsiao-Tuan and Koillinen, Hannele and Brown, Chester and Urraca, Nora and Mostafavi, Roya and Bernes, Saunder and Roeder, Elizabeth R and Nugent, Kimberly M and Bader, Patricia I and Bellus, Gary and Cummings, Michael and Northrup, Hope and Ashfaq, Myla and Westman, Rachel and Wildin, Robert and Beck, Anita E and Immken, LaDonna and Elton, Lindsay and Varghese, Shaun and Buchanan, Edward and Faivre, Laurence and Lefebvre, Mathilde and Schaaf, Christian P and Walkiewicz, Magdalena and Yang, Yaping and Kang, Sung-Hae L and Lalani, Seema R and Bacino, Carlos A and Beaudet, Arthur L and Breman, Amy M and Smith, Janice L and Cheung, Sau Wai and Lupski, James R and Patel, Ankita and Shaw, Chad A and Stankiewicz, Pawe{\l}} } @article {357, title = {Lessons learned from additional research analyses of unsolved clinical exome cases.}, journal = {Genome Med}, volume = {9}, year = {2017}, month = {2017 03 21}, pages = {26}, abstract = {

BACKGROUND: Given the rarity of most single-gene Mendelian disorders, concerted efforts of data exchange between clinical and scientific communities are critical to optimize molecular diagnosis and novel disease gene discovery.

METHODS: We designed and implemented protocols for the study of cases for which a plausible molecular diagnosis was not achieved in a clinical genomics diagnostic laboratory (i.e. unsolved clinical exomes). Such cases were recruited to a research laboratory for further analyses, in order to potentially: (1) accelerate novel disease gene discovery; (2) increase the molecular diagnostic yield of whole exome sequencing (WES); and (3) gain insight into the genetic mechanisms of disease. Pilot project data included 74 families, consisting mostly of parent-offspring trios. Analyses performed on a research basis employed both WES from additional family members and complementary bioinformatics approaches and protocols.

RESULTS: Analysis of all possible modes of Mendelian inheritance, focusing on both single nucleotide variants (SNV) and copy number variant (CNV) alleles, yielded a likely contributory variant in 36\% (27/74) of cases. If one includes candidate genes with variants identified within a single family, a potential contributory variant was identified in a total of ~51\% (38/74) of cases enrolled in this pilot study. The molecular diagnosis was achieved in 30/63 trios (47.6\%). Besides this, the analysis workflow yielded evidence for pathogenic variants in disease-associated genes in 4/6 singleton cases (66.6\%), 1/1 multiplex family involving three affected siblings, and 3/4 (75\%) quartet families. Both the analytical pipeline and the collaborative efforts between the diagnostic and research laboratories provided insights that allowed recent disease gene discoveries (PURA, TANGO2, EMC1, GNB5, ATAD3A, and MIPEP) and increased the number of novel genes, defined in this study as genes identified in more than one family (DHX30 and EBF3).

CONCLUSION: An efficient genomics pipeline in which clinical sequencing in a diagnostic laboratory is followed by the detailed reanalysis of unsolved cases in a research environment, supplemented with WES data from additional family members, and subject to adjuvant bioinformatics analyses including relaxed variant filtering parameters in informatics pipelines, can enhance the molecular diagnostic yield and provide mechanistic insights into Mendelian disorders. Implementing these approaches requires collaborative clinical molecular diagnostic and research efforts.

}, keywords = {Adenosine Triphosphatases, ATPases Associated with Diverse Cellular Activities, Computational Biology, DNA Copy Number Variations, DNA-Binding Proteins, Exome, Female, Genetic Diseases, Inborn, Genomics, GTP-Binding Protein beta Subunits, Humans, Male, Membrane Proteins, Metalloendopeptidases, Mitochondrial Proteins, Pilot Projects, Polymorphism, Single Nucleotide, Sequence Analysis, DNA, Transcription Factors}, issn = {1756-994X}, doi = {10.1186/s13073-017-0412-6}, author = {Eldomery, Mohammad K and Coban-Akdemir, Zeynep and Harel, Tamar and Rosenfeld, Jill A and Gambin, Tomasz and Stray-Pedersen, Asbj{\o}rg and K{\"u}ry, S{\'e}bastien and Mercier, Sandra and Lessel, Davor and Denecke, Jonas and Wiszniewski, Wojciech and Penney, Samantha and Liu, Pengfei and Bi, Weimin and Lalani, Seema R and Schaaf, Christian P and Wangler, Michael F and Bacino, Carlos A and Lewis, Richard Alan and Potocki, Lorraine and Graham, Brett H and Belmont, John W and Scaglia, Fernando and Orange, Jordan S and Jhangiani, Shalini N and Chiang, Theodore and Doddapaneni, Harsha and Hu, Jianhong and Muzny, Donna M and Xia, Fan and Beaudet, Arthur L and Boerwinkle, Eric and Eng, Christine M and Plon, Sharon E and Sutton, V Reid and Gibbs, Richard A and Posey, Jennifer E and Yang, Yaping and Lupski, James R} } @article {348, title = {An Organismal CNV Mutator Phenotype Restricted to Early Human Development.}, journal = {Cell}, volume = {168}, year = {2017}, month = {2017 02 23}, pages = {830-842.e7}, abstract = {

De novo copy number variants (dnCNVs) arising at~multiple loci in a personal genome have usually been considered to reflect cancer somatic genomic instabilities. We describe a multiple dnCNV (MdnCNV) phenomenon in which individuals with genomic disorders carry five to ten constitutional dnCNVs. These CNVs originate from independent formation incidences, are predominantly tandem duplications or complex gains, exhibit breakpoint junction features reminiscent of replicative repair, and show increased de novo point mutations flanking the rearrangement junctions. The active CNV mutation shower appears to be restricted to a transient perizygotic period. We~propose that a defect in the CNV formation process is responsible for the "CNV-mutator state," and this state is dampened after early embryogenesis. The constitutional MdnCNV phenomenon resembles chromosomal instability in various cancers. Investigations of this phenomenon may provide unique access to understanding genomic disorders, structural variant mutagenesis, human evolution, and cancer biology.

}, keywords = {Chromosome Aberrations, Chromosome Breakpoints, Chromosome Duplication, DNA Copy Number Variations, DNA Replication, Embryonic Development, Female, Gametogenesis, Genetic Diseases, Inborn, Genomic Instability, Humans, Male, Mutation}, issn = {1097-4172}, doi = {10.1016/j.cell.2017.01.037}, author = {Liu, Pengfei and Yuan, Bo and Carvalho, Claudia M B and Wuster, Arthur and Walter, Klaudia and Zhang, Ling and Gambin, Tomasz and Chong, Zechen and Campbell, Ian M and Coban Akdemir, Zeynep and Gelowani, Violet and Writzl, Karin and Bacino, Carlos A and Lindsay, Sarah J and Withers, Marjorie and Gonzaga-Jauregui, Claudia and Wiszniewska, Joanna and Scull, Jennifer and Stankiewicz, Pawe{\l} and Jhangiani, Shalini N and Muzny, Donna M and Zhang, Feng and Chen, Ken and Gibbs, Richard A and Rautenstrauss, Bernd and Cheung, Sau Wai and Smith, Janice and Breman, Amy and Shaw, Chad A and Patel, Ankita and Hurles, Matthew E and Lupski, James R} } @article {30, title = {Copy-Number Variation Contributes to the Mutational Load of Bardet-Biedl Syndrome.}, journal = {Am J Hum Genet}, volume = {99}, year = {2016}, month = {2016 Aug 04}, pages = {318-36}, abstract = {

Bardet-Biedl syndrome (BBS) is a defining ciliopathy, notable for extensive allelic and genetic heterogeneity, almost all of which has been identified through sequencing. Recent data have suggested that copy-number variants (CNVs) also contribute to BBS. We used a custom oligonucleotide array comparative genomic hybridization (aCGH) covering 20 genes that encode intraflagellar transport (IFT) components and 74 ciliopathy loci to screen 92 unrelated individuals with BBS, irrespective of their known mutational burden. We identified 17 individuals with exon-disruptive CNVs (18.5\%), including 13 different deletions in eight BBS genes (BBS1, BBS2, ARL6/BBS3, BBS4, BBS5, BBS7, BBS9, and NPHP1) and a deletion and a duplication in other ciliopathy-associated genes (ALMS1 and NPHP4, respectively). By contrast, we found a single heterozygous exon-disruptive event in a BBS-associated gene (BBS9) in 229 control subjects. Superimposing these data with resequencing revealed CNVs to (1) be sufficient to cause disease, (2) Mendelize heterozygous deleterious alleles, and (3) contribute oligogenic alleles by combining point mutations and exonic CNVs in multiple genes. Finally, we report a deletion and a splice site mutation in IFT74, inherited under a recessive paradigm, defining a candidate BBS locus. Our data suggest that CNVs contribute pathogenic alleles to a substantial fraction of BBS-affected individuals and highlight how either deletions or point mutations in discrete splice isoforms can induce hypomorphic mutations in genes otherwise intolerant to deleterious variation. Our data also suggest that CNV analyses and resequencing studies unbiased for previous mutational burden is necessary to delineate the complexity of disease architecture.

}, keywords = {Adolescent, Adult, Alleles, Animals, Bardet-Biedl Syndrome, Child, Child, Preschool, Chromosome Breakpoints, Cytoskeletal Proteins, DNA Copy Number Variations, Exons, Female, Gastrulation, Genes, Recessive, Humans, Infant, Male, Mutation, Pedigree, Young Adult, Zebrafish, Zebrafish Proteins}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2015.04.023}, author = {Lindstrand, Anna and Frangakis, Stephan and Carvalho, Claudia M B and Richardson, Ellen B and McFadden, Kelsey A and Willer, Jason R and Pehlivan, Davut and Liu, Pengfei and Pediaditakis, Igor L and Sabo, Aniko and Lewis, Richard Alan and Banin, Eyal and Lupski, James R and Davis, Erica E and Katsanis, Nicholas} } @article {41, title = {Nonrecurrent PMP22-RAI1 contiguous gene deletions arise from replication-based mechanisms and result in Smith-Magenis syndrome with evident peripheral neuropathy.}, journal = {Hum Genet}, volume = {135}, year = {2016}, month = {2016 Oct}, pages = {1161-74}, abstract = {

Hereditary neuropathy with liability to pressure palsies (HNPP) and Smith-Magenis syndrome (SMS) are genomic disorders associated with deletion copy number variants involving chromosome 17p12 and 17p11.2, respectively. Nonallelic homologous recombination (NAHR)-mediated recurrent deletions are responsible for the majority of HNPP and SMS cases; the rearrangement products encompass the key dosage-sensitive genes PMP22 and RAI1, respectively, and result in haploinsufficiency for these genes. Less frequently, nonrecurrent genomic rearrangements occur at this locus. Contiguous gene duplications encompassing both PMP22 and RAI1, i.e., PMP22-RAI1 duplications, have been investigated, and replication-based mechanisms rather than NAHR have been proposed for these rearrangements. In the current study, we report molecular and clinical characterizations of six subjects with the reciprocal phenomenon of deletions spanning both genes, i.e., PMP22-RAI1 deletions. Molecular studies utilizing high-resolution array comparative genomic hybridization and breakpoint junction sequencing identified mutational signatures that were suggestive of replication-based mechanisms. Systematic clinical studies revealed features consistent with SMS, including features of intellectual disability, speech and gross motor delays, behavioral problems and ocular abnormalities. Five out of six subjects presented clinical signs and/or objective electrophysiologic studies of peripheral neuropathy. Clinical profiling may improve the clinical management of this unique group of subjects, as the peripheral neuropathy can be more severe or of earlier onset as compared to SMS patients having the common recurrent deletion. Moreover, the current study, in combination with the previous report of PMP22-RAI1 duplications, contributes to the understanding of rare complex phenotypes involving multiple dosage-sensitive genes from a genetic mechanistic standpoint.

}, keywords = {Adolescent, Adult, Child, Child, Preschool, Chromosomes, Human, Pair 17, DNA Copy Number Variations, DNA Replication, Female, Gene Deletion, Haploinsufficiency, Homologous Recombination, Humans, Intellectual Disability, Male, Mutation, Myelin Proteins, Smith-Magenis Syndrome, Trans-Activators, Transcription Factors}, issn = {1432-1203}, doi = {10.1007/s00439-016-1703-5}, author = {Yuan, Bo and Neira, Juanita and Gu, Shen and Harel, Tamar and Liu, Pengfei and Brice{\~n}o, Ignacio and Elsea, Sarah H and G{\'o}mez, Alberto and Potocki, Lorraine and Lupski, James R} } @article {185, title = {Absence of heterozygosity due to template switching during replicative rearrangements.}, journal = {Am J Hum Genet}, volume = {96}, year = {2015}, month = {2015 Apr 02}, pages = {555-64}, abstract = {

We investigated complex genomic rearrangements (CGRs) consisting of triplication copy-number variants (CNVs) that were accompanied by extended regions of copy-number-neutral absence of heterozygosity (AOH) in subjects with multiple congenital abnormalities. Molecular analyses provided observational evidence that in humans, post-zygotically generated CGRs can lead to regional uniparental disomy (UPD) due to template switches between homologs versus sister chromatids by using microhomology to prime DNA replication-a prediction of the replicative repair model, MMBIR. Our findings suggest that replication-based mechanisms might underlie the formation of diverse types of genomic alterations (CGRs and AOH) implicated in constitutional disorders.

}, keywords = {Base Sequence, DNA Copy Number Variations, DNA Repair, DNA Replication, Gene Rearrangement, Humans, In Situ Hybridization, Fluorescence, Loss of Heterozygosity, Models, Genetic, Molecular Sequence Data, Netherlands, Polymerase Chain Reaction, Polymorphism, Single Nucleotide, Sequence Analysis, DNA, Uniparental Disomy}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2015.01.021}, author = {Carvalho, Claudia M B and Pfundt, Rolph and King, Daniel A and Lindsay, Sarah J and Zuccherato, Luciana W and Macville, Merryn V E and Liu, Pengfei and Johnson, Diana and Stankiewicz, Pawel and Brown, Chester W and Shaw, Chad A and Hurles, Matthew E and Ira, Grzegorz and Hastings, P J and Brunner, Han G and Lupski, James R} }