@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 {515, title = {Clinical exome sequencing reveals locus heterogeneity and phenotypic variability of cohesinopathies.}, journal = {Genet Med}, volume = {21}, year = {2019}, month = {2019 03}, pages = {663-675}, abstract = {

PURPOSE: Defects in the cohesin pathway are associated with cohesinopathies, notably Cornelia de Lange syndrome (CdLS). We aimed to delineate pathogenic variants~in known and candidate cohesinopathy genes from a clinical exome perspective.

METHODS: We retrospectively studied patients referred for clinical exome sequencing (CES, N = 10,698). Patients with causative variants in novel or recently described cohesinopathy genes were enrolled for phenotypic characterization.

RESULTS: Pathogenic or likely pathogenic single-nucleotide and insertion/deletion variants (SNVs/indels) were identified in established disease genes including NIPBL (N = 5), SMC1A (N = 14), SMC3 (N = 4), RAD21 (N = 2), and HDAC8 (N = 8). The phenotypes in this genetically defined cohort skew towards the mild end of CdLS spectrum as compared with phenotype-driven cohorts. Candidate or recently reported cohesinopathy genes were supported by de novo SNVs/indels in STAG1 (N = 3), STAG2 (N = 5), PDS5A (N = 1), and WAPL (N = 1), and one inherited SNV in PDS5A. We also identified copy-number deletions affecting STAG1 (two de novo, one of unknown inheritance) and STAG2 (one of unknown inheritance). Patients with STAG1 and STAG2 variants presented with overlapping features yet without characteristic facial features of CdLS.

CONCLUSION: CES effectively identified disease-causing alleles at the mild end of the cohensinopathy spectrum and enabled characterization of candidate disease genes.

}, keywords = {Adolescent, Alleles, Antigens, Nuclear, Biological Variation, Population, Carrier Proteins, Cell Cycle Proteins, Child, Child, Preschool, Chromosomal Proteins, Non-Histone, Cohort Studies, De Lange Syndrome, Exome, Female, Gene Frequency, Genetic Heterogeneity, Humans, INDEL Mutation, Male, Mutation, Nuclear Proteins, Phenotype, Polymorphism, Single Nucleotide, Proto-Oncogene Proteins, Retrospective Studies, Whole Exome Sequencing}, issn = {1530-0366}, doi = {10.1038/s41436-018-0085-6}, author = {Yuan, Bo and Neira, Juanita and Pehlivan, Davut and Santiago-Sim, Teresa and Song, Xiaofei and Rosenfeld, Jill and Posey, Jennifer E and Patel, Vipulkumar and Jin, Weihong and Adam, Margaret P and Baple, Emma L and Dean, John and Fong, Chin-To and Hickey, Scott E and Hudgins, Louanne and Leon, Eyby and Madan-Khetarpal, Suneeta and Rawlins, Lettie and Rustad, Cecilie F and Stray-Pedersen, Asbj{\o}rg and Tveten, Kristian and Wenger, Olivia and Diaz, Jullianne and Jenkins, Laura and Martin, Laura and McGuire, Marianne and Pietryga, Marguerite and Ramsdell, Linda and Slattery, Leah and Abid, Farida and Bertuch, Alison A and Grange, Dorothy and Immken, LaDonna and Schaaf, Christian P and Van Esch, Hilde and Bi, Weimin and Cheung, Sau Wai and Breman, Amy M and Smith, Janice L and Shaw, Chad and Crosby, Andrew H and Eng, Christine and Yang, Yaping and Lupski, James R and Xiao, Rui and Liu, Pengfei} } @article {663, title = {Copy number variant and runs of homozygosity detection by microarrays enabled more precise molecular diagnoses in 11,020 clinical exome cases.}, journal = {Genome Med}, volume = {11}, year = {2019}, month = {2019 05 17}, pages = {30}, abstract = {

BACKGROUND: Exome sequencing (ES) has been successfully applied in clinical detection of single nucleotide variants (SNVs) and small indels. However, identification of copy number variants (CNVs) using ES data remains challenging. The purpose of this study is to understand the contribution of CNVs and copy neutral runs of homozygosity (ROH) in molecular diagnosis of patients referred for ES.

METHODS: In a cohort of 11,020 consecutive ES patients, an Illumina SNP array analysis interrogating mostly coding SNPs was performed as a quality control (QC) measurement and for CNV/ROH detection. Among these patients, clinical chromosomal microarray analysis (CMA) was performed at Baylor Genetics (BG) on 3229 patients, either before, concurrently, or after ES. We retrospectively analyzed the findings from CMA and the QC array.

RESULTS: The QC array can detect ~ 70\% of pathogenic/likely pathogenic CNVs (PCNVs) detectable by CMA. Out of the 11,020 ES cases, the QC array identified PCNVs in 327 patients and uniparental disomy (UPD) disorder-related ROH in 10 patients. The overall PCNV/UPD detection rate was 5.9\% in the 3229 ES patients who also had CMA at BG; PCNV/UPD detection rate was higher in concurrent ES and CMA than in ES with prior CMA (7.2\% vs 4.6\%). The PCNVs/UPD contributed to the molecular diagnoses in 17.4\%~(189/1089) of molecularly diagnosed ES cases with CMA and~were estimated to contribute in 10.6\% of all molecularly diagnosed ES cases. Dual diagnoses with both PCNVs and SNVs were detected in 38 patients. PCNVs affecting single recessive disorder genes in a compound heterozygous state with SNVs were detected in 4 patients, and homozygous deletions~(mostly exonic deletions) were detected in 17 patients. A higher PCNV detection rate was observed for patients with syndromic phenotypes and/or cardiovascular abnormalities.

CONCLUSIONS: Our clinical genomics study demonstrates that detection of PCNV/UPD through the QC array or CMA increases ES diagnostic rate, provides more precise molecular diagnosis for dominant as well as recessive traits, and enables more complete genetic diagnoses in patients with dual or multiple molecular diagnoses. Concurrent ES and CMA using an array with exonic coverage for disease genes enables most effective detection of both CNVs and SNVs and therefore is recommended especially in time-sensitive clinical situations.

}, issn = {1756-994X}, doi = {10.1186/s13073-019-0639-5}, author = {Dharmadhikari, Avinash V and Ghosh, Rajarshi and Yuan, Bo and Liu, Pengfei and Dai, Hongzheng and Al Masri, Sami and Scull, Jennifer and Posey, Jennifer E and Jiang, Allen H and He, Weimin and Vetrini, Francesco and Braxton, Alicia A and Ward, Patricia and Chiang, Theodore and Qu, Chunjing and Gu, Shen and Shaw, Chad A and Smith, Janice L and Lalani, Seema and Stankiewicz, Pawel and Cheung, Sau-Wai and Bacino, Carlos A and Patel, Ankita and Breman, Amy M and Wang, Xia and Meng, Linyan and Xiao, Rui and Xia, Fan and Muzny, Donna and Gibbs, Richard A and Beaudet, Arthur L and Eng, Christine M and Lupski, James R and Yang, Yaping 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 {344, title = {Complex inheritance of ABCA4 disease: four mutations in a family with multiple macular phenotypes.}, journal = {Hum Genet}, volume = {135}, year = {2016}, month = {2016 Jan}, pages = {9-19}, abstract = {

Over 800 mutations in the ABCA4 gene cause autosomal recessive Stargardt disease. Due to extensive genetic heterogeneity, observed variant-associated phenotypes can manifest tremendous variability of expression. Furthermore, the high carrier frequency of pathogenic ABCA4 alleles in the general population (~1:20) often results in pseudo-dominant inheritance patterns further complicating the diagnosis and characterization of affected individuals. This study describes a genotype/phenotype analysis of an unusual family with multiple macular disease phenotypes spanning across two generations and segregating four distinct ABCA4 mutant alleles. Complete sequencing of ABCA4 discovered two known missense mutations, p.C54Y and p.G1961E. Array comparative genomic hybridization revealed a large novel deletion combined with a small insertion, c.6148-698_c.6670del/insTGTGCACCTCCCTAG, and complete sequencing of the entire ABCA4 genomic locus uncovered a new deep intronic variant, c.302+68C>T. Patients with the p.G1961E mutation had the mildest, confined maculopathy phenotype with peripheral flecks while those with all other mutant allele combinations exhibited a more advanced stage of generalized retinal and choriocapillaris atrophy. This family epitomizes the clinical and genetic complexity of ABCA4-associated diseases. It contained variants from all classes of mutations, in the coding region, deep intronic, both single nucleotide variants and copy number variants that accounted for varying phenotypes segregating in an apparent dominant fashion. Unequivocally defining disease-associated alleles in the ABCA4 locus requires a multifaceted approach that includes advanced mutation detection methods and a thorough analysis of clinical phenotypes.

}, keywords = {Adult, Aged, ATP-Binding Cassette Transporters, Comparative Genomic Hybridization, DNA Copy Number Variations, Electroretinography, Female, High-Throughput Nucleotide Sequencing, Humans, Macula Lutea, Macular Degeneration, Male, Middle Aged, Mutation, Pedigree, Phenotype}, issn = {1432-1203}, doi = {10.1007/s00439-015-1605-y}, author = {Lee, Winston and Xie, Yajing and Zernant, Jana and Yuan, Bo and Bearelly, Srilaxmi and Tsang, Stephen H and Lupski, James R and Allikmets, Rando} } @article {54, title = {Copy number analysis of the low-copy repeats at the primate NPHP1 locus by array comparative genomic hybridization.}, journal = {Genom Data}, volume = {8}, year = {2016}, month = {2016 Jun}, pages = {106-9}, abstract = {

Array comparative genomic hybridization (aCGH) has been widely used to detect copy number variants (CNVs) in both research and clinical settings. A customizable aCGH platform may greatly facilitate copy number analyses in genomic regions with higher-order complexity, such as low-copy repeats (LCRs). Here we present the aCGH analyses focusing on the 45~kb LCRs [1] at the NPHP1 region with diverse copy numbers in humans. Also, the interspecies aCGH analysis comparing human and nonhuman primates revealed dynamic copy number transitions of the human 45~kb LCR orthologues during primate evolution and therefore shed light on the origin of complexity at this locus. The original aCGH data are available at GEO under GSE73962.

}, issn = {2213-5960}, doi = {10.1016/j.gdata.2016.04.008}, author = {Yuan, Bo and Liu, Pengfei and Rogers, Jeffrey and Lupski, James R} } @article {107, title = {Comparative Genomic Analyses of the Human NPHP1 Locus Reveal Complex Genomic Architecture and Its Regional Evolution in Primates.}, journal = {PLoS Genet}, volume = {11}, year = {2015}, month = {2015 Dec}, pages = {e1005686}, abstract = {

Many loci in the human genome harbor complex genomic structures that can result in susceptibility to genomic rearrangements leading to various genomic disorders. Nephronophthisis 1 (NPHP1, MIM$\#$ 256100) is an autosomal recessive disorder that can be caused by defects of NPHP1; the gene maps within the human 2q13 region where low copy repeats (LCRs) are abundant. Loss of function of NPHP1 is responsible for approximately 85\% of the NPHP1 cases-about 80\% of such individuals carry a large recurrent homozygous NPHP1 deletion that occurs via nonallelic homologous recombination (NAHR) between two flanking directly oriented ~45 kb LCRs. Published data revealed a non-pathogenic inversion polymorphism involving the NPHP1 gene flanked by two inverted ~358 kb LCRs. Using optical mapping and array-comparative genomic hybridization, we identified three potential novel structural variant (SV) haplotypes at the NPHP1 locus that may protect a haploid genome from the NPHP1 deletion. Inter-species comparative genomic analyses among primate genomes revealed massive genomic changes during evolution. The aggregated data suggest that dynamic genomic rearrangements occurred historically within the NPHP1 locus and generated SV haplotypes observed in the human population today, which may confer differential susceptibility to genomic instability and the NPHP1 deletion within a personal genome. Our study documents diverse SV haplotypes at a complex LCR-laden human genomic region. Comparative analyses provide a model for how this complex region arose during primate evolution, and studies among humans suggest that intra-species polymorphism may potentially modulate an individual{\textquoteright}s susceptibility to acquiring disease-associated alleles.

}, keywords = {Adaptor Proteins, Signal Transducing, Alleles, Animals, Comparative Genomic Hybridization, Evolution, Molecular, Gene Dosage, Gene Rearrangement, Genome, Human, Genomic Structural Variation, Haplotypes, Humans, Kidney Diseases, Cystic, Membrane Proteins, Primates}, issn = {1553-7404}, doi = {10.1371/journal.pgen.1005686}, author = {Yuan, Bo and Liu, Pengfei and Gupta, Aditya and Beck, Christine R and Tejomurtula, Anusha and Campbell, Ian M and Gambin, Tomasz and Simmons, Alexandra D and Withers, Marjorie A and Harris, R Alan and Rogers, Jeffrey and Schwartz, David C and Lupski, James R} } @article {346, title = {Complex genomic rearrangements at the PLP1 locus include triplication and quadruplication.}, journal = {PLoS Genet}, volume = {11}, year = {2015}, month = {2015 Mar}, pages = {e1005050}, abstract = {

Inverted repeats (IRs) can facilitate structural variation as crucibles of genomic rearrangement. Complex duplication-inverted triplication-duplication (DUP-TRP/INV-DUP) rearrangements that contain breakpoint junctions within IRs have been recently associated with both MECP2 duplication syndrome (MIM$\#$300260) and Pelizaeus-Merzbacher disease (PMD, MIM$\#$312080). We investigated 17 unrelated PMD subjects with copy number gains at the PLP1 locus including triplication and quadruplication of specific genomic intervals-16/17 were found to have a DUP-TRP/INV-DUP rearrangement product. An IR distal to PLP1 facilitates DUP-TRP/INV-DUP formation as well as an inversion structural variation found frequently amongst normal individuals. We show that a homology-or homeology-driven replicative mechanism of DNA repair can apparently mediate template switches within stretches of microhomology. Moreover, we provide evidence that quadruplication and potentially higher order amplification of a genomic interval can occur in a manner consistent with rolling circle amplification as predicted by the microhomology-mediated break induced replication (MMBIR) model.

}, keywords = {Chromosome Breakpoints, Chromosome Inversion, Gene Dosage, Gene Duplication, Humans, Myelin Proteolipid Protein, Pelizaeus-Merzbacher Disease}, issn = {1553-7404}, doi = {10.1371/journal.pgen.1005050}, author = {Beck, Christine R and Carvalho, Claudia M B and Banser, Linda and Gambin, Tomasz and Stubbolo, Danielle and Yuan, Bo and Sperle, Karen and McCahan, Suzanne M and Henneke, Marco and Seeman, Pavel and Garbern, James Y and Hobson, Grace M and Lupski, James R} }