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Nomakuchi TT, Alves CAP, Beslow LA, Zarnow D, Goyal N, Zackai EH, Reynoso Santos FJ. Subdural Hemorrhage as an Early Presentation in a Case of Sotos Syndrome. Neuropediatrics 2024; 55:71-74. [PMID: 36914163 DOI: 10.1055/a-2052-8750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
Subdural hemorrhages (SDHs) in the pediatric population are associated with a high mortality and morbidity and may present in the context of abusive head trauma. Diagnostic investigations for such cases often include evaluation for rare genetic and metabolic disorders that can have associated SDH. Sotos syndrome is an overgrowth syndrome associated with macrocephaly and increased subarachnoid spaces and rarely with neurovascular complications. Here, we report two cases of Sotos syndrome, one with SDH during infancy who underwent repeated evaluation for suspected child abuse prior to the Sotos syndrome diagnosis and the other with enlarged extra-axial cerebrospinal fluid spaces, demonstrating a possible mechanism for SDH development in this setting. These cases suggest that some individuals with Sotos syndrome may be at elevated risk of developing SDH in infancy and that Sotos syndrome should be on the differential diagnosis during a medical genetics evaluation in cases of unexplained SDH, especially in the setting of macrocephaly.
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Affiliation(s)
- Tomoki T Nomakuchi
- Division of Human Genetics, Children's Hospital of Philadelphia, Pennsylvania, United States
| | - Cesar Augusto P Alves
- Division of Neuroradiology, Children's Hospital of Philadelphia, Pennsylvania, United States
| | - Lauren A Beslow
- Division of Neurology, Children's Hospital of Philadelphia, Pennsylvania, United States
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Pennsylvania, United States
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Pennsylvania, United States
| | - Deborah Zarnow
- Division of Neuroradiology, Children's Hospital of Philadelphia, Pennsylvania, United States
- Department of Radiology Perelman School of Medicine, University of Pennsylvania, Pennsylvania, United States
| | - Neera Goyal
- Department of Pediatrics, Nemours Children's Health and Sidney Kimmel College of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, United States
| | - Elaine H Zackai
- Division of Human Genetics, Children's Hospital of Philadelphia, Pennsylvania, United States
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Pennsylvania, United States
| | - Francis Jeshira Reynoso Santos
- Division of Human Genetics, Children's Hospital of Philadelphia, Pennsylvania, United States
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Pennsylvania, United States
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2
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Yuan B, Schulze KV, Assia Batzir N, Sinson J, Dai H, Zhu W, Bocanegra F, Fong CT, Holder J, Nguyen J, Schaaf CP, Yang Y, Bi W, Eng C, Shaw C, Lupski JR, Liu P. Sequencing individual genomes with recurrent genomic disorder deletions: an approach to characterize genes for autosomal recessive rare disease traits. Genome Med 2022; 14:113. [PMID: 36180924 PMCID: PMC9526336 DOI: 10.1186/s13073-022-01113-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 09/02/2022] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND In medical genetics, discovery and characterization of disease trait contributory genes and alleles depends on genetic reasoning, study design, and patient ascertainment; we suggest a segmental haploid genetics approach to enhance gene discovery and molecular diagnostics. METHODS We constructed a genome-wide map for nonallelic homologous recombination (NAHR)-mediated recurrent genomic deletions and used this map to estimate population frequencies of NAHR deletions based on large-scale population cohorts and region-specific studies. We calculated recessive disease carrier burden using high-quality pathogenic or likely pathogenic variants from ClinVar and gnomAD. We developed a NIRD (NAHR deletion Impact to Recessive Disease) score for recessive disorders by quantifying the contribution of NAHR deletion to the overall allele load that enumerated all pairwise combinations of disease-causing alleles; we used a Punnett square approach based on an assumption of random mating. Literature mining was conducted to identify all reported patients with defects in a gene with a high NIRD score; meta-analysis was performed on these patients to estimate the representation of NAHR deletions in recessive traits from contemporary human genomics studies. Retrospective analyses of extant clinical exome sequencing (cES) were performed for novel rare recessive disease trait gene and allele discovery from individuals with NAHR deletions. RESULTS We present novel genomic insights regarding the genome-wide impact of NAHR recurrent segmental variants on recessive disease burden; we demonstrate the utility of NAHR recurrent deletions to enhance discovery in the challenging context of autosomal recessive (AR) traits and biallelic variation. Computational results demonstrate new mutations mediated by NAHR, involving recurrent deletions at 30 genomic regions, likely drive recessive disease burden for over 74% of loci within these segmental deletions or at least 2% of loci genome-wide. Meta-analyses on 170 literature-reported patients implicate that NAHR deletions are depleted from the ascertained pool of AR trait alleles. Exome reanalysis of personal genomes from subjects harboring recurrent deletions uncovered new disease-contributing variants in genes including COX10, ERCC6, PRRT2, and OTUD7A. CONCLUSIONS Our results demonstrate that genomic sequencing of personal genomes with NAHR deletions could dramatically improve allele and gene discovery and enhance clinical molecular diagnosis. Moreover, results suggest NAHR events could potentially enable human haploid genetic screens as an approach to experimental inquiry into disease biology.
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Affiliation(s)
- Bo Yuan
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.39382.330000 0001 2160 926XHuman Genome Sequencing Center, Baylor College of Medicine, Houston, TX USA
| | - Katharina V. Schulze
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.510928.7Baylor Genetics, Houston, TX USA
| | - Nurit Assia Batzir
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Jefferson Sinson
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Hongzheng Dai
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.510928.7Baylor Genetics, Houston, TX USA
| | - Wenmiao Zhu
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.510928.7Baylor Genetics, Houston, TX USA
| | | | - Chin-To Fong
- grid.412750.50000 0004 1936 9166Department of Pediatrics, University of Rochester Medical Center, Rochester, NY USA
| | - Jimmy Holder
- grid.39382.330000 0001 2160 926XDepartment of Pediatrics, Baylor College of Medicine, Houston, TX USA
| | - Joanne Nguyen
- grid.267308.80000 0000 9206 2401Department of Pediatrics, University of Texas Health Science Center, Houston, TX USA
| | - Christian P. Schaaf
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.7700.00000 0001 2190 4373Institute of Human Genetics, Heidelberg University, Heidelberg, Germany
| | - Yaping Yang
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Weimin Bi
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.510928.7Baylor Genetics, Houston, TX USA
| | - Christine Eng
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.510928.7Baylor Genetics, Houston, TX USA
| | - Chad Shaw
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.21940.3e0000 0004 1936 8278Department of Statistics, Rice University, Houston, TX USA
| | - James R. Lupski
- grid.39382.330000 0001 2160 926XDepartment of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.39382.330000 0001 2160 926XHuman Genome Sequencing Center, Baylor College of Medicine, Houston, TX USA ,grid.39382.330000 0001 2160 926XDepartment of Pediatrics, Baylor College of Medicine, Houston, TX USA ,grid.416975.80000 0001 2200 2638Texas Children’s Hospital, Houston, TX USA
| | - Pengfei Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA. .,Baylor Genetics, Houston, TX, USA.
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3
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Gažiová M, Sládeček T, Pös O, Števko M, Krampl W, Pös Z, Hekel R, Hlavačka M, Kucharík M, Radvánszky J, Budiš J, Szemes T. Automated prediction of the clinical impact of structural copy number variations. Sci Rep 2022; 12:555. [PMID: 35017614 PMCID: PMC8752772 DOI: 10.1038/s41598-021-04505-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 11/01/2021] [Indexed: 11/09/2022] Open
Abstract
Copy number variants (CNVs) play an important role in many biological processes, including the development of genetic diseases, making them attractive targets for genetic analyses. The interpretation of the effect of these structural variants is a challenging problem due to highly variable numbers of gene, regulatory, or other genomic elements affected by the CNV. This led to the demand for the interpretation tools that would relieve researchers, laboratory diagnosticians, genetic counselors, and clinical geneticists from the laborious process of annotation and classification of CNVs. We designed and validated a prediction method (ISV; Interpretation of Structural Variants) that is based on boosted trees which takes into account annotations of CNVs from several publicly available databases. The presented approach achieved more than 98% prediction accuracy on both copy number loss and copy number gain variants while also allowing CNVs being assigned "uncertain" significance in predictions. We believe that ISV's prediction capability and explainability have a great potential to guide users to more precise interpretations and classifications of CNVs.
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Affiliation(s)
- M Gažiová
- Geneton Ltd, 84104, Bratislava, Slovakia
- Department of Computer Science, Faculty of Mathematics, Physics and Informatics, Comenius University, 84248, Bratislava, Slovakia
| | - T Sládeček
- Geneton Ltd, 84104, Bratislava, Slovakia
| | - O Pös
- Geneton Ltd, 84104, Bratislava, Slovakia
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, 84215, Bratislava, Slovakia
- Comenius University Science Park, 84104, Bratislava, Slovakia
| | - M Števko
- Geneton Ltd, 84104, Bratislava, Slovakia
| | - W Krampl
- Geneton Ltd, 84104, Bratislava, Slovakia
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, 84215, Bratislava, Slovakia
- Comenius University Science Park, 84104, Bratislava, Slovakia
| | - Z Pös
- Geneton Ltd, 84104, Bratislava, Slovakia
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, 84215, Bratislava, Slovakia
- Institute of Clinical and Translational Research, Biomedical Research Center, Slovak Academy of Sciences, 84505, Bratislava, Slovakia
| | - R Hekel
- Geneton Ltd, 84104, Bratislava, Slovakia
- Comenius University Science Park, 84104, Bratislava, Slovakia
- Slovak Center of Scientific and Technical Information, 81104, Bratislava, Slovakia
| | - M Hlavačka
- Geneton Ltd, 84104, Bratislava, Slovakia
| | - M Kucharík
- Geneton Ltd, 84104, Bratislava, Slovakia
- Comenius University Science Park, 84104, Bratislava, Slovakia
| | - J Radvánszky
- Geneton Ltd, 84104, Bratislava, Slovakia
- Institute of Clinical and Translational Research, Biomedical Research Center, Slovak Academy of Sciences, 84505, Bratislava, Slovakia
- Comenius University Science Park, 84104, Bratislava, Slovakia
| | - J Budiš
- Geneton Ltd, 84104, Bratislava, Slovakia.
- Comenius University Science Park, 84104, Bratislava, Slovakia.
- Slovak Center of Scientific and Technical Information, 81104, Bratislava, Slovakia.
| | - T Szemes
- Geneton Ltd, 84104, Bratislava, Slovakia
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, 84215, Bratislava, Slovakia
- Comenius University Science Park, 84104, Bratislava, Slovakia
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4
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Park KB, Nam KE, Cho AR, Jang W, Kim M, Park JH. Effects of Copy Number Variations on Developmental Aspects of Children With Delayed Development. Ann Rehabil Med 2019; 43:215-223. [PMID: 31072088 PMCID: PMC6509583 DOI: 10.5535/arm.2019.43.2.215] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 10/19/2018] [Indexed: 11/06/2022] Open
Abstract
Objective To determine effects of copy number variations (CNV) on developmental aspects of children suspected of having delayed development. Methods A retrospective chart review was done for 65 children who underwent array-comparative genomic hybridization after visiting physical medicine & rehabilitation department of outpatient clinic with delayed development as chief complaints. Children were evaluated with Denver Developmental Screening Test II (DDST-II), Sequenced Language Scale for Infants (SELSI), or Preschool Receptive-Expressive Language Scale (PRES). A Mann-Whitney U test was conducted to determine statistical differences of developmental quotient (DQ), receptive language quotient (RLQ), and expressive language quotient (ELQ) between children with CNV (CNV(+) group, n=16) and children without CNV (CNV(–) group, n=37). Results Of these subjects, the average age was 35.1 months (mean age, 35.1±24.2 months). Sixteen (30.2%) patients had copy number variations. In the CNV(+) group, 14 children underwent DDST-II. In the CNV(–) group, 29 children underwent DDST-II. Among variables, gross motor scale was significantly (p=0.038) lower in the CNV(+) group compared with the CNV(–) group. In the CNV(+) group, 5 children underwent either SELSI or PRES. In the CNV(–) group, 27 children underwent above language assessment examination. Both RLQ and ELQ were similar between the two groups. Conclusion The gross motor domain in DQ was significantly lower in children with CNV compared to that in children without CNV. This result suggests that additional genetic factors contribute to this variability. Active detection of genomic imbalance could play a vital role when prominent gross motor delay is presented in children with delayed development.
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Affiliation(s)
- Kee-Boem Park
- Department of Rehabilitation Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Kyung Eun Nam
- Department of Rehabilitation Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Ah-Ra Cho
- Department of Rehabilitation Medicine, St. Paul's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Woori Jang
- Department of Laboratory Medicine College of Medicine, The Catholic University of Korea, Seoul, Korea.,Department of Catholic Genetic Laboratory Center, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Myungshin Kim
- Department of Laboratory Medicine College of Medicine, The Catholic University of Korea, Seoul, Korea.,Department of Catholic Genetic Laboratory Center, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Joo Hyun Park
- Department of Rehabilitation Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
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5
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Ma YL, Wen YF, Cao XK, Cheng J, Huang YZ, Ma Y, Hu LY, Lei CZ, Qi XL, Cao H, Chen H. Copy number variation (CNV) in the IGF1R gene across four cattle breeds and its association with economic traits. Arch Anim Breed 2019; 62:171-179. [PMID: 31807627 PMCID: PMC6852844 DOI: 10.5194/aab-62-171-2019] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 03/27/2019] [Indexed: 01/21/2023] Open
Abstract
The insulin-like growth factor 1 receptor (IGF1R) plays a vital role in
immunomodulation and muscle and bone growth. The copy number variation (CNV) is
believed to the reason for many complex phenotypic variations. In
this paper, we statistically analyzed the copy number and the expression
profiling in different tissue types of the IGF1R gene using the
422 samples from four Chinese beef cattle breeds, and the mRNA of
IGF1R was widely expressed in nine tissue types of adult cattle (heart,
liver, kidney, muscle, fat, stomach, spleen, lung and testis). Results of CNV and growth traits indicated that the IGF1R CNV
was significantly associated with body weight and body height of Jinnan (JN)
cattle and was significantly associated with body height and hucklebone width
of Qinchuan (QC) cattle, making IGF1R CNV a promising molecular
marker to improve meat production in beef cattle breeding. Bioinformatics
predictions show that the CNV region is highly similar to the human genome,
and there are a large number of transcription factors, DNase I hypersensitive
sites, and high levels of histone acetylation, suggesting that this region may
play a role in transcriptional regulation, providing directions for further
study of the role of bovine CNV and economic traits.
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Affiliation(s)
- Yi-Lei Ma
- College of Animal Science and Technology, Northwest A&F University, Yangling Shaanxi, 712100, P. R. China
| | - Yi-Fan Wen
- College of Animal Science and Technology, Northwest A&F University, Yangling Shaanxi, 712100, P. R. China
| | - Xiu-Kai Cao
- College of Animal Science and Technology, Northwest A&F University, Yangling Shaanxi, 712100, P. R. China
| | - Jie Cheng
- College of Animal Science and Technology, Northwest A&F University, Yangling Shaanxi, 712100, P. R. China
| | - Yong-Zhen Huang
- College of Animal Science and Technology, Northwest A&F University, Yangling Shaanxi, 712100, P. R. China
| | - Yun Ma
- College of Life Sciences, Xinyang Normal University, Institute for Conservation and Utilization of Agro-Bioresources in Dabie Mountains, Xinyang, Henan, 464000, P. R. China
| | - Lin-Yong Hu
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, Qinghai, 810001, P. R. China
| | - Chu-Zhao Lei
- College of Animal Science and Technology, Northwest A&F University, Yangling Shaanxi, 712100, P. R. China
| | - Xing-Lei Qi
- Bureau of Animal Husbandry of Biyang County, Biyang, Henan, 463700, P. R. China
| | - Hui Cao
- Shaanxi Kingbull Animal Husbandry Co. Ltd., Yangling, Shaanxi, 712100, P. R. China
| | - Hong Chen
- College of Animal Science and Technology, Northwest A&F University, Yangling Shaanxi, 712100, P. R. China
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6
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Lupski JR. 2018 Victor A. McKusick Leadership Award: Molecular Mechanisms for Genomic and Chromosomal Rearrangements. Am J Hum Genet 2019; 104:391-406. [PMID: 30849326 DOI: 10.1016/j.ajhg.2018.12.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, and Texas Children's Hospital, Houston, TX 77030, USA.
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7
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Harel T, Lupski JR. Genomic disorders 20 years on-mechanisms for clinical manifestations. Clin Genet 2017; 93:439-449. [PMID: 28950406 DOI: 10.1111/cge.13146] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 09/01/2017] [Accepted: 09/21/2017] [Indexed: 12/18/2022]
Abstract
Genomic disorders result from copy-number variants (CNVs) or submicroscopic rearrangements of the genome rather than from single nucleotide variants (SNVs). Diverse technologies, including array comparative genomic hybridization (aCGH) and single nucleotide polymorphism (SNP) microarrays, and more recently, whole genome sequencing and whole-exome sequencing, have enabled robust genome-wide unbiased detection of CNVs in affected individuals and in reportedly healthy controls. Sequencing of breakpoint junctions has allowed for elucidation of upstream mechanisms leading to genomic instability and resultant structural variation, whereas studies of the association between CNVs and specific diseases or susceptibility to morbid traits have enhanced our understanding of the downstream effects. In this review, we discuss the hallmarks of genomic disorders as they were defined during the first decade of the field, including genomic instability and the mechanism for rearrangement defined as nonallelic homologous recombination (NAHR); recurrent vs nonrecurrent rearrangements; and gene dosage sensitivity. Moreover, we highlight the exciting advances of the second decade of this field, including a deeper understanding of genomic instability and the mechanisms underlying complex rearrangements, mechanisms for constitutional and somatic chromosomal rearrangements, structural intra-species polymorphisms and susceptibility to NAHR, the role of CNVs in the context of genome-wide copy number and single nucleotide variation, and the contribution of noncoding CNVs to human disease.
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Affiliation(s)
- T Harel
- Department of Genetic and Metabolic Diseases, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - J R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Department of Pediatrics, Baylor College of Medicine, Houston, Texas.,Texas Children's Hospital, Houston, Texas.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas
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8
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Boocock J, Chagné D, Merriman TR, Black MA. The distribution and impact of common copy-number variation in the genome of the domesticated apple, Malus x domestica Borkh. BMC Genomics 2015; 16:848. [PMID: 26493398 PMCID: PMC4618995 DOI: 10.1186/s12864-015-2096-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 10/15/2015] [Indexed: 11/14/2022] Open
Abstract
Background Copy number variation (CNV) is a common feature of eukaryotic genomes, and a growing body of evidence suggests that genes affected by CNV are enriched in processes that are associated with environmental responses. Here we use next generation sequence (NGS) data to detect copy-number variable regions (CNVRs) within the Malus x domestica genome, as well as to examine their distribution and impact. Methods CNVRs were detected using NGS data derived from 30 accessions of M. x domestica analyzed using the read-depth method, as implemented in the CNVrd2 software. To improve the reliability of our results, we developed a quality control and analysis procedure that involved checking for organelle DNA, not repeat masking, and the determination of CNVR identity using a permutation testing procedure. Results Overall, we identified 876 CNVRs, which spanned 3.5 % of the apple genome. To verify that detected CNVRs were not artifacts, we analyzed the B- allele-frequencies (BAF) within a single nucleotide polymorphism (SNP) array dataset derived from a screening of 185 individual apple accessions and found the CNVRs were enriched for SNPs having aberrant BAFs (P < 1e-13, Fisher’s Exact test). Putative CNVRs overlapped 845 gene models and were enriched for resistance (R) gene models (P < 1e-22, Fisher’s exact test). Of note was a cluster of resistance gene models on chromosome 2 near a region containing multiple major gene loci conferring resistance to apple scab. Conclusion We present the first analysis and catalogue of CNVRs in the M. x domestica genome. The enrichment of the CNVRs with R gene models and their overlap with gene loci of agricultural significance draw attention to a form of unexplored genetic variation in apple. This research will underpin further investigation of the role that CNV plays within the apple genome. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-2096-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- James Boocock
- Department of Biochemistry, University of Otago, Dunedin, New Zealand. .,The Virtual Institute of Statistical Genetics (VISG), Rotorua, New Zealand.
| | - David Chagné
- The Virtual Institute of Statistical Genetics (VISG), Rotorua, New Zealand.,The New Zealand Institute for Plant & Food Research Ltd, Palmerston North, New Zealand
| | - Tony R Merriman
- Department of Biochemistry, University of Otago, Dunedin, New Zealand.,The Virtual Institute of Statistical Genetics (VISG), Rotorua, New Zealand
| | - Michael A Black
- Department of Biochemistry, University of Otago, Dunedin, New Zealand. .,The Virtual Institute of Statistical Genetics (VISG), Rotorua, New Zealand.
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9
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Poot M, Haaf T. Mechanisms of Origin, Phenotypic Effects and Diagnostic Implications of Complex Chromosome Rearrangements. Mol Syndromol 2015; 6:110-34. [PMID: 26732513 DOI: 10.1159/000438812] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/23/2015] [Indexed: 01/08/2023] Open
Abstract
Complex chromosome rearrangements (CCRs) are currently defined as structural genome variations that involve more than 2 chromosome breaks and result in exchanges of chromosomal segments. They are thought to be extremely rare, but their detection rate is rising because of improvements in molecular cytogenetic technology. Their population frequency is also underestimated, since many CCRs may not elicit a phenotypic effect. CCRs may be the result of fork stalling and template switching, microhomology-mediated break-induced repair, breakage-fusion-bridge cycles, or chromothripsis. Patients with chromosomal instability syndromes show elevated rates of CCRs due to impaired DNA double-strand break responses during meiosis. Therefore, the putative functions of the proteins encoded by ATM, BLM, WRN, ATR, MRE11, NBS1, and RAD51 in preventing CCRs are discussed. CCRs may exert a pathogenic effect by either (1) gene dosage-dependent mechanisms, e.g. haploinsufficiency, (2) mechanisms based on disruption of the genomic architecture, such that genes, parts of genes or regulatory elements are truncated, fused or relocated and thus their interactions disturbed - these mechanisms will predominantly affect gene expression - or (3) mixed mutation mechanisms in which a CCR on one chromosome is combined with a different type of mutation on the other chromosome. Such inferred mechanisms of pathogenicity need corroboration by mRNA sequencing. Also, future studies with in vitro models, such as inducible pluripotent stem cells from patients with CCRs, and transgenic model organisms should substantiate current inferences regarding putative pathogenic effects of CCRs. The ramifications of the growing body of information on CCRs for clinical and experimental genetics and future treatment modalities are briefly illustrated with 2 cases, one of which suggests KDM4C (JMJD2C) as a novel candidate gene for mental retardation.
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Affiliation(s)
- Martin Poot
- Department of Human Genetics, University of Würzburg, Würzburg, Germany
| | - Thomas Haaf
- Department of Human Genetics, University of Würzburg, Würzburg, Germany
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10
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Zhang F, Lupski JR. Non-coding genetic variants in human disease. Hum Mol Genet 2015; 24:R102-10. [PMID: 26152199 DOI: 10.1093/hmg/ddv259] [Citation(s) in RCA: 375] [Impact Index Per Article: 41.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Accepted: 07/03/2015] [Indexed: 01/16/2023] Open
Abstract
Genetic variants, including single-nucleotide variants (SNVs) and copy number variants (CNVs), in the non-coding regions of the human genome can play an important role in human traits and complex diseases. Most of the genome-wide association study (GWAS) signals map to non-coding regions and potentially point to non-coding variants, whereas their functional interpretation is challenging. In this review, we discuss the human non-coding variants and their contributions to human diseases in the following four parts. (i) Functional annotations of non-coding SNPs mapped by GWAS: we discuss recent progress revealing some of the molecular mechanisms for GWAS signals affecting gene function. (ii) Technical progress in interpretation of non-coding variants: we briefly describe some of the technologies for functional annotations of non-coding variants, including the methods for genome-wide mapping of chromatin interaction, computational tools for functional predictions and the new genome editing technologies useful for dissecting potential functional consequences of non-coding variants. (iii) Non-coding CNVs in human diseases: we review our emerging understanding the role of non-coding CNVs in human disease. (iv) Compound inheritance of large genomic deletions and non-coding variants: compound inheritance at a locus consisting of coding variants plus non-coding ones is described.
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Affiliation(s)
- Feng Zhang
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA and Texas Children's Hospital, Houston, TX 77030, USA
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11
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English AC, Salerno WJ, Hampton OA, Gonzaga-Jauregui C, Ambreth S, Ritter DI, Beck CR, Davis CF, Dahdouli M, Ma S, Carroll A, Veeraraghavan N, Bruestle J, Drees B, Hastie A, Lam ET, White S, Mishra P, Wang M, Han Y, Zhang F, Stankiewicz P, Wheeler DA, Reid JG, Muzny DM, Rogers J, Sabo A, Worley KC, Lupski JR, Boerwinkle E, Gibbs RA. Assessing structural variation in a personal genome-towards a human reference diploid genome. BMC Genomics 2015; 16:286. [PMID: 25886820 PMCID: PMC4490614 DOI: 10.1186/s12864-015-1479-3] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 03/23/2015] [Indexed: 01/19/2023] Open
Abstract
Background Characterizing large genomic variants is essential to expanding the research and clinical applications of genome sequencing. While multiple data types and methods are available to detect these structural variants (SVs), they remain less characterized than smaller variants because of SV diversity, complexity, and size. These challenges are exacerbated by the experimental and computational demands of SV analysis. Here, we characterize the SV content of a personal genome with Parliament, a publicly available consensus SV-calling infrastructure that merges multiple data types and SV detection methods. Results We demonstrate Parliament’s efficacy via integrated analyses of data from whole-genome array comparative genomic hybridization, short-read next-generation sequencing, long-read (Pacific BioSciences RSII), long-insert (Illumina Nextera), and whole-genome architecture (BioNano Irys) data from the personal genome of a single subject (HS1011). From this genome, Parliament identified 31,007 genomic loci between 100 bp and 1 Mbp that are inconsistent with the hg19 reference assembly. Of these loci, 9,777 are supported as putative SVs by hybrid local assembly, long-read PacBio data, or multi-source heuristics. These SVs span 59 Mbp of the reference genome (1.8%) and include 3,801 events identified only with long-read data. The HS1011 data and complete Parliament infrastructure, including a BAM-to-SV workflow, are available on the cloud-based service DNAnexus. Conclusions HS1011 SV analysis reveals the limits and advantages of multiple sequencing technologies, specifically the impact of long-read SV discovery. With the full Parliament infrastructure, the HS1011 data constitute a public resource for novel SV discovery, software calibration, and personal genome structural variation analysis. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1479-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Adam C English
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - William J Salerno
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Oliver A Hampton
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Claudia Gonzaga-Jauregui
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Shruthi Ambreth
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Deborah I Ritter
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Christine R Beck
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Caleb F Davis
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Mahmoud Dahdouli
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Singer Ma
- DNAnexus, Mountain View, CA, 94040, USA.
| | | | | | | | - Becky Drees
- Spiral Genetics Inc, Seattle, WA, 98117, USA.
| | - Alex Hastie
- BioNano Genomics Inc, San Diego, CA, 92121, USA.
| | - Ernest T Lam
- BioNano Genomics Inc, San Diego, CA, 92121, USA.
| | - Simon White
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Pamela Mishra
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Min Wang
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Yi Han
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Feng Zhang
- Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, 200438, China.
| | - Pawel Stankiewicz
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - David A Wheeler
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Jeffrey G Reid
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Donna M Muzny
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Jeffrey Rogers
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Aniko Sabo
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Kim C Worley
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - James R Lupski
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA. .,Texas Children's Hospital, Houston, TX, 77030, USA.
| | - Eric Boerwinkle
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA. .,Human Genetics Center, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA.
| | - Richard A Gibbs
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.
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12
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Shashi V, McConkie-Rosell A, Schoch K, Kasturi V, Rehder C, Jiang YH, Goldstein DB, McDonald MT. Practical considerations in the clinical application of whole-exome sequencing. Clin Genet 2015; 89:173-81. [PMID: 25678066 DOI: 10.1111/cge.12569] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Revised: 02/04/2015] [Accepted: 02/08/2015] [Indexed: 01/17/2023]
Abstract
Despite the exciting advent of whole-exome sequencing (WES) in medical genetics practices, the optimal interpretation of results requires further actions such as reconsidering clinical information and obtaining further laboratory testing. There are no published data to guide clinicians in this process. In a retrospective study on 93 patients who underwent clinical WES, we set out to assess and resolve these practical challenges. With the laboratories reporting a molecular diagnostic rate of 25.8%, the medical geneticists and the laboratories were 90% concordant in their interpretation of the WES results. Divergence occurred when the medical geneticist reconsidered clinical information and/or additional information regarding pathogenicity of a variant. Variants of uncertain significance were reported in 86% of patients, with 53.7% needing follow-up, such as additional laboratory tests and genotyping of family members. By layering clinical data (e.g. mode of inheritance and phenotypic fit) on to the laboratory results, we developed clinical categories for the WES results. These categories of definite diagnosis (14/93), likely diagnosis (8/93), possible diagnosis (13/93) and no diagnosis (58/93) could be used to convey results to patients uniformly. Our framework for a clinically informed interpretation of the results enhances the utility of WES within medical genetics practices.
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Affiliation(s)
- V Shashi
- Department of Pediatrics, Division of Medical Genetics, Duke University Medical Center, Durham, NC, USA
| | - A McConkie-Rosell
- Department of Pediatrics, Division of Medical Genetics, Duke University Medical Center, Durham, NC, USA
| | - K Schoch
- Department of Pediatrics, Division of Medical Genetics, Duke University Medical Center, Durham, NC, USA
| | - V Kasturi
- Department of Pediatrics, Division of Medical Genetics, Duke University Medical Center, Durham, NC, USA
| | - C Rehder
- Department of Pathology, Duke University Medical Center, Durham, NC, USA
| | - Y H Jiang
- Department of Pediatrics, Division of Medical Genetics, Duke University Medical Center, Durham, NC, USA
| | - D B Goldstein
- Center for Human Genome Variation, Duke University Medical Center, Durham, NC, USA
| | - M T McDonald
- Department of Pediatrics, Division of Medical Genetics, Duke University Medical Center, Durham, NC, USA
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13
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Wu N, Ming X, Xiao J, Wu Z, Chen X, Shinawi M, Shen Y, Yu G, Liu J, Xie H, Gucev ZS, Liu S, Yang N, Al-Kateb H, Chen J, Zhang J, Hauser N, Zhang T, Tasic V, Liu P, Su X, Pan X, Liu C, Wang L, Shen J, Shen J, Chen Y, Zhang T, Zhang J, Choy KW, Wang J, Wang Q, Li S, Zhou W, Guo J, Wang Y, Zhang C, Zhao H, An Y, Zhao Y, Wang J, Liu Z, Zuo Y, Tian Y, Weng X, Sutton VR, Wang H, Ming Y, Kulkarni S, Zhong TP, Giampietro PF, Dunwoodie SL, Cheung SW, Zhang X, Jin L, Lupski JR, Qiu G, Zhang F. TBX6 null variants and a common hypomorphic allele in congenital scoliosis. N Engl J Med 2015; 372:341-50. [PMID: 25564734 PMCID: PMC4326244 DOI: 10.1056/nejmoa1406829] [Citation(s) in RCA: 210] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Congenital scoliosis is a common type of vertebral malformation. Genetic susceptibility has been implicated in congenital scoliosis. METHODS We evaluated 161 Han Chinese persons with sporadic congenital scoliosis, 166 Han Chinese controls, and 2 pedigrees, family members of which had a 16p11.2 deletion, using comparative genomic hybridization, quantitative polymerase-chain-reaction analysis, and DNA sequencing. We carried out tests of replication using an additional series of 76 Han Chinese persons with congenital scoliosis and a multicenter series of 42 persons with 16p11.2 deletions. RESULTS We identified a total of 17 heterozygous TBX6 null mutations in the 161 persons with sporadic congenital scoliosis (11%); we did not observe any null mutations in TBX6 in 166 controls (P<3.8×10(-6)). These null alleles include copy-number variants (12 instances of a 16p11.2 deletion affecting TBX6) and single-nucleotide variants (1 nonsense and 4 frame-shift mutations). However, the discordant intrafamilial phenotypes of 16p11.2 deletion carriers suggest that heterozygous TBX6 null mutation is insufficient to cause congenital scoliosis. We went on to identify a common TBX6 haplotype as the second risk allele in all 17 carriers of TBX6 null mutations (P<1.1×10(-6)). Replication studies involving additional persons with congenital scoliosis who carried a deletion affecting TBX6 confirmed this compound inheritance model. In vitro functional assays suggested that the risk haplotype is a hypomorphic allele. Hemivertebrae are characteristic of TBX6-associated congenital scoliosis. CONCLUSIONS Compound inheritance of a rare null mutation and a hypomorphic allele of TBX6 accounted for up to 11% of congenital scoliosis cases in the series that we analyzed. (Funded by the National Basic Research Program of China and others.).
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Affiliation(s)
- N Wu
- The authors' affiliations are listed in the Appendix
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14
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de Ligt J, Boone PM, Pfundt R, Vissers LELM, Richmond T, Geoghegan J, O'Moore K, de Leeuw N, Shaw C, Brunner HG, Lupski JR, Veltman JA, Hehir-Kwa JY. Detection of clinically relevant copy number variants with whole-exome sequencing. Hum Mutat 2013; 34:1439-48. [PMID: 23893877 DOI: 10.1002/humu.22387] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 07/17/2013] [Indexed: 12/22/2022]
Abstract
Copy number variation (CNV) is a common source of genetic variation that has been implicated in many genomic disorders. This has resulted in the widespread application of genomic microarrays as a first-tier diagnostic tool for CNV detection. More recently, whole-exome sequencing (WES) has been proven successful for the detection of clinically relevant point mutations and small insertion-deletions exome wide. We evaluate the utility of short-read WES (SOLiD 5500xl) to detect clinically relevant CNVs in DNA from 10 patients with intellectual disability and compare these results to data from two independent high-resolution microarrays. Eleven of the 12 clinically relevant CNVs were detected via read-depth analysis of WES data; a heterozygous single-exon deletion remained undetected by all algorithms evaluated. Although the detection power of WES for small CNVs currently does not match that of high-resolution microarray platforms, we show that the majority (88%) of rare coding CNVs containing three or more exons are successfully identified by WES. These results show that the CNV detection resolution of WES is comparable to that of medium-resolution genomic microarrays commonly used as clinical assays. The combined detection of point mutations, indels, and CNVs makes WES a very attractive first-tier diagnostic test for genetically heterogeneous disorders.
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Affiliation(s)
- Joep de Ligt
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Institute for Genetic and Metabolic Disease, Radboud University Medical Centre, Nijmegen, 6500 HB, The Netherlands
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15
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Albers CA, Newbury-Ecob R, Ouwehand WH, Ghevaert C. New insights into the genetic basis of TAR (thrombocytopenia-absent radii) syndrome. Curr Opin Genet Dev 2013; 23:316-23. [PMID: 23602329 DOI: 10.1016/j.gde.2013.02.015] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 02/15/2013] [Accepted: 02/25/2013] [Indexed: 12/31/2022]
Abstract
Thrombocytopenia with absent radii (TAR) syndrome is a rare disorder combining specific skeletal abnormalities with a reduced platelet count. Rare proximal microdeletions of 1q21.1 are found in the majority of patients but are also found in unaffected parents. Recently it was shown that TAR syndrome is caused by the compound inheritance of a low-frequency noncoding SNP and a rare null allele in RBM8A, a gene encoding the exon-junction complex subunit member Y14 located in the deleted region. This finding provides new insight into the complex inheritance pattern and new clues to the molecular mechanisms underlying TAR syndrome. We discuss TAR syndrome in the context of abnormal phenotypes associated with proximal and distal 1q21.1 microdeletion and microduplications with incomplete penetrance and variable expressivity.
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16
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Rosenfeld JA, Kim KH, Angle B, Troxell R, Gorski JL, Westemeyer M, Frydman M, Senturias Y, Earl D, Torchia B, Schultz RA, Ellison JW, Tsuchiya K, Zimmerman S, Smolarek TA, Ballif BC, Shaffer LG. Further Evidence of Contrasting Phenotypes Caused by Reciprocal Deletions and Duplications: Duplication of NSD1 Causes Growth Retardation and Microcephaly. Mol Syndromol 2013; 3:247-54. [PMID: 23599694 DOI: 10.1159/000345578] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/29/2012] [Indexed: 12/15/2022] Open
Abstract
Microduplications of the Sotos syndrome region containing NSD1 on 5q35 have recently been proposed to cause a syndrome of microcephaly, short stature and developmental delay. To further characterize this emerging syndrome, we report the clinical details of 12 individuals from 8 families found to have interstitial duplications involving NSD1, ranging in size from 370 kb to 3.7 Mb. All individuals are microcephalic, and height and childhood weight range from below average to severely restricted. Mild-to-moderate learning disabilities and/or developmental delay are present in all individuals, including carrier family members of probands; dysmorphic features and digital anomalies are present in a majority. Craniosynostosis is present in the individual with the largest duplication, though the duplication does not include MSX2, mutations of which can cause craniosynostosis, on 5q35.2. A comparison of the smallest duplication in our cohort that includes the entire NSD1 gene to the individual with the largest duplication that only partially overlaps NSD1 suggests that whole-gene duplication of NSD1 in and of itself may be sufficient to cause the abnormal growth parameters seen in these patients. NSD1 duplications may therefore be added to a growing list of copy number variations for which deletion and duplication of specific genes have contrasting effects on body development.
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Affiliation(s)
- J A Rosenfeld
- Signature Genomic Laboratories, PerkinElmer, Inc., Spokane, Wash., USA
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17
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Migdalska AM, van der Weyden L, Ismail O, Rust AG, Rashid M, White JK, Sánchez-Andrade G, Lupski JR, Logan DW, Arends MJ, Adams DJ. Generation of the Sotos syndrome deletion in mice. Mamm Genome 2012; 23:749-57. [PMID: 22926222 PMCID: PMC3510424 DOI: 10.1007/s00335-012-9416-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Accepted: 07/16/2012] [Indexed: 11/28/2022]
Abstract
Haploinsufficiency of the human 5q35 region spanning the NSD1 gene results in a rare genomic disorder known as Sotos syndrome (Sotos), with patients displaying a variety of clinical features, including pre- and postnatal overgrowth, intellectual disability, and urinary/renal abnormalities. We used chromosome engineering to generate a segmental monosomy, i.e., mice carrying a heterozygous 1.5-Mb deletion of 36 genes on mouse chromosome 13 (4732471D19Rik-B4galt7), syntenic with 5q35.2–q35.3 in humans (Df(13)Ms2Dja+/− mice). Surprisingly Df(13)Ms2Dja+/− mice were significantly smaller for their gestational age and also showed decreased postnatal growth, in contrast to Sotos patients. Df(13)Ms2Dja+/− mice did, however, display deficits in long-term memory retention and dilation of the pelvicalyceal system, which in part may model the learning difficulties and renal abnormalities observed in Sotos patients. Thus, haploinsufficiency of genes within the mouse 4732471D19Rik–B4galt7 deletion interval play important roles in growth, memory retention, and the development of the renal pelvicalyceal system.
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Affiliation(s)
- Anna M Migdalska
- Experimental Cancer Genetics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1HH, UK
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18
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Abstract
During the past decade, widespread use of microarray-based technologies, including oligonucleotide array comparative genomic hybridization (aCGH) and single nucleotide polymorphism (SNP) genotyping arrays have dramatically changed our perspective on genome-wide structural variation. Submicroscopic genomic rearrangements or copy-number variation (CNV) have proven to be an important factor responsible for primate evolution, phenotypic differences between individuals and populations, and susceptibility to many diseases. The number of diseases caused by chromosomal microdeletions and microduplications, also referred to as genomic disorders, has been increasing at a rapid pace. Microdeletions and microduplications are found in patients with a wide variety of phenotypes, including Mendelian diseases as well as common complex traits, such as developmental delay/intellectual disability, autism, schizophrenia, obesity, and epilepsy. This chapter provides an overview of common microdeletion and microduplication syndromes and their clinical phenotypes, and discusses the genomic structures and molecular mechanisms of formation. In addition, an explanation for how these genomic rearrangements convey abnormal phenotypes is provided.
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Affiliation(s)
- Lisenka E L M Vissers
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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19
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Dasouki MJ, Youngs EL, Hovanes K. Structural Chromosome Abnormalities Associated with Obesity: Report of Four New subjects and Review of Literature. Curr Genomics 2011; 12:190-203. [PMID: 22043167 PMCID: PMC3137004 DOI: 10.2174/138920211795677930] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 03/29/2011] [Accepted: 03/30/2011] [Indexed: 11/22/2022] Open
Abstract
Obesity in humans is a complex polygenic trait with high inter-individual heritability estimated at 40-70%. Candidate gene, DNA linkage and genome-wide association studies (GWAS) have allowed for the identification of a large set of genes and genomic regions associated with obesity. Structural chromosome abnormalities usually result in congenital anomalies, growth retardation and developmental delay. Occasionally, they are associated with hyperphagia and obesity rather than growth delay. We report four new individuals with structural chromosome abnormalities involving 10q22.3-23.2, 16p11.2 and Xq27.1-q28 chromosomal regions with early childhood obesity and developmental delay. We also searched and summarized the literature for structural chromosome abnormalities reported in association with childhood obesity.
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Affiliation(s)
- Majed J Dasouki
- Departments of Pediatrics and Internal Medicine, Kansas University Medical Center, Kansas City, Kansas, USA
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20
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Stankiewicz P, Kulkarni S, Dharmadhikari AV, Sampath S, Bhatt SS, Shaikh TH, Xia Z, Pursley AN, Cooper ML, Shinawi M, Paciorkowski AR, Grange DK, Noetzel MJ, Saunders S, Simons P, Summar M, Lee B, Scaglia F, Fellmann F, Martinet D, Beckmann JS, Asamoah A, Platky K, Sparks S, Martin AS, Madan-Khetarpal S, Hoover J, Medne L, Bonnemann CG, Moeschler JB, Vallee SE, Parikh S, Irwin P, Dalzell VP, Smith WE, Banks VC, Flannery DB, Lovell CM, Bellus GA, Golden-Grant K, Gorski JL, Kussmann JL, McGregor TL, Hamid R, Pfotenhauer J, Ballif BC, Shaw CA, Kang SHL, Bacino CA, Patel A, Rosenfeld JA, Cheung SW, Shaffer LG. Recurrent deletions and reciprocal duplications of 10q11.21q11.23 including CHAT and SLC18A3 are likely mediated by complex low-copy repeats. Hum Mutat 2011; 33:165-79. [PMID: 21948486 DOI: 10.1002/humu.21614] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Accepted: 09/06/2011] [Indexed: 11/11/2022]
Abstract
We report 24 unrelated individuals with deletions and 17 additional cases with duplications at 10q11.21q21.1 identified by chromosomal microarray analysis. The rearrangements range in size from 0.3 to 12 Mb. Nineteen of the deletions and eight duplications are flanked by large, directly oriented segmental duplications of >98% sequence identity, suggesting that nonallelic homologous recombination (NAHR) caused these genomic rearrangements. Nine individuals with deletions and five with duplications have additional copy number changes. Detailed clinical evaluation of 20 patients with deletions revealed variable clinical features, with developmental delay (DD) and/or intellectual disability (ID) as the only features common to a majority of individuals. We suggest that some of the other features present in more than one patient with deletion, including hypotonia, sleep apnea, chronic constipation, gastroesophageal and vesicoureteral refluxes, epilepsy, ataxia, dysphagia, nystagmus, and ptosis may result from deletion of the CHAT gene, encoding choline acetyltransferase, and the SLC18A3 gene, mapping in the first intron of CHAT and encoding vesicular acetylcholine transporter. The phenotypic diversity and presence of the deletion in apparently normal carrier parents suggest that subjects carrying 10q11.21q11.23 deletions may exhibit variable phenotypic expressivity and incomplete penetrance influenced by additional genetic and nongenetic modifiers.
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Affiliation(s)
- Paweł Stankiewicz
- Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA.
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Lupski JR, Belmont JW, Boerwinkle E, Gibbs RA. Clan genomics and the complex architecture of human disease. Cell 2011; 147:32-43. [PMID: 21962505 PMCID: PMC3656718 DOI: 10.1016/j.cell.2011.09.008] [Citation(s) in RCA: 261] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Revised: 09/07/2011] [Accepted: 09/09/2011] [Indexed: 01/12/2023]
Abstract
Human diseases are caused by alleles that encompass the full range of variant types, from single-nucleotide changes to copy-number variants, and these variations span a broad frequency spectrum, from the very rare to the common. The picture emerging from analysis of whole-genome sequences, the 1000 Genomes Project pilot studies, and targeted genomic sequencing derived from very large sample sizes reveals an abundance of rare and private variants. One implication of this realization is that recent mutation may have a greater influence on disease susceptibility or protection than is conferred by variations that arose in distant ancestors.
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Affiliation(s)
- James R. Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
- Texas Children’s Hospital, University of Texas Health Science Center at Houston, Houston, TX 77030-1501, USA
| | - John W. Belmont
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Eric Boerwinkle
- Human Genetics Center, University of Texas Health Science Center at Houston, Houston, TX 77030-1501, USA
- The Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Richard A. Gibbs
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- The Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
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Abstract
It is now well recognized that as well as having a characteristic facial dysmorphology and a range of congenital abnormalities, individuals with chromosome 22q11 deletion syndrome (22q11DS) have a greatly increased risk of developing psychosis, in particular schizophrenia. The majority of deletions span a large 3Mb region at 22q11. However, the presence of affected individuals carrying smaller deletions have not been sufficient to satisfactorily reduce the critical region for the behavioral phenotype beyond a ~1.5Mb region that contains at least 28 genes. By having a shared genetic variant that greatly increases risk to psychosis, individuals with 22q11DS are a relatively homogeneous population to study psychiatric disease. Despite this, the large volume of research performed over the last 15 years suggest that the mechanism by which haploinsufficiency at 22q11 increases risk to psychiatric illness is likely to be complex and it remains uncertain why individuals carrying identical 22q11 deletions can present with such a wide range of neuropsychiatric phenotypes. This review will therefore consider the ways in which deletions at 22q11 are expected to increase risk to develop psychiatric disease by summarizing the work that has been done to investigate three of the most likely disease causing mechanisms: (a) gene dosage sensitivity; (b) unmasking of recessive alleles or functional polymorphism; and (c) position effect.
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Affiliation(s)
- Nigel M. Williams
- To whom correspondence should be addressed; tel: +44-(0)2920-687070, e-mail:
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23
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Hérault Y, Duchon A, Maréchal D, Raveau M, Pereira PL, Dalloneau E, Brault V. Controlled somatic and germline copy number variation in the mouse model. Curr Genomics 2011; 11:470-80. [PMID: 21358991 PMCID: PMC3018727 DOI: 10.2174/138920210793176038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2010] [Revised: 05/24/2010] [Accepted: 05/27/2010] [Indexed: 12/20/2022] Open
Abstract
Changes in the number of chromosomes, but also variations in the copy number of chromosomal regions have been described in various pathological conditions, such as cancer and aneuploidy, but also in normal physiological condition. Our classical view of DNA replication and mitotic preservation of the chromosomal integrity is now challenged as new technologies allow us to observe such mosaic somatic changes in copy number affecting regions of chromosomes with various sizes. In order to go further in the understanding of copy number influence in normal condition we could take advantage of the novel strategy called Targeted Asymmetric Sister Chromatin Event of Recombination (TASCER) to induce recombination during the G2 phase so that we can generate deletions and duplications of regions of interest prior to mitosis. Using this approach in the mouse we could address the effects of copy number variation and segmental aneuploidy in daughter cells and allow us to explore somatic mosaics for large region of interest in the mouse.
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Affiliation(s)
- Yann Hérault
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, Université de Strasbourg, Illkirch, France
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24
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Chinen J, Martinez-Gallo M, Gu W, Cols M, Cerutti A, Radigan L, Zhang L, Potocki L, Withers M, Lupski JR, Cunningham-Rundles C. Transmembrane activator and CAML interactor (TACI) haploinsufficiency results in B-cell dysfunction in patients with Smith-Magenis syndrome. J Allergy Clin Immunol 2011; 127:1579-86. [PMID: 21514638 DOI: 10.1016/j.jaci.2011.02.046] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Revised: 01/06/2011] [Accepted: 02/08/2011] [Indexed: 12/19/2022]
Abstract
BACKGROUND Heterozygous deleterious mutations in the gene encoding the tumor necrosis factor receptor superfamily member 13b (TNFRSF13B), or transmembrane activator and CAML interactor (TACI), have been associated with the development of common variable immunodeficiency. Smith-Magenis syndrome (SMS) is a genetic disorder characterized by developmental delay, behavioral disturbances, craniofacial anomalies, and recurrent respiratory tract infections. Eighty percent of subjects have a chromosome 17p11.2 microdeletion, which includes TACI. The remaining subjects have mutations sparing this gene. OBJECTIVE We examined TACI protein expression and function in patients with SMS to define the role of TACI haploinsufficiency in B-cell function. METHODS We studied TACI expression and function in a cohort of 29 patients with SMS. RESULTS In patients with SMS with only 1 TACI allele, we found decreased B-cell extracellular and intracellular expression of TACI, reduced binding of a proliferation-inducing ligand, and decreased TACI-induced expression of activation-induced cytidine deaminase mRNA, but these were normal for cells from patients with SMS and 2 TACI alleles. Impaired upregulation of B-cell surface TACI expression by a Toll-like receptor 9 agonist was also observed in cells from patients with 1 TACI allele. Gene sequence analysis of the remaining TACI allele revealed common polymorphisms, with the exception of 1 patient with an amino acid change of uncertain significance. Patients with SMS with the lowest TACI expression had significantly reduced antibody responses to pneumococcal vaccine serotypes. DISCUSSION Our findings suggest that haploinsufficiency of the TACI gene results in humoral immune dysfunction, highlighting the role of genomic copy number variants in complex traits.
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Affiliation(s)
- Javier Chinen
- Department of Pediatrics, Baylor College of Medicine and Texas Children's Hospital, Houston, TX, USA
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25
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Abstract
The number of known mutations in human nuclear genes, underlying or associated with human inherited disease, has now exceeded 100,000 in more than 3700 different genes (Human Gene Mutation Database). However, for a variety of reasons, this figure is likely to represent only a small proportion of the clinically relevant genetic variants that remain to be identified in the human genome (the 'mutome'). With the advent of next-generation sequencing, we are currently witnessing a revolution in medical genetics. In particular, whole-genome sequencing (WGS) has the potential to identify all disease-causing or disease-associated DNA variants in a given individual. Here, we use examples of recent advances in our understanding of mutational/pathogenic mechanisms to guide our thinking about possible locations outwith gene-coding sequences for those disease-causing or disease-associated variants that are likely so often to have been overlooked because of the inadequacy of current mutation screening protocols. Such considerations are important not only for improving mutation-screening strategies but also for enhancing the interpretation of findings derived from genome-wide association studies, whole-exome sequencing and WGS. An improved understanding of the human mutome will not only lead to the development of improved diagnostic testing procedures but should also improve our understanding of human genome biology.
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Affiliation(s)
- J M Chen
- Etablissement Français du Sang (EFS) - Bretagne, Brest, France.
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26
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Poot M, van der Smagt J, Brilstra E, Bourgeron T. Disentangling the Myriad Genomics of Complex Disorders, Specifically Focusing on Autism, Epilepsy, and Schizophrenia. Cytogenet Genome Res 2011; 135:228-40. [DOI: 10.1159/000334064] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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27
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Ramocki MB, Bartnik M, Szafranski P, Kołodziejska KE, Xia Z, Bravo J, Miller GS, Rodriguez DL, Williams CA, Bader PI, Szczepanik E, Mazurczak T, Antczak-Marach D, Coldwell JG, Akman CI, McAlmon K, Cohen MP, McGrath J, Roeder E, Mueller J, Kang SHL, Bacino CA, Patel A, Bocian E, Shaw CA, Cheung SW, Mazurczak T, Stankiewicz P. Recurrent distal 7q11.23 deletion including HIP1 and YWHAG identified in patients with intellectual disabilities, epilepsy, and neurobehavioral problems. Am J Hum Genet 2010; 87:857-65. [PMID: 21109226 DOI: 10.1016/j.ajhg.2010.10.019] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2010] [Revised: 10/12/2010] [Accepted: 10/22/2010] [Indexed: 11/19/2022] Open
Abstract
We report 26 individuals from ten unrelated families who exhibit variable expression and/or incomplete penetrance of epilepsy, learning difficulties, intellectual disabilities, and/or neurobehavioral abnormalities as a result of a heterozygous microdeletion distally adjacent to the Williams-Beuren syndrome region on chromosome 7q11.23. In six families with a common recurrent ∼1.2 Mb deletion that includes the Huntingtin-interacting protein 1 (HIP1) and tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein gamma (YWHAG) genes and that is flanked by large complex low-copy repeats, we identified sites for nonallelic homologous recombination in two patients. There were no cases of this ∼1.2 Mb distal 7q11.23 deletion copy number variant identified in over 20,000 control samples surveyed. Three individuals with smaller, nonrecurrent deletions (∼180-500 kb) that include HIP1 but not YWHAG suggest that deletion of HIP1 is sufficient to cause neurological disease. Mice with targeted mutation in the Hip1 gene (Hip1⁻(/)⁻) develop a neurological phenotype characterized by failure to thrive, tremor, and gait ataxia. Overall, our data characterize a neurodevelopmental and epilepsy syndrome that is likely caused by recurrent and nonrecurrent deletions, including HIP1. These data do not exclude the possibility that YWHAG loss of function is also sufficient to cause neurological phenotypes. Based on the current knowledge of Hip1 protein function and its proposed role in AMPA and NMDA ionotropic glutamate receptor trafficking, we believe that HIP1 haploinsufficiency in humans will be amenable to rational drug design for improved seizure control and cognitive and behavioral function.
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Affiliation(s)
- Melissa B Ramocki
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
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28
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Boone PM, Bacino CA, Shaw CA, Eng PA, Hixson PM, Pursley AN, Kang SHL, Yang Y, Wiszniewska J, Nowakowska BA, del Gaudio D, Xia Z, Simpson-Patel G, Immken LL, Gibson JB, Tsai ACH, Bowers JA, Reimschisel TE, Schaaf CP, Potocki L, Scaglia F, Gambin T, Sykulski M, Bartnik M, Derwinska K, Wisniowiecka-Kowalnik B, Lalani SR, Probst FJ, Bi W, Beaudet AL, Patel A, Lupski JR, Cheung SW, Stankiewicz P. Detection of clinically relevant exonic copy-number changes by array CGH. Hum Mutat 2010; 31:1326-42. [PMID: 20848651 DOI: 10.1002/humu.21360] [Citation(s) in RCA: 201] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Accepted: 09/02/2010] [Indexed: 12/22/2022]
Abstract
Array comparative genomic hybridization (aCGH) is a powerful tool for the molecular elucidation and diagnosis of disorders resulting from genomic copy-number variation (CNV). However, intragenic deletions or duplications--those including genomic intervals of a size smaller than a gene--have remained beyond the detection limit of most clinical aCGH analyses. Increasing array probe number improves genomic resolution, although higher cost may limit implementation, and enhanced detection of benign CNV can confound clinical interpretation. We designed an array with exonic coverage of selected disease and candidate genes and used it clinically to identify losses or gains throughout the genome involving at least one exon and as small as several hundred base pairs in size. In some patients, the detected copy-number change occurs within a gene known to be causative of the observed clinical phenotype, demonstrating the ability of this array to detect clinically relevant CNVs with subkilobase resolution. In summary, we demonstrate the utility of a custom-designed, exon-targeted oligonucleotide array to detect intragenic copy-number changes in patients with various clinical phenotypes.
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Affiliation(s)
- Philip M Boone
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
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Girirajan S, Eichler EE. Phenotypic variability and genetic susceptibility to genomic disorders. Hum Mol Genet 2010; 19:R176-87. [PMID: 20807775 PMCID: PMC2953748 DOI: 10.1093/hmg/ddq366] [Citation(s) in RCA: 199] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Revised: 07/28/2010] [Accepted: 08/24/2010] [Indexed: 11/13/2022] Open
Abstract
The duplication architecture of the human genome predisposes our species to recurrent copy number variation and disease. Emerging data suggest that this mechanism of mutation contributes to both common and rare diseases. Two features regarding this form of mutation have emerged. First, common structural polymorphisms create susceptible and protective chromosomal architectures. These structural polymorphisms occur at varying frequencies in populations, leading to different susceptibility and ethnic predilection. Second, a subset of rearrangements shows extreme variability in expressivity. We propose that two types of genomic disorders may be distinguished: syndromic forms where the phenotypic features are largely invariant and those where the same molecular lesion associates with a diverse set of diagnoses including epilepsy, schizophrenia, autism, intellectual disability and congenital malformations. Copy number variation analyses of patient genomes reveal that disease type and severity may be explained by the occurrence of additional rare events and their inheritance within families. We propose that the overall burden of copy number variants creates differing sensitized backgrounds during development leading to different thresholds and disease outcomes. We suggest that the accumulation of multiple high-penetrant alleles of low frequency may serve as a more general model for complex genetic diseases, posing a significant challenge for diagnostics and disease management.
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Affiliation(s)
| | - Evan E. Eichler
- Department of Genome Sciences, Howard Hughes Medical Institute,University of Washington School of Medicine, PO Box 355065, Foege S413C, 3720 15th Avenue NE, Seattle, WA 98195, USA
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30
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Deletion and duplication of 15q24: Molecular mechanisms and potential modification by additional copy number variants. Genet Med 2010; 12:573-86. [DOI: 10.1097/gim.0b013e3181eb9b4a] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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31
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Abstract
During the last quarter of the twentieth century, our knowledge about human genetic variation was limited mainly to the heterochromatin polymorphisms, large enough to be visible in the light microscope, and the single nucleotide polymorphisms (SNPs) identified by traditional PCR-based DNA sequencing. In the past five years, the rapid development and expanded use of microarray technologies, including oligonucleotide array comparative genomic hybridization and SNP genotyping arrays, as well as next-generation sequencing with “paired-end” methods, has enabled a whole-genome analysis with essentially unlimited resolution. The discovery of submicroscopic copy-number variations (CNVs) present in our genomes has changed dramatically our perspective on DNA structural variation and disease. It is now thought that CNVs encompass more total nucleotides and arise more frequently than SNPs. CNVs, to a larger extent than SNPs, have been shown to be responsible for human evolution, genetic diversity between individuals, and a rapidly increasing number of traits or susceptibility to traits; such conditions have been referred to as genomic disorders. In addition to well-known sporadic chromosomal microdeletion syndromes and Mendelian diseases, many common complex traits including autism and schizophrenia can result from CNVs. Both recombination- and replication-based mechanisms for CNV formation have been described.
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Affiliation(s)
| | - James R. Lupski
- Departments of Molecular and Human Genetics, Houston, Texas 77030
- Departments of Pediatrics, Baylor College of Medicine, Houston, Texas 77030
- Departments of Texas Children's Hospital, Houston, Texas 77030
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32
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Shinawi M, Liu P, Kang SHL, Shen J, Belmont JW, Scott DA, Probst FJ, Craigen WJ, Graham BH, Pursley A, Clark G, Lee J, Proud M, Stocco A, Rodriguez DL, Kozel BA, Sparagana S, Roeder ER, McGrew SG, Kurczynski TW, Allison LJ, Amato S, Savage S, Patel A, Stankiewicz P, Beaudet AL, Cheung SW, Lupski JR. Recurrent reciprocal 16p11.2 rearrangements associated with global developmental delay, behavioural problems, dysmorphism, epilepsy, and abnormal head size. J Med Genet 2009; 47:332-41. [PMID: 19914906 DOI: 10.1136/jmg.2009.073015] [Citation(s) in RCA: 363] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND Deletion and the reciprocal duplication in 16p11.2 were recently associated with autism and developmental delay. METHOD We indentified 27 deletions and 18 duplications of 16p11.2 were identified in 0.6% of all samples submitted for clinical array-CGH (comparative genomic hybridisation) analysis. Detailed molecular and phenotypic characterisations were performed on 17 deletion subjects and ten subjects with the duplication. RESULTS The most common clinical manifestations in 17 deletion and 10 duplication subjects were speech/language delay and cognitive impairment. Other phenotypes in the deletion patients included motor delay (50%), seizures ( approximately 40%), behavioural problems ( approximately 40%), congenital anomalies ( approximately 30%), and autism ( approximately 20%). The phenotypes among duplication patients included motor delay (6/10), behavioural problems (especially attention deficit hyperactivity disorder (ADHD)) (6/10), congenital anomalies (5/10), and seizures (3/10). Patients with the 16p11.2 deletion had statistically significant macrocephaly (p<0.0017) and 6 of the 10 patients with the duplication had microcephaly. One subject with the deletion was asymptomatic and another with the duplication had a normal cognitive and behavioural phenotype. Genomic analyses revealed additional complexity to the 16p11.2 region with mechanistic implications. The chromosomal rearrangement was de novo in all but 2 of the 10 deletion cases in which parental studies were available. Additionally, 2 de novo cases were apparently mosaic for the deletion in the analysed blood sample. Three de novo and 2 inherited cases were observed in the 5 of 10 duplication patients where data were available. CONCLUSIONS Recurrent reciprocal 16p11.2 deletion and duplication are characterised by a spectrum of primarily neurocognitive phenotypes that are subject to incomplete penetrance and variable expressivity. The autism and macrocephaly observed with deletion and ADHD and microcephaly seen in duplication patients support a diametric model of autism spectrum and psychotic spectrum behavioural phenotypes in genomic sister disorders.
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Affiliation(s)
- Marwan Shinawi
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, NAB 2015, Houston, Texas 77030, USA;
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Carvalho CMB, Zhang F, Liu P, Patel A, Sahoo T, Bacino CA, Shaw C, Peacock S, Pursley A, Tavyev YJ, Ramocki MB, Nawara M, Obersztyn E, Vianna-Morgante AM, Stankiewicz P, Zoghbi HY, Cheung SW, Lupski JR. Complex rearrangements in patients with duplications of MECP2 can occur by fork stalling and template switching. Hum Mol Genet 2009; 18:2188-203. [PMID: 19324899 DOI: 10.1093/hmg/ddp151] [Citation(s) in RCA: 156] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Duplication at the Xq28 band including the MECP2 gene is one of the most common genomic rearrangements identified in neurodevelopmentally delayed males. Such duplications are non-recurrent and can be generated by a non-homologous end joining (NHEJ) mechanism. We investigated the potential mechanisms for MECP2 duplication and examined whether genomic architectural features may play a role in their origin using a custom designed 4-Mb tiling-path oligonucleotide array CGH assay. Each of the 30 patients analyzed showed a unique duplication varying in size from approximately 250 kb to approximately 2.6 Mb. Interestingly, in 77% of these non-recurrent duplications, the distal breakpoints grouped within a 215 kb genomic interval, located 47 kb telomeric to the MECP2 gene. The genomic architecture of this region contains both direct and inverted low-copy repeat (LCR) sequences; this same region undergoes polymorphic structural variation in the general population. Array CGH revealed complex rearrangements in eight patients; in six patients the duplication contained an embedded triplicated segment, and in the other two, stretches of non-duplicated sequences occurred within the duplicated region. Breakpoint junction sequencing was achieved in four duplications and identified an inversion in one patient, demonstrating further complexity. We propose that the presence of LCRs in the vicinity of the MECP2 gene may generate an unstable DNA structure that can induce DNA strand lesions, such as a collapsed fork, and facilitate a Fork Stalling and Template Switching event producing the complex rearrangements involving MECP2.
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Affiliation(s)
- Claudia M B Carvalho
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
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Abstract
Copy number variation (CNV) is a source of genetic diversity in humans. Numerous CNVs are being identified with various genome analysis platforms, including array comparative genomic hybridization (aCGH), single nucleotide polymorphism (SNP) genotyping platforms, and next-generation sequencing. CNV formation occurs by both recombination-based and replication-based mechanisms and de novo locus-specific mutation rates appear much higher for CNVs than for SNPs. By various molecular mechanisms, including gene dosage, gene disruption, gene fusion, position effects, etc., CNVs can cause Mendelian or sporadic traits, or be associated with complex diseases. However, CNV can also represent benign polymorphic variants. CNVs, especially gene duplication and exon shuffling, can be a predominant mechanism driving gene and genome evolution.
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Affiliation(s)
- Feng Zhang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
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35
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Hereditary pancreatitis caused by a double gain-of-function trypsinogen mutation. Hum Genet 2008; 123:521-9. [PMID: 18461367 DOI: 10.1007/s00439-008-0508-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Accepted: 04/28/2008] [Indexed: 01/28/2023]
Abstract
Hereditary pancreatitis, an autosomal dominant disease with approximately 80% penetrance, can be caused by both 'gain-of-function' missense and copy number mutations in the cationic trypsinogen gene (PRSS1). Here we demonstrate a heterozygous hybrid PRSS2 (encoding anionic trypsinogen)/PRSS1 gene in a French white family with hereditary pancreatitis, by means of quantitative fluorescent multiplex PCR and RT-PCR analyses. The hybrid gene, in which exons 1 and 2 are derived from PRSS2 and exons 3-5 from PRSS1, apparently resulted from a non-allelic homologous recombination (NAHR) event between the chromosome 7 homologs or sister chromatids during meiosis. Interestingly, this hybrid gene causes the disease through a combination of its inherent 'double gain-of-function' effect, acting simultaneously as a 'quantitative' copy number mutation and a 'qualitative' missense mutation (i.e. the known disease-causing p.N29I mutation). Our finding reveals a previously unknown mechanism causing human inherited disease, enriches the lexicon of human genetic variation and goes beyond the known interaction between copy number variations (CNVs) and single nucleotide substitutions in health and disease. Our finding should also stimulate more interest in analyzing both types of genetic variation whenever one tries to determine the contribution of a specific locus to a given disease phenotype.
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Microduplications of 22q11.2 are frequently inherited and are associated with variable phenotypes. Genet Med 2008; 10:267-77. [DOI: 10.1097/gim.0b013e31816b64c2] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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37
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Flipsen-ten Berg K, van Hasselt PM, Eleveld MJ, van der Wijst SE, Hol FA, de Vroede MAM, Beemer FA, Hochstenbach PFR, Poot M. Unmasking of a hemizygous WFS1 gene mutation by a chromosome 4p deletion of 8.3 Mb in a patient with Wolf–Hirschhorn syndrome. Eur J Hum Genet 2007; 15:1132-8. [PMID: 17637805 DOI: 10.1038/sj.ejhg.5201899] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The Wolf-Hirschhorn syndrome (WHS (MIM 194190)), which is characterized by growth delay, mental retardation, epilepsy, facial dysmorphisms, and midline fusion defects, shows extensive phenotypic variability. Several of the proposed mutational and epigenetic mechanisms in this and other chromosomal deletion syndromes fail to explain the observed phenotypic variability. To explain the complex phenotype of a patient with WHS and features reminiscent of Wolfram syndrome (WFS (MIM 222300)), we performed extensive clinical evaluation and classical and molecular cytogenetic (GTG banding, FISH and array-CGH) and WFS1 gene mutation analyses. We detected an 8.3 Mb terminal deletion and an adjacent 2.6 Mb inverted duplication in the short arm of chromosome 4, which encompasses a gene associated with WFS (WFS1). In addition, a nonsense mutation in exon 8 of the WFS1 gene was found on the structurally normal chromosome 4. The combination of the 4p deletion with the WFS1 point mutation explains the complex phenotype presented by our patient. This case further illustrates that unmasking of hemizygous recessive mutations by chromosomal deletions represents an additional explanation for the phenotypic variability observed in chromosomal deletion disorders.
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Affiliation(s)
- Klara Flipsen-ten Berg
- Department of Medical Genetics, University Medical Centre Utrecht, Utrecht, The Netherlands.
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38
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Abstract
Rearrangements of our genome can be responsible for inherited as well as sporadic traits. The analyses of chromosome breakpoints in the proximal short arm of Chromosome 17 (17p) reveal nonallelic homologous recombination (NAHR) as a major mechanism for recurrent rearrangements whereas nonhomologous end-joining (NHEJ) can be responsible for many of the nonrecurrent rearrangements. Genome architectural features consisting of low-copy repeats (LCRs), or segmental duplications, can stimulate and mediate NAHR, and there are hotspots for the crossovers within the LCRs. Rearrangements introduce variation into our genome for selection to act upon and as such serve an evolutionary function analogous to base pair changes. Genomic rearrangements may cause Mendelian diseases, produce complex traits such as behaviors, or represent benign polymorphic changes. The mechanisms by which rearrangements convey phenotypes are diverse and include gene dosage, gene interruption, generation of a fusion gene, position effects, unmasking of recessive coding region mutations (single nucleotide polymorphisms, SNPs, in coding DNA) or other functional SNPs, and perhaps by effects on transvection.
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Affiliation(s)
- James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, and at the Texas Children's Hospital, Houston, Texas, United States of America.
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