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Elert-Dobkowska E, Stepniak I, Radziwonik-Fraczyk W, Jahic A, Beetz C, Sulek A. SPAST Intragenic CNVs Lead to Hereditary Spastic Paraplegia via a Haploinsufficiency Mechanism. Int J Mol Sci 2024; 25:5008. [PMID: 38732227 PMCID: PMC11084448 DOI: 10.3390/ijms25095008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 04/26/2024] [Accepted: 04/30/2024] [Indexed: 05/13/2024] Open
Abstract
The most common form of hereditary spastic paraplegia (HSP), SPG4 is caused by single nucleotide variants and microrearrangements in the SPAST gene. The high percentage of multi-exonic deletions or duplications observed in SPG4 patients is predisposed by the presence of a high frequency of Alu sequences in the gene sequence. In the present study, we analyzed DNA and RNA samples collected from patients with different microrearrangements in SPAST to map gene breakpoints and evaluate the mutation mechanism. The study group consisted of 69 individuals, including 50 SPG4 patients and 19 healthy relatives from 18 families. Affected family members from 17 families carried varying ranges of microrearrangements in the SPAST gene, while one individual had a single nucleotide variant in the 5'UTR of SPAST. To detect the breakpoints of the SPAST gene, long-range PCR followed by sequencing was performed. The breakpoint sequence was detected for five different intragenic SPAST deletions and one duplication, revealing Alu-mediated microhomology at breakpoint junctions resulting from non-allelic homologous recombination in these patients. Furthermore, SPAST gene expression analysis was performed using patient RNA samples extracted from whole blood. Quantitative real-time PCR tests performed in 14 patients suggest no expression of transcripts with microrearrangements in 5 of them. The obtained data indicate that nonsense-mediated decay degradation is not the only mechanism of hereditary spastic paraplegia in patients with SPAST microrearrangements.
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Affiliation(s)
- Ewelina Elert-Dobkowska
- Department of Genetics, Institute of Psychiatry and Neurology, 02-957 Warsaw, Poland; (E.E.-D.); (I.S.); (W.R.-F.)
| | - Iwona Stepniak
- Department of Genetics, Institute of Psychiatry and Neurology, 02-957 Warsaw, Poland; (E.E.-D.); (I.S.); (W.R.-F.)
| | - Wiktoria Radziwonik-Fraczyk
- Department of Genetics, Institute of Psychiatry and Neurology, 02-957 Warsaw, Poland; (E.E.-D.); (I.S.); (W.R.-F.)
| | - Amir Jahic
- Institute of Diagnostic Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Charité–Universitätsmedizin, 10117 Berlin, Germany;
| | - Christian Beetz
- Department of Chemistry and Laboratory Medicine, Jena University Hospital, 07747 Jena, Germany;
- Centogene, 18055 Rostock, Germany
| | - Anna Sulek
- Faculty of Medicine, Lazarski University, 02-662 Warsaw, Poland
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da Costa SS, Fishman V, Pinheiro M, Rodrigueiro A, Sanseverino MT, Zielinsky P, Carvalho CMB, Rosenberg C, Krepischi ACV. A germline chimeric KANK1-DMRT1 transcript derived from a complex structural variant is associated with a congenital heart defect segregating across five generations. Chromosome Res 2024; 32:6. [PMID: 38504027 DOI: 10.1007/s10577-024-09750-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 02/27/2024] [Accepted: 03/08/2024] [Indexed: 03/21/2024]
Abstract
Structural variants (SVs) pose a challenge to detect and interpret, but their study provides novel biological insights and molecular diagnosis underlying rare diseases. The aim of this study was to resolve a 9p24 rearrangement segregating in a family through five generations with a congenital heart defect (congenital pulmonary and aortic valvular stenosis and pulmonary artery stenosis), by applying a combined genomic analysis. The analysis involved multiple techniques, including karyotype, chromosomal microarray analysis (CMA), FISH, genome sequencing (GS), RNA-seq, and optical genome mapping (OGM). A complex 9p24 SV was hinted at by CMA results, showing three interspersed duplicated segments. Combined GS and OGM analyses revealed that the 9p24 duplications constitute a complex SV, on which a set of breakpoints matches the boundaries of the CMA duplicated sequences. The proposed structure for this complex rearrangement implies three duplications associated with an inversion of ~ 2 Mb region on chromosome 9 and a SINE element insertion at the more distal breakpoint. Interestingly, this genomic structure of rearrangement forms a chimeric transcript of the KANK1/DMRT1 loci, which was confirmed by both RNA-seq and Sanger sequencing on blood samples from 9p24 rearrangement carriers. Altogether with breakpoint amplification and FISH analysis, this combined approach allowed a deep characterization of this complex rearrangement. Although the genotype-phenotype correlation remains elusive from the molecular mechanism point of view, this study identified a large genomic rearrangement at 9p24 segregating with a familial congenital heart defect, revealing a genetic biomarker that was successfully applied for embryo selection, changing the reproductive perspective of affected individuals.
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Affiliation(s)
- Silvia Souza da Costa
- Human Genome and Stem-Cell Research Center, Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
| | - Veniamin Fishman
- Human Genome and Stem-Cell Research Center, Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
- The Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - Mara Pinheiro
- Human Genome and Stem-Cell Research Center, Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
| | | | - Maria Teresa Sanseverino
- Medical Genetics Service, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
- School of Medicine, Pontifícia Universidade Catolica do Rio Grande Do Sul, Porto Alegre, Brazil
| | - Paulo Zielinsky
- Department of Pediatrics and Childcare, Federal University of the Rio Grande do Sul, Porto Alegre, Brazil
| | | | - Carla Rosenberg
- Human Genome and Stem-Cell Research Center, Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
| | - Ana Cristina Victorino Krepischi
- Human Genome and Stem-Cell Research Center, Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil.
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Konečná K, Zapletalová P, Freiberger T, Tichý L. LDLR gene rearrangements in Czech FH patients likely arise from one mutational event. Lipids Health Dis 2024; 23:36. [PMID: 38308247 PMCID: PMC10835926 DOI: 10.1186/s12944-024-02013-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 01/09/2024] [Indexed: 02/04/2024] Open
Abstract
BACKGROUND Large deletions and duplications within the low-density lipoprotein receptor (LDLR) gene make up approximately 10% of LDLR pathogenic variants found in Czech patients with familial hypercholesterolemia. The goal of this study was to test the hypothesis that all probands with each rearrangement share identical breakpoints inherited from a common ancestor and to determine the role of Alu repetitive elements in the generation of these rearrangements. METHODS The breakpoint sequence was determined by PCR amplification and Sanger sequencing. To confirm the breakpoint position, an NGS analysis was performed. Haplotype analysis of common LDLR variants was performed using PCR and Sanger sequencing. RESULTS The breakpoints of 8 rearrangements within the LDLR gene were analysed, including the four most common LDLR rearrangements in the Czech population (number of probands ranging from 8 to 28), and four less common rearrangements (1-4 probands). Probands with a specific rearrangement shared identical breakpoint positions and haplotypes associated with the rearrangement, suggesting a shared origin from a common ancestor. All breakpoints except for one were located inside an Alu element. In 6 out of 8 breakpoints, there was high homology (≥ 70%) between the two Alu repeats in which the break occurred. CONCLUSIONS The most common rearrangements of the LDLR gene in the Czech population likely arose from one mutational event. Alu elements likely played a role in the generation of the majority of rearrangements inside the LDLR gene.
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Affiliation(s)
- Kateřina Konečná
- Centre of Molecular Biology and Genetics, University Hospital Brno, Jihlavská 20, Brno, 625 00, Czech Republic
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, Brno, 625 00, Czech Republic
- Faculty of Medicine, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic
| | - Petra Zapletalová
- Centre of Molecular Biology and Genetics, University Hospital Brno, Jihlavská 20, Brno, 625 00, Czech Republic
| | - Tomáš Freiberger
- Faculty of Medicine, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic
- Centre for Cardiovascular Surgery and Transplantation, Pekařská 53, 656 91, Brno, Czech Republic
| | - Lukáš Tichý
- Centre of Molecular Biology and Genetics, University Hospital Brno, Jihlavská 20, Brno, 625 00, Czech Republic.
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Sakamoto M, Kurosawa K, Tanoue K, Iwama K, Ishida F, Watanabe Y, Okamoto N, Tsuchida N, Uchiyama Y, Koshimizu E, Fujita A, Misawa K, Miyatake S, Mizuguchi T, Matsumoto N. A heterozygous germline deletion within USP8 causes severe neurodevelopmental delay with multiorgan abnormalities. J Hum Genet 2024; 69:85-90. [PMID: 38030753 DOI: 10.1038/s10038-023-01209-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 11/14/2023] [Accepted: 11/14/2023] [Indexed: 12/01/2023]
Abstract
Ubiquitin-specific protease 8 (USP8) is a deubiquitinating enzyme involved in deubiquitinating the enhanced epidermal growth factor receptor for escape from degradation. Somatic variants at a hotspot in USP8 are a cause of Cushing's disease, and a de novo germline USP8 variant at this hotspot has been described only once previously, in a girl with Cushing's disease and developmental delay. In this study, we investigated an exome-negative patient with severe developmental delay, dysmorphic features, and multiorgan dysfunction by long-read sequencing, and identified a 22-kb de novo germline deletion within USP8 (chr15:50469966-50491995 [GRCh38]). The deletion involved the variant hotspot, one rhodanese domain, and two SH3 binding motifs, and was presumed to be generated through nonallelic homologous recombination through Alu elements. Thus, the patient may have perturbation of the endosomal sorting system and mitochondrial autophagy through the USP8 defect. This is the second reported case of a germline variant in USP8.
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Affiliation(s)
- Masamune Sakamoto
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
- Department of Pediatrics, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
- Department of Rare Disease Genomics, Yokohama City University Hospital, Yokohama, Japan
| | - Kenji Kurosawa
- Division of Medical Genetics, Kanagawa Children's Medical Center, Yokohama, Japan
| | - Koji Tanoue
- Department of General Medicine, Kanagawa Children's Medical Center, Yokohama, Japan
| | - Kazuhiro Iwama
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
- Perinatal Center for Maternity and Neonate, Yokohama City University Medical Center, Yokohama, Japan
| | - Fumihiko Ishida
- Perinatal Center for Maternity and Neonate, Yokohama City University Medical Center, Yokohama, Japan
| | - Yoshihiro Watanabe
- Children's Medical Center, Yokohama City University Medical Center, Yokohama, Japan
| | - Nobuhiko Okamoto
- Department of Medical Genetics, Osaka Women's and Children's Hospital, Izumi, Japan
| | - Naomi Tsuchida
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
- Department of Rare Disease Genomics, Yokohama City University Hospital, Yokohama, Japan
| | - Yuri Uchiyama
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
- Department of Rare Disease Genomics, Yokohama City University Hospital, Yokohama, Japan
| | - Eriko Koshimizu
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Atsushi Fujita
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Kazuharu Misawa
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
- Riken Center for Advanced Intelligence Project, Tokyo, Japan
| | - Satoko Miyatake
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
- Department of Clinical Genetics, Yokohama City University Hospital, Yokohama, Japan
| | - Takeshi Mizuguchi
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama, Japan.
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Costa SS, Fishman V, Pinheiro M, Rodrigueiro A, Sanseverino MT, Zielinsky P, Carvalho CMB, Rosenberg C, Krepischi ACV. A germline chimeric KANK1-DMRT1 transcript derived from a complex structural variant is associated with a congenital heart defect segregating across five generations. RESEARCH SQUARE 2023:rs.3.rs-3740005. [PMID: 38168413 PMCID: PMC10760254 DOI: 10.21203/rs.3.rs-3740005/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Structural variants (SVs) pose a challenge to detect and interpret, but their study provides novel biological insights and molecular diagnosis underlying rare diseases. The aim of this study was to resolve a 9p24 rearrangement segregating in a family through five generations with a congenital heart defect (congenital pulmonary and aortic valvular stenosis, and pulmonary artery stenosis), by applying a combined genomic analysis. The analysis involved multiple techniques, including karyotype, chromosomal microarray analysis (CMA), FISH, whole-genome sequencing (WGS), RNA-seq and optical genome mapping (OGM). A complex 9p24 SV was hinted at by CMA results, showing three interspersed duplicated segments. Combined WGS and OGM analyses revealed that the 9p24 duplications constitute a complex SV, on which a set of breakpoints match the boundaries of the CMA duplicated sequences. The proposed structure for this complex rearrangement implies three duplications associated with an inversion of ~ 2Mb region on chromosome 9 with a SINE element insertion at the more distal breakpoint. Interestingly, this hypothesized genomic structure of rearrangement forms a chimeric transcript of the KANK1/DMRT1 loci, which was confirmed by RNA-seq on blood from 9p24 rearrangement carriers. Altogether with breakpoint amplification and FISH analysis, this combined approach allowed a deep characterization of this complex rearrangement. Although the genotype-phenotype correlation remains elusive from the molecular mechanism point of view, this study identified a large genomic rearrangement at 9p segregating with a familial congenital clinical trait, revealing a genetic biomarker that was successfully applied for embryo selection, changing the reproductive perspective of affected individuals.
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6
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Hinch R, Donnelly P, Hinch AG. Meiotic DNA breaks drive multifaceted mutagenesis in the human germ line. Science 2023; 382:eadh2531. [PMID: 38033082 PMCID: PMC7615360 DOI: 10.1126/science.adh2531] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 09/29/2023] [Indexed: 12/02/2023]
Abstract
Meiotic recombination commences with hundreds of programmed DNA breaks; however, the degree to which they are accurately repaired remains poorly understood. We report that meiotic break repair is eightfold more mutagenic for single-base substitutions than was previously understood, leading to de novo mutation in one in four sperm and one in 12 eggs. Its impact on indels and structural variants is even higher, with 100- to 1300-fold increases in rates per break. We uncovered new mutational signatures and footprints relative to break sites, which implicate unexpected biochemical processes and error-prone DNA repair mechanisms, including translesion synthesis and end joining in meiotic break repair. We provide evidence that these mechanisms drive mutagenesis in human germ lines and lead to disruption of hundreds of genes genome wide.
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Affiliation(s)
- Robert Hinch
- Big Data Institute, University of Oxford; Oxford, UK
| | - Peter Donnelly
- Wellcome Centre for Human Genetics, University of Oxford; Oxford, UK
- Genomics plc; Oxford, UK
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Ghasemi A, Sadr Z, Babanejad M, Rohani M, Alavi A. Copy Number Variations in Hereditary Spastic Paraplegia-Related Genes: Evaluation of an Iranian Hereditary Spastic Paraplegia Cohort and Literature Review. Mol Syndromol 2023; 14:477-484. [PMID: 38058755 PMCID: PMC10697729 DOI: 10.1159/000531507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 06/07/2023] [Indexed: 12/08/2023] Open
Abstract
Introduction In human genetic disorders, copy number variations (CNVs) are considered a considerable underlying cause. CNVs are generally detected by array-based methods but can also be discovered by read-depth analysis of whole-exome sequencing (WES) data. We performed WES-based CNV identification in a cohort of 35 Iranian families with hereditary spastic paraplegia (HSP) patients. Methods Thirty-five patients whose routine single-nucleotide variants (SNVs) and insertion/deletion analyses from exome data were unrevealing underwent a pipeline of CNV analysis using the read-depth detection method. Subsequently, a comprehensive search about the existence of CNVs in all 84 known HSP-causing genes was carried out in all reported HSP cases, so far. Results and Discussion CNV analysis of exome data indicated that 1 patient harbored a heterozygous deletion in exon 17 of the SPAST gene. Multiplex ligation-dependent probe amplification analysis confirmed this deletion in the proband and his affected father. Literature review demonstrated that, to date, pathogenic CNVs have been identified in 30 out of 84 HSP-causing genes (∼36%). However, CNVs in only 17 of these genes were specifically associated with the HSP phenotype. Among them, CNVs were more common in L1CAM, PLP1, SPAST, SPG7, SPG11, and REEP1 genes. The identification of the CNV in 1 of our patients suggests that WES allows the detection of both SNVs and CNVs from a single method without additional costs and execution time. However, because of intrinsic issues of WES in the detection of large rearrangements, it may not yet be exploited to replace the CNV detection methods in standard clinical practice.
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Affiliation(s)
- Aida Ghasemi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Zahra Sadr
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Mojgan Babanejad
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Mohammad Rohani
- Department of Neurology, Iran University of Medical Sciences, Hazrat Rasool Hospital, Tehran, Iran
| | - Afagh Alavi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
- Neuromuscular Research Center, Tehran University of Medical Sciences, Tehran, Iran
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Fukuda H, Mizuguchi T, Doi H, Kameyama S, Kunii M, Joki H, Takahashi T, Komiya H, Sasaki M, Miyaji Y, Ohori S, Koshimizu E, Uchiyama Y, Tsuchida N, Fujita A, Hamanaka K, Misawa K, Miyatake S, Tanaka F, Matsumoto N. Long-read sequencing revealing intragenic deletions in exome-negative spastic paraplegias. J Hum Genet 2023; 68:689-697. [PMID: 37308565 DOI: 10.1038/s10038-023-01170-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 05/01/2023] [Accepted: 06/04/2023] [Indexed: 06/14/2023]
Abstract
Hereditary spastic paraplegias (HSPs) are a heterogeneous group of neurodegenerative disorders characterized by progressive spasticity and weakness in the lower extremities. To date, a total of 88 types of SPG are known. To diagnose HSP, multiple technologies, including microarray, direct sequencing, multiplex ligation-dependent probe amplification, and short-read next-generation sequencing, are often chosen based on the frequency of HSP subtypes. Exome sequencing (ES) is commonly used. We used ES to analyze ten cases of HSP from eight families. We identified pathogenic variants in three cases (from three different families); however, we were unable to determine the cause of the other seven cases using ES. We therefore applied long-read sequencing to the seven undetermined HSP cases (from five families). We detected intragenic deletions within the SPAST gene in four families, and a deletion within PSEN1 in the remaining family. The size of the deletion ranged from 4.7 to 12.5 kb and involved 1-7 exons. All deletions were entirely included in one long read. We retrospectively performed an ES-based copy number variation analysis focusing on pathogenic deletions, but were not able to accurately detect these deletions. This study demonstrated the efficiency of long-read sequencing in detecting intragenic pathogenic deletions in ES-negative HSP patients.
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Affiliation(s)
- Hiromi Fukuda
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
| | - Takeshi Mizuguchi
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan.
| | - Hiroshi Doi
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
| | - Shinichi Kameyama
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
- Department of Pathology, Keio University School of Medicine, Tokyo, 160-8582, Japan
| | - Misako Kunii
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
| | - Hideto Joki
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
- Department of Neurology, National Hospital Organization Yokohama Medical Center, Yokohama, Kanagawa, 245-8575, Japan
| | - Tatsuya Takahashi
- Department of Neurology, National Hospital Organization Yokohama Medical Center, Yokohama, Kanagawa, 245-8575, Japan
| | - Hiroyasu Komiya
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
| | - Mei Sasaki
- Department of Neurology, Yokohama Minami Kyosai Hospital, Yokohama, 236-0037, Japan
| | - Yosuke Miyaji
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
| | - Sachiko Ohori
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
- Department of Clinical Genetics, Yokohama City University Hospital, Yokohama, 236-0004, Japan
- Department of Genetics, Kitasato University Hospital, Sagamihara, 252-0375, Japan
| | - Eriko Koshimizu
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
| | - Yuri Uchiyama
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
- Department of Rare Disease Genomics, Yokohama City University Hospital, Yokohama, 236-0004, Japan
| | - Naomi Tsuchida
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
- Department of Rare Disease Genomics, Yokohama City University Hospital, Yokohama, 236-0004, Japan
| | - Atsushi Fujita
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
| | - Kohei Hamanaka
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
| | - Kazuharu Misawa
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
- RIKEN Center for Advanced Intelligence Project, 1-4-1 Nihonbashi, Chuo-ku, Tokyo, 103-0027, Japan
| | - Satoko Miyatake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
- Department of Clinical Genetics, Yokohama City University Hospital, Yokohama, 236-0004, Japan
| | - Fumiaki Tanaka
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan.
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9
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Chen YJ, Wang MW, Qiu YS, Yuan RY, Wang N, Lin X, Chen WJ. Alu Retrotransposition Event in SPAST Gene as a Novel Cause of Hereditary Spastic Paraplegia. Mov Disord 2023; 38:1750-1755. [PMID: 37394769 DOI: 10.1002/mds.29522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 06/05/2023] [Accepted: 06/12/2023] [Indexed: 07/04/2023] Open
Abstract
OBJECTIVES To diagnose the molecular cause of hereditary spastic paraplegia (HSP) observed in a four-generation family with autosomal dominant inheritance. METHODS Multiplex ligation-dependent probe amplification (MLPA), whole-exome sequencing (WES), and RNA sequencing (RNA-seq) of peripheral blood leukocytes were performed. Reverse transcription polymerase chain reaction (RT-PCR) and Sanger sequencing were used to characterize target regions of SPAST. RESULTS A 121-bp AluYb9 insertion with a 30-bp poly-A tail flanked by 15-bp direct repeats on both sides was identified in the edge of intron 16 in SPAST that segregated with the disease phenotype. CONCLUSIONS We identified an intronic AluYb9 insertion inducing splicing alteration in SPAST causing pure HSP phenotype that was not detected by routine WES analysis. Our findings suggest RNA-seq is a recommended implementation for undiagnosed cases by first-line diagnostic approaches. © 2023 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Yi-Jun Chen
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
- Department of Geriatrics, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
- Department of Geriatrics, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
| | - Meng-Wen Wang
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Yu-Sen Qiu
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Ru-Ying Yuan
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Ning Wang
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
- Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, China
| | - Xiang Lin
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
- Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, China
| | - Wan-Jin Chen
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
- Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, China
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10
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Smirnov D, Konstantinovskiy N, Prokisch H. Integrative omics approaches to advance rare disease diagnostics. J Inherit Metab Dis 2023; 46:824-838. [PMID: 37553850 DOI: 10.1002/jimd.12663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 07/26/2023] [Accepted: 07/27/2023] [Indexed: 08/10/2023]
Abstract
Over the past decade high-throughput DNA sequencing approaches, namely whole exome and whole genome sequencing became a standard procedure in Mendelian disease diagnostics. Implementation of these technologies greatly facilitated diagnostics and shifted the analysis paradigm from variant identification to prioritisation and evaluation. The diagnostic rates vary widely depending on the cohort size, heterogeneity and disease and range from around 30% to 50% leaving the majority of patients undiagnosed. Advances in omics technologies and computational analysis provide an opportunity to increase these unfavourable rates by providing evidence for disease-causing variant validation and prioritisation. This review aims to provide an overview of the current application of several omics technologies including RNA-sequencing, proteomics, metabolomics and DNA-methylation profiling for diagnostics of rare genetic diseases in general and inborn errors of metabolism in particular.
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Affiliation(s)
- Dmitrii Smirnov
- School of Medicine, Institute of Human Genetics, Technical University of Munich, Munich, Germany
- Institute of Neurogenomics, Computational Health Center, Helmholtz Munich, Neuherberg, Germany
| | - Nikita Konstantinovskiy
- School of Medicine, Institute of Human Genetics, Technical University of Munich, Munich, Germany
| | - Holger Prokisch
- School of Medicine, Institute of Human Genetics, Technical University of Munich, Munich, Germany
- Institute of Neurogenomics, Computational Health Center, Helmholtz Munich, Neuherberg, Germany
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11
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Khan S, Focșa IO, Budișteanu M, Stoica C, Nedelea F, Bohîlțea L, Caba L, Butnariu L, Pânzaru M, Rusu C, Jurcă C, Chirita-Emandi A, Bănescu C, Abbas W, Sadeghpour A, Baig SM, Bălgrădean M, Davis EE. Exome sequencing in a Romanian Bardet-Biedl syndrome cohort revealed an overabundance of causal BBS12 variants. Am J Med Genet A 2023; 191:2376-2391. [PMID: 37293956 PMCID: PMC10524726 DOI: 10.1002/ajmg.a.63322] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/16/2023] [Accepted: 05/26/2023] [Indexed: 06/10/2023]
Abstract
Bardet-Biedl syndrome (BBS), is an emblematic ciliopathy hallmarked by pleiotropy, phenotype variability, and extensive genetic heterogeneity. BBS is a rare (~1/140,000 to ~1/160,000 in Europe) autosomal recessive pediatric disorder characterized by retinal degeneration, truncal obesity, polydactyly, cognitive impairment, renal dysfunction, and hypogonadism. Twenty-eight genes involved in ciliary structure or function have been implicated in BBS, and explain the molecular basis for ~75%-80% of individuals. To investigate the mutational spectrum of BBS in Romania, we ascertained a cohort of 24 individuals in 23 families. Following informed consent, we performed proband exome sequencing (ES). We detected 17 different putative disease-causing single nucleotide variants or small insertion-deletions and two pathogenic exon disruptive copy number variants in known BBS genes in 17 pedigrees. The most frequently impacted genes were BBS12 (35%), followed by BBS4, BBS7, and BBS10 (9% each) and BBS1, BBS2, and BBS5 (4% each). Homozygous BBS12 p.Arg355* variants were present in seven pedigrees of both Eastern European and Romani origin. Our data show that although the diagnostic rate of BBS in Romania is likely consistent with other worldwide cohorts (74%), we observed a unique distribution of causal BBS genes, including overrepresentation of BBS12 due to a recurrent nonsense variant, that has implications for regional diagnostics.
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Affiliation(s)
- Sheraz Khan
- Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA
- Human Molecular Genetics Lab, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE-C), Faisalabad, Pakistan
- Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan
| | - Ina Ofelia Focșa
- University of Medicine and Pharmacy "Carol Davila", Bucharest, Romania
- Cytogenomic Medical Laboratory, Bucharest, Romania
| | - Magdalena Budișteanu
- Psychiatry Research Laboratory, "Prof. Dr. Alexandru Obregia" Clinical Hospital of Psychiatry, Bucharest, Romania
- Medical Genetic Laboratory, "Victor Babeș" National Institute of Pathology, Bucharest, Romania
- Department of Medical Genetics, Faculty of Medicine, "Titu Maiorescu" University, Bucharest, Romania
| | - Cristina Stoica
- University of Medicine and Pharmacy "Carol Davila", Bucharest, Romania
- Department of Pediatrics, Clinical Institute Fundeni, Bucharest, Romania
| | - Florina Nedelea
- University of Medicine and Pharmacy "Carol Davila", Bucharest, Romania
- Genetics Department, Clinical Hospital Filantropia, Bucharest, Romania
| | | | - Lavinia Caba
- Department of Medical Genetics, "Grigore T. Popa" University of Medicine and Pharmacy, Iași, Romania
| | - Lăcrămioara Butnariu
- Department of Medical Genetics, "Grigore T. Popa" University of Medicine and Pharmacy, Iași, Romania
- Regional Medical Genetics Centre, "Sf. Maria" Children's Hospital, Iași, Romania
| | - Monica Pânzaru
- Department of Medical Genetics, "Grigore T. Popa" University of Medicine and Pharmacy, Iași, Romania
- Regional Medical Genetics Centre, "Sf. Maria" Children's Hospital, Iași, Romania
| | - Cristina Rusu
- Department of Medical Genetics, "Grigore T. Popa" University of Medicine and Pharmacy, Iași, Romania
- Regional Medical Genetics Centre, "Sf. Maria" Children's Hospital, Iași, Romania
| | - Claudia Jurcă
- Department of Genetics, Faculty of Medicine and Pharmacy, University of Oradea, Oradea, Romania
- Department of Pediatrics, "Dr. Gavril Curteanu" Municipal Clinical Hospital, Oradea, Romania
| | - Adela Chirita-Emandi
- Emergency Hospital for Children Louis Turcanu, Regional Center of Medical Genetics Timis, Timisoara, Romania
- Victor Babes University of Medicine and Pharmacy Timisoara, Department of Microscopic Morphology Genetics, Center for Genomic Medicine, Timisoara, Romania
| | - Claudia Bănescu
- "George Emil Palade" University of Medicine, Pharmacy, Sciences and Technology, Târgu Mureş, Romania
| | - Wasim Abbas
- Human Molecular Genetics Lab, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE-C), Faisalabad, Pakistan
- Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan
| | - Azita Sadeghpour
- Center for Human Disease Modeling, Duke University Medical Center, Durham, North Carolina, USA
- Duke Precision Medicine Program, Department of Medicine, Division of General Internal Medicine, Duke University Medical Center, Durham, NC, USA
| | - Shahid Mahmood Baig
- Pakistan Science Foundation (PSF), Islamabad, Pakistan
- Department of Biological and Biomedical Sciences, Agha Khan University Karachi, Karachi, Pakistan
| | - Mihaela Bălgrădean
- University of Medicine and Pharmacy "Carol Davila", Bucharest, Romania
- Department of Pediatrics and Pediatric Nephrology, Emergency Clinical Hospital for Children "Maria Skłodowska Curie", Bucharest, Romania
| | - Erica E Davis
- Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA
- Department of Pediatrics and Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
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12
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Kim H, Shim Y, Lee TG, Won D, Choi JR, Shin S, Lee ST. Copy-number analysis by base-level normalization: An intuitive visualization tool for evaluating copy number variations. Clin Genet 2023; 103:35-44. [PMID: 36152294 DOI: 10.1111/cge.14236] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 09/19/2022] [Accepted: 09/20/2022] [Indexed: 12/13/2022]
Abstract
Next-generation sequencing (NGS) facilitates comprehensive molecular analyses that help with diagnosing unsolved disorders. In addition to detecting single-nucleotide variations and small insertions/deletions, bioinformatics tools can identify copy number variations (CNVs) in NGS data, which improves the diagnostic yield. However, due to the possibility of false positives, subsequent confirmation tests are generally performed. Here, we introduce Copy-number Analysis by BAse-level NormAlization (CABANA), a visualization tool that allows users to intuitively identify candidate CNVs using the normalized single-base-level read depth calculated from NGS data. To demonstrate how CABANA works, NGS data were obtained from 474 patients with neuromuscular disorders. CNVs were screened using a conventional bioinformatics tool, ExomeDepth, and then we normalized and visualized those data at the single-base level using CABANA, followed by manual inspection by geneticists to filter out false positives and determine candidate CNVs. In doing so, we identified 31 candidate CNVs (7%) in 474 patients and subsequently confirmed all of them to be true using multiplex ligation-dependent probe amplification. The performance of CABANA was deemed acceptable by comparing its diagnostic yield with previous data about neuromuscular disorders. Despite some limitations, we expect CABANA to help researchers accurately identify CNVs and reduce the need for subsequent confirmation testing.
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Affiliation(s)
- Hongkyung Kim
- Department of Laboratory Medicine, Yonsei University College of Medicine, Severance Hospital, Seoul, Republic of Korea
| | - Yeeun Shim
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, Republic of Korea
| | - Taek Gyu Lee
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, Republic of Korea
| | - Dongju Won
- Department of Laboratory Medicine, Yonsei University College of Medicine, Severance Hospital, Seoul, Republic of Korea
| | - Jong Rak Choi
- Department of Laboratory Medicine, Yonsei University College of Medicine, Severance Hospital, Seoul, Republic of Korea.,Dxome Co. Ltd, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - Saeam Shin
- Department of Laboratory Medicine, Yonsei University College of Medicine, Severance Hospital, Seoul, Republic of Korea
| | - Seung-Tae Lee
- Department of Laboratory Medicine, Yonsei University College of Medicine, Severance Hospital, Seoul, Republic of Korea.,Dxome Co. Ltd, Seongnam-si, Gyeonggi-do, Republic of Korea
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13
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Chen Z, Chen J, Gao M, Liu Y, Wu Y, Wang Y, Gong Y, Yu S, Liu W, Wan X, Sun X. Comprehensive analysis of the PRPF31 gene in retinitis pigmentosa patients: Four novel Alu-mediated copy number variations at the PRPF31 locus. Hum Mutat 2022; 43:2279-2294. [PMID: 36317469 DOI: 10.1002/humu.24494] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 10/10/2022] [Accepted: 10/24/2022] [Indexed: 11/11/2022]
Abstract
Retinitis pigmentosa (RP) is a monogenic disease characterized by irreversible degeneration of the retina. PRPF31, the second most common causative gene of autosomal dominant RP, frequently harbors copy number variations (CNVs), but the underlying mechanism is unclear. In this study, we summarized the phenotypic and genotypic characteristics of 18 RP families (F01-F18) with variants in PRPF31. The prevalence of PRPF31 variants in our cohort of Chinese RP families was 1.7% (18/1024). Seventeen different variants in PRPF31 were detected, including eight novel variants. Notably, four novel CNVs encompassing PRPF31, with a proportion of 22.2% (4/18), were validated to harbor gross deletions involving Alu/Alu-mediated rearrangements (AAMRs) in the same orientation. Among a total of 12 CNVs of PRPF31 with breakpoints mapped on nucleotide-resolution, 10 variants (83.3%) were presumably mediated by Alu elements. Furthermore, we described the correlation between the genotypes and phenotypes in PRPF31-related RP. Our findings expand the mutational spectrum of the PRPF31 gene and provide strong evidence that Alu elements of PRPF31 probably contribute to the susceptibility to genomic rearrangement in this locus.
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Affiliation(s)
- Zhixuan Chen
- Department of Ophthalmology, School of Medicine, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, Shanghai, China.,Department of Ophthalmology, National Clinical Research Center for Eye Diseases, Shanghai, China.,Department of Ophthalmology, Shanghai Key Laboratory of Fundus Diseases, Shanghai, China.,Department of Ophthalmology, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
| | - Jieqiong Chen
- Department of Ophthalmology, School of Medicine, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, Shanghai, China.,Department of Ophthalmology, National Clinical Research Center for Eye Diseases, Shanghai, China.,Department of Ophthalmology, Shanghai Key Laboratory of Fundus Diseases, Shanghai, China.,Department of Ophthalmology, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
| | - Min Gao
- Department of Ophthalmology, School of Medicine, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, Shanghai, China.,Department of Ophthalmology, National Clinical Research Center for Eye Diseases, Shanghai, China.,Department of Ophthalmology, Shanghai Key Laboratory of Fundus Diseases, Shanghai, China.,Department of Ophthalmology, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
| | - Yang Liu
- Department of Ophthalmology, School of Medicine, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, Shanghai, China.,Department of Ophthalmology, National Clinical Research Center for Eye Diseases, Shanghai, China.,Department of Ophthalmology, Shanghai Key Laboratory of Fundus Diseases, Shanghai, China.,Department of Ophthalmology, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
| | - Yidong Wu
- Department of Ophthalmology, School of Medicine, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, Shanghai, China.,Department of Ophthalmology, National Clinical Research Center for Eye Diseases, Shanghai, China.,Department of Ophthalmology, Shanghai Key Laboratory of Fundus Diseases, Shanghai, China.,Department of Ophthalmology, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
| | - Yafang Wang
- Department of Ophthalmology, School of Medicine, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, Shanghai, China.,Department of Ophthalmology, National Clinical Research Center for Eye Diseases, Shanghai, China.,Department of Ophthalmology, Shanghai Key Laboratory of Fundus Diseases, Shanghai, China.,Department of Ophthalmology, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
| | - Yuanyuan Gong
- Department of Ophthalmology, School of Medicine, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, Shanghai, China.,Department of Ophthalmology, National Clinical Research Center for Eye Diseases, Shanghai, China.,Department of Ophthalmology, Shanghai Key Laboratory of Fundus Diseases, Shanghai, China.,Department of Ophthalmology, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
| | - Suqin Yu
- Department of Ophthalmology, School of Medicine, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, Shanghai, China.,Department of Ophthalmology, National Clinical Research Center for Eye Diseases, Shanghai, China.,Department of Ophthalmology, Shanghai Key Laboratory of Fundus Diseases, Shanghai, China.,Department of Ophthalmology, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
| | - Wenjia Liu
- Department of Ophthalmology, School of Medicine, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, Shanghai, China.,Department of Ophthalmology, National Clinical Research Center for Eye Diseases, Shanghai, China.,Department of Ophthalmology, Shanghai Key Laboratory of Fundus Diseases, Shanghai, China.,Department of Ophthalmology, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
| | - Xiaoling Wan
- Department of Ophthalmology, School of Medicine, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, Shanghai, China.,Department of Ophthalmology, National Clinical Research Center for Eye Diseases, Shanghai, China.,Department of Ophthalmology, Shanghai Key Laboratory of Fundus Diseases, Shanghai, China.,Department of Ophthalmology, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
| | - Xiaodong Sun
- Department of Ophthalmology, School of Medicine, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University, Shanghai, China.,Department of Ophthalmology, National Clinical Research Center for Eye Diseases, Shanghai, China.,Department of Ophthalmology, Shanghai Key Laboratory of Fundus Diseases, Shanghai, China.,Department of Ophthalmology, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
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14
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Rad52's DNA annealing activity drives template switching associated with restarted DNA replication. Nat Commun 2022; 13:7293. [PMID: 36435847 PMCID: PMC9701231 DOI: 10.1038/s41467-022-35060-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 11/17/2022] [Indexed: 11/28/2022] Open
Abstract
It is thought that many of the simple and complex genomic rearrangements associated with congenital diseases and cancers stem from mistakes made during the restart of collapsed replication forks by recombination enzymes. It is hypothesised that this recombination-mediated restart process transitions from a relatively accurate initiation phase to a less accurate elongation phase characterised by extensive template switching between homologous, homeologous and microhomologous DNA sequences. Using an experimental system in fission yeast, where fork collapse is triggered by a site-specific replication barrier, we show that ectopic recombination, associated with the initiation of recombination-dependent replication (RDR), is driven mainly by the Rad51 recombinase, whereas template switching, during the elongation phase of RDR, relies more on DNA annealing by Rad52. This finding provides both evidence and a mechanistic basis for the transition hypothesis.
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15
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Jourdy Y, Chatron N, Fretigny M, Dericquebourg A, Sanlaville D, Vinciguerra C. Comprehensive analysis of F8 large deletions: Characterization of full breakpoint junctions and description of a possible DNA breakage hotspot in intron 6. J Thromb Haemost 2022; 20:2293-2305. [PMID: 35894111 DOI: 10.1111/jth.15835] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 07/20/2022] [Accepted: 07/25/2022] [Indexed: 11/30/2022]
Abstract
BACKGROUND Large F8 deletions represent 3-5% of the variations found in severe hemophilia A patients, but only a few deletion breakpoints have been characterized precisely. OBJECTIVES Resolving at the nucleotide level 24 F8 large deletions to provide new data on the mechanisms involved in these rearrangements. METHODS Breakpoint junctions of 24 F8 large deletions were characterized using a combination of long-range polymerase chain reaction, whole F8 NGS sequencing, and Sanger sequencing. Repeat elements, non-B DNA, and secondary structures were analyzed around the breakpoints. RESULTS Deletions ranged from 1.667 kb to 0.5 Mb in size. Nine involved F8 neighboring genes. Simple blunt ends and 2-4 bp microhomologies were identified at the breakpoint junctions of 10 (42%) and 8 (33%) deletions, respectively. Five (21%) deletions resulted from homeologous recombination between two Alu elements. The remaining case corresponded to a more complex rearrangement with an insertion of a 19 bp-inverted sequence at the junction. Four different breakpoints were located in a 562-bp region in F8 intron 6. This finding suggested that this region, composed of two Alu elements, is a DNA breakage hotspot. Non-B DNA and secondary structures were identified in the junction regions and may contribute to DNA breakage. CONCLUSION Molecular characterization of deletion breakpoints revealed that non-homologous non-replicative DNA repair mechanisms and replication-based mechanisms seemed to be the main causative mechanisms of F8 large deletions. Moreover, we identified a possible F8 DNA breakage hotspot involved in non-recurrent rearrangements.
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Affiliation(s)
- Yohann Jourdy
- Hospices Civils de Lyon, Groupe Hospitalier Est, Service d'hématologie biologique, Bron, France
- Université Claude Bernard Lyon 1, UR 4609, Hémostase et thrombose, Lyon, France
| | - Nicolas Chatron
- Hospices Civils de Lyon, Groupe Hospitalier Est, Service de génétique, Bron, France
- Univ Lyon, Univ Lyon 1, CNRS, INSERM, Physiopathologie et Génétique du Neurone et du Muscle, UMR5261, U1315, Institut NeuroMyoGène, Lyon, France
| | - Mathilde Fretigny
- Hospices Civils de Lyon, Groupe Hospitalier Est, Service d'hématologie biologique, Bron, France
| | - Amy Dericquebourg
- Hospices Civils de Lyon, Groupe Hospitalier Est, Service d'hématologie biologique, Bron, France
- Université Claude Bernard Lyon 1, UR 4609, Hémostase et thrombose, Lyon, France
| | - Damien Sanlaville
- Hospices Civils de Lyon, Groupe Hospitalier Est, Service de génétique, Bron, France
- Univ Lyon, Univ Lyon 1, CNRS, INSERM, Physiopathologie et Génétique du Neurone et du Muscle, UMR5261, U1315, Institut NeuroMyoGène, Lyon, France
| | - Christine Vinciguerra
- Hospices Civils de Lyon, Groupe Hospitalier Est, Service d'hématologie biologique, Bron, France
- Université Claude Bernard Lyon 1, UR 4609, Hémostase et thrombose, Lyon, France
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16
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van de Kooij B, Kruswick A, van Attikum H, Yaffe MB. Multi-pathway DNA-repair reporters reveal competition between end-joining, single-strand annealing and homologous recombination at Cas9-induced DNA double-strand breaks. Nat Commun 2022; 13:5295. [PMID: 36075911 PMCID: PMC9458747 DOI: 10.1038/s41467-022-32743-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 08/11/2022] [Indexed: 11/25/2022] Open
Abstract
DNA double-strand breaks (DSB) are repaired by multiple distinct pathways, with outcomes ranging from error-free repair to mutagenesis and genomic loss. DSB-repair pathway cross-talk and compensation is incompletely understood, despite its importance for genomic stability, oncogenesis, and genome editing using CRISPR/Cas9. To address this, we constructed and validated three fluorescent Cas9-based reporters, named DSB-Spectrum, that simultaneously quantify the contribution of multiple DNA repair pathways at a DSB. DSB-Spectrum reporters distinguish between DSB-repair by error-free canonical non-homologous end-joining (c-NHEJ) versus homologous recombination (HR; reporter 1), mutagenic repair versus HR (reporter 2), and mutagenic end-joining versus single strand annealing (SSA) versus HR (reporter 3). Using these reporters, we show that inhibiting the c-NHEJ factor DNA-PKcs increases repair by HR, but also substantially increases mutagenic SSA. Our data indicate that SSA-mediated DSB-repair also occurs at endogenous genomic loci, driven by Alu elements or homologous gene regions. Finally, we demonstrate that long-range end-resection factors DNA2 and Exo1 promote SSA and reduce HR, when both pathways compete for the same substrate. These new Cas9-based DSB-Spectrum reporters facilitate the comprehensive analysis of repair pathway crosstalk and DSB-repair outcome.
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Affiliation(s)
- Bert van de Kooij
- Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2333 ZC, Leiden, the Netherlands
- Koch Institute for Integrative Cancer Research, MIT Center for Precision Cancer Medicine, Departments of Biology and Bioengineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Alex Kruswick
- Koch Institute for Integrative Cancer Research, MIT Center for Precision Cancer Medicine, Departments of Biology and Bioengineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Haico van Attikum
- Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2333 ZC, Leiden, the Netherlands.
| | - Michael B Yaffe
- Koch Institute for Integrative Cancer Research, MIT Center for Precision Cancer Medicine, Departments of Biology and Bioengineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Department of Surgery, Beth Israel Deaconess Medical Center, Divisions of Acute Care Surgery, Trauma, and Critical Care and Surgical Oncology, Harvard Medical School, Boston, MA, USA.
- Surgical Oncology Program, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
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17
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Damert A. SVA retrotransposons and a low copy repeat in humans and great apes: a mobile connection. Mol Biol Evol 2022; 39:6586216. [PMID: 35574660 PMCID: PMC9132208 DOI: 10.1093/molbev/msac103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Segmental duplications (SDs) constitute a considerable fraction of primate genomes. They contribute to genetic variation and provide raw material for evolution. Groups of SDs are characterized by the presence of shared core duplicons. One of these core duplicons, low copy repeat (lcr)16a, has been shown to be particularly active in the propagation of interspersed SDs in primates. The underlying mechanisms are, however, only partially understood. Alu short interspersed elements (SINEs) are frequently found at breakpoints and have been implicated in the expansion of SDs. Detailed analysis of lcr16a-containing SDs shows that the hominid-specific SVA (SINE-R-VNTR-Alu) retrotransposon is an integral component of the core duplicon in Asian and African great apes. In orang-utan, it provides breakpoints and contributes to both interchromosomal and intrachromosomal lcr16a mobility by inter-element recombination. Furthermore, the data suggest that in hominines (human, chimpanzee, gorilla) SVA recombination-mediated integration of a circular intermediate is the founding event of a lineage-specific lcr16a expansion. One of the hominine lcr16a copies displays large flanking direct repeats, a structural feature shared by other SDs in the human genome. Taken together, the results obtained extend the range of SVAs’ contribution to genome evolution from RNA-mediated transduction to DNA-based recombination. In addition, they provide further support for a role of circular intermediates in SD mobilization.
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Affiliation(s)
- Annette Damert
- Infection Biology Unit and Primate Genetics Laboratory, German Primate Center, Leibniz Institute for Primate Research, Göttingen, Germany
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18
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Marwaha S, Knowles JW, Ashley EA. A guide for the diagnosis of rare and undiagnosed disease: beyond the exome. Genome Med 2022; 14:23. [PMID: 35220969 PMCID: PMC8883622 DOI: 10.1186/s13073-022-01026-w] [Citation(s) in RCA: 83] [Impact Index Per Article: 41.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 02/10/2022] [Indexed: 02/07/2023] Open
Abstract
AbstractRare diseases affect 30 million people in the USA and more than 300–400 million worldwide, often causing chronic illness, disability, and premature death. Traditional diagnostic techniques rely heavily on heuristic approaches, coupling clinical experience from prior rare disease presentations with the medical literature. A large number of rare disease patients remain undiagnosed for years and many even die without an accurate diagnosis. In recent years, gene panels, microarrays, and exome sequencing have helped to identify the molecular cause of such rare and undiagnosed diseases. These technologies have allowed diagnoses for a sizable proportion (25–35%) of undiagnosed patients, often with actionable findings. However, a large proportion of these patients remain undiagnosed. In this review, we focus on technologies that can be adopted if exome sequencing is unrevealing. We discuss the benefits of sequencing the whole genome and the additional benefit that may be offered by long-read technology, pan-genome reference, transcriptomics, metabolomics, proteomics, and methyl profiling. We highlight computational methods to help identify regionally distant patients with similar phenotypes or similar genetic mutations. Finally, we describe approaches to automate and accelerate genomic analysis. The strategies discussed here are intended to serve as a guide for clinicians and researchers in the next steps when encountering patients with non-diagnostic exomes.
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19
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Mohan N, Qiang L, Morfini G, Baas PW. Therapeutic Strategies for Mutant SPAST-Based Hereditary Spastic Paraplegia. Brain Sci 2021; 11:brainsci11081081. [PMID: 34439700 PMCID: PMC8394973 DOI: 10.3390/brainsci11081081] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/13/2021] [Accepted: 08/16/2021] [Indexed: 12/16/2022] Open
Abstract
Mutations of the SPAST gene that encodes the microtubule-severing enzyme called spastin are the chief cause of Hereditary Spastic Paraplegia. Growing evidence indicates that pathogenic mutations functionally compromise the spastin protein and endow it with toxic gain-of-function properties. With each of these two factors potentially relevant to disease etiology, the present article discusses possible therapeutic strategies that may ameliorate symptoms in patients suffering from SPAST-based Hereditary Spastic Paraplegia, which is usually termed SPG4-HSP.
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Affiliation(s)
- Neha Mohan
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19422, USA; (N.M.); (L.Q.)
| | - Liang Qiang
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19422, USA; (N.M.); (L.Q.)
| | - Gerardo Morfini
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612, USA;
| | - Peter W. Baas
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19422, USA; (N.M.); (L.Q.)
- Correspondence: ; Tel.: +1-215-991-8289; Fax: +1-215-843-9082
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20
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Duan R, Saadi NW, Grochowski CM, Bhadila G, Faridoun A, Mitani T, Du H, Fatih JM, Jhangiani SN, Akdemir ZC, Gibbs RA, Pehlivan D, Posey JE, Marafi D, Lupski JR. A novel homozygous SLC13A5 whole-gene deletion generated by Alu/Alu-mediated rearrangement in an Iraqi family with epileptic encephalopathy. Am J Med Genet A 2021; 185:1972-1980. [PMID: 33797191 DOI: 10.1002/ajmg.a.62192] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 02/10/2021] [Accepted: 03/05/2021] [Indexed: 01/05/2023]
Abstract
Biallelic loss-of-function (LoF) of SLC13A5 (solute carrier family 13, member 5) induced deficiency in sodium/citrate transporter (NaCT) causes autosomal recessive developmental epileptic encephalopathy 25 with hypoplastic amelogenesis imperfecta (DEE25; MIM #615905). Many pathogenic SLC13A5 single nucleotide variants (SNVs) and small indels have been described; however, no cases with copy number variants (CNVs) have been sufficiently investigated. We describe a consanguineous Iraqi family harboring an 88.5 kb homozygous deletion including SLC13A5 in Chr17p13.1. The three affected male siblings exhibit neonatal-onset epilepsy with fever-sensitivity, recurrent status epilepticus, global developmental delay/intellectual disability (GDD/ID), and other variable neurological findings as shared phenotypical features of DEE25. Two of the three affected subjects exhibit hypoplastic amelogenesis imperfecta (AI), while the proband shows no evidence of dental abnormalities or AI at 2 years of age with apparently unaffected primary dentition. Characterization of the genomic architecture at this locus revealed evidence for genomic instability generated by an Alu/Alu-mediated rearrangement; confirmed by break-point junction Sanger sequencing. This multiplex family from a distinct population elucidates the phenotypic consequence of complete LoF of SLC13A5 and illustrates the importance of read-depth-based CNV detection in comprehensive exome sequencing analysis to solve cases that otherwise remain molecularly unsolved.
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Affiliation(s)
- Ruizhi Duan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Nebal Waill Saadi
- College of Medicine, University of Baghdad, Baghdad, Iraq.,Children Welfare Teaching Hospital, Medical City Complex, Baghdad, Iraq
| | | | - Ghalia Bhadila
- Department of Advanced Oral Sciences and Therapeutics, University of Maryland School of Dentistry, Baltimore, Maryland, USA.,Department of Pediatric Dentistry, Faculty of Dentistry, King AbdulAziz University, Jeddah, Saudi Arabia
| | - Afnan Faridoun
- Department of General Dental Practice, Faculty of Dentistry, Kuwait University, Kuwait
| | - Tadahiro Mitani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Haowei Du
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Jawid M Fatih
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Shalini N Jhangiani
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
| | - Zeynep C Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Richard A Gibbs
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
| | - Davut Pehlivan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA.,Texas Children's Hospital, Houston, Texas, USA.,Section of Pediatric Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine & Texas Children's Hospital, Houston, Texas, USA
| | - Jennifer E Posey
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Dana Marafi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA.,Department of Pediatrics, Faculty of Medicine, Kuwait University, Safat, Kuwait
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA.,Texas Children's Hospital, Houston, Texas, USA.,Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
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21
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Bravo JI, Nozownik S, Danthi PS, Benayoun BA. Transposable elements, circular RNAs and mitochondrial transcription in age-related genomic regulation. Development 2020; 147:dev175786. [PMID: 32527937 PMCID: PMC10680986 DOI: 10.1242/dev.175786] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Our understanding of the molecular regulation of aging and age-related diseases is still in its infancy, requiring in-depth characterization of the molecular landscape shaping these complex phenotypes. Emerging classes of molecules with promise as aging modulators include transposable elements, circRNAs and the mitochondrial transcriptome. Analytical complexity means that these molecules are often overlooked, even though they exhibit strong associations with aging and, in some cases, may directly contribute to its progress. Here, we review the links between these novel factors and age-related phenotypes, and we suggest tools that can be easily incorporated into existing pipelines to better understand the aging process.
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Affiliation(s)
- Juan I Bravo
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
- Graduate Program in the Biology of Aging, University of Southern California, Los Angeles, CA 90089, USA
| | - Séverine Nozownik
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
- Magistère européen de Génétique, Université Paris Diderot-Paris 7, Paris 75014, France
| | - Prakroothi S Danthi
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
| | - Bérénice A Benayoun
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA 90089, USA
- USC Norris Comprehensive Cancer Center, Epigenetics and Gene Regulation, Los Angeles, CA 90089, USA
- USC Stem Cell Initiative, Los Angeles, CA 90089, USA
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22
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Distinct patterns of complex rearrangements and a mutational signature of microhomeology are frequently observed in PLP1 copy number gain structural variants. Genome Med 2019; 11:80. [PMID: 31818324 PMCID: PMC6902434 DOI: 10.1186/s13073-019-0676-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 10/10/2019] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND We investigated the features of the genomic rearrangements in a cohort of 50 male individuals with proteolipid protein 1 (PLP1) copy number gain events who were ascertained with Pelizaeus-Merzbacher disease (PMD; MIM: 312080). We then compared our new data to previous structural variant mutagenesis studies involving the Xq22 region of the human genome. The aggregate data from 159 sequenced join-points (discontinuous sequences in the reference genome that are joined during the rearrangement process) were studied. Analysis of these data from 150 individuals enabled the spectrum and relative distribution of the underlying genomic mutational signatures to be delineated. METHODS Genomic rearrangements in PMD individuals with PLP1 copy number gain events were investigated by high-density customized array or clinical chromosomal microarray analysis and breakpoint junction sequence analysis. RESULTS High-density customized array showed that the majority of cases (33/50; ~ 66%) present with single duplications, although complex genomic rearrangements (CGRs) are also frequent (17/50; ~ 34%). Breakpoint mapping to nucleotide resolution revealed further previously unknown structural and sequence complexities, even in single duplications. Meta-analysis of all studied rearrangements that occur at the PLP1 locus showed that single duplications were found in ~ 54% of individuals and that, among all CGR cases, triplication flanked by duplications is the most frequent CGR array CGH pattern observed. Importantly, in ~ 32% of join-points, there is evidence for a mutational signature of microhomeology (highly similar yet imperfect sequence matches). CONCLUSIONS These data reveal a high frequency of CGRs at the PLP1 locus and support the assertion that replication-based mechanisms are prominent contributors to the formation of CGRs at Xq22. We propose that microhomeology can facilitate template switching, by stabilizing strand annealing of the primer using W-C base complementarity, and is a mutational signature for replicative repair.
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23
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Kadnikova VA, Rudenskaya GE, Stepanova AA, Sermyagina IG, Ryzhkova OP. Mutational Spectrum of Spast (Spg4) and Atl1 (Spg3a) Genes In Russian Patients With Hereditary Spastic Paraplegia. Sci Rep 2019; 9:14412. [PMID: 31594988 PMCID: PMC6783457 DOI: 10.1038/s41598-019-50911-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 09/13/2019] [Indexed: 01/15/2023] Open
Abstract
Hereditary spastic paraplegia (HSP) comprises a heterogeneous group of neurodegenerative disorders, it share common symptom - of progressive lower spastic paraparesis. The most common autosomal dominant (AD) forms of HSP are SPG4 (SPAST gene) and SPG3 (ATL1 gene). In the current research we investigated for the first time the distribution of pathogenic mutations in SPAST and ATL1 genes within a large cohort of Russian HSP patients (122 probands; 69 famillial cases). We determined the frequencies of genetic abnormalities using Sanger sequencing, multiplex ligation-dependent probe amplification (MLPA), and Next Generation Sequencing (NGS) of targeted gene panels. As a result, SPG4 was diagnosed in 30.3% (37/122) of HSP cases, where the familial cases represented 37.7% (26/69) of SPG4. In total 31 pathogenic and likely pathogenic variants were detected in SPAST, with 14 new mutations. Among all detected SPAST variants, 29% were gross deletions and duplications. The proportion of SPG3 variants in Russian cohort was 8.2% (10/122) that were all familial cases. All 10 detected ATL1 mutations were missense substitutions, most of which were in the mutational hot spots of 4, 7, 8, 12 exons, with 2 novel mutations. This work will be helpful for the populational genetics of HSP understanding.
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Affiliation(s)
- V A Kadnikova
- Federal State Budgetary Institution "Research Centre For Medical Genetics", Moscow, 115478, Russia.
| | - G E Rudenskaya
- Federal State Budgetary Institution "Research Centre For Medical Genetics", Moscow, 115478, Russia
| | - A A Stepanova
- Federal State Budgetary Institution "Research Centre For Medical Genetics", Moscow, 115478, Russia
| | - I G Sermyagina
- Federal State Budgetary Institution "Research Centre For Medical Genetics", Moscow, 115478, Russia
| | - O P Ryzhkova
- Federal State Budgetary Institution "Research Centre For Medical Genetics", Moscow, 115478, Russia
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24
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Oliver GR, Tang X, Schultz-Rogers LE, Vidal-Folch N, Jenkinson WG, Schwab TL, Gaonkar K, Cousin MA, Nair A, Basu S, Chanana P, Oglesbee D, Klee EW. A tailored approach to fusion transcript identification increases diagnosis of rare inherited disease. PLoS One 2019; 14:e0223337. [PMID: 31577830 PMCID: PMC6774566 DOI: 10.1371/journal.pone.0223337] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 09/18/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND RNA sequencing has been proposed as a means of increasing diagnostic rates in studies of undiagnosed rare inherited disease. Recent studies have reported diagnostic improvements in the range of 7.5-35% by profiling splicing, gene expression quantification and allele specific expression. To-date however, no study has systematically assessed the presence of gene-fusion transcripts in cases of germline disease. Fusion transcripts are routinely identified in cancer studies and are increasingly recognized as having diagnostic, prognostic or therapeutic relevance. Isolated reports exist of fusion transcripts being detected in cases of developmental and neurological phenotypes, and thus, systematic application of fusion detection to germline conditions may further increase diagnostic rates. However, current fusion detection methods are unsuited to the investigation of germline disease due to performance biases arising from their development using tumor, cell-line or in-silico data. METHODS We describe a tailored approach to fusion candidate identification and prioritization in a cohort of 47 undiagnosed, suspected inherited disease patients. We modify an existing fusion transcript detection algorithm by eliminating its cell line-derived filtering steps, and instead, prioritize candidates using a custom workflow that integrates genomic and transcriptomic sequence alignment, biological and technical annotations, customized categorization logic, and phenotypic prioritization. RESULTS We demonstrate that our approach to fusion transcript identification and prioritization detects genuine fusion events excluded by standard analyses and efficiently removes phenotypically unimportant candidates and false positive events, resulting in a reduced candidate list enriched for events with potential phenotypic relevance. We describe the successful genetic resolution of two previously undiagnosed disease cases through the detection of pathogenic fusion transcripts. Furthermore, we report the experimental validation of five additional cases of fusion transcripts with potential phenotypic relevance. CONCLUSIONS The approach we describe can be implemented to enable the detection of phenotypically relevant fusion transcripts in studies of rare inherited disease. Fusion transcript detection has the potential to increase diagnostic rates in rare inherited disease and should be included in RNA-based analytical pipelines aimed at genetic diagnosis.
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Affiliation(s)
- Gavin R. Oliver
- Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, United States of America
- Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Xiaojia Tang
- Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, United States of America
- Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Laura E. Schultz-Rogers
- Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, United States of America
- Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Noemi Vidal-Folch
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - W. Garrett Jenkinson
- Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, United States of America
- Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Tanya L. Schwab
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Krutika Gaonkar
- Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, United States of America
- Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Margot A. Cousin
- Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, United States of America
- Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Asha Nair
- Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, United States of America
- Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Shubham Basu
- Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, United States of America
- Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Pritha Chanana
- Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, United States of America
- Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Devin Oglesbee
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Medical Genetics, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Eric W. Klee
- Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, United States of America
- Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Clinical Genomics, Mayo Clinic, Rochester, Minnesota, United States of America
- * E-mail:
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25
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Newton T, Allison R, Edgar JR, Lumb JH, Rodger CE, Manna PT, Rizo T, Kohl Z, Nygren AOH, Arning L, Schüle R, Depienne C, Goldberg L, Frahm C, Stevanin G, Durr A, Schöls L, Winner B, Beetz C, Reid E. Mechanistic basis of an epistatic interaction reducing age at onset in hereditary spastic paraplegia. Brain 2019; 141:1286-1299. [PMID: 29481671 PMCID: PMC5917785 DOI: 10.1093/brain/awy034] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 01/04/2018] [Indexed: 12/20/2022] Open
Abstract
Many genetic neurological disorders exhibit variable expression within affected families, often exemplified by variations in disease age at onset. Epistatic effects (i.e. effects of modifier genes on the disease gene) may underlie this variation, but the mechanistic basis for such epistatic interactions is rarely understood. Here we report a novel epistatic interaction between SPAST and the contiguous gene DPY30, which modifies age at onset in hereditary spastic paraplegia, a genetic axonopathy. We found that patients with hereditary spastic paraplegia caused by genomic deletions of SPAST that extended into DPY30 had a significantly younger age at onset. We show that, like spastin, the protein encoded by SPAST, the DPY30 protein controls endosomal tubule fission, traffic of mannose 6-phosphate receptors from endosomes to the Golgi, and lysosomal ultrastructural morphology. We propose that additive effects on this pathway explain the reduced age at onset of hereditary spastic paraplegia in patients who are haploinsufficient for both genes.
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Affiliation(s)
- Timothy Newton
- Department of Medical Genetics and Cambridge Institute for Medical Research, University of Cambridge, UK
| | - Rachel Allison
- Department of Medical Genetics and Cambridge Institute for Medical Research, University of Cambridge, UK
| | - James R Edgar
- Department of Clinical Biochemistry and Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Jennifer H Lumb
- Department of Medical Genetics and Cambridge Institute for Medical Research, University of Cambridge, UK
| | - Catherine E Rodger
- Department of Medical Genetics and Cambridge Institute for Medical Research, University of Cambridge, UK
| | - Paul T Manna
- Department of Clinical Biochemistry and Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Tania Rizo
- Department of Stem Cell Biology, Friedrich-Alexander University Erlangen-Nuernberg (FAU), Erlangen, Germany
| | - Zacharias Kohl
- Department of Molecular Neurology, Friedrich-Alexander University Erlangen-Nuernberg (FAU), Erlangen, Germany
| | | | - Larissa Arning
- Department of Human Genetics, Ruhr-University, Bochum, Germany
| | - Rebecca Schüle
- Center for Neurology and Hertie Institute for Clinical Brain Research, Eberhard-Karls-University, 72076 Tübingen, Germany.,German Center of Neurodegenerative Diseases (DZNE), 72076 Tübingen, Germany
| | - Christel Depienne
- ICM Brain and Spine Institute, INSERM U1127, CNRS UMR7225, Sorbonne Universites, UPMC Univ Paris VI UMR_S1127, Paris, France.,APHP, Genetic Department, Pitie-Salpêtrière University Hospital, Paris, France
| | - Lisa Goldberg
- Department of Clinical Chemistry and Laboratory Diagnostics, Jena University Hospital, Jena, Germany
| | - Christiane Frahm
- Hans Berger Department of Neurology, Jena University Hospital, Jena, Germany
| | - Giovanni Stevanin
- ICM Brain and Spine Institute, INSERM U1127, CNRS UMR7225, Sorbonne Universites, UPMC Univ Paris VI UMR_S1127, Paris, France.,APHP, Genetic Department, Pitie-Salpêtrière University Hospital, Paris, France.,Ecole Pratique des Hautes Etudes, PSL Research University, Paris, France
| | - Alexandra Durr
- ICM Brain and Spine Institute, INSERM U1127, CNRS UMR7225, Sorbonne Universites, UPMC Univ Paris VI UMR_S1127, Paris, France.,APHP, Genetic Department, Pitie-Salpêtrière University Hospital, Paris, France
| | - Ludger Schöls
- Center for Neurology and Hertie Institute for Clinical Brain Research, Eberhard-Karls-University, 72076 Tübingen, Germany.,German Center of Neurodegenerative Diseases (DZNE), 72076 Tübingen, Germany
| | - Beate Winner
- Department of Molecular Neurology, Friedrich-Alexander University Erlangen-Nuernberg (FAU), Erlangen, Germany
| | - Christian Beetz
- Department of Clinical Chemistry and Laboratory Diagnostics, Jena University Hospital, Jena, Germany
| | - Evan Reid
- Department of Medical Genetics and Cambridge Institute for Medical Research, University of Cambridge, UK
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26
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Qiang L, Piermarini E, Baas PW. New hypothesis for the etiology of SPAST-based hereditary spastic paraplegia. Cytoskeleton (Hoboken) 2019; 76:289-297. [PMID: 31108029 DOI: 10.1002/cm.21528] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 05/14/2019] [Accepted: 05/15/2019] [Indexed: 01/26/2023]
Abstract
Mutations of the SPAST gene are the chief cause of hereditary spastic paraplegia. Controversy exists in the medical community as to whether the etiology of the disease is haploinsufficiency or toxic gain-of-function properties of the mutant spastin proteins. In recognition of strong reasons that support each possible mechanism, here we present a novel perspective, based in part on new studies with mouse models and in part on the largest study to date on patients with the disease. We posit that haploinsufficiency does not cause the disease but makes the corticospinal tracts vulnerable to a second hit, which is usually the mutant spastin proteins but could also be proteins generated by mutations of other genes that may or may not cause the disease on their own.
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Affiliation(s)
- Liang Qiang
- Department of Neurobiology and Anatomy, Drexel University, College of Medicine, Philadelphia, Pennsylvania
| | - Emanuela Piermarini
- Department of Neurobiology and Anatomy, Drexel University, College of Medicine, Philadelphia, Pennsylvania
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University, College of Medicine, Philadelphia, Pennsylvania
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27
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Qiang L, Piermarini E, Muralidharan H, Yu W, Leo L, Hennessy LE, Fernandes S, Connors T, Yates PL, Swift M, Zholudeva LV, Lane MA, Morfini G, Alexander GM, Heiman-Patterson TD, Baas PW. Hereditary spastic paraplegia: gain-of-function mechanisms revealed by new transgenic mouse. Hum Mol Genet 2019; 28:1136-1152. [PMID: 30520996 DOI: 10.1093/hmg/ddy419] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Revised: 10/31/2018] [Accepted: 12/02/2018] [Indexed: 12/17/2022] Open
Abstract
Mutations of the SPAST gene, which encodes the microtubule-severing protein spastin, are the most common cause of hereditary spastic paraplegia (HSP). Haploinsufficiency is the prevalent opinion as to the mechanism of the disease, but gain-of-function toxicity of the mutant proteins is another possibility. Here, we report a new transgenic mouse (termed SPASTC448Y mouse) that is not haploinsufficient but expresses human spastin bearing the HSP pathogenic C448Y mutation. Expression of the mutant spastin was documented from fetus to adult, but gait defects reminiscent of HSP (not observed in spastin knockout mice) were adult onset, as is typical of human patients. Results of histological and tracer studies on the mouse are consistent with progressive dying back of corticospinal axons, which is characteristic of the disease. The C448Y-mutated spastin alters microtubule stability in a manner that is opposite to the expectations of haploinsufficiency. Neurons cultured from the mouse display deficits in organelle transport typical of axonal degenerative diseases, and these deficits were worsened by depletion of endogenous mouse spastin. These results on the SPASTC448Y mouse are consistent with a gain-of-function mechanism underlying HSP, with spastin haploinsufficiency exacerbating the toxicity of the mutant spastin proteins. These findings reveal the need for a different therapeutic approach than indicated by haploinsufficiency alone.
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Affiliation(s)
| | | | | | | | | | - Laura E Hennessy
- Department of Neurology, Drexel University College of Medicine, Queen Lane, Philadelphia, PA, USA
| | | | | | | | | | | | | | - Gerardo Morfini
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - Guillermo M Alexander
- Department of Neurology, Drexel University College of Medicine, Queen Lane, Philadelphia, PA, USA
| | - Terry D Heiman-Patterson
- Department of Neurology, Drexel University College of Medicine, Queen Lane, Philadelphia, PA, USA
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28
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Zamborsky R, Kokavec M, Harsanyi S, Attia D, Danisovic L. Developmental Dysplasia of Hip: Perspectives in Genetic Screening. Med Sci (Basel) 2019; 7:medsci7040059. [PMID: 30979092 PMCID: PMC6524033 DOI: 10.3390/medsci7040059] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 02/16/2019] [Accepted: 04/10/2019] [Indexed: 12/18/2022] Open
Abstract
Development dysplasia of the hip (DDH) is a complex developmental disorder despite being a relatively common condition mainly caused by incompatibility of the femoral head and the abnormal joint socket. Development dysplasia of the hip describes a wide spectrum of disorders ranging from minor acetabular dysplasia to irreducible dislocation of the hip. Modern medicine still suffers from lack of information about screening and precise genetic examination. Genome wide linkage and association studies have brought significant progress to DDH diagnosis. Association studies managed to identify many candidate (susceptible) genes, such as PAPPA2, COL2A1, HOXD9, GDF-5, and TGFB1, which play a considerable role in the pathogenesis of DDH. Early detection of DDH has a big chance to help in preventing further disability and improve the psychological health and quality of life in those children. This emphasizes the importance to establish a universal screening program along with the genetic counseling.
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Affiliation(s)
- Radoslav Zamborsky
- Department of Orthopaedics, Faculty of Medicine, Comenius University and National Institute of Children's Diseases, Limbova 1, 833 40 Bratislava, Slovakia.
| | - Milan Kokavec
- Department of Orthopaedics, Faculty of Medicine, Comenius University and National Institute of Children's Diseases, Limbova 1, 833 40 Bratislava, Slovakia.
| | - Stefan Harsanyi
- Institute of Medical Biology, Genetics and Clinical Genetics, Faculty of Medicine, Comenius University, Sasinkova 4, 811 08 Bratislava, Slovakia.
| | - Doaa Attia
- Department of Internal Medicine, Faculty of Medicine, Alexandria University, Chamblion St., Azarita, 21131 Alexandria, Egypt.
| | - Lubos Danisovic
- Institute of Medical Biology, Genetics and Clinical Genetics, Faculty of Medicine, Comenius University, Sasinkova 4, 811 08 Bratislava, Slovakia.
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29
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Lin YL, Gokcumen O. Fine-Scale Characterization of Genomic Structural Variation in the Human Genome Reveals Adaptive and Biomedically Relevant Hotspots. Genome Biol Evol 2019; 11:1136-1151. [PMID: 30887040 PMCID: PMC6475128 DOI: 10.1093/gbe/evz058] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/16/2019] [Indexed: 12/25/2022] Open
Abstract
Genomic structural variants (SVs) are distributed nonrandomly across the human genome. The "hotspots" of SVs have been implicated in evolutionary innovations, as well as medical conditions. However, the evolutionary and biomedical features of these hotspots remain incompletely understood. Here, we analyzed data from 2,504 genomes to construct a refined map of 1,148 SV hotspots in human genomes. We confirmed that segmental duplication-related nonallelic homologous recombination is an important mechanistic driver of SV hotspot formation. However, to our surprise, we also found that a majority of SVs in hotspots do not form through such recombination-based mechanisms, suggesting diverse mechanistic and selective forces shaping hotspots. Indeed, our evolutionary analyses showed that the majority of SV hotspots are within gene-poor regions and evolve under relaxed negative selection or neutrality. However, we still found a small subset of SV hotspots harboring genes that are enriched for anthropologically crucial functions and evolve under geography-specific and balancing adaptive forces. These include two independent hotspots on different chromosomes affecting alpha and beta hemoglobin gene clusters. Biomedically, we found that the SV hotspots coincide with breakpoints of clinically relevant, large de novo SVs, significantly more often than genome-wide expectations. For example, we showed that the breakpoints of multiple large SVs, which lead to idiopathic short stature, coincide with SV hotspots. Therefore, the mutational instability in SV hotpots likely enables chromosomal breaks that lead to pathogenic structural variation formations. Overall, our study contributes to a better understanding of the mutational and adaptive landscape of the genome.
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Affiliation(s)
- Yen-Lung Lin
- Department of Biological Sciences, University at Buffalo
| | - Omer Gokcumen
- Department of Biological Sciences, University at Buffalo
- Corresponding author: E-mail: or
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30
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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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31
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Bis-Brewer DM, Züchner S. Perspectives on the Genomics of HSP Beyond Mendelian Inheritance. Front Neurol 2018; 9:958. [PMID: 30534106 PMCID: PMC6275194 DOI: 10.3389/fneur.2018.00958] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Accepted: 10/25/2018] [Indexed: 12/12/2022] Open
Abstract
Hereditary Spastic Paraplegia is an extraordinarily heterogeneous disease caused by over 50 Mendelian genes. Recent applications of next-generation sequencing, large scale data analysis, and data sharing/matchmaking, have discovered a quickly expanding set of additional HSP genes. Since most recently discovered HSP genes are rare causes of the disease, there is a growing concern of a persisting diagnostic gap, estimated at 30-40%, and even higher for sporadic cases. This missing heritability may not be fully closed by classic Mendelian mutations in protein coding genes. Here we show strategies and published examples of broadening areas of attention for Mendelian and non-Mendelian causes of HSP. We suggest a more inclusive perspective on the potential final architecture of HSP genomics. Efforts to narrow the heritability gap will ultimately lead to more precise and comprehensive genetic diagnoses, which is the starting point for emerging, highly specific gene therapies.
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Affiliation(s)
- Dana M. Bis-Brewer
- Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL, United States
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Stephan Züchner
- Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL, United States
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, United States
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32
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Nazaryan-Petersen L, Eisfeldt J, Pettersson M, Lundin J, Nilsson D, Wincent J, Lieden A, Lovmar L, Ottosson J, Gacic J, Mäkitie O, Nordgren A, Vezzi F, Wirta V, Käller M, Hjortshøj TD, Jespersgaard C, Houssari R, Pignata L, Bak M, Tommerup N, Lundberg ES, Tümer Z, Lindstrand A. Replicative and non-replicative mechanisms in the formation of clustered CNVs are indicated by whole genome characterization. PLoS Genet 2018; 14:e1007780. [PMID: 30419018 PMCID: PMC6258378 DOI: 10.1371/journal.pgen.1007780] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 11/26/2018] [Accepted: 10/23/2018] [Indexed: 01/25/2023] Open
Abstract
Clustered copy number variants (CNVs) as detected by chromosomal microarray analysis (CMA) are often reported as germline chromothripsis. However, such cases might need further investigations by massive parallel whole genome sequencing (WGS) in order to accurately define the underlying complex rearrangement, predict the occurrence mechanisms and identify additional complexities. Here, we utilized WGS to delineate the rearrangement structure of 21 clustered CNV carriers first investigated by CMA and identified a total of 83 breakpoint junctions (BPJs). The rearrangements were further sub-classified depending on the patterns observed: I) Cases with only deletions (n = 8) often had additional structural rearrangements, such as insertions and inversions typical to chromothripsis; II) cases with only duplications (n = 7) or III) combinations of deletions and duplications (n = 6) demonstrated mostly interspersed duplications and BPJs enriched with microhomology. In two cases the rearrangement mutational signatures indicated both a breakage-fusion-bridge cycle process and haltered formation of a ring chromosome. Finally, we observed two cases with Alu- and LINE-mediated rearrangements as well as two unrelated individuals with seemingly identical clustered CNVs on 2p25.3, possibly a rare European founder rearrangement. In conclusion, through detailed characterization of the derivative chromosomes we show that multiple mechanisms are likely involved in the formation of clustered CNVs and add further evidence for chromoanagenesis mechanisms in both “simple” and highly complex chromosomal rearrangements. Finally, WGS characterization adds positional information, important for a correct clinical interpretation and deciphering mechanisms involved in the formation of these rearrangements. Clustered copy number variants (CNVs) as detected by chromosomal microarray are often reported as germline chromoanagenesis. However, such cases might need further investigation by whole genome sequencing (WGS) to accurately resolve the complexity of the structural rearrangement and predict underlying mutational mechanisms. Here, we used WGS to characterize 83 breakpoint-junctions (BPJs) from 21 clustered CNVs, and outlined the rearrangement connectivity pictures. Cases with only deletions often had additional structural rearrangements, such as insertions and inversions, which could be a result of multiple double-strand DNA breaks followed by non-homologous repair, typical to chromothripsis. In contrast, cases with only duplications or combinations of deletions and duplications, demonstrated mostly interspersed duplications and BPJs enriched with microhomology, consistent with serial template switching during DNA replication (chromoanasynthesis). Only two rearrangements were repeat mediated. In aggregate, our results suggest that multiple CNVs clustered on a single chromosome may arise through either chromothripsis or chromoanasynthesis.
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Affiliation(s)
- Lusine Nazaryan-Petersen
- Wilhelm Johannsen Center for Functional Genome Research, Institute of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Jesper Eisfeldt
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institute, Stockholm, Sweden
- Science for Life Laboratory, Karolinska Institutet Science Park, Solna, Sweden
| | - Maria Pettersson
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institute, Stockholm, Sweden
| | - Johanna Lundin
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institute, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Daniel Nilsson
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institute, Stockholm, Sweden
- Science for Life Laboratory, Karolinska Institutet Science Park, Solna, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Josephine Wincent
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institute, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Agne Lieden
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institute, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Lovisa Lovmar
- Department of Clinical Genetics, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Jesper Ottosson
- Department of Clinical Genetics, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Jelena Gacic
- Department of Clinical Genetics, Linköping University Hospital, Linköping, Sweden
| | - Outi Mäkitie
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institute, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
- Children’s Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Folkhälsan Institute of Genetics, Helsinki, Finland
| | - Ann Nordgren
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institute, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Francesco Vezzi
- SciLifeLab, Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Valtteri Wirta
- SciLifeLab, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Stockholm, Sweden
- SciLifeLab, Department of Microbiology, Tumor and Cell biology, Karolinska Institutet, Stockholm, Sweden
| | - Max Käller
- SciLifeLab, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Stockholm, Sweden
- SciLifeLab, Department of Microbiology, Tumor and Cell biology, Karolinska Institutet, Stockholm, Sweden
| | - Tina Duelund Hjortshøj
- Kennedy Center, Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet, Glostrup, Denmark
| | - Cathrine Jespersgaard
- Kennedy Center, Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet, Glostrup, Denmark
| | - Rayan Houssari
- Kennedy Center, Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet, Glostrup, Denmark
| | - Laura Pignata
- Kennedy Center, Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet, Glostrup, Denmark
| | - Mads Bak
- Wilhelm Johannsen Center for Functional Genome Research, Institute of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Niels Tommerup
- Wilhelm Johannsen Center for Functional Genome Research, Institute of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Elisabeth Syk Lundberg
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institute, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Zeynep Tümer
- Kennedy Center, Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet, Glostrup, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
- * E-mail: (AL); (ZT)
| | - Anna Lindstrand
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institute, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
- * E-mail: (AL); (ZT)
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33
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Jabbari K, Bobbili DR, Lal D, Reinthaler EM, Schubert J, Wolking S, Sinha V, Motameny S, Thiele H, Kawalia A, Altmüller J, Toliat MR, Kraaij R, van Rooij J, Uitterlinden AG, Ikram MA, Zara F, Lehesjoki AE, Krause R, Zimprich F, Sander T, Neubauer BA, May P, Lerche H, Nürnberg P. Rare gene deletions in genetic generalized and Rolandic epilepsies. PLoS One 2018; 13:e0202022. [PMID: 30148849 PMCID: PMC6110470 DOI: 10.1371/journal.pone.0202022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 07/26/2018] [Indexed: 12/30/2022] Open
Abstract
Genetic Generalized Epilepsy (GGE) and benign epilepsy with centro-temporal spikes or Rolandic Epilepsy (RE) are common forms of genetic epilepsies. Rare copy number variants have been recognized as important risk factors in brain disorders. We performed a systematic survey of rare deletions affecting protein-coding genes derived from exome data of patients with common forms of genetic epilepsies. We analysed exomes from 390 European patients (196 GGE and 194 RE) and 572 population controls to identify low-frequency genic deletions. We found that 75 (32 GGE and 43 RE) patients out of 390, i.e. ~19%, carried rare genic deletions. In particular, large deletions (>400 kb) represent a higher burden in both GGE and RE syndromes as compared to controls. The detected low-frequency deletions (1) share genes with brain-expressed exons that are under negative selection, (2) overlap with known autism and epilepsy-associated candidate genes, (3) are enriched for CNV intolerant genes recorded by the Exome Aggregation Consortium (ExAC) and (4) coincide with likely disruptive de novo mutations from the NPdenovo database. Employing several knowledge databases, we discuss the most prominent epilepsy candidate genes and their protein-protein networks for GGE and RE.
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Affiliation(s)
- Kamel Jabbari
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
- Cologne Biocenter, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Dheeraj R. Bobbili
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Dennis Lal
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
- Psychiatric and Neurodevelopmental Genetics Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Eva M. Reinthaler
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Julian Schubert
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Stefan Wolking
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Vishal Sinha
- Institute for Molecular Medicine FIMM, University of Helsinki, Helsinki, Finland
| | - Susanne Motameny
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Holger Thiele
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Amit Kawalia
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Janine Altmüller
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
- Institute of Human Genetics, University of Cologne, Cologne, Germany
| | | | - Robert Kraaij
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Jeroen van Rooij
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands
| | | | - M. Arfan Ikram
- Departments of Epidemiology, Neurology, and Radiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | | | - Federico Zara
- Laboratory of Neurogenetics and Neuroscience, Institute G. Gaslini, Genova, Italy
| | - Anna-Elina Lehesjoki
- Folkhälsan Institute of Genetics, Folkhälsan Research Center, Helsinki, Finland
- Neuroscience Center and Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
| | - Roland Krause
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Fritz Zimprich
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Thomas Sander
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Bernd A. Neubauer
- Department of Neuropediatrics, Medical Faculty University Giessen, Giessen, Germany
| | - Patrick May
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Peter Nürnberg
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
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34
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Szafranski P, Kośmider E, Liu Q, Karolak JA, Currie L, Parkash S, Kahler SG, Roeder E, Littlejohn RO, DeNapoli TS, Shardonofsky FR, Henderson C, Powers G, Poisson V, Bérubé D, Oligny L, Michaud JL, Janssens S, De Coen K, Van Dorpe J, Dheedene A, Harting MT, Weaver MD, Khan AM, Tatevian N, Wambach J, Gibbs KA, Popek E, Gambin A, Stankiewicz P. LINE- and Alu-containing genomic instability hotspot at 16q24.1 associated with recurrent and nonrecurrent CNV deletions causative for ACDMPV. Hum Mutat 2018; 39:1916-1925. [PMID: 30084155 DOI: 10.1002/humu.23608] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 08/01/2018] [Accepted: 08/02/2018] [Indexed: 01/20/2023]
Abstract
Transposable elements modify human genome by inserting into new loci or by mediating homology-, microhomology-, or homeology-driven DNA recombination or repair, resulting in genomic structural variation. Alveolar capillary dysplasia with misalignment of pulmonary veins (ACDMPV) is a rare lethal neonatal developmental lung disorder caused by point mutations or copy-number variant (CNV) deletions of FOXF1 or its distant tissue-specific enhancer. Eighty-five percent of 45 ACDMPV-causative CNV deletions, of which junctions have been sequenced, had at least one of their two breakpoints located in a retrotransposon, with more than half of them being Alu elements. We describe a novel ∼35 kb-large genomic instability hotspot at 16q24.1, involving two evolutionarily young LINE-1 (L1) elements, L1PA2 and L1PA3, flanking AluY, two AluSx, AluSx1, and AluJr elements. The occurrence of L1s at this location coincided with the branching out of the Homo-Pan-Gorilla clade, and was preceded by the insertion of AluSx, AluSx1, and AluJr. Our data show that, in addition to mediating recurrent CNVs, L1 and Alu retrotransposons can predispose the human genome to formation of variably sized CNVs, both of clinical and evolutionary relevance. Nonetheless, epigenetic or other genomic features of this locus might also contribute to its increased instability.
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Affiliation(s)
- Przemyslaw Szafranski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Ewelina Kośmider
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Faculty of Mathematics, Informatics and Mechanics, University of Warsaw, Warsaw, Poland
| | - Qian Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Justyna A Karolak
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Department of Genetics and Pharmaceutical Microbiology, Poznan University of Medical Sciences, Poznan, Poland
| | - Lauren Currie
- Maritime Medical Genetics Service, IWK Health Centre, Halifax, Canada
| | - Sandhya Parkash
- Maritime Medical Genetics Service, IWK Health Centre, Halifax, Canada
| | - Stephen G Kahler
- Section of Genetics and Metabolism, Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Elizabeth Roeder
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Department of Pediatrics, Baylor College of Medicine, San Antonio, Texas
| | | | - Thomas S DeNapoli
- Department of Pathology, Children's Hospital of San Antonio, San Antonio, Texas
| | - Felix R Shardonofsky
- Pediatric Pulmonary Center, Children's Hospital of San Antonio, San Antonio, Texas
| | - Cody Henderson
- Department of Pediatrics, Baylor College of Medicine, San Antonio, Texas.,Neonatal-Perinatal Medicine, Children's Hospital of San Antonio, San Antonio, Texas
| | - George Powers
- Department of Pediatrics, Baylor College of Medicine, San Antonio, Texas.,Neonatal-Perinatal Medicine, Children's Hospital of San Antonio, San Antonio, Texas
| | | | | | | | | | - Sandra Janssens
- Center for Medical Genetics, Ghent University, Ghent, Belgium
| | - Kris De Coen
- Department of Neonatal Intensive Care, Ghent University, Ghent, Belgium
| | - Jo Van Dorpe
- Department of Pathology, Ghent University, Ghent, Belgium
| | | | | | | | - Amir M Khan
- McGovern Medical School at UTHealth, Houston, Texas
| | | | - Jennifer Wambach
- Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri
| | - Kathleen A Gibbs
- Children's Hospital of Philadelphia, and University of Pennsylvania, Philadelphia, Pennsylvania
| | - Edwina Popek
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas
| | - Anna Gambin
- Faculty of Mathematics, Informatics and Mechanics, University of Warsaw, Warsaw, Poland
| | - Paweł Stankiewicz
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
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35
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Pettersson M, Vaz R, Hammarsjö A, Eisfeldt J, Carvalho CMB, Hofmeister W, Tham E, Horemuzova E, Voss U, Nishimura G, Klintberg B, Nordgren A, Nilsson D, Grigelioniene G, Lindstrand A. Alu-Alu mediated intragenic duplications in IFT81 and MATN3 are associated with skeletal dysplasias. Hum Mutat 2018; 39:1456-1467. [PMID: 30080953 DOI: 10.1002/humu.23605] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 07/09/2018] [Accepted: 08/02/2018] [Indexed: 01/22/2023]
Abstract
Skeletal dysplasias are a diverse group of rare Mendelian disorders with clinical and genetic heterogeneity. Here, we used targeted copy number variant (CNV) screening and identified intragenic exonic duplications, formed through Alu-Alu fusion events, in two individuals with skeletal dysplasia and negative exome sequencing results. First, we detected a homozygous tandem duplication of exon 9 and 10 in IFT81 in a boy with Jeune syndrome, or short-rib thoracic dysplasia (SRTD) (MIM# 208500). Western blot analysis did not detect any wild-type IFT81 protein in fibroblasts from the patient with the IFT81 duplication, but only a shorter isoform of IFT81 that was also present in the normal control samples. Complementary zebrafish studies suggested that loss of full-length IFT81 protein but expression of a shorter form of IFT81 protein affects the phenotype while being compatible with life. Second, a de novo tandem duplication of exons 2 to 5 in MATN3 was identified in a girl with multiple epiphyseal dysplasia (MED) type 5 (MIM# 607078). Our data highlights the importance of detection and careful characterization of intragenic duplication CNVs, presenting them as a novel and very rare genetic mechanism in IFT81-related Jeune syndrome and MATN3-related MED.
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Affiliation(s)
- Maria Pettersson
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet and Clinical Genetics, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
| | - Raquel Vaz
- Department of Molecular Medicine and Surgery and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Anna Hammarsjö
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet and Clinical Genetics, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
| | - Jesper Eisfeldt
- Department of Molecular Medicine and Surgery and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Science for Life Laboratory, Karolinska Institutet Science Park, Solna, Sweden
| | - Claudia M B Carvalho
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Wolfgang Hofmeister
- Department of Molecular Medicine and Surgery and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Emma Tham
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet and Clinical Genetics, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
| | - Eva Horemuzova
- Department of Women's and Children's Health, Karolinska Institutet and Paediatric Endocrinology Unit, Karolinska University Hospital, Stockholm, Sweden
| | - Ulrika Voss
- Department of Pediatric Radiology, Karolinska University Hospital, Stockholm, Sweden
| | - Gen Nishimura
- Intractable Disease Center, Saitama University Hospital, Saitama, Japan
| | - Bo Klintberg
- Department of Pediatrics, Visby Hospital, Visby, Sweden
| | - Ann Nordgren
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet and Clinical Genetics, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
| | - Daniel Nilsson
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet and Clinical Genetics, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden.,Science for Life Laboratory, Karolinska Institutet Science Park, Solna, Sweden
| | - Giedre Grigelioniene
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet and Clinical Genetics, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
| | - Anna Lindstrand
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet and Clinical Genetics, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
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36
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Song X, Beck CR, Du R, Campbell IM, Coban-Akdemir Z, Gu S, Breman AM, Stankiewicz P, Ira G, Shaw CA, Lupski JR. Predicting human genes susceptible to genomic instability associated with Alu/ Alu-mediated rearrangements. Genome Res 2018; 28:1228-1242. [PMID: 29907612 PMCID: PMC6071635 DOI: 10.1101/gr.229401.117] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 06/06/2018] [Indexed: 12/14/2022]
Abstract
Alu elements, the short interspersed element numbering more than 1 million copies per human genome, can mediate the formation of copy number variants (CNVs) between substrate pairs. These Alu/Alu-mediated rearrangements (AAMRs) can result in pathogenic variants that cause diseases. To investigate the impact of AAMR on gene variation and human health, we first characterized Alus that are involved in mediating CNVs (CNV-Alus) and observed that these Alus tend to be evolutionarily younger. We then computationally generated, with the assistance of a supercomputer, a test data set consisting of 78 million Alu pairs and predicted ∼18% of them are potentially susceptible to AAMR. We further determined the relative risk of AAMR in 12,074 OMIM genes using the count of predicted CNV-Alu pairs and experimentally validated the predictions with 89 samples selected by correlating predicted hotspots with a database of CNVs identified by clinical chromosomal microarrays (CMAs) on the genomes of approximately 54,000 subjects. We fine-mapped 47 duplications, 40 deletions, and two complex rearrangements and examined a total of 52 breakpoint junctions of simple CNVs. Overall, 94% of the candidate breakpoints were at least partially Alu mediated. We successfully predicted all (100%) of Alu pairs that mediated deletions (n = 21) and achieved an 87% positive predictive value overall when including AAMR-generated deletions and duplications. We provided a tool, AluAluCNVpredictor, for assessing AAMR hotspots and their role in human disease. These results demonstrate the utility of our predictive model and provide insights into the genomic features and molecular mechanisms underlying AAMR.
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Affiliation(s)
- Xiaofei Song
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Christine R Beck
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Renqian Du
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Ian M Campbell
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Zeynep Coban-Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Shen Gu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Amy M Breman
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
- Baylor Genetics, Houston, Texas 77021, USA
| | - Pawel Stankiewicz
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
- Baylor Genetics, Houston, Texas 77021, USA
| | - Grzegorz Ira
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Chad A Shaw
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
- Baylor Genetics, Houston, Texas 77021, USA
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas 77030, USA
- Texas Children's Hospital, Houston, Texas 77030, USA
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37
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Krestel H, Meier JC. RNA Editing and Retrotransposons in Neurology. Front Mol Neurosci 2018; 11:163. [PMID: 29875629 PMCID: PMC5974252 DOI: 10.3389/fnmol.2018.00163] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 04/30/2018] [Indexed: 12/28/2022] Open
Abstract
Compared to sites in protein-coding sequences many more targets undergoing adenosine to inosine (A-to-I) RNA editing were discovered in non-coding regions of human cerebral transcripts, particularly in genetic transposable elements called retrotransposons. We review here the interaction mechanisms of RNA editing and retrotransposons and their impact on normal function and human neurological diseases. Exemplarily, A-to-I editing of retrotransposons embedded in protein-coding mRNAs can contribute to protein abundance and function via circular RNA formation, alternative splicing, and exonization or silencing of retrotransposons. Interactions leading to disease are not very well understood. We describe human diseases with involvement of the central nervous system including inborn errors of metabolism, neurodevelopmental disorders, neuroinflammatory and neurodegenerative and paroxysmal diseases, in which retrotransposons (Alu and/or L1 elements) appear to be causally involved in genetic rearrangements. Sole binding of single-stranded retrotransposon transcripts by RNA editing enzymes rather than enzymatic deamination may have a homeostatic effect on retrotransposon turnover. We also review evidence in support of the emerging pathophysiological function of A-to-I editing of retrotransposons in inflammation and its implication for different neurological diseases including amyotrophic lateral sclerosis, frontotemporal dementia, Alzheimer's and Parkinson's disease, and epilepsy.
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Affiliation(s)
- Heinz Krestel
- Department of Neurology, Bern University Hospital and University of Bern, Bern, Switzerland.,Department for BioMedical Research, Bern University Hospital and University of Bern, Bern, Switzerland
| | - Jochen C Meier
- Division Cell Physiology, Zoological Institute, Technical University Braunschweig, Braunschweig, Germany
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38
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Geoffroy V, Stoetzel C, Scheidecker S, Schaefer E, Perrault I, Bär S, Kröll A, Delbarre M, Antin M, Leuvrey AS, Henry C, Blanché H, Decker E, Kloth K, Klaus G, Mache C, Martin-Coignard D, McGinn S, Boland A, Deleuze JF, Friant S, Saunier S, Rozet JM, Bergmann C, Dollfus H, Muller J. Whole-genome sequencing in patients with ciliopathies uncovers a novel recurrent tandem duplication in IFT140. Hum Mutat 2018; 39:983-992. [PMID: 29688594 DOI: 10.1002/humu.23539] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 04/10/2018] [Accepted: 04/16/2018] [Indexed: 12/30/2022]
Abstract
Ciliopathies represent a wide spectrum of rare diseases with overlapping phenotypes and a high genetic heterogeneity. Among those, IFT140 is implicated in a variety of phenotypes ranging from isolated retinis pigmentosa to more syndromic cases. Using whole-genome sequencing in patients with uncharacterized ciliopathies, we identified a novel recurrent tandem duplication of exon 27-30 (6.7 kb) in IFT140, c.3454-488_4182+2588dup p.(Tyr1152_Thr1394dup), missed by whole-exome sequencing. Pathogenicity of the mutation was assessed on the patients' skin fibroblasts. Several hundreds of patients with a ciliopathy phenotype were screened and biallelic mutations were identified in 11 families representing 12 pathogenic variants of which seven are novel. Among those unrelated families especially with a Mainzer-Saldino syndrome, eight carried the same tandem duplication (two at the homozygous state and six at the heterozygous state). In conclusion, we demonstrated the implication of structural variations in IFT140-related diseases expanding its mutation spectrum. We also provide evidences for a unique genomic event mediated by an Alu-Alu recombination occurring on a shared haplotype. We confirm that whole-genome sequencing can be instrumental in the ability to detect structural variants for genomic disorders.
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Affiliation(s)
- Véronique Geoffroy
- Laboratoire de Génétique médicale, UMR_S INSERM U1112, IGMA, Faculté de Médecine FMTS, Université de Strasbourg, Strasbourg, France
| | - Corinne Stoetzel
- Laboratoire de Génétique médicale, UMR_S INSERM U1112, IGMA, Faculté de Médecine FMTS, Université de Strasbourg, Strasbourg, France
| | - Sophie Scheidecker
- Laboratoire de Génétique médicale, UMR_S INSERM U1112, IGMA, Faculté de Médecine FMTS, Université de Strasbourg, Strasbourg, France.,Laboratoires de Diagnostic Génétique, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Elise Schaefer
- Laboratoire de Génétique médicale, UMR_S INSERM U1112, IGMA, Faculté de Médecine FMTS, Université de Strasbourg, Strasbourg, France.,Service de Génétique Médicale, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Isabelle Perrault
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR1163, Institute of Genetic Diseases, Imagine, Paris Descartes University, Paris, France
| | - Séverine Bär
- Department of Molecular and Cellular Genetics, UMR7156, Centre National de Recherche Scientifique (CNRS), Université de Strasbourg, Strasbourg, France
| | - Ariane Kröll
- Laboratoire de Génétique médicale, UMR_S INSERM U1112, IGMA, Faculté de Médecine FMTS, Université de Strasbourg, Strasbourg, France
| | - Marion Delbarre
- Laboratoires de Diagnostic Génétique, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Manuela Antin
- Laboratoires de Diagnostic Génétique, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Anne-Sophie Leuvrey
- Laboratoires de Diagnostic Génétique, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | | | - Hélène Blanché
- Centre d'études du polymorphisme humain-Fondation Jean Dausset, Paris, France
| | - Eva Decker
- Center for Human Genetics, Bioscientia, Ingelheim, Germany
| | - Katja Kloth
- Institut für Humangenetik, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Günter Klaus
- University Marburg, KfH-Nierenzentrum für Kinder und Jugendliche, Marburg, Germany
| | - Christoph Mache
- Department of Pediatrics, Medical University of Graz, Graz, Austria
| | | | - Steven McGinn
- CNRGH, Institut de Biologie François Jacob, DRF, CEA, Evry, France
| | - Anne Boland
- CNRGH, Institut de Biologie François Jacob, DRF, CEA, Evry, France
| | - Jean-François Deleuze
- Centre d'études du polymorphisme humain-Fondation Jean Dausset, Paris, France.,CNRGH, Institut de Biologie François Jacob, DRF, CEA, Evry, France
| | - Sylvie Friant
- Department of Molecular and Cellular Genetics, UMR7156, Centre National de Recherche Scientifique (CNRS), Université de Strasbourg, Strasbourg, France
| | | | - Jean-Michel Rozet
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR1163, Institute of Genetic Diseases, Imagine, Paris Descartes University, Paris, France
| | - Carsten Bergmann
- Center for Human Genetics, Bioscientia, Ingelheim, Germany.,Department of Medicine, University Hospital Freiburg, Freiburg, Germany
| | - Hélène Dollfus
- Laboratoire de Génétique médicale, UMR_S INSERM U1112, IGMA, Faculté de Médecine FMTS, Université de Strasbourg, Strasbourg, France.,Centre de Référence pour les affections rares en génétique ophtalmologique, CARGO, Filière SENSGENE, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Jean Muller
- Laboratoire de Génétique médicale, UMR_S INSERM U1112, IGMA, Faculté de Médecine FMTS, Université de Strasbourg, Strasbourg, France.,Laboratoires de Diagnostic Génétique, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
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39
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Larsen PA, Hunnicutt KE, Larsen RJ, Yoder AD, Saunders AM. Warning SINEs: Alu elements, evolution of the human brain, and the spectrum of neurological disease. Chromosome Res 2018; 26:93-111. [PMID: 29460123 PMCID: PMC5857278 DOI: 10.1007/s10577-018-9573-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 01/14/2018] [Accepted: 01/15/2018] [Indexed: 12/28/2022]
Abstract
Alu elements are a highly successful family of primate-specific retrotransposons that have fundamentally shaped primate evolution, including the evolution of our own species. Alus play critical roles in the formation of neurological networks and the epigenetic regulation of biochemical processes throughout the central nervous system (CNS), and thus are hypothesized to have contributed to the origin of human cognition. Despite the benefits that Alus provide, deleterious Alu activity is associated with a number of neurological and neurodegenerative disorders. In particular, neurological networks are potentially vulnerable to the epigenetic dysregulation of Alu elements operating across the suite of nuclear-encoded mitochondrial genes that are critical for both mitochondrial and CNS function. Here, we highlight the beneficial neurological aspects of Alu elements as well as their potential to cause disease by disrupting key cellular processes across the CNS. We identify at least 37 neurological and neurodegenerative disorders wherein deleterious Alu activity has been implicated as a contributing factor for the manifestation of disease, and for many of these disorders, this activity is operating on genes that are essential for proper mitochondrial function. We conclude that the epigenetic dysregulation of Alu elements can ultimately disrupt mitochondrial homeostasis within the CNS. This mechanism is a plausible source for the incipient neuronal stress that is consistently observed across a spectrum of sporadic neurological and neurodegenerative disorders.
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Affiliation(s)
- Peter A Larsen
- Department of Biology, Duke University, Durham, NC, 27708, USA.
- Duke Lemur Center, Duke University, Durham, NC, 27708, USA.
- Department of Biology, Duke University, 130 Science Drive, Box 90338, Durham, NC, 27708, USA.
| | | | - Roxanne J Larsen
- Duke University School of Medicine, Duke University, Durham, NC, 27710, USA
| | - Anne D Yoder
- Department of Biology, Duke University, Durham, NC, 27708, USA
- Duke Lemur Center, Duke University, Durham, NC, 27708, USA
| | - Ann M Saunders
- Zinfandel Pharmaceuticals Inc, Chapel Hill, NC, 27709, USA
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40
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White JJ, Mazzeu JF, Coban-Akdemir Z, Bayram Y, Bahrambeigi V, Hoischen A, van Bon BWM, Gezdirici A, Gulec EY, Ramond F, Touraine R, Thevenon J, Shinawi M, Beaver E, Heeley J, Hoover-Fong J, Durmaz CD, Karabulut HG, Marzioglu-Ozdemir E, Cayir A, Duz MB, Seven M, Price S, Ferreira BM, Vianna-Morgante AM, Ellard S, Parrish A, Stals K, Flores-Daboub J, Jhangiani SN, Gibbs RA, Brunner HG, Sutton VR, Lupski JR, Carvalho CMB. WNT Signaling Perturbations Underlie the Genetic Heterogeneity of Robinow Syndrome. Am J Hum Genet 2018; 102:27-43. [PMID: 29276006 DOI: 10.1016/j.ajhg.2017.10.002] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 10/06/2017] [Indexed: 12/12/2022] Open
Abstract
Locus heterogeneity characterizes a variety of skeletal dysplasias often due to interacting or overlapping signaling pathways. Robinow syndrome is a skeletal disorder historically refractory to molecular diagnosis, potentially stemming from substantial genetic heterogeneity. All current known pathogenic variants reside in genes within the noncanonical Wnt signaling pathway including ROR2, WNT5A, and more recently, DVL1 and DVL3. However, ∼70% of autosomal-dominant Robinow syndrome cases remain molecularly unsolved. To investigate this missing heritability, we recruited 21 families with at least one family member clinically diagnosed with Robinow or Robinow-like phenotypes and performed genetic and genomic studies. In total, four families with variants in FZD2 were identified as well as three individuals from two families with biallelic variants in NXN that co-segregate with the phenotype. Importantly, both FZD2 and NXN are relevant protein partners in the WNT5A interactome, supporting their role in skeletal development. In addition to confirming that clustered -1 frameshifting variants in DVL1 and DVL3 are the main contributors to dominant Robinow syndrome, we also found likely pathogenic variants in candidate genes GPC4 and RAC3, both linked to the Wnt signaling pathway. These data support an initial hypothesis that Robinow syndrome results from perturbation of the Wnt/PCP pathway, suggest specific relevant domains of the proteins involved, and reveal key contributors in this signaling cascade during human embryonic development. Contrary to the view that non-allelic genetic heterogeneity hampers gene discovery, this study demonstrates the utility of rare disease genomic studies to parse gene function in human developmental pathways.
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Affiliation(s)
- Janson J White
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston TX 77030, USA
| | - Juliana F Mazzeu
- University of Brasilia, Brasilia 70910, Brazil; Robinow Syndrome Foundation, Anoka, MN 55303, USA
| | - Zeynep Coban-Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston TX 77030, USA
| | - Yavuz Bayram
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston TX 77030, USA
| | - Vahid Bahrambeigi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston TX 77030, USA; Graduate Program in Diagnostic Genetics, School of Health Professions, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Alexander Hoischen
- Department of Human Genetics, Radboud Institute of Molecular Life Sciences, Radboud University Medical Center, 6500 HB Nijmegen, the Netherlands; Department of Internal Medicine and Radboud Center for Infectious Diseases (RCI), Radboud University Medical Center, 6500 HB Nijmegen, the Netherlands
| | - Bregje W M van Bon
- Department of Human Genetics, Radboud Institute of Molecular Life Sciences, Radboud University Medical Center, 6500 HB Nijmegen, the Netherlands
| | - Alper Gezdirici
- Department of Medical Genetics, Kanuni Sultan Suleyman Training and Research Hospital, Istanbul 34303, Turkey
| | - Elif Yilmaz Gulec
- Department of Medical Genetics, Kanuni Sultan Suleyman Training and Research Hospital, Istanbul 34303, Turkey
| | - Francis Ramond
- Service de Génétique, CHU-Hôpital Nord, 42000 Saint-Etienne, France
| | - Renaud Touraine
- Service de Génétique, CHU-Hôpital Nord, 42000 Saint-Etienne, France
| | - Julien Thevenon
- Inserm UMR 1231 GAD team, Genetics of Developmental Anomalies, Université de Bourgogne-Franche Comté, 21000 Dijon, France; FHU-TRANSLAD, Université de Bourgogne, 21000 CHU Dijon, France; Centre de génétique, Hôpital Couple-Enfant, CHU de Grenoble-Alpes, 38700 La Tronche, France
| | - Marwan Shinawi
- Division of Genetics and Genomic Medicine, Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Erin Beaver
- Mercy Clinic-Kids Genetics, Mercy Children's Hospital St. Louis, St. Louis, MO 63141, USA
| | - Jennifer Heeley
- Mercy Clinic-Kids Genetics, Mercy Children's Hospital St. Louis, St. Louis, MO 63141, USA
| | - Julie Hoover-Fong
- Greenberg Center for Skeletal Dysplasias, McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University, Baltimore, MD 21287, USA
| | - Ceren D Durmaz
- Department of Medical Genetics, Ankara University School of Medicine, 06100 Ankara, Turkey
| | - Halil Gurhan Karabulut
- Department of Medical Genetics, Ankara University School of Medicine, 06100 Ankara, Turkey
| | - Ebru Marzioglu-Ozdemir
- Department of Medical Genetics, Erzurum Regional and Training Hospital, 25070 Erzurum, Turkey
| | - Atilla Cayir
- Erzurum Training and Research Hospital, Department of Pediatric Endocrinology, 25070 Erzurum, Turkey
| | - Mehmet B Duz
- Department of Medical Genetics, Cerrahpasa Medical School, Istanbul University, 34452 Istanbul, Turkey
| | - Mehmet Seven
- Department of Medical Genetics, Cerrahpasa Medical School, Istanbul University, 34452 Istanbul, Turkey
| | - Susan Price
- Oxford Centre for Genomic Medicine, Nuffield Orthopaedic Centre, Oxford OX3 7LD, UK
| | | | - Angela M Vianna-Morgante
- Department of Genetics and Evolutionary Biology, Institute of Biosciences, Sao Paulo - SP 05508-090, Brazil
| | - Sian Ellard
- Department of Molecular Genetics, Royal Devon and Exeter NHS Foundation Trust, Exeter EX2 5DW, UK; Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX1 2LU, UK
| | - Andrew Parrish
- Department of Molecular Genetics, Royal Devon and Exeter NHS Foundation Trust, Exeter EX2 5DW, UK
| | - Karen Stals
- Department of Molecular Genetics, Royal Devon and Exeter NHS Foundation Trust, Exeter EX2 5DW, UK
| | - Josue Flores-Daboub
- Department of Pediatric Genetics, University of Utah School of Medicine, Salt Lake City, UT 84108, USA
| | - Shalini N Jhangiani
- 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; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Han G Brunner
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6500 HB Nijmegen, the Netherlands; Department of Clinical Genetics, GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, 6202 AZ Maastricht, the Netherlands
| | - V Reid Sutton
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA
| | - Claudia M B Carvalho
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston TX 77030, USA.
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41
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Leo L, Weissmann C, Burns M, Kang M, Song Y, Qiang L, Brady ST, Baas PW, Morfini G. Mutant spastin proteins promote deficits in axonal transport through an isoform-specific mechanism involving casein kinase 2 activation. Hum Mol Genet 2017; 26:2321-2334. [PMID: 28398512 DOI: 10.1093/hmg/ddx125] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 03/24/2017] [Indexed: 01/19/2023] Open
Abstract
Mutations of various genes cause hereditary spastic paraplegia (HSP), a neurological disease involving dying-back degeneration of upper motor neurons. From these, mutations in the SPAST gene encoding the microtubule-severing protein spastin account for most HSP cases. Cumulative genetic and experimental evidence suggests that alterations in various intracellular trafficking events, including fast axonal transport (FAT), may contribute to HSP pathogenesis. However, the mechanisms linking SPAST mutations to such deficits remain largely unknown. Experiments presented here using isolated squid axoplasm reveal inhibition of FAT as a common toxic effect elicited by spastin proteins with different HSP mutations, independent of microtubule-binding or severing activity. Mutant spastin proteins produce this toxic effect only when presented as the tissue-specific M1 isoform, not when presented as the ubiquitously-expressed shorter M87 isoform. Biochemical and pharmacological experiments further indicate that the toxic effects of mutant M1 spastins on FAT involve casein kinase 2 (CK2) activation. In mammalian cells, expression of mutant M1 spastins, but not their mutant M87 counterparts, promotes abnormalities in the distribution of intracellular organelles that are correctable by pharmacological CK2 inhibition. Collectively, these results demonstrate isoform-specific toxic effects of mutant M1 spastin on FAT, and identify CK2 as a critical mediator of these effects.
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Affiliation(s)
- Lanfranco Leo
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Carina Weissmann
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - Matthew Burns
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - Minsu Kang
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA.,Marine Biological Laboratory, Woods Hole, MA, USA
| | - Yuyu Song
- Marine Biological Laboratory, Woods Hole, MA, USA.,Department of Genetics, School of Medicine, Yale University, New Haven, CT, USA
| | - Liang Qiang
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Scott T Brady
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA.,Marine Biological Laboratory, Woods Hole, MA, USA
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Gerardo Morfini
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA.,Marine Biological Laboratory, Woods Hole, MA, USA
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42
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Gambin T, Akdemir ZC, Yuan B, Gu S, Chiang T, Carvalho CMB, Shaw C, Jhangiani S, Boone PM, Eldomery MK, Karaca E, Bayram Y, Stray-Pedersen A, Muzny D, Charng WL, Bahrambeigi V, Belmont JW, Boerwinkle E, Beaudet AL, Gibbs RA, Lupski JR. Homozygous and hemizygous CNV detection from exome sequencing data in a Mendelian disease cohort. Nucleic Acids Res 2017; 45:1633-1648. [PMID: 27980096 PMCID: PMC5389578 DOI: 10.1093/nar/gkw1237] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 11/29/2016] [Indexed: 11/14/2022] Open
Abstract
We developed an algorithm, HMZDelFinder, that uses whole exome sequencing (WES) data to identify rare and intragenic homozygous and hemizygous (HMZ) deletions that may represent complete loss-of-function of the indicated gene. HMZDelFinder was applied to 4866 samples in the Baylor–Hopkins Center for Mendelian Genomics (BHCMG) cohort and detected 773 HMZ deletion calls (567 homozygous or 206 hemizygous) with an estimated sensitivity of 86.5% (82% for single-exonic and 88% for multi-exonic calls) and precision of 78% (53% single-exonic and 96% for multi-exonic calls). Out of 773 HMZDelFinder-detected deletion calls, 82 were subjected to array comparative genomic hybridization (aCGH) and/or breakpoint PCR and 64 were confirmed. These include 18 single-exon deletions out of which 8 were exclusively detected by HMZDelFinder and not by any of seven other CNV detection tools examined. Further investigation of the 64 validated deletion calls revealed at least 15 pathogenic HMZ deletions. Of those, 7 accounted for 17–50% of pathogenic CNVs in different disease cohorts where 7.1–11% of the molecular diagnosis solved rate was attributed to CNVs. In summary, we present an algorithm to detect rare, intragenic, single-exon deletion CNVs using WES data; this tool can be useful for disease gene discovery efforts and clinical WES analyses.
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Affiliation(s)
- Tomasz Gambin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.,Institute of Computer Science, Warsaw University of Technology, Warsaw, 00-665 Warsaw, Poland
| | - Zeynep C Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Bo Yuan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Shen Gu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Theodore Chiang
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Claudia M B Carvalho
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Chad Shaw
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Shalini Jhangiani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Philip M Boone
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Mohammad K Eldomery
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ender Karaca
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yavuz Bayram
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Asbjørg Stray-Pedersen
- Norwegian National Unit for Newborn Screening, Division for Pediatric and Adolescent Medicine, Oslo University Hospital, N-0424 Oslo, Norway
| | - Donna Muzny
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Wu-Lin Charng
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Vahid Bahrambeigi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.,Graduate Program in Diagnostic Genetics, School of Health Professions, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - John W Belmont
- Department of Molecular and Human Genetics, Baylor College of Medicine, 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
| | - Arthur L Beaudet
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.,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.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.,Human Genome Sequencing Center, 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
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43
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Gambin T, Yuan B, Bi W, Liu P, Rosenfeld JA, Coban-Akdemir Z, Pursley AN, Nagamani SCS, Marom R, Golla S, Dengle L, Petrie HG, Matalon R, Emrick L, Proud MB, Treadwell-Deering D, Chao HT, Koillinen H, Brown C, Urraca N, Mostafavi R, Bernes S, Roeder ER, Nugent KM, Bader PI, Bellus G, Cummings M, Northrup H, Ashfaq M, Westman R, Wildin R, Beck AE, Immken L, Elton L, Varghese S, Buchanan E, Faivre L, Lefebvre M, Schaaf CP, Walkiewicz M, Yang Y, Kang SHL, Lalani SR, Bacino CA, Beaudet AL, Breman AM, Smith JL, Cheung SW, Lupski JR, Patel A, Shaw CA, Stankiewicz P. Identification of novel candidate disease genes from de novo exonic copy number variants. Genome Med 2017; 9:83. [PMID: 28934986 PMCID: PMC5607840 DOI: 10.1186/s13073-017-0472-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 09/01/2017] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Exon-targeted microarrays can detect small (<1000 bp) intragenic copy number variants (CNVs), including those that affect only a single exon. This genome-wide high-sensitivity approach increases the molecular diagnosis for conditions with known disease-associated genes, enables better genotype-phenotype correlations, and facilitates variant allele detection allowing novel disease gene discovery. METHODS We retrospectively analyzed data from 63,127 patients referred for clinical chromosomal microarray analysis (CMA) at Baylor Genetics laboratories, including 46,755 individuals tested using exon-targeted arrays, from 2007 to 2017. Small CNVs harboring a single gene or two to five non-disease-associated genes were identified; the genes involved were evaluated for a potential disease association. RESULTS In this clinical population, among rare CNVs involving any single gene reported in 7200 patients (11%), we identified 145 de novo autosomal CNVs (117 losses and 28 intragenic gains), 257 X-linked deletion CNVs in males, and 1049 inherited autosomal CNVs (878 losses and 171 intragenic gains); 111 known disease genes were potentially disrupted by de novo autosomal or X-linked (in males) single-gene CNVs. Ninety-one genes, either recently proposed as candidate disease genes or not yet associated with diseases, were disrupted by 147 single-gene CNVs, including 37 de novo deletions and ten de novo intragenic duplications on autosomes and 100 X-linked CNVs in males. Clinical features in individuals with de novo or X-linked CNVs encompassing at most five genes (224 bp to 1.6 Mb in size) were compared to those in individuals with larger-sized deletions (up to 5 Mb in size) in the internal CMA database or loss-of-function single nucleotide variants (SNVs) detected by clinical or research whole-exome sequencing (WES). This enabled the identification of recently published genes (BPTF, NONO, PSMD12, TANGO2, and TRIP12), novel candidate disease genes (ARGLU1 and STK3), and further confirmation of disease association for two recently proposed disease genes (MEIS2 and PTCHD1). Notably, exon-targeted CMA detected several pathogenic single-exon CNVs missed by clinical WES analyses. CONCLUSIONS Together, these data document the efficacy of exon-targeted CMA for detection of genic and exonic CNVs, complementing and extending WES in clinical diagnostics, and the potential for discovery of novel disease genes by genome-wide assay.
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Affiliation(s)
- Tomasz Gambin
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA.,Institute of Computer Science, Warsaw University of Technology, Warsaw, 00-665, Poland.,Department of Medical Genetics, Institute of Mother and Child, Warsaw, 01-211, Poland
| | - Bo Yuan
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA.,Baylor Genetics, Houston, TX, 77021, USA
| | - Weimin Bi
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA.,Baylor Genetics, Houston, TX, 77021, USA
| | - Pengfei Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA.,Baylor Genetics, Houston, TX, 77021, USA
| | - Jill A Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - Zeynep Coban-Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - Amber N Pursley
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - Sandesh C S Nagamani
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - Ronit Marom
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA
| | - Sailaja Golla
- Division of Pediatric Neurology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Lauren Dengle
- Division of Pediatric Neurology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | | | - Reuben Matalon
- Department of Pediatrics, University of Texas Medical Branch, Galveston, TX, 77555, USA.,Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Lisa Emrick
- Department of Pediatric, Section of Child Neurology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Monica B Proud
- Department of Pediatric, Section of Child Neurology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Diane Treadwell-Deering
- Department of Psychiatry and Behavioral Sciences, Child and Adolescent Psychiatry Division, Baylor College of Medicine, Houston, TX, 77030, USA.,Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Hsiao-Tuan Chao
- Department of Pediatric, Section of Child Neurology, Baylor College of Medicine, Houston, TX, 77030, USA.,Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, 77030, USA
| | - Hannele Koillinen
- Department of Clinical Genetics, Helsinki University Hospital, Helsinki, 00029, Finland
| | - Chester Brown
- Genetics Division, Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN, 38105, USA.,Le Bonheur Children's Hospital, Memphis, TN, 38103, USA
| | - Nora Urraca
- Le Bonheur Children's Hospital, Memphis, TN, 38103, USA
| | | | | | - Elizabeth R Roeder
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA.,Department of Pediatrics, Baylor College of Medicine, San Antonio, TX, 78207, USA
| | - Kimberly M Nugent
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA.,Department of Pediatrics, Baylor College of Medicine, San Antonio, TX, 78207, USA
| | - Patricia I Bader
- Northeast Indiana Genetic Counseling Center, Wayne, IN, 46804, USA
| | - Gary Bellus
- Section of Clinical Genetics & Metabolism, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - Michael Cummings
- Department of Psychiatry Erie County Medical Center, Buffalo, NY, 14215, USA
| | - Hope Northrup
- Division of Medical Genetics, Department of Pediatrics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Myla Ashfaq
- Division of Medical Genetics, Department of Pediatrics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | | | - Robert Wildin
- St. Luke's Children's Hospital, Boise, ID, 83702, USA.,The National Human Genome Research Institute, Bethesda, MD, 20892, USA
| | - Anita E Beck
- Seattle Children's Hospital, Seattle, WA, 98105, USA.,Department of Pediatrics, Division of Genetic Medicine, University of Washington, Seattle, WA, 98195, USA
| | | | - Lindsay Elton
- Child Neurology Consultants of Austin, Austin, TX, 78731, USA
| | - Shaun Varghese
- THINK Neurology for Kids/Children's Memorial Hermann Hospital, The Woodlands, TX, 77380, USA
| | - Edward Buchanan
- Division of Plastic Surgery, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Laurence Faivre
- Centre de Génétique et Centre de Référence Anomalies du Développement et Syndromes Malformatifs de l'Est, FHU-TRANSLAD, CHU Dijon, Dijon, France
| | - Mathilde Lefebvre
- Centre de Génétique et Centre de Référence Anomalies du Développement et Syndromes Malformatifs de l'Est, FHU-TRANSLAD, CHU Dijon, Dijon, France
| | - Christian P Schaaf
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, 77030, USA
| | - Magdalena Walkiewicz
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA.,Baylor Genetics, Houston, TX, 77021, USA
| | - Yaping Yang
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA.,Baylor Genetics, Houston, TX, 77021, USA
| | - Sung-Hae L Kang
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA.,Baylor Genetics, Houston, TX, 77021, USA
| | - Seema R Lalani
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA.,Baylor Genetics, Houston, TX, 77021, USA.,Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Carlos A Bacino
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA.,Baylor Genetics, Houston, TX, 77021, USA.,Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Arthur L Beaudet
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA.,Baylor Genetics, Houston, TX, 77021, USA.,Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Amy M Breman
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA.,Baylor Genetics, Houston, TX, 77021, USA
| | - Janice L Smith
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA.,Baylor Genetics, Houston, TX, 77021, USA
| | - Sau Wai Cheung
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA.,Baylor Genetics, Houston, TX, 77021, USA
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA.,Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA.,Texas Children's Hospital, Houston, TX, 77030, USA
| | - Ankita Patel
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA.,Baylor Genetics, Houston, TX, 77021, USA
| | - Chad A Shaw
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA.,Baylor Genetics, Houston, TX, 77021, USA
| | - Paweł Stankiewicz
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030-3411, USA. .,Baylor Genetics, Houston, TX, 77021, USA.
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44
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Van Schil K, Naessens S, Van de Sompele S, Carron M, Aslanidis A, Van Cauwenbergh C, Kathrin Mayer A, Van Heetvelde M, Bauwens M, Verdin H, Coppieters F, Greenberg ME, Yang MG, Karlstetter M, Langmann T, De Preter K, Kohl S, Cherry TJ, Leroy BP, De Baere E. Mapping the genomic landscape of inherited retinal disease genes prioritizes genes prone to coding and noncoding copy-number variations. Genet Med 2017; 20:202-213. [PMID: 28749477 PMCID: PMC5787040 DOI: 10.1038/gim.2017.97] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 05/19/2017] [Indexed: 01/08/2023] Open
Abstract
PurposePart of the hidden genetic variation in heterogeneous genetic conditions such as inherited retinal diseases (IRDs) can be explained by copy-number variations (CNVs). Here, we explored the genomic landscape of IRD genes listed in RetNet to identify and prioritize those genes susceptible to CNV formation.MethodsRetNet genes underwent an assessment of genomic features and of CNV occurrence in the Database of Genomic Variants and literature. CNVs identified in an IRD cohort were characterized using targeted locus amplification (TLA) on extracted genomic DNA.ResultsExhaustive literature mining revealed 1,345 reported CNVs in 81 different IRD genes. Correlation analysis between rankings of genomic features and CNV occurrence demonstrated the strongest correlation between gene size and CNV occurrence of IRD genes. Moreover, we identified and delineated 30 new CNVs in IRD cases, 13 of which are novel and three of which affect noncoding, putative cis-regulatory regions. Finally, the breakpoints of six complex CNVs were determined using TLA in a hypothesis-neutral manner.ConclusionWe propose a ranking of CNV-prone IRD genes and demonstrate the efficacy of TLA for the characterization of CNVs on extracted DNA. Finally, this IRD-oriented CNV study can serve as a paradigm for other genetically heterogeneous Mendelian diseases with hidden genetic variation.
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Affiliation(s)
- Kristof Van Schil
- Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Sarah Naessens
- Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Stijn Van de Sompele
- Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Marjolein Carron
- Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Alexander Aslanidis
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne, Germany
| | | | - Anja Kathrin Mayer
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Tuebingen, Germany
| | - Mattias Van Heetvelde
- Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Miriam Bauwens
- Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Hannah Verdin
- Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Frauke Coppieters
- Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Michael E Greenberg
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Marty G Yang
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Marcus Karlstetter
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne, Germany
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne, Germany
| | - Katleen De Preter
- Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Susanne Kohl
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Tuebingen, Germany
| | - Timothy J Cherry
- Department of Pediatrics, University of Washington School of Medicine, Seattle, Washington, USA.,Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Bart P Leroy
- Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium.,Department of Ophthalmology, Ghent University and Ghent University Hospital, Ghent, Belgium.,Division of Ophthalmology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | | | - Elfride De Baere
- Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium
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45
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Morrow CA, Nguyen MO, Fower A, Wong IN, Osman F, Bryer C, Whitby MC. Inter-Fork Strand Annealing causes genomic deletions during the termination of DNA replication. eLife 2017; 6. [PMID: 28586299 PMCID: PMC5461108 DOI: 10.7554/elife.25490] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 05/22/2017] [Indexed: 11/29/2022] Open
Abstract
Problems that arise during DNA replication can drive genomic alterations that are instrumental in the development of cancers and many human genetic disorders. Replication fork barriers are a commonly encountered problem, which can cause fork collapse and act as hotspots for replication termination. Collapsed forks can be rescued by homologous recombination, which restarts replication. However, replication restart is relatively slow and, therefore, replication termination may frequently occur by an active fork converging on a collapsed fork. We find that this type of non-canonical fork convergence in fission yeast is prone to trigger deletions between repetitive DNA sequences via a mechanism we call Inter-Fork Strand Annealing (IFSA) that depends on the recombination proteins Rad52, Exo1 and Mus81, and is countered by the FANCM-related DNA helicase Fml1. Based on our findings, we propose that IFSA is a potential threat to genomic stability in eukaryotes. DOI:http://dx.doi.org/10.7554/eLife.25490.001
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Affiliation(s)
- Carl A Morrow
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Michael O Nguyen
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Andrew Fower
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Io Nam Wong
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Fekret Osman
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Claire Bryer
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Matthew C Whitby
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
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46
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Liu P, Yuan B, Carvalho CMB, Wuster A, Walter K, Zhang L, Gambin T, Chong Z, Campbell IM, Coban Akdemir Z, Gelowani V, Writzl K, Bacino CA, Lindsay SJ, Withers M, Gonzaga-Jauregui C, Wiszniewska J, Scull J, Stankiewicz P, Jhangiani SN, Muzny DM, Zhang F, Chen K, Gibbs RA, Rautenstrauss B, Cheung SW, Smith J, Breman A, Shaw CA, Patel A, Hurles ME, Lupski JR. An Organismal CNV Mutator Phenotype Restricted to Early Human Development. Cell 2017; 168:830-842.e7. [PMID: 28235197 DOI: 10.1016/j.cell.2017.01.037] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Revised: 10/13/2016] [Accepted: 01/27/2017] [Indexed: 01/07/2023]
Abstract
De novo copy number variants (dnCNVs) arising at multiple loci in a personal genome have usually been considered to reflect cancer somatic genomic instabilities. We describe a multiple dnCNV (MdnCNV) phenomenon in which individuals with genomic disorders carry five to ten constitutional dnCNVs. These CNVs originate from independent formation incidences, are predominantly tandem duplications or complex gains, exhibit breakpoint junction features reminiscent of replicative repair, and show increased de novo point mutations flanking the rearrangement junctions. The active CNV mutation shower appears to be restricted to a transient perizygotic period. We propose that a defect in the CNV formation process is responsible for the "CNV-mutator state," and this state is dampened after early embryogenesis. The constitutional MdnCNV phenomenon resembles chromosomal instability in various cancers. Investigations of this phenomenon may provide unique access to understanding genomic disorders, structural variant mutagenesis, human evolution, and cancer biology.
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Affiliation(s)
- Pengfei Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Baylor Genetics, Houston, TX 77021, USA.
| | - Bo Yuan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Claudia M B Carvalho
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Arthur Wuster
- Wellcome Trust Sanger Institute, Hinxton CB10 1SA, UK
| | | | - Ling Zhang
- Collaborative Innovation Center of Genetics and Development, Institute of Reproduction and Development, Obstetrics and Gynecology Hospital of Fudan University, Shanghai 200011, China
| | - Tomasz Gambin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zechen Chong
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Ian M Campbell
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zeynep Coban Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Violet Gelowani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Karin Writzl
- Clinical Institute of Medical Genetics, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia
| | - Carlos A Bacino
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Baylor Genetics, Houston, TX 77021, USA; Texas Children's Hospital, Houston, TX 77030, USA
| | | | - Marjorie Withers
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | | | - Joanna Wiszniewska
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jennifer Scull
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Baylor Genetics, Houston, TX 77021, USA
| | - Paweł Stankiewicz
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Baylor Genetics, Houston, TX 77021, USA
| | - Shalini N Jhangiani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Donna M Muzny
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Feng Zhang
- Collaborative Innovation Center of Genetics and Development, Institute of Reproduction and Development, Obstetrics and Gynecology Hospital of Fudan University, Shanghai 200011, China
| | - Ken Chen
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Richard A Gibbs
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | | | - Sau Wai Cheung
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Baylor Genetics, Houston, TX 77021, USA
| | - Janice Smith
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Baylor Genetics, Houston, TX 77021, USA
| | - Amy Breman
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Baylor Genetics, Houston, TX 77021, USA
| | - Chad A Shaw
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Baylor Genetics, Houston, TX 77021, USA
| | - Ankita Patel
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Baylor Genetics, Houston, TX 77021, USA
| | | | - 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; Texas Children's Hospital, Houston, TX 77030, USA.
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47
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Zhang L, Wang J, Zhang C, Li D, Carvalho CM, Ji H, Xiao J, Wu Y, Zhou W, Wang H, Jin L, Luo Y, Wu X, Lupski JR, Zhang F, Jiang Y. Efficient CNV breakpoint analysis reveals unexpected structural complexity and correlation of dosage-sensitive genes with clinical severity in genomic disorders. Hum Mol Genet 2017; 26:1927-1941. [PMID: 28334874 PMCID: PMC6075079 DOI: 10.1093/hmg/ddx102] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 03/08/2017] [Accepted: 03/10/2017] [Indexed: 01/13/2023] Open
Abstract
Genomic disorders are the clinical conditions manifested by submicroscopic genomic rearrangements including copy number variants (CNVs). The CNVs can be identified by array-based comparative genomic hybridization (aCGH), the most commonly used technology for molecular diagnostics of genomic disorders. However, clinical aCGH only informs CNVs in the probe-interrogated regions. Neither orientational information nor the resulting genomic rearrangement structure is provided, which is a key to uncovering mutational and pathogenic mechanisms underlying genomic disorders. Long-range polymerase chain reaction (PCR) is a traditional approach to obtain CNV breakpoint junction, but this method is inefficient when challenged by structural complexity such as often found at the PLP1 locus in association with Pelizaeus-Merzbacher disease (PMD). Here we introduced 'capture and single-molecule real-time sequencing' (cap-SMRT-seq) and newly developed 'asymmetry linker-mediated nested PCR walking' (ALN-walking) for CNV breakpoint sequencing in 49 subjects with PMD-associated CNVs. Remarkably, 29 (94%) of the 31 CNV breakpoint junctions unobtainable by conventional long-range PCR were resolved by cap-SMRT-seq and ALN-walking. Notably, unexpected CNV complexities, including inter-chromosomal rearrangements that cannot be resolved by aCGH, were revealed by efficient breakpoint sequencing. These sequence-based structures of PMD-associated CNVs further support the role of DNA replicative mechanisms in CNV mutagenesis, and facilitate genotype-phenotype correlation studies. Intriguingly, the lengths of gained segments by CNVs are strongly correlated with clinical severity in PMD, potentially reflecting the functional contribution of other dosage-sensitive genes besides PLP1. Our study provides new efficient experimental approaches (especially ALN-walking) for CNV breakpoint sequencing and highlights their importance in uncovering CNV mutagenesis and pathogenesis in genomic disorders.
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Affiliation(s)
- Ling Zhang
- Obstetrics and Gynecology Hospital, State Key Laboratory of Genetic Engineering at School of Life Sciences, Institute of Reproduction and Development, Fudan University, Shanghai 200011, China
- Key Laboratory of Reproduction Regulation of NPFPC, Collaborative Innovation Center of Genetics and Development, Fudan University, Shanghai 200032, China
- Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Shanghai 200011, China
| | - Jingmin Wang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Cheng Zhang
- Obstetrics and Gynecology Hospital, State Key Laboratory of Genetic Engineering at School of Life Sciences, Institute of Reproduction and Development, Fudan University, Shanghai 200011, China
| | - Dongxiao Li
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Claudia M.B. Carvalho
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Haoran Ji
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Jianqiu Xiao
- Obstetrics and Gynecology Hospital, State Key Laboratory of Genetic Engineering at School of Life Sciences, Institute of Reproduction and Development, Fudan University, Shanghai 200011, China
| | - Ye Wu
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Weichen Zhou
- Obstetrics and Gynecology Hospital, State Key Laboratory of Genetic Engineering at School of Life Sciences, Institute of Reproduction and Development, Fudan University, Shanghai 200011, China
| | - Hongyan Wang
- Obstetrics and Gynecology Hospital, State Key Laboratory of Genetic Engineering at School of Life Sciences, Institute of Reproduction and Development, Fudan University, Shanghai 200011, China
- Key Laboratory of Reproduction Regulation of NPFPC, Collaborative Innovation Center of Genetics and Development, Fudan University, Shanghai 200032, China
- Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Shanghai 200011, China
| | - Li Jin
- Obstetrics and Gynecology Hospital, State Key Laboratory of Genetic Engineering at School of Life Sciences, Institute of Reproduction and Development, Fudan University, Shanghai 200011, China
- Key Laboratory of Reproduction Regulation of NPFPC, Collaborative Innovation Center of Genetics and Development, Fudan University, Shanghai 200032, China
| | - Yang Luo
- MOE Key Laboratory of Medical Cell Biology, The Research Center for Medical Genomics, College of Basic Medical Science, China Medical University, Shenyang 110001, China
| | - Xiru Wu
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, 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
- Texas Children’s Hospital, Houston, TX 77030, USA
| | - Feng Zhang
- Obstetrics and Gynecology Hospital, State Key Laboratory of Genetic Engineering at School of Life Sciences, Institute of Reproduction and Development, Fudan University, Shanghai 200011, China
- Key Laboratory of Reproduction Regulation of NPFPC, Collaborative Innovation Center of Genetics and Development, Fudan University, Shanghai 200032, China
- Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Shanghai 200011, China
| | - Yuwu Jiang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
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48
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Larsen PA, Lutz MW, Hunnicutt KE, Mihovilovic M, Saunders AM, Yoder AD, Roses AD. The Alu neurodegeneration hypothesis: A primate-specific mechanism for neuronal transcription noise, mitochondrial dysfunction, and manifestation of neurodegenerative disease. Alzheimers Dement 2017; 13:828-838. [PMID: 28242298 PMCID: PMC6647845 DOI: 10.1016/j.jalz.2017.01.017] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 01/12/2017] [Accepted: 01/24/2017] [Indexed: 01/13/2023]
Abstract
It is hypothesized that retrotransposons have played a fundamental role in primate evolution and that enhanced neurologic retrotransposon activity in humans may underlie the origin of higher cognitive function. As a potential consequence of this enhanced activity, it is likely that neurons are susceptible to deleterious retrotransposon pathways that can disrupt mitochondrial function. An example is observed in the TOMM40 gene, encoding a β-barrel protein critical for mitochondrial preprotein transport. Primate-specific Alu retrotransposons have repeatedly inserted into TOMM40 introns, and at least one variant associated with late-onset Alzheimer’s disease originated from an Alu insertion event. We provide evidence of enriched Alu content in mitochondrial genes and postulate that Alus can disrupt mitochondrial populations in neurons, thereby setting the stage for progressive neurologic dysfunction. This Alu neurodegeneration hypothesis is compatible with decades of research and offers a plausible mechanism for the disruption of neuronal mitochondrial homeostasis, ultimately cascading into neurodegenerative disease.
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Affiliation(s)
- Peter A Larsen
- Department of Biology, Duke University, Durham, NC, USA.
| | - Michael W Lutz
- Department of Neurology, Duke University School of Medicine, Durham, NC, USA
| | | | - Mirta Mihovilovic
- Department of Neurology, Duke University School of Medicine, Durham, NC, USA
| | - Ann M Saunders
- Department of Neurology, Duke University School of Medicine, Durham, NC, USA
| | - Anne D Yoder
- Department of Biology, Duke University, Durham, NC, USA; Duke Lemur Center, Duke University, Durham, NC, USA
| | - Allen D Roses
- Department of Neurology, Duke University School of Medicine, Durham, NC, USA; Zinfandel Pharmaceuticals, Inc, Durham, NC, USA
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49
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Nilsson D, Pettersson M, Gustavsson P, Förster A, Hofmeister W, Wincent J, Zachariadis V, Anderlid BM, Nordgren A, Mäkitie O, Wirta V, Käller M, Vezzi F, Lupski JR, Nordenskjöld M, Lundberg ES, Carvalho CMB, Lindstrand A. Whole-Genome Sequencing of Cytogenetically Balanced Chromosome Translocations Identifies Potentially Pathological Gene Disruptions and Highlights the Importance of Microhomology in the Mechanism of Formation. Hum Mutat 2017; 38:180-192. [PMID: 27862604 PMCID: PMC5225243 DOI: 10.1002/humu.23146] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 11/01/2016] [Indexed: 11/07/2022]
Abstract
Most balanced translocations are thought to result mechanistically from nonhomologous end joining or, in rare cases of recurrent events, by nonallelic homologous recombination. Here, we use low-coverage mate pair whole-genome sequencing to fine map rearrangement breakpoint junctions in both phenotypically normal and affected translocation carriers. In total, 46 junctions from 22 carriers of balanced translocations were characterized. Genes were disrupted in 48% of the breakpoints; recessive genes in four normal carriers and known dominant intellectual disability genes in three affected carriers. Finally, seven candidate disease genes were disrupted in five carriers with neurocognitive disabilities (SVOPL, SUSD1, TOX, NCALD, SLC4A10) and one XX-male carrier with Tourette syndrome (LYPD6, GPC5). Breakpoint junction analyses revealed microhomology and small templated insertions in a substantive fraction of the analyzed translocations (17.4%; n = 4); an observation that was substantiated by reanalysis of 37 previously published translocation junctions. Microhomology associated with templated insertions is a characteristic seen in the breakpoint junctions of rearrangements mediated by error-prone replication-based repair mechanisms. Our data implicate that a mechanism involving template switching might contribute to the formation of at least 15% of the interchromosomal translocation events.
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Affiliation(s)
- Daniel Nilsson
- Department of Molecular Medicine and Surgery, Karolinska Institutet, 171 76 Stockholm, Sweden
- Center for Molecular Medicine, Karolinska Institutet, 171 76 Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, 171 76 Stockholm, Sweden
- Science for Life Laboratory, Karolinska Institutet Science Park, 171 21 Solna, Sweden
| | - Maria Pettersson
- Department of Molecular Medicine and Surgery, Karolinska Institutet, 171 76 Stockholm, Sweden
- Center for Molecular Medicine, Karolinska Institutet, 171 76 Stockholm, Sweden
| | - Peter Gustavsson
- Department of Molecular Medicine and Surgery, Karolinska Institutet, 171 76 Stockholm, Sweden
- Center for Molecular Medicine, Karolinska Institutet, 171 76 Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, 171 76 Stockholm, Sweden
| | - Alisa Förster
- Department of Molecular Medicine and Surgery, Karolinska Institutet, 171 76 Stockholm, Sweden
- Center for Molecular Medicine, Karolinska Institutet, 171 76 Stockholm, Sweden
| | - Wolfgang Hofmeister
- Department of Molecular Medicine and Surgery, Karolinska Institutet, 171 76 Stockholm, Sweden
- Center for Molecular Medicine, Karolinska Institutet, 171 76 Stockholm, Sweden
| | - Josephine Wincent
- Department of Molecular Medicine and Surgery, Karolinska Institutet, 171 76 Stockholm, Sweden
- Center for Molecular Medicine, Karolinska Institutet, 171 76 Stockholm, Sweden
| | - Vasilios Zachariadis
- Department of Molecular Medicine and Surgery, Karolinska Institutet, 171 76 Stockholm, Sweden
- Center for Molecular Medicine, Karolinska Institutet, 171 76 Stockholm, Sweden
| | - Britt-Marie Anderlid
- Department of Molecular Medicine and Surgery, Karolinska Institutet, 171 76 Stockholm, Sweden
- Center for Molecular Medicine, Karolinska Institutet, 171 76 Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, 171 76 Stockholm, Sweden
| | - Ann Nordgren
- Department of Molecular Medicine and Surgery, Karolinska Institutet, 171 76 Stockholm, Sweden
- Center for Molecular Medicine, Karolinska Institutet, 171 76 Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, 171 76 Stockholm, Sweden
| | - Outi Mäkitie
- Department of Molecular Medicine and Surgery, Karolinska Institutet, 171 76 Stockholm, Sweden
- Center for Molecular Medicine, Karolinska Institutet, 171 76 Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, 171 76 Stockholm, Sweden
- Children's Hospital, Helsinki University Central Hospital and University of Helsinki, 00290 Helsinki, Finland
- Folkhälsan Institute of Genetics, 00290 Helsinki, Finland
| | - Valtteri Wirta
- SciLifeLab, School of Biotechnology, KTH Royal Institute of Technology, 171 71 Stockholm, Sweden
| | - Max Käller
- SciLifeLab, School of Biotechnology, KTH Royal Institute of Technology, 171 71 Stockholm, Sweden
| | - Francesco Vezzi
- SciLifeLab, Department of Biochemistry and Biophysics, Stockholm University, 171 21 Stockholm, Sweden
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, 77030 Houston TX, USA
- Texas Children’s Hospital, 77030 Houston TX, USA
| | - Magnus Nordenskjöld
- Department of Molecular Medicine and Surgery, Karolinska Institutet, 171 76 Stockholm, Sweden
- Center for Molecular Medicine, Karolinska Institutet, 171 76 Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, 171 76 Stockholm, Sweden
| | - Elisabeth Syk Lundberg
- Department of Molecular Medicine and Surgery, Karolinska Institutet, 171 76 Stockholm, Sweden
- Center for Molecular Medicine, Karolinska Institutet, 171 76 Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, 171 76 Stockholm, Sweden
| | - Claudia M. B. Carvalho
- Department of Molecular and Human Genetics, Baylor College of Medicine, 77030 Houston TX, USA
| | - Anna Lindstrand
- Department of Molecular Medicine and Surgery, Karolinska Institutet, 171 76 Stockholm, Sweden
- Center for Molecular Medicine, Karolinska Institutet, 171 76 Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, 171 76 Stockholm, Sweden
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50
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Jahic A, Hinreiner S, Emberger W, Hehr U, Zuchner S, Beetz C. Doublet-Mediated DNA Rearrangement-A Novel and Potentially Underestimated Mechanism for the Formation of Recurrent Pathogenic Deletions. Hum Mutat 2016; 38:275-278. [PMID: 28008689 DOI: 10.1002/humu.23162] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 12/02/2016] [Accepted: 12/14/2016] [Indexed: 11/09/2022]
Abstract
Deletions and duplications of genomic DNA contribute to evolution, phenotypic diversity, and human disease. The underlying mechanisms are incompletely understood. We identified deletions of exon 10 of the SPAST gene in two unrelated families with hereditary spastic paraplegia. We excluded a founder event, but observed that the breakpoints map to identical repeat regions. These regions likely represent an intragenic "doublet," that is, an enigmatic class of local duplications. The fusion sequences for both deletions are compatible with recombination-based as well as with replication-based mechanisms. Searching the literature, we identified a partial SLC24A4 deletion that involved two copies of another doublet, and was likely formed in an analogous way. Comparing the SPAST and the SLC24A4 doublets with doublets identified previously suggested that many additional doublets have a high potential for triggering rearrangements. Considering that doublets are still being formed in the human genome, and that they likely create high local instability, we suggest that a two-step mechanism consisting of doublet generation and subsequent doublet-mediated deletion/duplication may underlie certain copy-number changes for which other mechanisms are currently assumed. Further studies are necessary to delineate the significance of the thus-far understudied doublets for the formation of copy-number variation.
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Affiliation(s)
- Amir Jahic
- Department of Clinical Chemistry and Laboratory Medicine, Jena University Hospital, Jena, Germany
| | - Sophie Hinreiner
- Department of Human Genetics, University of Regensburg, Regensburg, Germany
| | - Werner Emberger
- Department of Human Genetics, Graz Medical University, Graz, Austria
| | - Ute Hehr
- Department of Human Genetics, University of Regensburg, Regensburg, Germany
| | - Stephan Zuchner
- John T. Macdonald Department of Human Genetics and John P. Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, Florida
| | - Christian Beetz
- Department of Clinical Chemistry and Laboratory Medicine, Jena University Hospital, Jena, Germany
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