1
|
Adams DR, Dm van Karnebeek C, Agullo SB, Faundes V, Jamuar SS, Lynch SA, Pintos-Morell G, Puri RD, Shai R, Steward CA, Tumiene B, Verloes A. Addressing Diagnostic Gaps and Priorities of the Global Rare Diseases Community: Recommendations from the IRDiRC Diagnostics Scientific Committee. Eur J Med Genet 2024:104951. [PMID: 38848991 DOI: 10.1016/j.ejmg.2024.104951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 06/05/2024] [Indexed: 06/09/2024]
Abstract
The International Rare Diseases Research Consortium (IRDiRC) Diagnostic Scientific Committee (DSC) is charged with discussion and contribution to progress on diagnostic aspects of the IRDiRC core mission. Specifically, IRDiRC goals include timely diagnosis, use of globally coordinated diagnostic pipelines, and assessing the impact of rare diseases on affected individuals. As part of this mission, the DSC endeavored to create a list of research priorities to achieve these goals. We present a discussion of those priorities along with aspects of current, global rare disease needs and opportunities that support our prioritization. In support of this discussion, we also provide clinical vignettes illustrating real-world examples of diagnostic challenges.
Collapse
Affiliation(s)
- David R Adams
- National Human Genome Research Institute, National Institutes of Health, USA.
| | - Clara Dm van Karnebeek
- Departments of Pediatrics and Human Genetics, Emma Center for Personalized Medicine, Amsterdam Gastro-enterology Endocrinology Metabolism, Amsterdam University Medical Centers, The Netherlands
| | - Sergi Beltran Agullo
- Centre Nacional d'Anàlisi Genòmica (CNAG), Spain; Departament de Genètica, Microbiologia i Estadística, Facultat de Biologia, Universitat de Barcelona (UB), Spain
| | - Víctor Faundes
- Laboratorio de Genética y Enfermedades Metabólicas, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile, Chile
| | - Saumya Shekhar Jamuar
- Genetics Service, KK Women's and Children's Hospital and Paediatrics ACP, Duke-NUS Medical School, Singapore; Singhealth Duke-NUS Institute of Precision Medicine, Singapore
| | | | - Guillem Pintos-Morell
- Vall d'Hebron Research Institute (VHIR), Vall d'Hebron Barcelona Hospital, Spain; MPS-Spain Patient Advocacy Organization, Spain
| | - Ratna Dua Puri
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital, India
| | - Ruty Shai
- Pediatric Cancer Molecular Lab, Sheba Medical Center, Israel
| | | | - Biruté Tumiene
- Vilnius University, Faculty of Medicine, Institute of Biomedical Sciences, Lithuania
| | - Alain Verloes
- Département de Génétique, CHU Paris - Hôpital Robert Debré, France
| |
Collapse
|
2
|
Agustinho DP, Fu Y, Menon VK, Metcalf GA, Treangen TJ, Sedlazeck FJ. Unveiling microbial diversity: harnessing long-read sequencing technology. Nat Methods 2024; 21:954-966. [PMID: 38689099 DOI: 10.1038/s41592-024-02262-1] [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: 09/08/2022] [Accepted: 03/29/2024] [Indexed: 05/02/2024]
Abstract
Long-read sequencing has recently transformed metagenomics, enhancing strain-level pathogen characterization, enabling accurate and complete metagenome-assembled genomes, and improving microbiome taxonomic classification and profiling. These advancements are not only due to improvements in sequencing accuracy, but also happening across rapidly changing analysis methods. In this Review, we explore long-read sequencing's profound impact on metagenomics, focusing on computational pipelines for genome assembly, taxonomic characterization and variant detection, to summarize recent advancements in the field and provide an overview of available analytical methods to fully leverage long reads. We provide insights into the advantages and disadvantages of long reads over short reads and their evolution from the early days of long-read sequencing to their recent impact on metagenomics and clinical diagnostics. We further point out remaining challenges for the field such as the integration of methylation signals in sub-strain analysis and the lack of benchmarks.
Collapse
Affiliation(s)
- Daniel P Agustinho
- Human Genome Sequencing center, Baylor College of Medicine, Houston, TX, USA
| | - Yilei Fu
- Department of Computer Science, Rice University, Houston, TX, USA
| | - Vipin K Menon
- Human Genome Sequencing center, Baylor College of Medicine, Houston, TX, USA
- Senior research project manager, Human Genetics, Genentech, South San Francisco, CA, USA
| | - Ginger A Metcalf
- Human Genome Sequencing center, Baylor College of Medicine, Houston, TX, USA
| | - Todd J Treangen
- Department of Computer Science, Rice University, Houston, TX, USA
- Department of Bioengineering, Rice University, Houston, TX, USA
| | - Fritz J Sedlazeck
- Human Genome Sequencing center, Baylor College of Medicine, Houston, TX, USA.
- Department of Computer Science, Rice University, Houston, TX, USA.
| |
Collapse
|
3
|
Hiatt L, Weisburd B, Dolzhenko E, VanNoy GE, Kurtas EN, Rehm HL, Quinlan A, Dashnow H. STRchive: a dynamic resource detailing population-level and locus-specific insights at tandem repeat disease loci. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.05.21.24307682. [PMID: 38826469 PMCID: PMC11142282 DOI: 10.1101/2024.05.21.24307682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Approximately 3% of the human genome consists of repetitive elements called tandem repeats (TRs), which include short tandem repeats (STRs) of 1-6bp motifs and variable number tandem repeats (VNTRs) of 7+bp motifs. TR variants contribute to several dozen mono- and polygenic diseases but remain understudied and "enigmatic," particularly relative to single nucleotide variants. It remains comparatively challenging to interpret the clinical significance of TR variants. Although existing resources provide portions of necessary data for interpretation at disease-associated loci, it is currently difficult or impossible to efficiently invoke the additional details critical to proper interpretation, such as motif pathogenicity, disease penetrance, and age of onset distributions. It is also often unclear how to apply population information to analyses. We present STRchive (S-T-archive, http://strchive.org/ ), a dynamic resource consolidating information on TR disease loci in humans from research literature, up-to-date clinical resources, and large-scale genomic databases, with the goal of streamlining TR variant interpretation at disease-associated loci. We apply STRchive -including pathogenic thresholds, motif classification, and clinical phenotypes-to a gnomAD cohort of ∼18.5k individuals genotyped at 60 disease-associated loci. Through detailed literature curation, we demonstrate that the majority of TR diseases affect children despite being thought of as adult diseases. Additionally, we show that pathogenic genotypes can be found within gnomAD which do not necessarily overlap with known disease prevalence, and leverage STRchive to interpret locus-specific findings therein. We apply a diagnostic blueprint empowered by STRchive to relevant clinical vignettes, highlighting possible pitfalls in TR variant interpretation. As a living resource, STRchive is maintained by experts, takes community contributions, and will evolve as understanding of TR diseases progresses.
Collapse
|
4
|
Fernández-Suárez E, González-Del Pozo M, Méndez-Vidal C, Martín-Sánchez M, Mena M, de la Morena-Barrio B, Corral J, Borrego S, Antiñolo G. Long-read sequencing improves the genetic diagnosis of retinitis pigmentosa by identifying an Alu retrotransposon insertion in the EYS gene. Mob DNA 2024; 15:9. [PMID: 38704576 PMCID: PMC11069205 DOI: 10.1186/s13100-024-00320-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 04/10/2024] [Indexed: 05/06/2024] Open
Abstract
BACKGROUND Biallelic variants in EYS are the major cause of autosomal recessive retinitis pigmentosa (arRP) in certain populations, a clinically and genetically heterogeneous disease that may lead to legal blindness. EYS is one of the largest genes (~ 2 Mb) expressed in the retina, in which structural variants (SVs) represent a common cause of disease. However, their identification using short-read sequencing (SRS) is not always feasible. Here, we conducted targeted long-read sequencing (T-LRS) using adaptive sampling of EYS on the MinION sequencing platform (Oxford Nanopore Technologies) to definitively diagnose an arRP family, whose affected individuals (n = 3) carried the heterozygous pathogenic deletion of exons 32-33 in the EYS gene. As this was a recurrent variant identified in three additional families in our cohort, we also aimed to characterize the known deletion at the nucleotide level to assess a possible founder effect. RESULTS T-LRS in family A unveiled a heterozygous AluYa5 insertion in the coding exon 43 of EYS (chr6(GRCh37):g.64430524_64430525ins352), which segregated with the disease in compound heterozygosity with the previously identified deletion. Visual inspection of previous SRS alignments using IGV revealed several reads containing soft-clipped bases, accompanied by a slight drop in coverage at the Alu insertion site. This prompted us to develop a simplified program using grep command to investigate the recurrence of this variant in our cohort from SRS data. Moreover, LRS also allowed the characterization of the CNV as a ~ 56.4kb deletion spanning exons 32-33 of EYS (chr6(GRCh37):g.64764235_64820592del). The results of further characterization by Sanger sequencing and linkage analysis in the four families were consistent with a founder variant. CONCLUSIONS To our knowledge, this is the first report of a mobile element insertion into the coding sequence of EYS, as a likely cause of arRP in a family. Our study highlights the value of LRS technology in characterizing and identifying hidden pathogenic SVs, such as retrotransposon insertions, whose contribution to the etiopathogenesis of rare diseases may be underestimated.
Collapse
Affiliation(s)
- Elena Fernández-Suárez
- Department of Maternofetal Medicine, Genetics and Reproduction, Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC, University of Seville, Seville, Spain
- Center for Biomedical Network Research On Rare Diseases (CIBERER), Seville, Spain
| | - María González-Del Pozo
- Department of Maternofetal Medicine, Genetics and Reproduction, Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC, University of Seville, Seville, Spain
- Center for Biomedical Network Research On Rare Diseases (CIBERER), Seville, Spain
| | - Cristina Méndez-Vidal
- Department of Maternofetal Medicine, Genetics and Reproduction, Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC, University of Seville, Seville, Spain
- Center for Biomedical Network Research On Rare Diseases (CIBERER), Seville, Spain
| | - Marta Martín-Sánchez
- Department of Maternofetal Medicine, Genetics and Reproduction, Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC, University of Seville, Seville, Spain
- Center for Biomedical Network Research On Rare Diseases (CIBERER), Seville, Spain
| | - Marcela Mena
- Department of Maternofetal Medicine, Genetics and Reproduction, Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC, University of Seville, Seville, Spain
- Center for Biomedical Network Research On Rare Diseases (CIBERER), Seville, Spain
| | - Belén de la Morena-Barrio
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, Universidad de Murcia, IMIB-Pascual Parrilla, CIBERER-ISCIII, Murcia, Spain
| | - Javier Corral
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, Universidad de Murcia, IMIB-Pascual Parrilla, CIBERER-ISCIII, Murcia, Spain
| | - Salud Borrego
- Department of Maternofetal Medicine, Genetics and Reproduction, Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC, University of Seville, Seville, Spain.
- Center for Biomedical Network Research On Rare Diseases (CIBERER), Seville, Spain.
| | - Guillermo Antiñolo
- Department of Maternofetal Medicine, Genetics and Reproduction, Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC, University of Seville, Seville, Spain.
- Center for Biomedical Network Research On Rare Diseases (CIBERER), Seville, Spain.
| |
Collapse
|
5
|
Jin B, Yoon JG, Kim A, Moon J, Kim HJ. Late-Onset Ataxia-Telangiectasia Presenting With Dystonia and Tremor: The Use of Nanopore Long-Read Sequencing Solving the Variant Phase. Neurol Genet 2024; 10:e200141. [PMID: 38854973 PMCID: PMC11157422 DOI: 10.1212/nxg.0000000000200141] [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] [Received: 12/21/2023] [Accepted: 01/24/2024] [Indexed: 06/11/2024]
Abstract
Objectives This study investigates atypical late-onset ataxia-telangiectasia (AT) cases in a Korean family, diagnosed via Nanopore long-read sequencing, diverging from the typical early childhood onset caused by biallelic pathogenic ATM variants. Methods A 52-year-old Korean woman exhibiting dystonia and tremor, with a family history of similar symptoms in her older sister, underwent comprehensive tests including routine laboratory tests, neuropsychological assessments, and neuroimaging. Genetic analysis was conducted through targeted sequencing of 29 dystonia-associated genes and Nanopore long-read sequencing to assess the configuration of 2 ATM gene variants. Results Routine blood tests and brain imaging studies returned normal results, except for elevated α-fetoprotein levels. Neurologic examination revealed dystonia in the face, hand, and trunk, along with cervical dystonia in the proband. Her sister exhibited similar symptoms without evident telangiectasia. Genetic testing revealed 2 heterozygous pathogenic ATM gene variants (p.Glu2014Ter and p.Glu2052Lys). Nanopore long-read sequencing confirmed these variants were in trans configuration, establishing a definite molecular diagnosis in the proband. Discussion This report expands the known clinical spectrum of AT, highlighting a familial case of atypical AT. Moreover, it underscores the clinical utility of Nanopore long-read sequencing in phasing variant haplotypes, essential for diagnosing autosomal recessive disorders, especially beneficial for cases without parental samples.
Collapse
Affiliation(s)
- Bora Jin
- From the Department of Neurology (B.J., J.M., H.-J.K.), Seoul National University Hospital and Seoul National University College of Medicine; Department of Genomic Medicine (J.G.Y., J.M.), Seoul National University Hospital; Department of Laboratory Medicine (J.G.Y), Gangnam Severance Hospital and Yonsei University College of Medicine; and Department of Neurology (A.K.), Chungbuk National University Hospital and Chungbuk National University College of Medicine, Cheongju-si, Republic of Korea
| | - Jihoon G Yoon
- From the Department of Neurology (B.J., J.M., H.-J.K.), Seoul National University Hospital and Seoul National University College of Medicine; Department of Genomic Medicine (J.G.Y., J.M.), Seoul National University Hospital; Department of Laboratory Medicine (J.G.Y), Gangnam Severance Hospital and Yonsei University College of Medicine; and Department of Neurology (A.K.), Chungbuk National University Hospital and Chungbuk National University College of Medicine, Cheongju-si, Republic of Korea
| | - Aryun Kim
- From the Department of Neurology (B.J., J.M., H.-J.K.), Seoul National University Hospital and Seoul National University College of Medicine; Department of Genomic Medicine (J.G.Y., J.M.), Seoul National University Hospital; Department of Laboratory Medicine (J.G.Y), Gangnam Severance Hospital and Yonsei University College of Medicine; and Department of Neurology (A.K.), Chungbuk National University Hospital and Chungbuk National University College of Medicine, Cheongju-si, Republic of Korea
| | - Jangsup Moon
- From the Department of Neurology (B.J., J.M., H.-J.K.), Seoul National University Hospital and Seoul National University College of Medicine; Department of Genomic Medicine (J.G.Y., J.M.), Seoul National University Hospital; Department of Laboratory Medicine (J.G.Y), Gangnam Severance Hospital and Yonsei University College of Medicine; and Department of Neurology (A.K.), Chungbuk National University Hospital and Chungbuk National University College of Medicine, Cheongju-si, Republic of Korea
| | - Han-Joon Kim
- From the Department of Neurology (B.J., J.M., H.-J.K.), Seoul National University Hospital and Seoul National University College of Medicine; Department of Genomic Medicine (J.G.Y., J.M.), Seoul National University Hospital; Department of Laboratory Medicine (J.G.Y), Gangnam Severance Hospital and Yonsei University College of Medicine; and Department of Neurology (A.K.), Chungbuk National University Hospital and Chungbuk National University College of Medicine, Cheongju-si, Republic of Korea
| |
Collapse
|
6
|
Mahmoud M, Harting J, Corbitt H, Chen X, Jhangiani SN, Doddapaneni H, Meng Q, Han T, Lambert C, Zhang S, Baybayan P, Henno G, Shen H, Hu J, Han Y, Riegler C, Metcalf G, Henno G, Chinn IK, Eberle MA, Kingan S, Farinholt T, Carvalho CM, Gibbs RA, Kronenberg Z, Muzny D, Sedlazeck FJ. Closing the gap: Solving complex medically relevant genes at scale. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.03.14.24304179. [PMID: 38562723 PMCID: PMC10984040 DOI: 10.1101/2024.03.14.24304179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Comprehending the mechanism behind human diseases with an established heritable component represents the forefront of personalized medicine. Nevertheless, numerous medically important genes are inaccurately represented in short-read sequencing data analysis due to their complexity and repetitiveness or the so-called 'dark regions' of the human genome. The advent of PacBio as a long-read platform has provided new insights, yet HiFi whole-genome sequencing (WGS) cost remains frequently prohibitive. We introduce a targeted sequencing and analysis framework, Twist Alliance Dark Genes Panel (TADGP), designed to offer phased variants across 389 medically important yet complex autosomal genes. We highlight TADGP accuracy across eleven control samples and compare it to WGS. This demonstrates that TADGP achieves variant calling accuracy comparable to HiFi-WGS data, but at a fraction of the cost. Thus, enabling scalability and broad applicability for studying rare diseases or complementing previously sequenced samples to gain insights into these complex genes. TADGP revealed several candidate variants across all cases and provided insight into LPA diversity when tested on samples from rare disease and cardiovascular disease cohorts. In both cohorts, we identified novel variants affecting individual disease-associated genes (e.g., IKZF1, KCNE1). Nevertheless, the annotation of the variants across these 389 medically important genes remains challenging due to their underrepresentation in ClinVar and gnomAD. Consequently, we also offer an annotation resource to enhance the evaluation and prioritization of these variants. Overall, we can demonstrate that TADGP offers a cost-efficient and scalable approach to routinely assess the dark regions of the human genome with clinical relevance.
Collapse
Affiliation(s)
- Medhat Mahmoud
- Baylor College of Medicine, Human Genome Sequencing Center, Houston, Texas, USA
| | - John Harting
- Pacific Biosciences, Menlo Park, California, USA
| | | | - Xiao Chen
- Pacific Biosciences, Menlo Park, California, USA
| | | | - Harsha Doddapaneni
- Baylor College of Medicine, Human Genome Sequencing Center, Houston, Texas, USA
| | - Qingchang Meng
- Baylor College of Medicine, Human Genome Sequencing Center, Houston, Texas, USA
| | - Tina Han
- Twist Bioscience, South San Francisco, USA
| | | | - Siyuan Zhang
- Pacific Biosciences, Menlo Park, California, USA
| | | | - Geoff Henno
- Pacific Biosciences, Menlo Park, California, USA
| | - Hua Shen
- Baylor College of Medicine, Human Genome Sequencing Center, Houston, Texas, USA
| | - Jianhong Hu
- Baylor College of Medicine, Human Genome Sequencing Center, Houston, Texas, USA
| | - Yi Han
- Baylor College of Medicine, Human Genome Sequencing Center, Houston, Texas, USA
| | | | - Ginger Metcalf
- Baylor College of Medicine, Human Genome Sequencing Center, Houston, Texas, USA
| | - Geoff Henno
- Pacific Biosciences, Menlo Park, California, USA
| | - Ivan K. Chinn
- Department of Pediatrics, Section of Immunology Allergy and Rheumatology, Center for Human Immunobiology, Texas Children’s Hospital and Baylor College of Medicine, Houston, Texas, USA
| | | | - Sarah Kingan
- Pacific Biosciences, Menlo Park, California, USA
| | | | | | - Richard A. Gibbs
- Baylor College of Medicine, Human Genome Sequencing Center, Houston, Texas, USA
| | | | - Donna Muzny
- Baylor College of Medicine, Human Genome Sequencing Center, Houston, Texas, USA
| | - Fritz J. Sedlazeck
- Baylor College of Medicine, Human Genome Sequencing Center, Houston, Texas, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- Department of Computer Science, Rice University, Houston, Texas, USA
| |
Collapse
|
7
|
Olivucci G, Iovino E, Innella G, Turchetti D, Pippucci T, Magini P. Long read sequencing on its way to the routine diagnostics of genetic diseases. Front Genet 2024; 15:1374860. [PMID: 38510277 PMCID: PMC10951082 DOI: 10.3389/fgene.2024.1374860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 02/26/2024] [Indexed: 03/22/2024] Open
Abstract
The clinical application of technological progress in the identification of DNA alterations has always led to improvements of diagnostic yields in genetic medicine. At chromosome side, from cytogenetic techniques evaluating number and gross structural defects to genomic microarrays detecting cryptic copy number variants, and at molecular level, from Sanger method studying the nucleotide sequence of single genes to the high-throughput next-generation sequencing (NGS) technologies, resolution and sensitivity progressively increased expanding considerably the range of detectable DNA anomalies and alongside of Mendelian disorders with known genetic causes. However, particular genomic regions (i.e., repetitive and GC-rich sequences) are inefficiently analyzed by standard genetic tests, still relying on laborious, time-consuming and low-sensitive approaches (i.e., southern-blot for repeat expansion or long-PCR for genes with highly homologous pseudogenes), accounting for at least part of the patients with undiagnosed genetic disorders. Third generation sequencing, generating long reads with improved mappability, is more suitable for the detection of structural alterations and defects in hardly accessible genomic regions. Although recently implemented and not yet clinically available, long read sequencing (LRS) technologies have already shown their potential in genetic medicine research that might greatly impact on diagnostic yield and reporting times, through their translation to clinical settings. The main investigated LRS application concerns the identification of structural variants and repeat expansions, probably because techniques for their detection have not evolved as rapidly as those dedicated to single nucleotide variants (SNV) identification: gold standard analyses are karyotyping and microarrays for balanced and unbalanced chromosome rearrangements, respectively, and southern blot and repeat-primed PCR for the amplification and sizing of expanded alleles, impaired by limited resolution and sensitivity that have not been significantly improved by the advent of NGS. Nevertheless, more recently, with the increased accuracy provided by the latest product releases, LRS has been tested also for SNV detection, especially in genes with highly homologous pseudogenes and for haplotype reconstruction to assess the parental origin of alleles with de novo pathogenic variants. We provide a review of relevant recent scientific papers exploring LRS potential in the diagnosis of genetic diseases and its potential future applications in routine genetic testing.
Collapse
Affiliation(s)
- Giulia Olivucci
- IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
- Department of Surgical and Oncological Sciences, University of Palermo, Palermo, Italy
| | - Emanuela Iovino
- IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Giovanni Innella
- Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Bologna, Italy
- Medical Genetics Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Daniela Turchetti
- Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Bologna, Italy
- Medical Genetics Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Tommaso Pippucci
- IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Pamela Magini
- Medical Genetics Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| |
Collapse
|
8
|
Porubsky D, Eichler EE. A 25-year odyssey of genomic technology advances and structural variant discovery. Cell 2024; 187:1024-1037. [PMID: 38290514 DOI: 10.1016/j.cell.2024.01.002] [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: 10/07/2023] [Revised: 12/20/2023] [Accepted: 01/02/2024] [Indexed: 02/01/2024]
Abstract
This perspective focuses on advances in genome technology over the last 25 years and their impact on germline variant discovery within the field of human genetics. The field has witnessed tremendous technological advances from microarrays to short-read sequencing and now long-read sequencing. Each technology has provided genome-wide access to different classes of human genetic variation. We are now on the verge of comprehensive variant detection of all forms of variation for the first time with a single assay. We predict that this transition will further transform our understanding of human health and biology and, more importantly, provide novel insights into the dynamic mutational processes shaping our genomes.
Collapse
Affiliation(s)
- David Porubsky
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Evan E Eichler
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA 98195, USA; Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA.
| |
Collapse
|
9
|
Ramirez P, Sun W, Kazempour Dehkordi S, Zare H, Fongang B, Bieniek KF, Frost B. Nanopore-based DNA long-read sequencing analysis of the aged human brain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.01.578450. [PMID: 38370753 PMCID: PMC10871260 DOI: 10.1101/2024.02.01.578450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Aging disrupts cellular processes such as DNA repair and epigenetic control, leading to a gradual buildup of genomic alterations that can have detrimental effects in post-mitotic cells. Genomic alterations in regions of the genome that are rich in repetitive sequences, often termed "dark loci," are difficult to resolve using traditional sequencing approaches. New long-read technologies offer promising avenues for exploration of previously inaccessible regions of the genome. Using nanopore-based long-read whole-genome sequencing of DNA extracted from aged 18 human brains, we identify previously unreported structural variants and methylation patterns within repetitive DNA, focusing on transposable elements ("jumping genes") as crucial sources of variation, particularly in dark loci. Our analyses reveal potential somatic insertion variants and provides DNA methylation frequencies for many retrotransposon families. We further demonstrate the utility of this technology for the study of these challenging genomic regions in brains affected by Alzheimer's disease and identify significant differences in DNA methylation in pathologically normal brains versus those affected by Alzheimer's disease. Highlighting the power of this approach, we discover specific polymorphic retrotransposons with altered DNA methylation patterns. These retrotransposon loci have the potential to contribute to pathology, warranting further investigation in Alzheimer's disease research. Taken together, our study provides the first long-read DNA sequencing-based analysis of retrotransposon sequences, structural variants, and DNA methylation in the aging brain affected with Alzheimer's disease neuropathology.
Collapse
Affiliation(s)
- Paulino Ramirez
- Barshop Institute for Longevity and Aging Studies, University of Texas Health San Antonio, San Antonio, Texas
- Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases, University of Texas Health San Antonio, San Antonio, Texas
- Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, Texas
| | - Wenyan Sun
- Barshop Institute for Longevity and Aging Studies, University of Texas Health San Antonio, San Antonio, Texas
- Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases, University of Texas Health San Antonio, San Antonio, Texas
- Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, Texas
- School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri
| | - Shiva Kazempour Dehkordi
- Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases, University of Texas Health San Antonio, San Antonio, Texas
- Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, Texas
| | - Habil Zare
- Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases, University of Texas Health San Antonio, San Antonio, Texas
- Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, Texas
| | - Bernard Fongang
- Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases, University of Texas Health San Antonio, San Antonio, Texas
- Department of Biochemistry & Structural Biology, University of Texas Health San Antonio, San Antonio, Texas
| | - Kevin F. Bieniek
- Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases, University of Texas Health San Antonio, San Antonio, Texas
- Department of Pathology, University of Texas Health San Antonio, San Antonio, Texas
| | - Bess Frost
- Barshop Institute for Longevity and Aging Studies, University of Texas Health San Antonio, San Antonio, Texas
- Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases, University of Texas Health San Antonio, San Antonio, Texas
- Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, Texas
| |
Collapse
|
10
|
Kawakami R, Hiraide T, Watanabe K, Miyamoto S, Hira K, Komatsu K, Ishigaki H, Sakaguchi K, Maekawa M, Yamashita K, Fukuda T, Miyairi I, Ogata T, Saitsu H. RNA sequencing and target long-read sequencing reveal an intronic transposon insertion causing aberrant splicing. J Hum Genet 2024; 69:91-99. [PMID: 38102195 DOI: 10.1038/s10038-023-01211-8] [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: 08/09/2023] [Revised: 11/28/2023] [Accepted: 12/01/2023] [Indexed: 12/17/2023]
Abstract
More than half of cases with suspected genetic disorders remain unsolved by genetic analysis using short-read sequencing such as exome sequencing (ES) and genome sequencing (GS). RNA sequencing (RNA-seq) and long-read sequencing (LRS) are useful for interpretation of candidate variants and detection of structural variants containing repeat sequences, respectively. Recently, adaptive sampling on nanopore sequencers enables target LRS more easily. Here, we present a Japanese girl with premature chromatid separation (PCS)/mosaic variegated aneuploidy (MVA) syndrome. ES detected a known pathogenic maternal heterozygous variant (c.1402-5A>G) in intron 10 of BUB1B (NM_001211.6), a known responsive gene for PCS/MVA syndrome with autosomal recessive inheritance. Minigene splicing assay revealed that almost all transcripts from the c.1402-5G allele have mis-splicing with 4-bp insertion. GS could not detect another pathogenic variant, while RNA-seq revealed abnormal reads in intron 2. To extensively explore variants in intron 2, we performed adaptive sampling and identified a paternal 3.0 kb insertion. Consensus sequence of 16 reads spanning the insertion showed that the insertion consists of Alu and SVA elements. Realignment of RNA-seq reads to the new reference sequence containing the insertion revealed that 16 reads have 5' splice site within the insertion and 3' splice site at exon 3, demonstrating causal relationship between the insertion and aberrant splicing. In addition, immunoblotting showed severely diminished BUB1B protein level in patient derived cells. These data suggest that detection of transcriptomic abnormalities by RNA-seq can be a clue for identifying pathogenic variants, and determination of insert sequences is one of merits of LRS.
Collapse
Affiliation(s)
- Ryota Kawakami
- Department of Pediatrics, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Takuya Hiraide
- Department of Pediatrics, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Kazuki Watanabe
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Sachiko Miyamoto
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Kota Hira
- Department of Pediatrics, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Kazuyuki Komatsu
- Department of Pediatrics, Hamamatsu University School of Medicine, Hamamatsu, Japan
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Hidetoshi Ishigaki
- Department of Pediatrics, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Kimiyoshi Sakaguchi
- Department of Pediatrics, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Masato Maekawa
- Department of Laboratory Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Keita Yamashita
- Department of Laboratory Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Tokiko Fukuda
- Department of Hamamatsu Child Health and Developmental Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Isao Miyairi
- Department of Pediatrics, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Tsutomu Ogata
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
- Department of Pediatrics, Hamamatsu Medical Center, Hamamatsu, Japan
| | - Hirotomo Saitsu
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan.
| |
Collapse
|
11
|
Owusu R, Savarese M. Long-read sequencing improves diagnostic rate in neuromuscular disorders. ACTA MYOLOGICA : MYOPATHIES AND CARDIOMYOPATHIES : OFFICIAL JOURNAL OF THE MEDITERRANEAN SOCIETY OF MYOLOGY 2023; 42:123-128. [PMID: 38406378 PMCID: PMC10883326 DOI: 10.36185/2532-1900-394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 12/05/2023] [Indexed: 02/27/2024]
Abstract
Massive parallel sequencing methods, such as exome, genome, and targeted DNA sequencing, have aided molecular diagnosis of genetic diseases in the last 20 years. However, short-read sequencing methods still have several limitations, such inaccurate genome assembly, the inability to detect large structural variants, and variants located in hard-to-sequence regions like highly repetitive areas. The recently emerged PacBio single-molecule real-time (SMRT) and Oxford nanopore technology (ONT) long-read sequencing (LRS) methods have been shown to overcome most of these technical issues, leading to an increase in diagnostic rate. LRS methods are contributing to the detection of repeat expansions in novel disease-causing genes (e.g., ABCD3, NOTCH2NLC and RILPL1 causing an Oculopharyngodistal myopathy or PLIN4 causing a Myopathy with rimmed ubiquitin-positive autophagic vacuolation), of structural variants (e.g., in DMD), and of single nucleotide variants in repetitive regions (TTN and NEB). Moreover, these methods have simplified the characterization of the D4Z4 repeats in DUX4, facilitating the diagnosis of Facioscapulohumeral muscular dystrophy (FSHD). We review recent studies that have used either ONT or PacBio SMRT sequencing methods and discuss different types of variants that have been detected using these approaches in individuals with neuromuscular disorders.
Collapse
Affiliation(s)
| | - Marco Savarese
- Folkhälsan Research Center, Helsinki, Finland
- University of Helsinki, Faculty of Medicine, Helsinki, Finland
| |
Collapse
|
12
|
Oakley J, Hill M, Giess A, Tanguy M, Elgar G. Long read sequencing characterises a novel structural variant, revealing underactive AKR1C1 with overactive AKR1C2 as a possible cause of severe chronic fatigue. J Transl Med 2023; 21:825. [PMID: 37978513 PMCID: PMC10655400 DOI: 10.1186/s12967-023-04711-5] [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: 09/04/2023] [Accepted: 11/07/2023] [Indexed: 11/19/2023] Open
Abstract
BACKGROUND Causative genetic variants cannot yet be found for many disorders with a clear heritable component, including chronic fatigue disorders like myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). These conditions may involve genes in difficult-to-align genomic regions that are refractory to short read approaches. Structural variants in these regions can be particularly hard to detect or define with short reads, yet may account for a significant number of cases. Long read sequencing can overcome these difficulties but so far little data is available regarding the specific analytical challenges inherent in such regions, which need to be taken into account to ensure that variants are correctly identified. Research into chronic fatigue disorders faces the additional challenge that the heterogeneous patient populations likely encompass multiple aetiologies with overlapping symptoms, rather than a single disease entity, such that each individual abnormality may lack statistical significance within a larger sample. Better delineation of patient subgroups is needed to target research and treatment. METHODS We use nanopore sequencing in a case of unexplained severe fatigue to identify and fully characterise a large inversion in a highly homologous region spanning the AKR1C gene locus, which was indicated but could not be resolved by short-read sequencing. We then use GC-MS/MS serum steroid analysis to investigate the functional consequences. RESULTS Several commonly used bioinformatics tools are confounded by the homology but a combined approach including visual inspection allows the variant to be accurately resolved. The DNA inversion appears to increase the expression of AKR1C2 while limiting AKR1C1 activity, resulting in a relative increase of inhibitory GABAergic neurosteroids and impaired progesterone metabolism which could suppress neuronal activity and interfere with cellular function in a wide range of tissues. CONCLUSIONS This study provides an example of how long read sequencing can improve diagnostic yield in research and clinical care, and highlights some of the analytical challenges presented by regions containing tandem arrays of genes. It also proposes a novel gene associated with a novel disease aetiology that may be an underlying cause of complex chronic fatigue. It reveals biomarkers that could now be assessed in a larger cohort, potentially identifying a subset of patients who might respond to treatments suggested by the aetiology.
Collapse
Affiliation(s)
| | - Martin Hill
- Department of Steroids and Proteofactors, Institute of Endocrinology, Národni 8, 11694, Prague, Czech Republic
| | - Adam Giess
- Scientific Research and Development, Genomics England, London, UK
| | - Mélanie Tanguy
- Scientific Research and Development, Genomics England, London, UK
| | - Greg Elgar
- Scientific Research and Development, Genomics England, London, UK.
| |
Collapse
|
13
|
Laufer VA, Glover TW, Wilson TE. Applications of advanced technologies for detecting genomic structural variation. MUTATION RESEARCH. REVIEWS IN MUTATION RESEARCH 2023; 792:108475. [PMID: 37931775 PMCID: PMC10792551 DOI: 10.1016/j.mrrev.2023.108475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 09/07/2023] [Accepted: 11/02/2023] [Indexed: 11/08/2023]
Abstract
Chromosomal structural variation (SV) encompasses a heterogenous class of genetic variants that exerts strong influences on human health and disease. Despite their importance, many structural variants (SVs) have remained poorly characterized at even a basic level, a discrepancy predicated upon the technical limitations of prior genomic assays. However, recent advances in genomic technology can identify and localize SVs accurately, opening new questions regarding SV risk factors and their impacts in humans. Here, we first define and classify human SVs and their generative mechanisms, highlighting characteristics leveraged by various SV assays. We next examine the first-ever gapless assembly of the human genome and the technical process of assembling it, which required third-generation sequencing technologies to resolve structurally complex loci. The new portions of that "telomere-to-telomere" and subsequent pangenome assemblies highlight aspects of SV biology likely to develop in the near-term. We consider the strengths and limitations of the most promising new SV technologies and when they or longstanding approaches are best suited to meeting salient goals in the study of human SV in population-scale genomics research, clinical, and public health contexts. It is a watershed time in our understanding of human SV when new approaches are expected to fundamentally change genomic applications.
Collapse
Affiliation(s)
- Vincent A Laufer
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
| | - Thomas W Glover
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
| | - Thomas E Wilson
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
| |
Collapse
|