1
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Salisbury SJ, Daniels RR, Monaghan SJ, Bron JE, Villamayor PR, Gervais O, Fast MD, Sveen L, Houston RD, Robinson N, Robledo D. Keratinocytes drive the epithelial hyperplasia key to sea lice resistance in coho salmon. BMC Biol 2024; 22:160. [PMID: 39075472 PMCID: PMC11287951 DOI: 10.1186/s12915-024-01952-8] [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: 11/15/2023] [Accepted: 06/28/2024] [Indexed: 07/31/2024] Open
Abstract
BACKGROUND Salmonid species have followed markedly divergent evolutionary trajectories in their interactions with sea lice. While sea lice parasitism poses significant economic, environmental, and animal welfare challenges for Atlantic salmon (Salmo salar) aquaculture, coho salmon (Oncorhynchus kisutch) exhibit near-complete resistance to sea lice, achieved through a potent epithelial hyperplasia response leading to rapid louse detachment. The molecular mechanisms underlying these divergent responses to sea lice are unknown. RESULTS We characterized the cellular and molecular responses of Atlantic salmon and coho salmon to sea lice using single-nuclei RNA sequencing. Juvenile fish were exposed to copepodid sea lice (Lepeophtheirus salmonis), and lice-attached pelvic fin and skin samples were collected 12 h, 24 h, 36 h, 48 h, and 60 h after exposure, along with control samples. Comparative analysis of control and treatment samples revealed an immune and wound-healing response that was common to both species, but attenuated in Atlantic salmon, potentially reflecting greater sea louse immunomodulation. Our results revealed unique but complementary roles of three layers of keratinocytes in the epithelial hyperplasia response leading to rapid sea lice rejection in coho salmon. Our results suggest that basal keratinocytes direct the expansion and mobility of intermediate and, especially, superficial keratinocytes, which eventually encapsulate the parasite. CONCLUSIONS Our results highlight the key role of keratinocytes in coho salmon's sea lice resistance and the diverged biological response of the two salmonid host species when interacting with this parasite. This study has identified key pathways and candidate genes that could be manipulated using various biotechnological solutions to improve Atlantic salmon sea lice resistance.
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Affiliation(s)
- S J Salisbury
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK.
| | - R Ruiz Daniels
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK
| | - S J Monaghan
- Institute of Aquaculture, University of Stirling, Stirling, UK
| | - J E Bron
- Institute of Aquaculture, University of Stirling, Stirling, UK
| | - P R Villamayor
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK
- Department of Genetics, University of Santiago de Compostela, Santiago de Compostela, Spain
| | - O Gervais
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK
| | - M D Fast
- Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Canada
| | | | - R D Houston
- Benchmark Genetics, 1 Pioneer BuildingMilton Bridge, Edinburgh TechnopolePenicuik, UK
| | - N Robinson
- Nofima AS, Tromsø, Norway.
- Sustainable Aquaculture Laboratory - Temperate and Tropical (SALTT), Deakin University, Melbourne, VIC, 3225, Australia.
| | - D Robledo
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK.
- Department of Genetics, University of Santiago de Compostela, Santiago de Compostela, Spain.
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2
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Vegezzi E, Ishiura H, Bragg DC, Pellerin D, Magrinelli F, Currò R, Facchini S, Tucci A, Hardy J, Sharma N, Danzi MC, Zuchner S, Brais B, Reilly MM, Tsuji S, Houlden H, Cortese A. Neurological disorders caused by novel non-coding repeat expansions: clinical features and differential diagnosis. Lancet Neurol 2024; 23:725-739. [PMID: 38876750 DOI: 10.1016/s1474-4422(24)00167-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 04/04/2024] [Accepted: 04/09/2024] [Indexed: 06/16/2024]
Abstract
Nucleotide repeat expansions in the human genome are a well-known cause of neurological disease. In the past decade, advances in DNA sequencing technologies have led to a better understanding of the role of non-coding DNA, that is, the DNA that is not transcribed into proteins. These techniques have also enabled the identification of pathogenic non-coding repeat expansions that cause neurological disorders. Mounting evidence shows that adult patients with familial or sporadic presentations of epilepsy, cognitive dysfunction, myopathy, neuropathy, ataxia, or movement disorders can be carriers of non-coding repeat expansions. The description of the clinical, epidemiological, and molecular features of these recently identified non-coding repeat expansion disorders should guide clinicians in the diagnosis and management of these patients, and help in the genetic counselling for patients and their families.
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Affiliation(s)
| | - Hiroyuki Ishiura
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - D Cristopher Bragg
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - David Pellerin
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK; Department of Neurology and Neurosurgery, Montreal Neurological Hospital and Institute, McGill University, Montreal, QC, Canada
| | - Francesca Magrinelli
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK
| | - Riccardo Currò
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK; Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
| | - Stefano Facchini
- IRCCS Mondino Foundation, Pavia, Italy; Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK
| | - Arianna Tucci
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK; William Harvey Research Institute, Queen Mary University of London, London, UK
| | - John Hardy
- Department of Neurogedengerative Disease, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK
| | - Nutan Sharma
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Matt C Danzi
- Department of Human Genetics and Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Stephan Zuchner
- Department of Human Genetics and Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Bernard Brais
- Department of Neurology and Neurosurgery, Montreal Neurological Hospital and Institute, McGill University, Montreal, QC, Canada
| | - Mary M Reilly
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK
| | - Shoji Tsuji
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; Institute of Medical Genomics, International University of Health and Welfare, Chiba, Japan
| | - Henry Houlden
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK
| | - Andrea Cortese
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK; Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy.
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3
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Rajan-Babu IS, Dolzhenko E, Eberle MA, Friedman JM. Sequence composition changes in short tandem repeats: heterogeneity, detection, mechanisms and clinical implications. Nat Rev Genet 2024; 25:476-499. [PMID: 38467784 DOI: 10.1038/s41576-024-00696-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/19/2024] [Indexed: 03/13/2024]
Abstract
Short tandem repeats (STRs) are a class of repetitive elements, composed of tandem arrays of 1-6 base pair sequence motifs, that comprise a substantial fraction of the human genome. STR expansions can cause a wide range of neurological and neuromuscular conditions, known as repeat expansion disorders, whose age of onset, severity, penetrance and/or clinical phenotype are influenced by the length of the repeats and their sequence composition. The presence of non-canonical motifs, depending on the type, frequency and position within the repeat tract, can alter clinical outcomes by modifying somatic and intergenerational repeat stability, gene expression and mutant transcript-mediated and/or protein-mediated toxicities. Here, we review the diverse structural conformations of repeat expansions, technological advances for the characterization of changes in sequence composition, their clinical correlations and the impact on disease mechanisms.
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Affiliation(s)
- Indhu-Shree Rajan-Babu
- Department of Medical Genetics, The University of British Columbia, and Children's & Women's Hospital, Vancouver, British Columbia, Canada.
| | | | | | - Jan M Friedman
- Department of Medical Genetics, The University of British Columbia, and Children's & Women's Hospital, Vancouver, British Columbia, Canada
- BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada
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4
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Rodrigues Alves Barbosa V, Maroilley T, Diao C, Colvin-James L, Perrier R, Tarailo-Graovac M. Single variant, yet "double trouble": TSC and KBG syndrome because of a large de novo inversion. Life Sci Alliance 2024; 7:e202302115. [PMID: 38253421 PMCID: PMC10803213 DOI: 10.26508/lsa.202302115] [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: 04/26/2023] [Revised: 01/12/2024] [Accepted: 01/16/2024] [Indexed: 01/24/2024] Open
Abstract
Despite the advances in high-throughput sequencing, many rare disease patients remain undiagnosed. In particular, the patients with well-defined clinical phenotypes and established clinical diagnosis, yet missing or partial genetic diagnosis, may hold a clue to more complex genetic mechanisms of a disease that could be missed by available clinical tests. Here, we report a patient with a clinical diagnosis of Tuberous sclerosis, combined with unusual secondary features, but negative clinical tests including TSC1 and TSC2 Short-read whole-genome sequencing combined with advanced bioinformatics analyses were successful in uncovering a de novo pericentric 87-Mb inversion with breakpoints in TSC2 and ANKRD11, which explains the TSC clinical diagnosis, and confirms a second underlying monogenic disorder, KBG syndrome. Our findings illustrate how complex variants, such as large inversions, may be missed by clinical tests and further highlight the importance of well-defined clinical diagnoses in uncovering complex molecular mechanisms of a disease, such as complex variants and "double trouble" effects.
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Affiliation(s)
- Victoria Rodrigues Alves Barbosa
- https://ror.org/03yjb2x39 Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Canada
| | - Tatiana Maroilley
- https://ror.org/03yjb2x39 Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Canada
| | - Catherine Diao
- https://ror.org/03yjb2x39 Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Canada
| | - Leslie Colvin-James
- https://ror.org/03yjb2x39 Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Canada
| | - Renee Perrier
- https://ror.org/03yjb2x39 Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Canada
| | - Maja Tarailo-Graovac
- https://ror.org/03yjb2x39 Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, Canada
- https://ror.org/03yjb2x39 Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Canada
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5
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Chaisson MJP, Sulovari A, Valdmanis PN, Miller DE, Eichler EE. Advances in the discovery and analyses of human tandem repeats. Emerg Top Life Sci 2023; 7:361-381. [PMID: 37905568 PMCID: PMC10806765 DOI: 10.1042/etls20230074] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 10/18/2023] [Accepted: 10/18/2023] [Indexed: 11/02/2023]
Abstract
Long-read sequencing platforms provide unparalleled access to the structure and composition of all classes of tandemly repeated DNA from STRs to satellite arrays. This review summarizes our current understanding of their organization within the human genome, their importance with respect to disease, as well as the advances and challenges in understanding their genetic diversity and functional effects. Novel computational methods are being developed to visualize and associate these complex patterns of human variation with disease, expression, and epigenetic differences. We predict accurate characterization of this repeat-rich form of human variation will become increasingly relevant to both basic and clinical human genetics.
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Affiliation(s)
- Mark J P Chaisson
- Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA 90089, U.S.A
- The Genomic and Epigenomic Regulation Program, USC Norris Cancer Center, University of Southern California, Los Angeles, CA 90089, U.S.A
| | - Arvis Sulovari
- Computational Biology, Cajal Neuroscience Inc, Seattle, WA 98102, U.S.A
| | - Paul N Valdmanis
- Division of Medical Genetics, Department of Medicine, University of Washington School of Medicine, Seattle, WA 98195, U.S.A
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA 98195, U.S.A
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, U.S.A
| | - Danny E Miller
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, U.S.A
- Brotman Baty Institute for Precision Medicine, University of Washington, Seattle, WA 98195, U.S.A
- Department of Pediatrics, University of Washington, Seattle, WA 98195, U.S.A
| | - Evan E Eichler
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA 98195, U.S.A
- Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, U.S.A
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6
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Mizuguchi T, Toyota T, Koshimizu E, Kameyama S, Fukuda H, Tsuchida N, Uchiyama Y, Hamanaka K, Fujita A, Misawa K, Miyatake S, Adachi H, Matsumoto N. Complete SAMD12 repeat expansion sequencing in a four-generation BAFME1 family with anticipation. J Hum Genet 2023; 68:875-878. [PMID: 37592133 DOI: 10.1038/s10038-023-01187-5] [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: 05/08/2023] [Revised: 06/29/2023] [Accepted: 07/31/2023] [Indexed: 08/19/2023]
Abstract
Benign adult familial myoclonic epilepsy type 1 (BAFME1) is an autosomal dominant, adult-onset neurological disease caused by SAMD12 repeat expansion. In BAFME1, anticipation, such as the earlier onset of tremor and/or seizures in the next generation, was reported. This could be explained by intergenerational repeat instability, leading to larger expansions in successive generations. We report a four-generation BAFME1-affected family with anticipation. Using Nanopore long-read sequencing, detailed information regarding the sizes, configurations, and compositions of the expanded SAMD12 repeats across generations was obtained. Unexpectedly, a grandmother-mother-daughter triad showed similar repeat structures but with slight repeat expansions, despite quite variable age of onset of seizures (range: 52-14 years old), implying a complex relationship between the SAMD12 repeat expansion sequence and anticipation. This study suggests that different factor(s) from repeat expansion could modify the anticipation in BAFME1.
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Affiliation(s)
- Takeshi Mizuguchi
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan.
| | - Tomoko Toyota
- Department of Neurology, University of Occupational and Environmental Health School of Medicine, Kitakyushu, 807-8555, Japan
| | - Eriko Koshimizu
- Department of Human Genetics, 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
| | - 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
| | - 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
| | - 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
| | - Kohei Hamanaka
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan
| | - Atsushi Fujita
- 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
| | - 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
| | - Hiroaki Adachi
- Department of Neurology, University of Occupational and Environmental Health School of Medicine, Kitakyushu, 807-8555, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, 236-0004, Japan.
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7
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Johannesen KM, Tümer Z, Weckhuysen S, Barakat TS, Bayat A. Solving the unsolved genetic epilepsies: Current and future perspectives. Epilepsia 2023; 64:3143-3154. [PMID: 37750451 DOI: 10.1111/epi.17780] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 09/21/2023] [Accepted: 09/22/2023] [Indexed: 09/27/2023]
Abstract
Many patients with epilepsy undergo exome or genome sequencing as part of a diagnostic workup; however, many remain genetically unsolved. There are various factors that account for negative results in exome/genome sequencing for patients with epilepsy: (1) the underlying cause is not genetic; (2) there is a complex polygenic explanation; (3) the illness is monogenic but the causative gene remains to be linked to a human disorder; (4) family segregation with reduced penetrance; (5) somatic mosaicism or the complexity of, for example, a structural rearrangement; or (6) limited knowledge or diagnostic tools that hinder the proper classification of a variant, resulting in its designation as a variant of unknown significance. The objective of this review is to outline some of the diagnostic options that lie beyond the exome/genome, and that might become clinically relevant within the foreseeable future. These options include: (1) re-analysis of older exome/genome data as knowledge increases or symptoms change; (2) looking for somatic mosaicism or long-read sequencing to detect low-complexity repeat variants or specific structural variants missed by traditional exome/genome sequencing; (3) exploration of the non-coding genome including disruption of topologically associated domains, long range non-coding RNA, or other regulatory elements; and finally (4) transcriptomics, DNA methylation signatures, and metabolomics as complementary diagnostic methods that may be used in the assessment of variants of unknown significance. Some of these tools are currently not integrated into standard diagnostic workup. However, it is reasonable to expect that they will become increasingly available and improve current diagnostic capabilities, thereby enabling precision diagnosis in patients who are currently undiagnosed.
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Affiliation(s)
- Katrine M Johannesen
- Department of Genetics, Copenhagen University Hospital, Copenhagen, Denmark
- Department of Epilepsy Genetics and Personalized Medicine, The Danish Epilepsy Center, Dianalund, Denmark
| | - Zeynep Tümer
- Department of Genetics, Copenhagen University Hospital, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sarah Weckhuysen
- Applied and Translational Neurogenomics Group, VIB Centre for Molecular Neurology, Antwerp, Belgium
- Translational Neurosciences, Faculty of Medicine and Health Science, University of Antwerp, Antwerp, Belgium
- Department of Neurology, University Hospital Antwerp, Antwerp, Belgium
- μNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
| | - Tahsin Stefan Barakat
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
- Discovery Unit, Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
- ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Allan Bayat
- Department of Epilepsy Genetics and Personalized Medicine, The Danish Epilepsy Center, Dianalund, Denmark
- Department of Regional Health Research, University of Southern Denmark, Odense, Denmark
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
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8
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Corbett MA, Depienne C, Veneziano L, Klein KM, Brancati F, Guerrini R, Zara F, Tsuji S, Gecz J. Genetics of familial adult myoclonus epilepsy: From linkage studies to noncoding repeat expansions. Epilepsia 2023; 64 Suppl 1:S14-S21. [PMID: 37021642 PMCID: PMC10952679 DOI: 10.1111/epi.17610] [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: 12/08/2022] [Revised: 03/27/2023] [Accepted: 04/04/2023] [Indexed: 04/07/2023]
Abstract
Familial adult myoclonus epilepsy (FAME) is a genetic epilepsy syndrome that for many years has resisted understanding of its underlying molecular cause. This review covers the history of FAME genetic studies worldwide, starting with linkage and culminating in the discovery of noncoding TTTTA and inserted TTTCA pentanucleotide repeat expansions within six different genes to date (SAMD12, STARD7, MARCHF6, YEATS2, TNRC6A, and RAPGEF2). FAME occurs worldwide; however, repeat expansions in particular genes have regional geographical distributions. FAME repeat expansions are dynamic in nature, changing in length and structure within germline and somatic tissues. This variation poses challenges for molecular diagnosis such that molecular methods used to identify FAME repeat expansions typically require a trade-off between cost and efficiency. A rigorous evaluation of the sensitivity and specificity of each molecular approach remains to be performed. The origin of FAME repeat expansions and the genetic and environmental factors that modulate repeat variability are not well defined. Longer repeats and particular arrangements of the TTTTA and TTTCA motifs within an expansion are correlated with earlier onset and increased severity of disease. Other factors such as maternal or paternal inheritance, parental age, and repeat length alone have been suggested to influence repeat variation; however, further research is required to confirm this. The history of FAME genetics to the present is a chronicle of perseverance and predominantly collaborative efforts that yielded a successful outcome. The discovery of FAME repeats will spark progress toward a deeper understanding of the molecular pathogenesis of FAME, discovery of new loci, and development of cell and animal models.
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Affiliation(s)
- Mark A. Corbett
- Robinson Research Institute and Adelaide Medical SchoolUniversity of AdelaideAdelaideSouth AustraliaAustralia
| | - Christel Depienne
- Institute of Human GeneticsUniversity Hospital Essen, University Duisburg–EssenEssenGermany
| | - Liana Veneziano
- Institute of Translational PharmacologyNational Research CouncilRomeItaly
| | - Karl Martin Klein
- Departments of Clinical Neurosciences, Medical Genetics, and Community Health Sciences, Hotchkiss Brain Institute and Alberta Children's HospitalResearch Institute, Cumming School of Medicine, University of CalgaryCalgaryAlbertaCanada
- Epilepsy Center Frankfurt Rhine–Main, Department of Neurology, Center of Neurology and NeurosurgeryCenter for Personalized Translational Epilepsy Research, University Hospital, Goethe University FrankfurtFrankfurt am MainGermany
| | - Francesco Brancati
- Institute of Translational PharmacologyNational Research CouncilRomeItaly
- Medical Genetics, Department of Life, Health, and Environmental SciencesUniversity of L'AquilaL'AquilaItaly
- Laboratory of Human Functional GenomicsIstituto di Ricovero e Cura a Carattere Scientifico (IRCCS) San RaffaeleRomeItaly
| | - Renzo Guerrini
- Neuroscience and Neurogenetics DepartmentMeyer Children's HospitalFlorenceItaly
| | - Federico Zara
- Laboratory of NeurogeneticsIRCCS Institute "G. Gaslini"GenoaItaly
| | - Shoji Tsuji
- Department of Neurology, Graduate School of MedicineUniversity of TokyoTokyoJapan
- Institute of Medical GenomicsInternational University of Health and WelfareChibaJapan
| | - Jozef Gecz
- Robinson Research Institute and Adelaide Medical SchoolUniversity of AdelaideAdelaideSouth AustraliaAustralia
- South Australian Health and Medical Research InstituteAdelaideSouth AustraliaAustralia
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