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Yazarlou F, Lipovich L, Loeb JA. Emerging roles of long non-coding RNAs in human epilepsy. Epilepsia 2024; 65:1491-1511. [PMID: 38687769 PMCID: PMC11166529 DOI: 10.1111/epi.17937] [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: 09/01/2023] [Revised: 02/18/2024] [Accepted: 02/19/2024] [Indexed: 05/02/2024]
Abstract
Genome-scale biological studies conducted in the post-genomic era have revealed that two-thirds of human genes do not encode proteins. Most functional non-coding RNA transcripts in humans are products of long non-coding RNA (lncRNA) genes, an abundant but still poorly understood class of human genes. As a result of their fundamental and multitasking regulatory roles, lncRNAs are associated with a wide range of human diseases, including neurological disorders. Approximately 40% of lncRNAs are specifically expressed in the brain, and many of them exhibit distinct spatiotemporal patterns of expression. Comparative genomics approaches have determined that 65%-75% of human lncRNA genes are primate-specific and hence can be posited as a contributing potential cause of the higher-order complexity of primates, including human, brains relative to those of other mammals. Although lncRNAs present important mechanistic examples of epileptogenic functions, the human/primate specificity of lncRNAs questions their relevance in rodent models. Here, we present an in-depth review that supports the contention that human lncRNAs are direct contributors to the etiology and pathogenesis of human epilepsy, as a means to accelerate the integration of lncRNAs into clinical practice as potential diagnostic biomarkers and therapeutic targets. Meta-analytically, the major finding of our review is the commonality of lncRNAs in epilepsy and cancer pathogenesis through mitogen-activated protein kinase (MAPK)-related pathways. In addition, neuroinflammation may be a relevant part of the common pathophysiology of cancer and epilepsy. LncRNAs affect neuroinflammation-related signaling pathways such as nuclear factor kappa- light- chain- enhancer of activated B cells (NF-κB), Notch, and phosphatidylinositol 3- kinase/ protein kinase B (Akt) (PI3K/AKT), with the NF-κB pathway being the most common. Besides the controversy over lncRNA research in non-primate models, whether neuroinflammation is triggered by injury and/or central nervous system (CNS) toxicity during epilepsy modeling in animals or is a direct consequence of epilepsy pathophysiology needs to be considered meticulously in future studies.
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Affiliation(s)
- Fatemeh Yazarlou
- Center for Childhood Cancer, Abigail Wexner Research Institute, Nationwide Children’s Hospital, Columbus, OH, U.S.A
| | - Leonard Lipovich
- Shenzhen Huayuan Biological Science Research Institute, Shenzhen Huayuan Biotechnology Co. Ltd., 601 Building C1, Guangming Science Park, Fenghuang Street, 518000, Shenzhen, Guangdong, People’s Republic of China
- College of Science, Mathematics, and Technology, Wenzhou-Kean University, 88 Daxue Road, Ouhai District, 325060, Wenzhou, Zhejiang, People’s Republic of China
- Center for Molecular Medicine and Genetics, School of Medicine, Wayne State University, 3222 Scott Hall, 540 E. Canfield St., Detroit, Michigan 48201, U.S.A
| | - Jeffrey A. Loeb
- Department of Neurology and Rehabilitation, University of Illinois at Chicago, Chicago, Illinois 60612, U.S.A
- University of Illinois NeuroRepository, University of Illinois at Chicago, Chicago, Illinois 60612, U.S.A
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2
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Kaur D, Khan H, Grewal AK, Singh TG. Glycosylation: A new signaling paradigm for the neurovascular diseases. Life Sci 2024; 336:122303. [PMID: 38016576 DOI: 10.1016/j.lfs.2023.122303] [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: 09/27/2023] [Revised: 11/14/2023] [Accepted: 11/23/2023] [Indexed: 11/30/2023]
Abstract
A wide range of life-threatening conditions with complicated pathogenesis involves neurovascular disorders encompassing Neurovascular unit (NVU) damage. The pathophysiology of NVU is characterized by several features including tissue hypoxia, stimulation of inflammatory and angiogenic processes, and the initiation of intricate molecular interactions, collectively leading to an elevation in blood-brain barrier permeability, atherosclerosis and ultimately, neurovascular diseases. The presence of compelling data about the significant involvement of the glycosylation in the development of diseases has sparked a discussion on whether the abnormal glycosylation may serve as a causal factor for neurovascular disorders, rather than being just recruited as a secondary player in regulating the critical events during the development processes like embryo growth and angiogenesis. An essential tool for both developing new anti-ischemic therapies and understanding the processes of ischemic brain damage is undertaking pre-clinical studies of neurovascular disorders. Together with the post-translational modification of proteins, the modulation of glycosylation and its enzymes implicates itself in several abnormal activities which are known to accelerate neuronal vasculopathy. Despite the failure of the majority of glycosylation-based preclinical and clinical studies over the past years, there is a significant probability to provide neuroprotection utilizing modern and advanced approaches to target abnormal glycosylation activity at embryonic stages as well. This article focuses on a variety of experimental evidence to postulate the interconnection between glycosylation and vascular disorders along with possible treatment options.
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Affiliation(s)
- Dapinder Kaur
- Chitkara College of Pharmacy, Chitkara University, 140401, Punjab, India
| | - Heena Khan
- Chitkara College of Pharmacy, Chitkara University, 140401, Punjab, India
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Kadam SD. Open Sesame: Door to Enriched Somatic Variants Underlying Sporadic mTLE. Epilepsy Curr 2023; 23:383-385. [PMID: 38269352 PMCID: PMC10805092 DOI: 10.1177/15357597231201127] [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: 01/26/2024] Open
Abstract
Contribution of Somatic Ras/Raf/Mitogen-Activated Protein Kinase Variants in the Hippocampus in Drug-Resistant Mesial Temporal Lobe Epilepsy Khoshkhoo S, Wang Y, Chahine Y, Erson-Omay EZ, Robert SM, Kiziltug E, Damisah EC, Nelson-Williams C, Zhu G, Kong W, Huang AY, Stronge E, Phillips HW, Chhouk BH, Bizzotto S, Chen MH, Adikari TN, Ye Z, Witkowski T, Lai D, Lee N, Lokan J, Scheffer IE, Berkovic SF, Haider S, Hildebrand MS, Yang E, Gunel M, Lifton RP, Richardson RM, Blümcke I, Alexandrescu S, Huttner A, Heinzen EL, Zhu J, Poduri A, DeLanerolle N, Spencer DD, Lee EA, Walsh CA, Kahle KT. JAMA Neurol . 2023;80(6):578-587. doi:10.1001/jamaneurol.2023.0473 Importance: Mesial temporal lobe epilepsy (MTLE) is the most common focal epilepsy subtype and is often refractory to antiseizure medications. While most patients with MTLE do not have pathogenic germline genetic variants, the contribution of postzygotic (i.e., somatic) variants in the brain is unknown. Objective: To test the association between pathogenic somatic variants in the hippocampus and MTLE. Design, Setting, and Participants: This case-control genetic association study analyzed the DNA derived from hippocampal tissue of neurosurgically treated patients with MTLE and age-matched and sex-matched neurotypical controls. Participants treated at level 4 epilepsy centers were enrolled from 1988 through 2019, and clinical data were collected retrospectively. Whole-exome and gene-panel sequencing (each genomic region sequenced more than 500 times on average) were used to identify candidate pathogenic somatic variants. A subset of novel variants was functionally evaluated using cellular and molecular assays. Patients with nonlesional and lesional (mesial temporal sclerosis, focal cortical dysplasia, and low-grade epilepsy–associated tumors) drug-resistant MTLE who underwent anterior medial temporal lobectomy were eligible. All patients with available frozen tissue and appropriate consent were included. Control brain tissue was obtained from neurotypical donors at brain banks. Data were analyzed from June 2020 to August 2022. Exposures: Drug-resistant MTLE. Main Outcomes and Measures: Presence and abundance of pathogenic somatic variants in the hippocampus vs the unaffected temporal neocortex. Results: Of 105 included patients with MTLE, 53 (50.5%) were female, and the median (IQR) age was 32 (26-44) years; of 30 neurotypical controls, 11 (36.7%) were female, and the median (IQR) age was 37 (18-53) years. Eleven pathogenic somatic variants enriched in the hippocampus relative to the unaffected temporal neocortex (median [IQR] variant allele frequency, 1.92 [1.5-2.7] vs 0.3 [0-0.9]; P = .01) were detected in patients with MTLE but not in controls. Ten of these variants were in PTPN11, SOS1, KRAS, BRAF, and NF1, all predicted to constitutively activate Ras/Raf/mitogen-activated protein kinase (MAPK) signaling. Immunohistochemical studies of variant-positive hippocampal tissue demonstrated increased Erk1/2 phosphorylation, indicative of Ras/Raf/MAPK activation, predominantly in glial cells. Molecular assays showed abnormal liquid-liquid phase separation for the PTPN11 variants as a possible dominant gain-of-function mechanism. Conclusions and Relevance: Hippocampal somatic variants, particularly those activating Ras/Raf/MAPK signaling, may contribute to the pathogenesis of sporadic, drug-resistant MTLE. These findings may provide a novel genetic mechanism and highlight new therapeutic targets for this common indication for epilepsy surgery.
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Stevelink R, Campbell C, Chen S, Abou-Khalil B, Adesoji OM, Afawi Z, Amadori E, Anderson A, Anderson J, Andrade DM, Annesi G, Auce P, Avbersek A, Bahlo M, Baker MD, Balagura G, Balestrini S, Barba C, Barboza K, Bartolomei F, Bast T, Baum L, Baumgartner T, Baykan B, Bebek N, Becker AJ, Becker F, Bennett CA, Berghuis B, Berkovic SF, Beydoun A, Bianchini C, Bisulli F, Blatt I, Bobbili DR, Borggraefe I, Bosselmann C, Braatz V, Bradfield JP, Brockmann K, Brody LC, Buono RJ, Busch RM, Caglayan H, Campbell E, Canafoglia L, Canavati C, Cascino GD, Castellotti B, Catarino CB, Cavalleri GL, Cerrato F, Chassoux F, Cherny SS, Cheung CL, Chinthapalli K, Chou IJ, Chung SK, Churchhouse C, Clark PO, Cole AJ, Compston A, Coppola A, Cosico M, Cossette P, Craig JJ, Cusick C, Daly MJ, Davis LK, de Haan GJ, Delanty N, Depondt C, Derambure P, Devinsky O, Di Vito L, Dlugos DJ, Doccini V, Doherty CP, El-Naggar H, Elger CE, Ellis CA, Eriksson JG, Faucon A, Feng YCA, Ferguson L, Ferraro TN, Ferri L, Feucht M, Fitzgerald M, Fonferko-Shadrach B, Fortunato F, Franceschetti S, Franke A, French JA, Freri E, Gagliardi M, Gambardella A, Geller EB, Giangregorio T, Gjerstad L, Glauser T, Goldberg E, Goldman A, Granata T, Greenberg DA, Guerrini R, Gupta N, Haas KF, Hakonarson H, Hallmann K, Hassanin E, Hegde M, Heinzen EL, Helbig I, Hengsbach C, Heyne HO, Hirose S, Hirsch E, Hjalgrim H, Howrigan DP, Hucks D, Hung PC, Iacomino M, Imbach LL, Inoue Y, Ishii A, Jamnadas-Khoda J, Jehi L, Johnson MR, Kälviäinen R, Kamatani Y, Kanaan M, Kanai M, Kantanen AM, Kara B, Kariuki SM, Kasperavičiūte D, Kasteleijn-Nolst Trenite D, Kato M, Kegele J, Kesim Y, Khoueiry-Zgheib N, King C, Kirsch HE, Klein KM, Kluger G, Knake S, Knowlton RC, Koeleman BPC, Korczyn AD, Koupparis A, Kousiappa I, Krause R, Krenn M, Krestel H, Krey I, Kunz WS, Kurki MI, Kurlemann G, Kuzniecky R, Kwan P, Labate A, Lacey A, Lal D, Landoulsi Z, Lau YL, Lauxmann S, Leech SL, Lehesjoki AE, Lemke JR, Lerche H, Lesca G, Leu C, Lewin N, Lewis-Smith D, Li GHY, Li QS, Licchetta L, Lin KL, Lindhout D, Linnankivi T, Lopes-Cendes I, Lowenstein DH, Lui CHT, Madia F, Magnusson S, Marson AG, May P, McGraw CM, Mei D, Mills JL, Minardi R, Mirza N, Møller RS, Molloy AM, Montomoli M, Mostacci B, Muccioli L, Muhle H, Müller-Schlüter K, Najm IM, Nasreddine W, Neale BM, Neubauer B, Newton CRJC, Nöthen MM, Nothnagel M, Nürnberg P, O’Brien TJ, Okada Y, Ólafsson E, Oliver KL, Özkara C, Palotie A, Pangilinan F, Papacostas SS, Parrini E, Pato CN, Pato MT, Pendziwiat M, Petrovski S, Pickrell WO, Pinsky R, Pippucci T, Poduri A, Pondrelli F, Powell RHW, Privitera M, Rademacher A, Radtke R, Ragona F, Rau S, Rees MI, Regan BM, Reif PS, Rhelms S, Riva A, Rosenow F, Ryvlin P, Saarela A, Sadleir LG, Sander JW, Sander T, Scala M, Scattergood T, Schachter SC, Schankin CJ, Scheffer IE, Schmitz B, Schoch S, Schubert-Bast S, Schulze-Bonhage A, Scudieri P, Sham P, Sheidley BR, Shih JJ, Sills GJ, Sisodiya SM, Smith MC, Smith PE, Sonsma ACM, Speed D, Sperling MR, Stefansson H, Stefansson K, Steinhoff BJ, Stephani U, Stewart WC, Stipa C, Striano P, Stroink H, Strzelczyk A, Surges R, Suzuki T, Tan KM, Taneja RS, Tanteles GA, Taubøll E, Thio LL, Thomas GN, Thomas RH, Timonen O, Tinuper P, Todaro M, Topaloğlu P, Tozzi R, Tsai MH, Tumiene B, Turkdogan D, Unnsteinsdóttir U, Utkus A, Vaidiswaran P, Valton L, van Baalen A, Vetro A, Vining EPG, Visscher F, von Brauchitsch S, von Wrede R, Wagner RG, Weber YG, Weckhuysen S, Weisenberg J, Weller M, Widdess-Walsh P, Wolff M, Wolking S, Wu D, Yamakawa K, Yang W, Yapıcı Z, Yücesan E, Zagaglia S, Zahnert F, Zara F, Zhou W, Zimprich F, Zsurka G, Zulfiqar Ali Q. GWAS meta-analysis of over 29,000 people with epilepsy identifies 26 risk loci and subtype-specific genetic architecture. Nat Genet 2023; 55:1471-1482. [PMID: 37653029 PMCID: PMC10484785 DOI: 10.1038/s41588-023-01485-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 07/21/2023] [Indexed: 09/02/2023]
Abstract
Epilepsy is a highly heritable disorder affecting over 50 million people worldwide, of which about one-third are resistant to current treatments. Here we report a multi-ancestry genome-wide association study including 29,944 cases, stratified into three broad categories and seven subtypes of epilepsy, and 52,538 controls. We identify 26 genome-wide significant loci, 19 of which are specific to genetic generalized epilepsy (GGE). We implicate 29 likely causal genes underlying these 26 loci. SNP-based heritability analyses show that common variants explain between 39.6% and 90% of genetic risk for GGE and its subtypes. Subtype analysis revealed markedly different genetic architectures between focal and generalized epilepsies. Gene-set analyses of GGE signals implicate synaptic processes in both excitatory and inhibitory neurons in the brain. Prioritized candidate genes overlap with monogenic epilepsy genes and with targets of current antiseizure medications. Finally, we leverage our results to identify alternate drugs with predicted efficacy if repurposed for epilepsy treatment.
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Miguel Sanz C, Martinez Navarro M, Caballero Diaz D, Sanchez-Elexpuru G, Di Donato V. Toward the use of novel alternative methods in epilepsy modeling and drug discovery. Front Neurol 2023; 14:1213969. [PMID: 37719765 PMCID: PMC10501616 DOI: 10.3389/fneur.2023.1213969] [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: 05/04/2023] [Accepted: 08/14/2023] [Indexed: 09/19/2023] Open
Abstract
Epilepsy is a chronic brain disease and, considering the amount of people affected of all ages worldwide, one of the most common neurological disorders. Over 20 novel antiseizure medications (ASMs) have been released since 1993, yet despite substantial advancements in our understanding of the molecular mechanisms behind epileptogenesis, over one-third of patients continue to be resistant to available therapies. This is partially explained by the fact that the majority of existing medicines only address seizure suppression rather than underlying processes. Understanding the origin of this neurological illness requires conducting human neurological and genetic studies. However, the limitation of sample sizes, ethical concerns, and the requirement for appropriate controls (many patients have already had anti-epileptic medication exposure) in human clinical trials underscore the requirement for supplemental models. So far, mammalian models of epilepsy have helped to shed light on the underlying causes of the condition, but the high costs related to breeding of the animals, low throughput, and regulatory restrictions on their research limit their usefulness in drug screening. Here, we present an overview of the state of art in epilepsy modeling describing gold standard animal models used up to date and review the possible alternatives for this research field. Our focus will be mainly on ex vivo, in vitro, and in vivo larval zebrafish models contributing to the 3R in epilepsy modeling and drug screening. We provide a description of pharmacological and genetic methods currently available but also on the possibilities offered by the continued development in gene editing methodologies, especially CRISPR/Cas9-based, for high-throughput disease modeling and anti-epileptic drugs testing.
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6
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Boßelmann CM, Leu C, Lal D. Technological and computational approaches to detect somatic mosaicism in epilepsy. Neurobiol Dis 2023:106208. [PMID: 37343892 DOI: 10.1016/j.nbd.2023.106208] [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: 03/05/2023] [Revised: 06/03/2023] [Accepted: 06/16/2023] [Indexed: 06/23/2023] Open
Abstract
Lesional epilepsy is a common and severe disease commonly associated with malformations of cortical development, including focal cortical dysplasia and hemimegalencephaly. Recent advances in sequencing and variant calling technologies have identified several genetic causes, including both short/single nucleotide and structural somatic variation. In this review, we aim to provide a comprehensive overview of the methodological advancements in this field while highlighting the unresolved technological and computational challenges that persist, including ultra-low variant allele fractions in bulk tissue, low availability of paired control samples, spatial variability of mutational burden within the lesion, and the issue of false-positive calls and validation procedures. Information from genetic testing in focal epilepsy may be integrated into clinical care to inform histopathological diagnosis, postoperative prognosis, and candidate precision therapies.
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Affiliation(s)
- Christian M Boßelmann
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA; Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Costin Leu
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA; Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, UK.
| | - Dennis Lal
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA; Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA; Stanley Center for Psychiatric Research, Broad Institute of Harvard and M.I.T., Cambridge, MA, USA; Cologne Center for Genomics (CCG), University of Cologne, Cologne, DE, USA
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7
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The Power of Clinical Diagnosis for Deciphering Complex Genetic Mechanisms in Rare Diseases. Genes (Basel) 2023; 14:genes14010196. [PMID: 36672937 PMCID: PMC9858967 DOI: 10.3390/genes14010196] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/05/2023] [Accepted: 01/09/2023] [Indexed: 01/13/2023] Open
Abstract
Complex genetic disease mechanisms, such as structural or non-coding variants, currently pose a substantial difficulty in frontline diagnostic tests. They thus may account for most unsolved rare disease patients regardless of the clinical phenotype. However, the clinical diagnosis can narrow the genetic focus to just a couple of genes for patients with well-established syndromes defined by prominent physical and/or unique biochemical phenotypes, allowing deeper analyses to consider complex genetic origin. Then, clinical-diagnosis-driven genome sequencing strategies may expedite the development of testing and analytical methods to account for complex disease mechanisms as well as to advance functional assays for the confirmation of complex variants, clinical management, and the development of new therapies.
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Singh SM, Win PW, Castellani CA. Complementary approaches involving monozygotic twins and single neuron genomics support postzygotic somatic mutations in schizophrenia. Schizophr Res 2022; 248:228-230. [PMID: 36108467 DOI: 10.1016/j.schres.2022.09.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 08/05/2022] [Accepted: 09/04/2022] [Indexed: 10/14/2022]
Affiliation(s)
- S M Singh
- Department of Biology, Western University, London, Canada
| | - P W Win
- Department of Biology, Western University, London, Canada; Department of Pathology and Laboratory Medicine, Western University, London, Canada
| | - C A Castellani
- Department of Pathology and Laboratory Medicine, Western University, London, Canada; Department of Epidemiology and Biostatistics, Western University, London, Canada.
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9
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Lai D, Gade M, Yang E, Koh HY, Lu J, Walley NM, Buckley AF, Sands TT, Akman CI, Mikati MA, McKhann GM, Goldman JE, Canoll P, Alexander AL, Park KL, Von Allmen GK, Rodziyevska O, Bhattacharjee MB, Lidov HGW, Vogel H, Grant GA, Porter BE, Poduri AH, Crino PB, Heinzen EL. Somatic variants in diverse genes leads to a spectrum of focal cortical malformations. Brain 2022; 145:2704-2720. [PMID: 35441233 PMCID: PMC9612793 DOI: 10.1093/brain/awac117] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 02/19/2022] [Accepted: 03/13/2022] [Indexed: 11/14/2022] Open
Abstract
Post-zygotically acquired genetic variants, or somatic variants, that arise during cortical development have emerged as important causes of focal epilepsies, particularly those due to malformations of cortical development. Pathogenic somatic variants have been identified in many genes within the PI3K-AKT-mTOR-signalling pathway in individuals with hemimegalencephaly and focal cortical dysplasia (type II), and more recently in SLC35A2 in individuals with focal cortical dysplasia (type I) or non-dysplastic epileptic cortex. Given the expanding role of somatic variants across different brain malformations, we sought to delineate the landscape of somatic variants in a large cohort of patients who underwent epilepsy surgery with hemimegalencephaly or focal cortical dysplasia. We evaluated samples from 123 children with hemimegalencephaly (n = 16), focal cortical dysplasia type I and related phenotypes (n = 48), focal cortical dysplasia type II (n = 44), or focal cortical dysplasia type III (n = 15). We performed high-depth exome sequencing in brain tissue-derived DNA from each case and identified somatic single nucleotide, indel and large copy number variants. In 75% of individuals with hemimegalencephaly and 29% with focal cortical dysplasia type II, we identified pathogenic variants in PI3K-AKT-mTOR pathway genes. Four of 48 cases with focal cortical dysplasia type I (8%) had a likely pathogenic variant in SLC35A2. While no other gene had multiple disease-causing somatic variants across the focal cortical dysplasia type I cohort, four individuals in this group had a single pathogenic or likely pathogenic somatic variant in CASK, KRAS, NF1 and NIPBL, genes previously associated with neurodevelopmental disorders. No rare pathogenic or likely pathogenic somatic variants in any neurological disease genes like those identified in the focal cortical dysplasia type I cohort were found in 63 neurologically normal controls (P = 0.017), suggesting a role for these novel variants. We also identified a somatic loss-of-function variant in the known epilepsy gene, PCDH19, present in a small number of alleles in the dysplastic tissue from a female patient with focal cortical dysplasia IIIa with hippocampal sclerosis. In contrast to focal cortical dysplasia type II, neither focal cortical dysplasia type I nor III had somatic variants in genes that converge on a unifying biological pathway, suggesting greater genetic heterogeneity compared to type II. Importantly, we demonstrate that focal cortical dysplasia types I, II and III are associated with somatic gene variants across a broad range of genes, many associated with epilepsy in clinical syndromes caused by germline variants, as well as including some not previously associated with radiographically evident cortical brain malformations.
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Affiliation(s)
- Dulcie Lai
- Division of Pharmacology and Experimental Therapeutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Meethila Gade
- Division of Pharmacology and Experimental Therapeutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Edward Yang
- Department of Radiology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Hyun Yong Koh
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Boston, MA 02115, USA.,Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Jinfeng Lu
- Division of Pharmacology and Experimental Therapeutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Nicole M Walley
- Division of Medical Genetics, Department of Pediatrics, Duke University School of Medicine, Durham, NC 27710, USA
| | - Anne F Buckley
- Department of Pathology, Duke University Medical Center, Durham, NC 27710, USA
| | - Tristan T Sands
- Institute for Genomic Medicine, Columbia University Medical Center, New York, NY 10032, USA.,Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA
| | - Cigdem I Akman
- Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA
| | - Mohamad A Mikati
- Department of Neurobiology, Duke University, Durham, NC 27708, USA.,Division of Pediatric Neurology, Duke University Medical Center, Durham, NC 27710, USA
| | - Guy M McKhann
- Department of Neurosurgery, Columbia University, New York Presbyterian Hospital, New York, NY 10032, USA
| | - James E Goldman
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Peter Canoll
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Allyson L Alexander
- Department of Neurosurgery, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Kristen L Park
- Department of Pediatrics and Neurology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Gretchen K Von Allmen
- Department of Neurology, McGovern Medical School, Houston, TX 77030, USA.,Division of Child Neurology, Department of Pediatrics, McGovern Medical School, Houston, TX 77030, USA
| | - Olga Rodziyevska
- Division of Child Neurology, Department of Pediatrics, McGovern Medical School, Houston, TX 77030, USA
| | | | - Hart G W Lidov
- Department of Pathology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Hannes Vogel
- Department of Pathology, Stanford University, School of Medicine, Stanford, CA 94305, USA
| | - Gerald A Grant
- Department of Neurosurgery, Lucile Packard Children's Hospital at Stanford, School of Medicine, Stanford, CA 94305, USA
| | - Brenda E Porter
- Department of Neurology and Neurological Sciences, Stanford University, School of Medicine, Stanford, CA 94305, USA
| | - Annapurna H Poduri
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Boston, MA 02115, USA.,Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Peter B Crino
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Erin L Heinzen
- Division of Pharmacology and Experimental Therapeutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Department of Genetics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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10
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Chen WL, Mefford HC. Diagnostic Considerations in the Epilepsies-Testing Strategies, Test Type Advantages, and Limitations. Neurotherapeutics 2021; 18:1468-1477. [PMID: 34532824 PMCID: PMC8608977 DOI: 10.1007/s13311-021-01121-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2021] [Indexed: 02/04/2023] Open
Abstract
The role of genetics in epilepsy has been recognized for a long time. Over the past decade, genome-wide technologies have identified numerous genes and variants associated with epilepsy. In the clinical setting, a myriad of genetic testing options are available, and a subset of specific genetic diagnoses have management implications. Furthermore, genetic testing can be a dynamic process. As a result, fundamental knowledge about genetics and genomics has become essential for all specialists. Here, we review current knowledge of the genetic contribution to various types of epilepsy, provide an overview of types of genetic variants, and discuss genetic testing options and their diagnostic yield. We also consider advantages and limitations of testing approaches.
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Affiliation(s)
- Wei-Liang Chen
- Department of Pediatrics, Division of Genetic Medicine, University of Washington and Seattle Children's Hospital, Seattle, WA, 98105, USA
| | - Heather C Mefford
- Department of Pediatrics, Division of Genetic Medicine, University of Washington and Seattle Children's Hospital, Seattle, WA, 98105, USA.
- Current Location: Center for Pediatric Neurological Disease Research, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA.
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Guerrini R, Cavallin M, Pippucci T, Rosati A, Bisulli F, Dimartino P, Barba C, Garbelli R, Buccoliero AM, Tassi L, Conti V. Is Focal Cortical Dysplasia/Epilepsy Caused by Somatic MTOR Mutations Always a Unilateral Disorder? NEUROLOGY-GENETICS 2020; 7:e540. [PMID: 33542949 PMCID: PMC7735020 DOI: 10.1212/nxg.0000000000000540] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Accepted: 10/21/2020] [Indexed: 11/15/2022]
Abstract
Objective To alert about the wide margin of unpredictability that distribution of somatic MTOR mosaicism may have in the brain and the risk for independent epileptogenesis arising from the seemingly healthy contralateral hemisphere after complete removal of epileptogenic focal cortical dysplasia (FCD). Methods Clinical, EEG, MRI, histopathology, and molecular genetics in 2 patients (1 and 2) treated with focal resections and subsequent complete hemispherectomy for epileptogenic FCD due to somatic MTOR mutations. Autoptic brain study of bilateral asymmetric hemispheric dysplasia and identification of alternative allele fraction (AAF) rates for AKT1 (patient 3). Results The strongly hyperactivating p.Ser2215Phe (patient 1) and p.Leu1460Pro (patient 2) MTOR mutations were at low-level AAF in the dysplastic tissue. After repeated resections and eventual complete hemispherectomy, both patients manifested intractable seizures arising from the contralateral, seemingly healthy hemisphere. In patient 3, the p.Glu17Lys AKT1 mutation exhibited random distribution and AAF rates in different tissues with double levels in the more severely dysplastic cerebral hemisphere. Conclusions Our understanding of the distribution of somatic mutations in the brain in relation to the type of malformation and its hypothesized time of origin may be faulty. Large studies may reveal that the risk of a first surgery being disappointing might be related more to the specific somatic mammalian target of rapamycin mutation identified than to completeness of resection and that the advantages of repeated resections after a first unsuccessful operation should be weighed against the risk of the contralateral hemisphere becoming in turn epileptogenic.
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Affiliation(s)
- Renzo Guerrini
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories (R. Guerrini, M.C., A.R, C.B., V.C.), Children's Hospital A. Meyer, University of Florence; Medical Genetics Unit (T.P.), Sant'Orsola-Malpighi University Hospital, Bologna; IRCCS Bologna Institute for Neurological Sciences (F.B.), Bologna. Member of ERN EpiCARE; Department of Medical and Surgical Sciences (P.D.), University of Bologna; Clinical Epileptology and Experimental Neurophysiology Unit (R. Garbelli), IRCCS Istituto Neurologico C. Besta, Milan; Pathology Unit (A.M.B.), Children's Hospital A. Meyer-University of Florence; and "C. Munari" Epilepsy Surgery Center (L.T.), Niguarda Hospital, Milan, Italy
| | - Mara Cavallin
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories (R. Guerrini, M.C., A.R, C.B., V.C.), Children's Hospital A. Meyer, University of Florence; Medical Genetics Unit (T.P.), Sant'Orsola-Malpighi University Hospital, Bologna; IRCCS Bologna Institute for Neurological Sciences (F.B.), Bologna. Member of ERN EpiCARE; Department of Medical and Surgical Sciences (P.D.), University of Bologna; Clinical Epileptology and Experimental Neurophysiology Unit (R. Garbelli), IRCCS Istituto Neurologico C. Besta, Milan; Pathology Unit (A.M.B.), Children's Hospital A. Meyer-University of Florence; and "C. Munari" Epilepsy Surgery Center (L.T.), Niguarda Hospital, Milan, Italy
| | - Tommaso Pippucci
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories (R. Guerrini, M.C., A.R, C.B., V.C.), Children's Hospital A. Meyer, University of Florence; Medical Genetics Unit (T.P.), Sant'Orsola-Malpighi University Hospital, Bologna; IRCCS Bologna Institute for Neurological Sciences (F.B.), Bologna. Member of ERN EpiCARE; Department of Medical and Surgical Sciences (P.D.), University of Bologna; Clinical Epileptology and Experimental Neurophysiology Unit (R. Garbelli), IRCCS Istituto Neurologico C. Besta, Milan; Pathology Unit (A.M.B.), Children's Hospital A. Meyer-University of Florence; and "C. Munari" Epilepsy Surgery Center (L.T.), Niguarda Hospital, Milan, Italy
| | - Anna Rosati
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories (R. Guerrini, M.C., A.R, C.B., V.C.), Children's Hospital A. Meyer, University of Florence; Medical Genetics Unit (T.P.), Sant'Orsola-Malpighi University Hospital, Bologna; IRCCS Bologna Institute for Neurological Sciences (F.B.), Bologna. Member of ERN EpiCARE; Department of Medical and Surgical Sciences (P.D.), University of Bologna; Clinical Epileptology and Experimental Neurophysiology Unit (R. Garbelli), IRCCS Istituto Neurologico C. Besta, Milan; Pathology Unit (A.M.B.), Children's Hospital A. Meyer-University of Florence; and "C. Munari" Epilepsy Surgery Center (L.T.), Niguarda Hospital, Milan, Italy
| | - Francesca Bisulli
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories (R. Guerrini, M.C., A.R, C.B., V.C.), Children's Hospital A. Meyer, University of Florence; Medical Genetics Unit (T.P.), Sant'Orsola-Malpighi University Hospital, Bologna; IRCCS Bologna Institute for Neurological Sciences (F.B.), Bologna. Member of ERN EpiCARE; Department of Medical and Surgical Sciences (P.D.), University of Bologna; Clinical Epileptology and Experimental Neurophysiology Unit (R. Garbelli), IRCCS Istituto Neurologico C. Besta, Milan; Pathology Unit (A.M.B.), Children's Hospital A. Meyer-University of Florence; and "C. Munari" Epilepsy Surgery Center (L.T.), Niguarda Hospital, Milan, Italy
| | - Paola Dimartino
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories (R. Guerrini, M.C., A.R, C.B., V.C.), Children's Hospital A. Meyer, University of Florence; Medical Genetics Unit (T.P.), Sant'Orsola-Malpighi University Hospital, Bologna; IRCCS Bologna Institute for Neurological Sciences (F.B.), Bologna. Member of ERN EpiCARE; Department of Medical and Surgical Sciences (P.D.), University of Bologna; Clinical Epileptology and Experimental Neurophysiology Unit (R. Garbelli), IRCCS Istituto Neurologico C. Besta, Milan; Pathology Unit (A.M.B.), Children's Hospital A. Meyer-University of Florence; and "C. Munari" Epilepsy Surgery Center (L.T.), Niguarda Hospital, Milan, Italy
| | - Carmen Barba
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories (R. Guerrini, M.C., A.R, C.B., V.C.), Children's Hospital A. Meyer, University of Florence; Medical Genetics Unit (T.P.), Sant'Orsola-Malpighi University Hospital, Bologna; IRCCS Bologna Institute for Neurological Sciences (F.B.), Bologna. Member of ERN EpiCARE; Department of Medical and Surgical Sciences (P.D.), University of Bologna; Clinical Epileptology and Experimental Neurophysiology Unit (R. Garbelli), IRCCS Istituto Neurologico C. Besta, Milan; Pathology Unit (A.M.B.), Children's Hospital A. Meyer-University of Florence; and "C. Munari" Epilepsy Surgery Center (L.T.), Niguarda Hospital, Milan, Italy
| | - Rita Garbelli
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories (R. Guerrini, M.C., A.R, C.B., V.C.), Children's Hospital A. Meyer, University of Florence; Medical Genetics Unit (T.P.), Sant'Orsola-Malpighi University Hospital, Bologna; IRCCS Bologna Institute for Neurological Sciences (F.B.), Bologna. Member of ERN EpiCARE; Department of Medical and Surgical Sciences (P.D.), University of Bologna; Clinical Epileptology and Experimental Neurophysiology Unit (R. Garbelli), IRCCS Istituto Neurologico C. Besta, Milan; Pathology Unit (A.M.B.), Children's Hospital A. Meyer-University of Florence; and "C. Munari" Epilepsy Surgery Center (L.T.), Niguarda Hospital, Milan, Italy
| | - Anna Maria Buccoliero
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories (R. Guerrini, M.C., A.R, C.B., V.C.), Children's Hospital A. Meyer, University of Florence; Medical Genetics Unit (T.P.), Sant'Orsola-Malpighi University Hospital, Bologna; IRCCS Bologna Institute for Neurological Sciences (F.B.), Bologna. Member of ERN EpiCARE; Department of Medical and Surgical Sciences (P.D.), University of Bologna; Clinical Epileptology and Experimental Neurophysiology Unit (R. Garbelli), IRCCS Istituto Neurologico C. Besta, Milan; Pathology Unit (A.M.B.), Children's Hospital A. Meyer-University of Florence; and "C. Munari" Epilepsy Surgery Center (L.T.), Niguarda Hospital, Milan, Italy
| | - Laura Tassi
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories (R. Guerrini, M.C., A.R, C.B., V.C.), Children's Hospital A. Meyer, University of Florence; Medical Genetics Unit (T.P.), Sant'Orsola-Malpighi University Hospital, Bologna; IRCCS Bologna Institute for Neurological Sciences (F.B.), Bologna. Member of ERN EpiCARE; Department of Medical and Surgical Sciences (P.D.), University of Bologna; Clinical Epileptology and Experimental Neurophysiology Unit (R. Garbelli), IRCCS Istituto Neurologico C. Besta, Milan; Pathology Unit (A.M.B.), Children's Hospital A. Meyer-University of Florence; and "C. Munari" Epilepsy Surgery Center (L.T.), Niguarda Hospital, Milan, Italy
| | - Valerio Conti
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories (R. Guerrini, M.C., A.R, C.B., V.C.), Children's Hospital A. Meyer, University of Florence; Medical Genetics Unit (T.P.), Sant'Orsola-Malpighi University Hospital, Bologna; IRCCS Bologna Institute for Neurological Sciences (F.B.), Bologna. Member of ERN EpiCARE; Department of Medical and Surgical Sciences (P.D.), University of Bologna; Clinical Epileptology and Experimental Neurophysiology Unit (R. Garbelli), IRCCS Istituto Neurologico C. Besta, Milan; Pathology Unit (A.M.B.), Children's Hospital A. Meyer-University of Florence; and "C. Munari" Epilepsy Surgery Center (L.T.), Niguarda Hospital, Milan, Italy
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