201
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Melikishvili G, Dulac O, Gataullina S. Neonatal SCN2A encephalopathy: A peculiar recognizable electroclinical sequence. Epilepsy Behav 2020; 111:107187. [PMID: 32603808 DOI: 10.1016/j.yebeh.2020.107187] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/22/2020] [Accepted: 05/22/2020] [Indexed: 10/24/2022]
Abstract
INTRODUCTION Sodium voltage-gated channel alpha subunit 2 (SCN2A) gene encodes the Nav1.2 subunit of voltage-gated sodium channel in pyramidal neurons. SCN2A gain-of-function mutations are identified more and more often with gene panels and whole exome sequencing. Phenotype ranges from benign neonatal or infantile seizures to severe epileptic encephalopathy. Although large series of patients targeting genetic background point out two main phenotypes with SCN2A encephalopathy, Ohtahara syndrome and malignant migrating partial seizures in infancy (EMPSI), we noticed that in fact, a peculiar clinical and electroencephalogram (EEG) sequence distinct from these syndromes should suggest the diagnosis early. PATIENTS AND METHODS We report three new cases with de novo SCN2A mutations - 166237617C>A p.(Asp1487Glu), c.407T>G p.(Met136Arg), and c.4633A>G p.(Met1545Val) - diagnosed by direct sequencing or genes panel, their follow-up ranging from 4 to 5 years. RESULTS For all three patients, seizures started at two days of life and consisted of apnea and cyanosis with partial clonic or tonic, alternating on both sides with, up to 100/day, evolving to generalized tonic-clonic seizures (GTCS) and epileptic spasms by three months. First EEG showed a discontinuous pattern, evolving to multifocal spikes, by 3 (two patients) and 6 months (one). Seizure frequency decreased progressively by the middle or end of the first year of life. Only less frequent GTCS persisted during the second year of life for two patients. Improvement was observed in two patients with sodium channel blocker (phenytoin) used at age of 1 month for one patient and at 2 years for another one. All patients remained with severe psychomotor delay. DISCUSSION All three infants share a condition different from Ohtahara syndrome in which tonic spasms predominate and suppression-burst pattern is obvious, and from EMPSI, in which partial migrating discharges involve successively the various parts of the brain including occipital regions with oculoclonic seizures, but there is neither discontinuous pattern nor therapeutic response to sodium channel blockers. CONCLUSION Neonatal SCN2A encephalopathy has a recognizable phenotype starting soon after birth with alternating partial motor seizures evolving to infantile spasms and a discontinuous EEG pattern. Seizures improve spontaneously in the first year of life. This electroclinical sequence should indicate the search of SCN2A mutation and suggest the administration of sodium channel blockers.
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Affiliation(s)
- Gia Melikishvili
- Department of Pediatrics, MediClubGeorgia Medical Center, Tbilisi, Georgia
| | | | - Svetlana Gataullina
- Services d'explorations fonctionnelles, Centre de médecine du sommeil, Hôpital Antoine-Béclère, AP-HP, Clamart, France; Service de pédiatrie, Centre hospitalier intercommunal André Grégoire, Montreuil, France.
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202
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Molecular diagnosis of epileptic encephalopathy of the first year of life applying a customized gene panel in a group of Argentinean patients. Epilepsy Behav 2020; 111:107322. [PMID: 32702657 DOI: 10.1016/j.yebeh.2020.107322] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/01/2020] [Accepted: 07/04/2020] [Indexed: 11/22/2022]
Abstract
OBJECTIVE The aim of this study was to perform a molecular characterization of 17 Argentinean pediatric patients with diagnosis of having epileptic encephalopathies (EEs) of the first year of life without known etiology, applying next-generation sequencing (NGS). METHODS We included 17 patients with EE with age of onset under 12 months without known etiology after ruling out structural abnormalities, metabolic disorders, and large chromosomal abnormalities. They presented with the following clinical phenotypes: Dravet syndrome (DS; n: 7), epilepsy of infancy with migrating focal seizures (EIMFS; n: 3), West syndrome (WS; n: 2), and undetermined epileptic encephalopathy (UEE; n: 5). Neurologic examinations, seizure semiology, brain magnetic resonance imaging, and standard electroencephalography (EEG) or video-EEG studies were performed in all cases. Using a custom amplicon strategy, we designed an NGS panel to study 47 genes associated with EEs. RESULTS Pathogenic variants were detected in 8 cases (47%), including seven novel pathogenic variants and one previously reported as being pathogenic. The pathogenic variants were identified in 6 patients with DS (SCN1A gene), one with EIMFS (SCN2A gene), and one with UEE (SLC2A1 gene). Nonrelevant variants were identified in the patients with WS. CONCLUSION We demonstrated the feasibility of an NGS-gene panel approach for the analysis of patients with EE in our setting. A genetic diagnosis was achieved in nearly 50% of patients, 87% of them presenting with nonpreviously reported variants. The early identification of the underlying causative genetic alteration will be a valuable tool for providing prognostic information and genetic counselling and also to improve therapeutic decisions in Argentinean patients.
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203
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Galer PD, Ganesan S, Lewis-Smith D, McKeown SE, Pendziwiat M, Helbig KL, Ellis CA, Rademacher A, Smith L, Poduri A, Seiffert S, von Spiczak S, Muhle H, van Baalen A, Thomas RH, Krause R, Weber Y, Helbig I, Thomas RH, Krause R, Weber Y, Helbig I. Semantic Similarity Analysis Reveals Robust Gene-Disease Relationships in Developmental and Epileptic Encephalopathies. Am J Hum Genet 2020; 107:683-697. [PMID: 32853554 PMCID: PMC7536581 DOI: 10.1016/j.ajhg.2020.08.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 07/31/2020] [Indexed: 12/21/2022] Open
Abstract
More than 100 genetic etiologies have been identified in developmental and epileptic encephalopathies (DEEs), but correlating genetic findings with clinical features at scale has remained a hurdle because of a lack of frameworks for analyzing heterogenous clinical data. Here, we analyzed 31,742 Human Phenotype Ontology (HPO) terms in 846 individuals with existing whole-exome trio data and assessed associated clinical features and phenotypic relatedness by using HPO-based semantic similarity analysis for individuals with de novo variants in the same gene. Gene-specific phenotypic signatures included associations of SCN1A with “complex febrile seizures” (HP: 0011172; p = 2.1 × 10−5) and “focal clonic seizures” (HP: 0002266; p = 8.9 × 10−6), STXBP1 with “absent speech” (HP: 0001344; p = 1.3 × 10−11), and SLC6A1 with “EEG with generalized slow activity” (HP: 0010845; p = 0.018). Of 41 genes with de novo variants in two or more individuals, 11 genes showed significant phenotypic similarity, including SCN1A (n = 16, p < 0.0001), STXBP1 (n = 14, p = 0.0021), and KCNB1 (n = 6, p = 0.011). Including genetic and phenotypic data of control subjects increased phenotypic similarity for all genetic etiologies, whereas the probability of observing de novo variants decreased, emphasizing the conceptual differences between semantic similarity analysis and approaches based on the expected number of de novo events. We demonstrate that HPO-based phenotype analysis captures unique profiles for distinct genetic etiologies, reflecting the breadth of the phenotypic spectrum in genetic epilepsies. Semantic similarity can be used to generate statistical evidence for disease causation analogous to the traditional approach of primarily defining disease entities through similar clinical features.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Rhys H Thomas
- Translational and Clinical Research Institute, Newcastle University, Newcastle-upon-Tyne NE1 7RU, UK; Royal Victoria Infirmary, Newcastle-upon-Tyne NE1 4LP, UK
| | - Roland Krause
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 4367 Belvaux, Luxembourg
| | - Yvonne Weber
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany; Department of Epileptology and Neurology, University of Aachen, 52074 Aachen, Germany
| | - Ingo Helbig
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA 19146, USA; Department of Neurology, University of Pennsylvania, Philadelphia, PA 19104, USA.
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204
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Turner TJ, Zourray C, Schorge S, Lignani G. Recent advances in gene therapy for neurodevelopmental disorders with epilepsy. J Neurochem 2020; 157:229-262. [PMID: 32880951 PMCID: PMC8436749 DOI: 10.1111/jnc.15168] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 08/18/2020] [Accepted: 08/20/2020] [Indexed: 12/14/2022]
Abstract
Neurodevelopmental disorders can be caused by mutations in neuronal genes fundamental to brain development. These disorders have severe symptoms ranging from intellectually disability, social and cognitive impairments, and a subset are strongly linked with epilepsy. In this review, we focus on those neurodevelopmental disorders that are frequently characterized by the presence of epilepsy (NDD + E). We loosely group the genes linked to NDD + E with different neuronal functions: transcriptional regulation, intrinsic excitability and synaptic transmission. All these genes have in common a pivotal role in defining the brain architecture and function during early development, and when their function is altered, symptoms can present in the first stages of human life. The relationship with epilepsy is complex. In some NDD + E, epilepsy is a comorbidity and in others seizures appear to be the main cause of the pathology, suggesting that either structural changes (NDD) or neuronal communication (E) can lead to these disorders. Furthermore, grouping the genes that cause NDD + E, we review the uses and limitations of current models of the different disorders, and how different gene therapy strategies are being developed to treat them. We highlight where gene replacement may not be a treatment option, and where innovative therapeutic tools, such as CRISPR‐based gene editing, and new avenues of delivery are required. In general this group of genetically defined disorders, supported increasing knowledge of the mechanisms leading to neurological dysfunction serve as an excellent collection for illustrating the translational potential of gene therapy, including newly emerging tools.
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Affiliation(s)
- Thomas J Turner
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Clara Zourray
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK.,Department of Pharmacology, UCL School of Pharmacy, London, UK
| | | | - Gabriele Lignani
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
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205
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Takai A, Yamaguchi M, Yoshida H, Chiyonobu T. Investigating Developmental and Epileptic Encephalopathy Using Drosophila melanogaster. Int J Mol Sci 2020; 21:ijms21176442. [PMID: 32899411 PMCID: PMC7503973 DOI: 10.3390/ijms21176442] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 08/30/2020] [Accepted: 09/01/2020] [Indexed: 12/16/2022] Open
Abstract
Developmental and epileptic encephalopathies (DEEs) are the spectrum of severe epilepsies characterized by early-onset, refractory seizures occurring in the context of developmental regression or plateauing. Early infantile epileptic encephalopathy (EIEE) is one of the earliest forms of DEE, manifesting as frequent epileptic spasms and characteristic electroencephalogram findings in early infancy. In recent years, next-generation sequencing approaches have identified a number of monogenic determinants underlying DEE. In the case of EIEE, 85 genes have been registered in Online Mendelian Inheritance in Man as causative genes. Model organisms are indispensable tools for understanding the in vivo roles of the newly identified causative genes. In this review, we first present an overview of epilepsy and its genetic etiology, especially focusing on EIEE and then briefly summarize epilepsy research using animal and patient-derived induced pluripotent stem cell (iPSC) models. The Drosophila model, which is characterized by easy gene manipulation, a short generation time, low cost and fewer ethical restrictions when designing experiments, is optimal for understanding the genetics of DEE. We therefore highlight studies with Drosophila models for EIEE and discuss the future development of their practical use.
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Affiliation(s)
- Akari Takai
- Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan;
| | - Masamitsu Yamaguchi
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 603-8585, Japan; (M.Y.); (H.Y.)
- Kansai Gakken Laboratory, Kankyo Eisei Yakuhin Co. Ltd., Kyoto 619-0237, Japan
| | - Hideki Yoshida
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 603-8585, Japan; (M.Y.); (H.Y.)
| | - Tomohiro Chiyonobu
- Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan;
- Correspondence:
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206
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Encinas AC, Watkins JC, Longoria IA, Johnson JP, Hammer MF. Variable patterns of mutation density among NaV1.1, NaV1.2 and NaV1.6 point to channel-specific functional differences associated with childhood epilepsy. PLoS One 2020; 15:e0238121. [PMID: 32845893 PMCID: PMC7449494 DOI: 10.1371/journal.pone.0238121] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 08/10/2020] [Indexed: 11/28/2022] Open
Abstract
Variants implicated in childhood epilepsy have been identified in all four voltage-gated sodium channels that initiate action potentials in the central nervous system. Previous research has focused on the functional effects of particular variants within the most studied of these channels (NaV1.1, NaV1.2 and NaV1.6); however, there have been few comparative studies across channels to infer the impact of mutations in patients with epilepsy. Here we compare patterns of variation in patient and public databases to test the hypothesis that regions of known functional significance within voltage-gated sodium (NaV) channels have an increased burden of deleterious variants. We assessed mutational burden in different regions of the Nav channels by (1) performing Fisher exact tests on odds ratios to infer excess variants in domains, segments, and loops of each channel in patient databases versus public “control” databases, and (2) comparing the cumulative distribution of variant sites along DNA sequences of each gene in patient and public databases (i.e., independent of protein structure). Patient variant density was concordant among channels in regions known to play a role in channel function, with statistically significant higher patient variant density in S4-S6 and DIII-DIV and an excess of public variants in SI-S3, DI-DII, DII-DIII. On the other hand, channel-specific patterns of patient burden were found in the NaV1.6 inactivation gate and NaV1.1 S5-S6 linkers, while NaV1.2 and NaV1.6 S4-S5 linkers and S5 segments shared patient variant patterns that contrasted with those in NaV1.1. These different patterns may reflect different roles played by the NaV1.6 inactivation gate in action potential propagation, and by NaV1.1 S5-S6 linkers in loss of function and haploinsufficiency. Interestingly, NaV1.2 and NaV1.6 both lack amino acid substitutions over significantly long stretches in both the patient and public databases suggesting that new mutations in these regions may cause embryonic lethality or a non-epileptic disease phenotype.
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Affiliation(s)
- Alejandra C. Encinas
- Graduate Program in Genetics, University of Arizona, Tucson, Arizona, United States of America
| | - Joseph C. Watkins
- Department of Mathematics, University of Arizona, Tucson, Arizona, United States of America
| | - Iris Arenas Longoria
- Department of Mathematics, University of Arizona, Tucson, Arizona, United States of America
| | | | - Michael F. Hammer
- Department of Neurology, University of Arizona, Tucson, Arizona, United States of America
- * E-mail:
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207
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Menezes LFS, Sabiá Júnior EF, Tibery DV, Carneiro LDA, Schwartz EF. Epilepsy-Related Voltage-Gated Sodium Channelopathies: A Review. Front Pharmacol 2020; 11:1276. [PMID: 33013363 PMCID: PMC7461817 DOI: 10.3389/fphar.2020.01276] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 07/31/2020] [Indexed: 12/29/2022] Open
Abstract
Epilepsy is a disease characterized by abnormal brain activity and a predisposition to generate epileptic seizures, leading to neurobiological, cognitive, psychological, social, and economic impacts for the patient. There are several known causes for epilepsy; one of them is the malfunction of ion channels, resulting from mutations. Voltage-gated sodium channels (NaV) play an essential role in the generation and propagation of action potential, and malfunction caused by mutations can induce irregular neuronal activity. That said, several genetic variations in NaV channels have been described and associated with epilepsy. These mutations can affect channel kinetics, modifying channel activation, inactivation, recovery from inactivation, and/or the current window. Among the NaV subtypes related to epilepsy, NaV1.1 is doubtless the most relevant, with more than 1500 mutations described. Truncation and missense mutations are the most observed alterations. In addition, several studies have already related mutated NaV channels with the electrophysiological functioning of the channel, aiming to correlate with the epilepsy phenotype. The present review provides an overview of studies on epilepsy-associated mutated human NaV1.1, NaV1.2, NaV1.3, NaV1.6, and NaV1.7.
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Affiliation(s)
- Luis Felipe Santos Menezes
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília, Brasília, Brazil
| | - Elias Ferreira Sabiá Júnior
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília, Brasília, Brazil
| | - Diogo Vieira Tibery
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília, Brasília, Brazil
| | - Lilian Dos Anjos Carneiro
- Faculdade de Medicina, Centro Universitário Euro Americano, Brasília, Brazil.,Faculdade de Medicina, Centro Universitário do Planalto Central, Brasília, Brazil
| | - Elisabeth Ferroni Schwartz
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília, Brasília, Brazil
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208
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Welzel T, Ziesenitz VC, Weber P, Datta AN, van den Anker JN, Gotta V. Drug-drug and drug-food interactions in an infant with early-onset SCN2A epilepsy treated with carbamazepine, phenytoin and a ketogenic diet. Br J Clin Pharmacol 2020; 87:1568-1573. [PMID: 32737897 DOI: 10.1111/bcp.14503] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 07/09/2020] [Accepted: 07/20/2020] [Indexed: 11/29/2022] Open
Abstract
Sodium channel 2 subunit α (SCN2A) mutations cause difficult-to-treat early-onset epilepsy. Effective treatment includes high-dose phenytoin or carbamazepine ± ketogenic diet (KD). We describe an infant with early-onset SCN2A-epilepsy with subtherapeutic carbamazepine concentration during transition from phenytoin treatment to avoid long-term neurotoxicity. The transition from high-dose phenytoin (20 mg kg-1 d-1 , concentration: ≥20 mg/L) with KD, to carbamazepine (50-75 mg kg-1 d-1 , concentration: 9-12 mg/L) lasted 85 days, which we suspected was due to significant drug-drug and/or drug-food interactions. Model-based analysis of carbamazepine pharmacokinetics quantified significant time- and dose-dependent phenytoin-mediated CYP3A4 induction and carbamazepine concentration-dependent auto-induction (apparent clearance increased up to 2.5/3-fold). Lower carbamazepine concentrations under KD were modelled as decreased relative bioavailability (44%), potentially related to decreased fraction absorbed (unexpected for this lipophilic drug), increased intestinal/hepatic metabolism and/or decreased protein-binding with KD. This suggests importance of carbamazepine-concentration monitoring during KD-introduction/removal and necessity of high carbamazepine doses to achieve therapeutic concentrations, especially in infants treated with high-dose phenytoin.
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Affiliation(s)
- Tatjana Welzel
- Pediatric Pharmacology and Pharmacometrics, University Children's Hospital Basel, University of Basel, Basel, Switzerland
| | - Victoria C Ziesenitz
- Pediatric Pharmacology and Pharmacometrics, University Children's Hospital Basel, University of Basel, Basel, Switzerland.,Pediatric Cardiology, Center for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Peter Weber
- Division of Pediatric Neurology and Developmental Medicine, University Children's Hospital Basel, University of Basel, Basel, Switzerland
| | - Alexandre N Datta
- Division of Pediatric Neurology and Developmental Medicine, University Children's Hospital Basel, University of Basel, Basel, Switzerland
| | - Johannes N van den Anker
- Pediatric Pharmacology and Pharmacometrics, University Children's Hospital Basel, University of Basel, Basel, Switzerland.,Divison of Clinical Pharmacology, Children's National Hospital, Washington, D. C, USA
| | - Verena Gotta
- Pediatric Pharmacology and Pharmacometrics, University Children's Hospital Basel, University of Basel, Basel, Switzerland
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209
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Heyne HO, Baez-Nieto D, Iqbal S, Palmer DS, Brunklaus A, May P, Johannesen KM, Lauxmann S, Lemke JR, Møller RS, Pérez-Palma E, Scholl UI, Syrbe S, Lerche H, Lal D, Campbell AJ, Wang HR, Pan J, Daly MJ. Predicting functional effects of missense variants in voltage-gated sodium and calcium channels. Sci Transl Med 2020; 12:eaay6848. [PMID: 32801145 DOI: 10.1126/scitranslmed.aay6848] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 11/20/2019] [Accepted: 07/22/2020] [Indexed: 12/30/2022]
Abstract
Malfunctions of voltage-gated sodium and calcium channels (encoded by SCNxA and CACNA1x family genes, respectively) have been associated with severe neurologic, psychiatric, cardiac, and other diseases. Altered channel activity is frequently grouped into gain or loss of ion channel function (GOF or LOF, respectively) that often corresponds not only to clinical disease manifestations but also to differences in drug response. Experimental studies of channel function are therefore important, but laborious and usually focus only on a few variants at a time. On the basis of known gene-disease mechanisms of 19 different diseases, we inferred LOF (n = 518) and GOF (n = 309) likely pathogenic variants from the disease phenotypes of variant carriers. By training a machine learning model on sequence- and structure-based features, we predicted LOF or GOF effects [area under the receiver operating characteristics curve (ROC) = 0.85] of likely pathogenic missense variants. Our LOF versus GOF prediction corresponded to molecular LOF versus GOF effects for 87 functionally tested variants in SCN1/2/8A and CACNA1I (ROC = 0.73) and was validated in exome-wide data from 21,703 cases and 128,957 controls. We showed respective regional clustering of inferred LOF and GOF nucleotide variants across the alignment of the entire gene family, suggesting shared pathomechanisms in the SCNxA/CACNA1x family genes.
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Affiliation(s)
- Henrike O Heyne
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA.
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, 5WR36M Helsinki, Finland
| | - David Baez-Nieto
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Sumaiya Iqbal
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Center for Development of Therapeutics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Duncan S Palmer
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Andreas Brunklaus
- Paediatric Neurosciences Research Group, Royal Hospital for Sick Children, Glasgow G51 4TF, UK
- School of Medicine, University of Glasgow, Glasgow G12 8QQ, UK
| | - Patrick May
- Luxembourg Centre for Systems Biomedicine, Belvaux, University of Luxembourg, 4365 Esch-sur-Alzette, Luxembourg
| | - Katrine M Johannesen
- Department of Epilepsy Genetics and Personalized Treatment, Danish Epilepsy Centre, 4293 Dianalund, Denmark
- Department of Regional Health Research, University of Southern Denmark, 5230 Odense, Denmark
| | - Stephan Lauxmann
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72076 Tuebingen, Germany
| | - Johannes R Lemke
- Institute of Human Genetics, University of Leipzig Medical Center, 04103 Leipzig, Germany
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Treatment, Danish Epilepsy Centre, 4293 Dianalund, Denmark
- Department of Regional Health Research, University of Southern Denmark, 5230 Odense, Denmark
| | - Eduardo Pérez-Palma
- Cologne Center for Genomics (CCG), University of Cologne, 50923, Germany
- Genomic Medicine Institute, Lemer Research Institute Cleveland Clinic, OH G92J47, USA
| | - Ute I Scholl
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Nephrology and Medical Intensive Care and BIH Center for Regenerative Therapies, 10178 Berlin, Germany
- Berlin Institute of Health (BIH), 10178 Berlin, Germany
| | - Steffen Syrbe
- Division of Pediatric Epileptology, Center for Paediatrics and Adolescent Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72076 Tuebingen, Germany
| | - Dennis Lal
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Cologne Center for Genomics (CCG), University of Cologne, 50923, Germany
- Genomic Medicine Institute, Lemer Research Institute Cleveland Clinic, OH G92J47, USA
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH G92J47, USA
| | - Arthur J Campbell
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Center for Development of Therapeutics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Hao-Ran Wang
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Jen Pan
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Mark J Daly
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA.
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, 5WR36M Helsinki, Finland
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210
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Sisodiya SM. Precision medicine and therapies of the future. Epilepsia 2020; 62 Suppl 2:S90-S105. [PMID: 32776321 PMCID: PMC8432144 DOI: 10.1111/epi.16539] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/20/2020] [Accepted: 04/21/2020] [Indexed: 12/24/2022]
Abstract
Precision medicine in the epilepsies has gathered much attention, especially with gene discovery pushing forward new understanding of disease biology. Several targeted treatments are emerging, some with considerable sophistication and individual‐level tailoring. There have been rare achievements in improving short‐term outcomes in a few very select patients with epilepsy. The prospects for further targeted, repurposed, or novel treatments seem promising. Along with much‐needed success, difficulties are also arising. Precision treatments do not always work, and sometimes are inaccessible or do not yet exist. Failures of precision medicine may not find their way to broader scrutiny. Precision medicine is not a new concept: It has been boosted by genetics and is often focused on genetically determined epilepsies, typically considered to be driven in an individual by a single genetic variant. Often the mechanisms generating the full clinical phenotype from such a perceived single cause are incompletely understood. The impact of additional genetic variation and other factors that might influence the clinical presentation represent complexities that are not usually considered. Precision success and precision failure are usually equally incompletely explained. There is a need for more comprehensive evaluation and a more rigorous framework, bringing together information that is both necessary and sufficient to explain clinical presentation and clinical responses to precision treatment in a precision approach that considers the full picture not only of the effects of a single variant, but also of its genomic and other measurable environment, within the context of the whole person. As we may be on the brink of a treatment revolution, progress must be considered and reasoned: One possible framework is proposed for the evaluation of precision treatments.
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Affiliation(s)
- Sanjay M Sisodiya
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK.,Chalfont Centre for Epilepsy, Bucks, UK
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211
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OXPHOS bioenergetic compensation does not explain disease penetrance in Leber hereditary optic neuropathy. Mitochondrion 2020; 54:113-121. [PMID: 32687992 DOI: 10.1016/j.mito.2020.07.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 04/24/2020] [Accepted: 07/14/2020] [Indexed: 11/23/2022]
Abstract
Leber hereditary optic neuropathy (LHON) is one of the most common primary mitochondrial diseases. It is caused by point mutations in mitochondrial DNA (mtDNA) genes and in some cases, it can result in irreversible vision loss, primarily in young men. It is currently unknown why LHON mutations affect only some carriers and whether bioenergetic compensation enables unaffected carriers to overcome mitochondrial impairment and preserve cellular function. Here, we conducted bioenergetic metabolic assays and RNA sequencing to address this question using male-only, age-matched, m.11778G > A lymphoblasts and primary fibroblasts from both unaffected carriers and affected individuals. Our work indicates that OXPHOS bioenergetic compensation in LHON peripheral cells does not explain disease phenotype. We show that complex I impairment is similar in cells from unaffected carrier and affected patients, despite a transcriptional downregulation of metabolic pathways including glycolysis in affected cells relative to carriers detected by RNA sequencing. Although we did not detect OXPHOS bioenergetic compensation in carrier cells under basal conditions, our results indicate that cells from affected patients suffer a growth impairment under metabolic challenge compared to carrier cells, which were unaffected by metabolic challenge. If recapitulated in retinal ganglion cells, decreased susceptibility to metabolic challenge in unaffected carriers may help preserve metabolic homeostasis in the face of the mitochondrial complex I bioenergetic defect.
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212
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Zaman T, Helbig KL, Clatot J, Thompson CH, Kang SK, Stouffs K, Jansen AE, Verstraete L, Jacquinet A, Parrini E, Guerrini R, Fujiwara Y, Miyatake S, Ben‐Zeev B, Bassan H, Reish O, Marom D, Hauser N, Vu T, Ackermann S, Spencer CE, Lippa N, Srinivasan S, Charzewska A, Hoffman‐Zacharska D, Fitzpatrick D, Harrison V, Vasudevan P, Joss S, Pilz DT, Fawcett KA, Helbig I, Matsumoto N, Kearney JA, Fry AE, Goldberg EM. SCN3A
‐Related Neurodevelopmental Disorder: A Spectrum of Epilepsy and Brain Malformation. Ann Neurol 2020; 88:348-362. [DOI: 10.1002/ana.25809] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 05/05/2020] [Accepted: 05/25/2020] [Indexed: 12/19/2022]
Affiliation(s)
- Tariq Zaman
- Division of Neurology, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
| | - Katherine L. Helbig
- Division of Neurology, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
- Epilepsy NeuroGenetics Initiative Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
| | - Jérôme Clatot
- Division of Neurology, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
- Epilepsy NeuroGenetics Initiative Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
| | - Christopher H. Thompson
- Department of Pharmacology Northwestern University Feinberg School of Medicine Chicago Illinois USA
| | - Seok Kyu Kang
- Department of Pharmacology Northwestern University Feinberg School of Medicine Chicago Illinois USA
| | - Katrien Stouffs
- Center for Medical Genetics/Research Center for Reproduction and Genetics University Hospital Brussels, Free University of Brussels Brussels Belgium
| | - Anna E. Jansen
- Pediatric Neurology Unit, Department of Pediatrics University Hospital Brussels Brussels Belgium
- Neurogenetics Research Group Free University of Brussels Brussels Belgium
| | | | - Adeline Jacquinet
- Human Genetics Service Sart Tilman University Hospital Center Liege Belgium
| | - Elena Parrini
- Pediatric Neurology, Neurogenetics, and Neurobiology Unit and Laboratories, Department of Neuroscience A. Meyer Children's Hospital, University of Florence Florence Italy
| | - Renzo Guerrini
- Pediatric Neurology, Neurogenetics, and Neurobiology Unit and Laboratories, Department of Neuroscience A. Meyer Children's Hospital, University of Florence Florence Italy
| | - Yuh Fujiwara
- Department of Pediatrics Yokohama City University Medical Center Yokohama Japan
| | - Satoko Miyatake
- Department of Human Genetics Yokohama City University Graduate School of Medicine Yokohama Japan
| | - Bruria Ben‐Zeev
- Pediatric Neurology Unit Edmond and Lili Safra Children's Hospital, Haim Sheba Medical Center Ramat Gan Israel
- Sackler School of Medicine Tel Aviv University Tel Aviv Israel
| | - Haim Bassan
- Sackler School of Medicine Tel Aviv University Tel Aviv Israel
- Pediatric Neurology & Development Center Shamir Medical Center (Assaf Harofe) Zerifin Israel
| | - Orit Reish
- Sackler School of Medicine Tel Aviv University Tel Aviv Israel
- Genetics Institute Shamir Medical Center (Assaf Harofe) Zerifin Zerifin Israel
| | - Daphna Marom
- Sackler School of Medicine Tel Aviv University Tel Aviv Israel
- Genetics Institute Shamir Medical Center (Assaf Harofe) Zerifin Zerifin Israel
| | - Natalie Hauser
- Inova Translational Medicine Institute Inova Health System Fairfax Virginia USA
| | - Thuy‐Anh Vu
- Department of Pediatric Neurology Children's National Medical Center, Washington, District of Columbia, and Pediatric Specialists of Virginia Fairfax Virginia USA
| | - Sally Ackermann
- Division of Paediatric Neurology, Department of Paediatrics and Child Health Red Cross War Memorial Children's Hospital, University of Cape Town Cape Town South Africa
| | - Careni E. Spencer
- Division of Human Genetics, Department of Medicine University of Cape Town, South Africa and Groote Schuur Hospital Cape Town South Africa
| | - Natalie Lippa
- Institute for Genomic Medicine Columbia University Medical Center New York New York USA
| | - Shraddha Srinivasan
- Department of Neurology Columbia University Medical Center New York New York USA
| | | | | | - David Fitzpatrick
- Medical Research Council Human Genetics Unit Medical Research Council Institute of Genetics and Molecular Medicine, University of Edinburgh Edinburgh United Kingdom
| | - Victoria Harrison
- Wessex Clinical Genetics Service Princess Anne Hospital Southampton United Kingdom
| | - Pradeep Vasudevan
- Department of Clinical Genetics University Hospitals Leicester National Health Service Trust Leicester United Kingdom
| | - Shelagh Joss
- West of Scotland Clinical Genetics Service Queen Elizabeth University Hospital Glasgow United Kingdom
| | - Daniela T. Pilz
- West of Scotland Clinical Genetics Service Queen Elizabeth University Hospital Glasgow United Kingdom
- Division of Cancer and Genetics School of Medicine, Cardiff University Cardiff United Kingdom
| | - Katherine A. Fawcett
- Medical Research Council (MRC) Computational Genomics Analysis and Training Programme, MRC Centre for Computational Biology, MRC Weatherall Institute of Molecular Medicine, John Radcliffe Hospital Oxford United Kingdom
| | - Ingo Helbig
- Division of Neurology, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
- Epilepsy NeuroGenetics Initiative Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
- Department of Neurology, Perelman School of Medicine University of Pennsylvania Philadelphia Pennsylvania USA
- Department of Biomedical and Health Informatics Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
| | - Naomichi Matsumoto
- Department of Human Genetics Yokohama City University Graduate School of Medicine Yokohama Japan
| | - Jennifer A. Kearney
- Department of Pharmacology Northwestern University Feinberg School of Medicine Chicago Illinois USA
| | - Andrew E. Fry
- Division of Cancer and Genetics School of Medicine, Cardiff University Cardiff United Kingdom
- Institute of Medical Genetics University Hospital of Wales Cardiff United Kingdom
| | - Ethan M. Goldberg
- Division of Neurology, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
- Epilepsy NeuroGenetics Initiative Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
- Department of Neurology, Perelman School of Medicine University of Pennsylvania Philadelphia Pennsylvania USA
- Department of Neuroscience Perelman School of Medicine, University of Pennsylvania Philadelphia Pennsylvania USA
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213
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Lammertse HCA, van Berkel AA, Iacomino M, Toonen RF, Striano P, Gambardella A, Verhage M, Zara F. Homozygous STXBP1 variant causes encephalopathy and gain-of-function in synaptic transmission. Brain 2020; 143:441-451. [PMID: 31855252 PMCID: PMC7009479 DOI: 10.1093/brain/awz391] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 10/09/2019] [Accepted: 10/29/2019] [Indexed: 11/14/2022] Open
Abstract
Heterozygous mutations in the STXBP1 gene encoding the presynaptic protein MUNC18-1 cause STXBP1 encephalopathy, characterized by developmental delay, intellectual disability and epilepsy. Impaired mutant protein stability leading to reduced synaptic transmission is considered the main underlying pathogenetic mechanism. Here, we report the first two cases carrying a homozygous STXBP1 mutation, where their heterozygous siblings and mother are asymptomatic. Both cases were diagnosed with Lennox-Gastaut syndrome. In Munc18-1 null mouse neurons, protein stability of the disease variant (L446F) is less dramatically affected than previously observed for heterozygous disease mutants. Neurons expressing Munc18L446F showed minor changes in morphology and synapse density. However, patch clamp recordings demonstrated that L446F causes a 2-fold increase in evoked synaptic transmission. Conversely, paired pulse plasticity was reduced and recovery after stimulus trains also. Spontaneous release frequency and amplitude, the readily releasable vesicle pool and the kinetics of short-term plasticity were all normal. Hence, the homozygous L446F mutation causes a gain-of-function phenotype regarding release probability and synaptic transmission while having less impact on protein levels than previously reported (heterozygous) mutations. These data show that STXBP1 mutations produce divergent cellular effects, resulting in different clinical features, while sharing the overarching encephalopathic phenotype (developmental delay, intellectual disability and epilepsy).
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Affiliation(s)
- Hanna C A Lammertse
- Department of Clinical Genetics, Center for Neurogenomics and Cognitive Research (CNCR), University Medical Center Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands.,Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Annemiek A van Berkel
- Department of Clinical Genetics, Center for Neurogenomics and Cognitive Research (CNCR), University Medical Center Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands.,Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Michele Iacomino
- Laboratory of Neurogenetics and Neuroscience, IRCCS Istituto G. Gaslini, Via Gerolamo Gaslini 5, 16147 Genova, Italy
| | - Ruud F Toonen
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Pasquale Striano
- IRCCS Istituto "G. Gaslini", Genova, Italy.,Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Genova, Italy
| | | | - Matthijs Verhage
- Department of Clinical Genetics, Center for Neurogenomics and Cognitive Research (CNCR), University Medical Center Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands.,Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Federico Zara
- Laboratory of Neurogenetics and Neuroscience, IRCCS Istituto G. Gaslini, Via Gerolamo Gaslini 5, 16147 Genova, Italy
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214
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Lee J, Lee C, Ki CS, Lee J. Determining the best candidates for next-generation sequencing-based gene panel for evaluation of early-onset epilepsy. Mol Genet Genomic Med 2020; 8:e1376. [PMID: 32613771 PMCID: PMC7507365 DOI: 10.1002/mgg3.1376] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 05/01/2020] [Accepted: 06/01/2020] [Indexed: 12/21/2022] Open
Abstract
Background Genetic testing is an emerging diagnostic approach in early‐onset epilepsy. Identification of the heterogeneous genetic causes of epilepsy may mitigate unnecessary evaluations and allow more accurate diagnosis and therapy. We aimed to uncover genetic causes of early‐onset epilepsy using next‐generation sequencing (NGS) to elucidate the diagnostic candidates and evaluate the diagnostic yield of targeted gene panel testing. Methods We evaluated 116 patients with early‐onset epilepsy developed before 2 years old and normal brain imaging using a NGS‐based targeted gene panel. Variants were classified according to their pathogenicity, and the diagnostic yield of the targeted genes and associated clinical factors were determined. Results We detected 40 disease‐causing variants with diagnostic yield of 34.5% (19 pathogenic, 21 likely pathogenic). Twelve variants were novel. The most commonly detected genes were SCN1A, associated with Dravet syndrome, and PRRT2, associated with benign familial infantile epilepsy. Other variants were identified in ARX, SCN2A, KCNQ2, PCDH19, STXBP1, DEPDC5, and SCN8A. The age of seizure onset and family history were associated with disease‐causing variants. Conclusion Next‐generation sequencing‐based targeted testing is an effective diagnostic test, with 30%–40% comparable diagnostic yield. Patients with earlier seizure onset and family history of epilepsy were the best candidates for testing. For pediatric patients with early‐onset epilepsy, genetic diagnosis is important for accurate prognosis and treatment.
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Affiliation(s)
- Jiwon Lee
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Chung Lee
- Samsung Genome Institute, Samsung Medical Center, Seoul, Korea
| | | | - Jeehun Lee
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
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215
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Trivisano M, Rivera M, Terracciano A, Ciolfi A, Napolitano A, Pepi C, Calabrese C, Digilio MC, Tartaglia M, Curatolo P, Vigevano F, Specchio N. Developmental and epileptic encephalopathy due to SZT2 genomic variants: Emerging features of a syndromic condition. Epilepsy Behav 2020; 108:107097. [PMID: 32402703 DOI: 10.1016/j.yebeh.2020.107097] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 04/04/2020] [Accepted: 04/04/2020] [Indexed: 10/24/2022]
Abstract
Seizure threshold 2 (SZT2) gene mutations have been associated with developmental and epileptic encephalopathies (DEEs). Following a literature review, we collected 22 patients and identified the main clinical features related to SZT2 variants that are epilepsy with onset within the first years of life, intellectual disability (ID), macrocephaly with dysmorphic facial features, corpus callosum (CC) shape abnormalities, and cortical migration disorders. Moreover, we identified the c.7825T>G homozygous missense variant in SZT2 in two female siblings presenting with focal seizures, mild-moderate ID, behavioral disturbances, and facial dysmorphisms. Interictal Electroencephalogram (EEG) and ictal EEG were both informative and revealed, respectively, temporal bilateral asynchronous slow and epileptiform abnormalities and a focal onset in both of them. Neuroimaging study revealed a thick and abnormally shaped CC. Seizure threshold 2 has been identified as a component of the KICSTOR complex, a newly recognized protein complex involved in the mammalian target of rapamycin (mTOR) pathway. mTOR signaling dysregulation represents common pathogenetic mechanisms that can explain the presence of both epileptogenesis and ID. Even if few cases had been reported, a new clinical phenotype is emerging, and recent hypothesis of hyperactivation of mTORC1 signaling might also open to targeted treatments, challenging an early diagnosis as of paramount importance.
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Affiliation(s)
- Marina Trivisano
- Rare and Complex Epilepsy Unit, Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Manuel Rivera
- Rare and Complex Epilepsy Unit, Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy; Departamento de Neuropediatria, Fleni, Montañeses 2325, C1428AQK Ciudad de Buenos Aires, Argentina
| | | | - Andrea Ciolfi
- Genetics and Rare Diseases Research Division, Bambino Gesù Children's Hospital, IRCSS, Rome, Italy
| | - Antonio Napolitano
- Neuroradiology Unit, Department of Imaging, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Chiara Pepi
- Child Neurology and Psychiatry Unit, Systems Medicine Department, Tor Vergata University, Via Montpellier 1, 00133 Rome, Italy
| | - Costanza Calabrese
- Rare and Complex Epilepsy Unit, Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Maria Cristina Digilio
- Medical Genetics, Department of Pediatrics, Bambino Gesù Children's Hospital, IRCSS, Rome, Italy
| | - Marco Tartaglia
- Genetics and Rare Diseases Research Division, Bambino Gesù Children's Hospital, IRCSS, Rome, Italy
| | - Paolo Curatolo
- Child Neurology and Psychiatry Unit, Systems Medicine Department, Tor Vergata University, Via Montpellier 1, 00133 Rome, Italy
| | - Federico Vigevano
- Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS, Rome; Member of European Reference Network EpiCARE
| | - Nicola Specchio
- Rare and Complex Epilepsy Unit, Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy; Member of European Reference Network EpiCARE.
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216
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Brunklaus A, Lal D. Sodium channel epilepsies and neurodevelopmental disorders: from disease mechanisms to clinical application. Dev Med Child Neurol 2020; 62:784-792. [PMID: 32227486 DOI: 10.1111/dmcn.14519] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/04/2020] [Indexed: 12/18/2022]
Abstract
Genetic variants in brain-expressed voltage-gated sodium channels (SCNs) have emerged as one of the most frequent causes of Mendelian forms of epilepsy and neurodevelopmental disorders (NDDs). This review explores the biological concepts that underlie sodium channel NDDs, explains their phenotypic heterogeneity, and appraises how this knowledge may inform clinical practice. We observe that excitatory/inhibitory neuronal expression ratios of sodium channels are important regulatory mechanisms underlying brain development, homeostasis, and neurological diseases. We hypothesize that a detailed understanding of gene expression, variant tolerance, location, and function, as well as timing of seizure onset can aid the understanding of how variants in SCN1A, SCN2A, SCN3A, and SCN8A contribute to seizure aetiology and inform treatment choice. We propose a model in which variant type, development-specific gene expression, and functions of SCNs explain the heterogeneity of sodium channel associated NDDs. Understanding of basic disease mechanisms and detailed knowledge of variant characteristics have increasing influence on clinical decision making, enabling us to stratify treatment and move closer towards precision medicine in sodium channel epilepsy and NDDs. WHAT THIS PAPER ADDS: Sodium-channel disorder heterogeneity is explained by variant-specific gene expression timing and function. Gene tolerance and location analyses aid sodium channel variant interpretation. Sodium-channel variant characteristics can contribute to clinical decision making.
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Affiliation(s)
- Andreas Brunklaus
- The Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, UK.,School of Medicine, University of Glasgow, Glasgow, UK
| | - Dennis Lal
- Cologne Center for Genomics, University Hospital Cologne, University of Cologne, Cologne, Germany.,Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA.,Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA, USA.,Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA.,Genomic Medicine Institute, Lerner Research Institute Cleveland Clinic, Cleveland, OH, USA
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217
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Lewis-Smith D, Ellis CA, Helbig I, Thomas RH. Early-onset genetic epilepsies reaching adult clinics. Brain 2020; 143:e19. [PMID: 32203577 DOI: 10.1093/brain/awaa029] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- David Lewis-Smith
- Translational and Clinical Research Institute, Newcastle University, Newcastle-upon-Tyne, UK.,Royal Victoria Infirmary, Newcastle-upon-Tyne, UK
| | - Colin A Ellis
- The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - Ingo Helbig
- The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA.,Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Rhys H Thomas
- Translational and Clinical Research Institute, Newcastle University, Newcastle-upon-Tyne, UK.,Royal Victoria Infirmary, Newcastle-upon-Tyne, UK
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218
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Targeted gene panel sequencing in early infantile onset developmental and epileptic encephalopathy. Brain Dev 2020; 42:438-448. [PMID: 32139178 DOI: 10.1016/j.braindev.2020.02.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 02/13/2020] [Accepted: 02/16/2020] [Indexed: 01/06/2023]
Abstract
BACKGROUND Early-onset developmental and epileptic encephalopathy (DEE) is characterized by repeated seizures beginning within 3 months of birth and severe interictal epileptiform discharge, including burst suppression. This study assessed the utility of targeted gene panel sequencing in the genetic diagnosis of this disease. MATERIALS AND METHODS Targeted gene panel sequencing was performed in 150 early infantile-onset DEE patients (≤3 months of age), and we extensively reviewed their clinical characteristics, including therapeutic efficacy, according to genotype. RESULTS Of the early infantile-onset DEE patients, 70 were neonatal-onset DEE and the other 80 patients began experiencing seizures from 1 to 3 months after birth. There were 11 different pathogenic or likely pathogenic variants among 34.7% (52/150) of patients with early infantile-onset DEE, in whom KCNQ2, STXBP1, CDKL5, and SCN1A were the major pathogenic variants. Among the neonatal-onset DEE patients, pathological genes were identified in 42.9% (30/70), indicating a significantly higher diagnostic yield than in 27.5% (22/80) of patients who experienced seizure onset 1 to 3 months after birth (p = 0.048). Among the neonatal-onset DEE group, variants in KCNQ2, STXBP1, and CDKL5 were detected at high frequencies, accounting for 66.7% (20/30) of the pathogenic or likely pathogenic variants found in this study. CONCLUSION Targeted gene panel sequencing demonstrated a high yield of pathogenic variants in the diagnosis of early-onset epileptic encephalopathy, especially in those with neonatal-onset DEE. Early diagnosis of early-onset epileptic encephalopathy may improve the prognosis of patients by earlier selection of appropriate treatment based on pathogenic variant.
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219
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Symonds JD, Zuberi SM, Stewart K, McLellan A, O'Regan M, MacLeod S, Jollands A, Joss S, Kirkpatrick M, Brunklaus A, Pilz DT, Shetty J, Dorris L, Abu-Arafeh I, Andrew J, Brink P, Callaghan M, Cruden J, Diver LA, Findlay C, Gardiner S, Grattan R, Lang B, MacDonnell J, McKnight J, Morrison CA, Nairn L, Slean MM, Stephen E, Webb A, Vincent A, Wilson M. Incidence and phenotypes of childhood-onset genetic epilepsies: a prospective population-based national cohort. Brain 2020; 142:2303-2318. [PMID: 31302675 PMCID: PMC6658850 DOI: 10.1093/brain/awz195] [Citation(s) in RCA: 211] [Impact Index Per Article: 52.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 04/19/2019] [Accepted: 05/06/2019] [Indexed: 01/24/2023] Open
Abstract
Epilepsy is common in early childhood. In this age group it is associated with high rates of therapy-resistance, and with cognitive, motor, and behavioural comorbidity. A large number of genes, with wide ranging functions, are implicated in its aetiology, especially in those with therapy-resistant seizures. Identifying the more common single-gene epilepsies will aid in targeting resources, the prioritization of diagnostic testing and development of precision therapy. Previous studies of genetic testing in epilepsy have not been prospective and population-based. Therefore, the population-incidence of common genetic epilepsies remains unknown. The objective of this study was to describe the incidence and phenotypic spectrum of the most common single-gene epilepsies in young children, and to calculate what proportion are amenable to precision therapy. This was a prospective national epidemiological cohort study. All children presenting with epilepsy before 36 months of age were eligible. Children presenting with recurrent prolonged (>10 min) febrile seizures; febrile or afebrile status epilepticus (>30 min); or with clusters of two or more febrile or afebrile seizures within a 24-h period were also eligible. Participants were recruited from all 20 regional paediatric departments and four tertiary children’s hospitals in Scotland over a 3-year period. DNA samples were tested on a custom-designed 104-gene epilepsy panel. Detailed clinical information was systematically gathered at initial presentation and during follow-up. Clinical and genetic data were reviewed by a multidisciplinary team of clinicians and genetic scientists. The pathogenic significance of the genetic variants was assessed in accordance with the guidelines of UK Association of Clinical Genetic Science (ACGS). Of the 343 patients who met inclusion criteria, 333 completed genetic testing, and 80/333 (24%) had a diagnostic genetic finding. The overall estimated annual incidence of single-gene epilepsies in this well-defined population was 1 per 2120 live births (47.2/100 000; 95% confidence interval 36.9–57.5). PRRT2 was the most common single-gene epilepsy with an incidence of 1 per 9970 live births (10.0/100 000; 95% confidence interval 5.26–14.8) followed by SCN1A: 1 per 12 200 (8.26/100 000; 95% confidence interval 3.93–12.6); KCNQ2: 1 per 17 000 (5.89/100 000; 95% confidence interval 2.24–9.56) and SLC2A1: 1 per 24 300 (4.13/100 000; 95% confidence interval 1.07–7.19). Presentation before the age of 6 months, and presentation with afebrile focal seizures were significantly associated with genetic diagnosis. Single-gene disorders accounted for a quarter of the seizure disorders in this cohort. Genetic testing is recommended to identify children who may benefit from precision treatment and should be mainstream practice in early childhood onset epilepsy.
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Affiliation(s)
- Joseph D Symonds
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, UK.,College of Medical, Veterinary and Life Sciences, University of Glasgow, UK
| | - Sameer M Zuberi
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, UK.,College of Medical, Veterinary and Life Sciences, University of Glasgow, UK
| | - Kirsty Stewart
- West of Scotland Regional Genetics Service, Queen Elizabeth University Hospitals, Glasgow, UK
| | - Ailsa McLellan
- Department of Paediatric Neurosciences, Royal Hospital for Sick Children, Sciennes Road, Edinburgh, UK
| | - Mary O'Regan
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, UK
| | - Stewart MacLeod
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, UK
| | - Alice Jollands
- Paediatric Neurology, Tayside Children's Hospital, Dundee, UK
| | - Shelagh Joss
- West of Scotland Regional Genetics Service, Queen Elizabeth University Hospitals, Glasgow, UK
| | | | - Andreas Brunklaus
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, UK.,College of Medical, Veterinary and Life Sciences, University of Glasgow, UK
| | - Daniela T Pilz
- West of Scotland Regional Genetics Service, Queen Elizabeth University Hospitals, Glasgow, UK
| | - Jay Shetty
- Department of Paediatric Neurosciences, Royal Hospital for Sick Children, Sciennes Road, Edinburgh, UK
| | - Liam Dorris
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, UK.,College of Medical, Veterinary and Life Sciences, University of Glasgow, UK
| | - Ishaq Abu-Arafeh
- Department of Paediatrics, Forth Valley Royal Hospital, Larbert, UK
| | - Jamie Andrew
- Department of Paediatrics, University Hospital Wishaw, Netherton Street, Wishaw, UK
| | - Philip Brink
- Paediatric Neurology, Tayside Children's Hospital, Dundee, UK
| | - Mary Callaghan
- Department of Paediatrics, University Hospital Wishaw, Netherton Street, Wishaw, UK
| | - Jamie Cruden
- Department of Paediatrics, Victoria Hospital, Kirkcaldy, UK
| | - Louise A Diver
- West of Scotland Regional Genetics Service, Queen Elizabeth University Hospitals, Glasgow, UK
| | - Christine Findlay
- Department of Paediatrics, University Hospital Crosshouse, Kilmarnock, UK
| | - Sarah Gardiner
- West of Scotland Regional Genetics Service, Queen Elizabeth University Hospitals, Glasgow, UK
| | - Rosemary Grattan
- Department of Paediatrics, Forth Valley Royal Hospital, Larbert, UK
| | - Bethan Lang
- Nuffield Department of Clinical Neurosciences, Level 6, West Wing, John Radcliffe Hospital, Oxford, UK
| | - Jane MacDonnell
- Department of Paediatrics, Borders General Hospital, Melrose, UK
| | - Jean McKnight
- Department of Paediatrics, Dumfries and Galloway Royal Infirmary, Dumfries, UK
| | - Calum A Morrison
- Department of Paediatrics, University Hospital Crosshouse, Kilmarnock, UK
| | - Lesley Nairn
- Department of Paediatrics, Royal Alexandra Hospital, Paisley, UK
| | - Meghan M Slean
- College of Medical, Veterinary and Life Sciences, University of Glasgow, UK
| | - Elma Stephen
- Department of Paediatrics, Royal Aberdeen Children's Hospital, Aberdeen, UK
| | - Alan Webb
- Department of Paediatrics, Raigmore Hospital, Inverness, UK
| | - Angela Vincent
- Nuffield Department of Clinical Neurosciences, Level 6, West Wing, John Radcliffe Hospital, Oxford, UK
| | - Margaret Wilson
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, UK
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220
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Zhao G, Li K, Li B, Wang Z, Fang Z, Wang X, Zhang Y, Luo T, Zhou Q, Wang L, Xie Y, Wang Y, Chen Q, Xia L, Tang Y, Tang B, Xia K, Li J. Gene4Denovo: an integrated database and analytic platform for de novo mutations in humans. Nucleic Acids Res 2020; 48:D913-D926. [PMID: 31642496 PMCID: PMC7145562 DOI: 10.1093/nar/gkz923] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 09/19/2019] [Accepted: 10/08/2019] [Indexed: 12/14/2022] Open
Abstract
De novo mutations (DNMs) significantly contribute to sporadic diseases, particularly in neuropsychiatric disorders. Whole-exome sequencing (WES) and whole-genome sequencing (WGS) provide effective methods for detecting DNMs and prioritizing candidate genes. However, it remains a challenge for scientists, clinicians, and biologists to conveniently access and analyse data regarding DNMs and candidate genes from scattered publications. To fill the unmet need, we integrated 580 799 DNMs, including 30 060 coding DNMs detected by WES/WGS from 23 951 individuals across 24 phenotypes and prioritized a list of candidate genes with different degrees of statistical evidence, including 346 genes with false discovery rates <0.05. We then developed a database called Gene4Denovo (http://www.genemed.tech/gene4denovo/), which allowed these genetic data to be conveniently catalogued, searched, browsed, and analysed. In addition, Gene4Denovo integrated data from >60 genomic sources to provide comprehensive variant-level and gene-level annotation and information regarding the DNMs and candidate genes. Furthermore, Gene4Denovo provides end-users with limited bioinformatics skills to analyse their own genetic data, perform comprehensive annotation, and prioritize candidate genes using custom parameters. In conclusion, Gene4Denovo conveniently allows for the accelerated interpretation of DNM pathogenicity and the clinical implication of DNMs in humans.
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Affiliation(s)
- Guihu Zhao
- National Clinical Research Centre for Geriatric Disorders, Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, Hunan, China.,Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Kuokuo Li
- Centre for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Bin Li
- National Clinical Research Centre for Geriatric Disorders, Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, Hunan, China.,Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Zheng Wang
- National Clinical Research Centre for Geriatric Disorders, Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Zhenghuan Fang
- Centre for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Xiaomeng Wang
- Centre for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Yi Zhang
- National Clinical Research Centre for Geriatric Disorders, Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Tengfei Luo
- Centre for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Qiao Zhou
- National Clinical Research Centre for Geriatric Disorders, Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Lin Wang
- Centre for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Yali Xie
- National Clinical Research Centre for Geriatric Disorders, Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yijing Wang
- Centre for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Qian Chen
- National Clinical Research Centre for Geriatric Disorders, Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Lu Xia
- Centre for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Yu Tang
- National Clinical Research Centre for Geriatric Disorders, Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Beisha Tang
- National Clinical Research Centre for Geriatric Disorders, Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, Hunan, China.,Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Kun Xia
- Centre for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Jinchen Li
- National Clinical Research Centre for Geriatric Disorders, Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, Hunan, China.,Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China.,Centre for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
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221
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Chow CY, Absalom N, Biggs K, King GF, Ma L. Venom-derived modulators of epilepsy-related ion channels. Biochem Pharmacol 2020; 181:114043. [PMID: 32445870 DOI: 10.1016/j.bcp.2020.114043] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 05/18/2020] [Indexed: 12/18/2022]
Abstract
Epilepsy is characterised by spontaneous recurrent seizures that are caused by an imbalance between neuronal excitability and inhibition. Since ion channels play fundamental roles in the generation and propagation of action potentials as well as neurotransmitter release at a subset of excitatory and inhibitory synapses, their dysfunction has been linked to a wide variety of epilepsies. Indeed, these unique proteins are the major biological targets for antiepileptic drugs. Selective targeting of a specific ion channel subtype remains challenging for small molecules, due to the high level of homology among members of the same channel family. As a consequence, there is a growing trend to target ion channels with biologics. Venoms are the best known natural source of ion channel modulators, and venom peptides are increasingly recognised as potential therapeutics due to their high selectivity and potency gained through millions of years of evolutionary selection pressure. Here we describe the major ion channel families involved in the pathogenesis of various types of epilepsy, including voltage-gated Na+, K+, Ca2+ channels, Cys-loop receptors, ionotropic glutamate receptors and P2X receptors, and currently available venom-derived peptides that target these channel proteins. Although only a small number of venom peptides have successfully progressed to the clinic, there is reason to be optimistic about their development as antiepileptic drugs, notwithstanding the challenges associated with development of any class of peptide drug.
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Affiliation(s)
- Chun Yuen Chow
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Nathan Absalom
- Brain and Mind Centre, School of Pharmacy, Faculty of Health and Medicine, The University of Sydney, Sydney, NSW 2050, Australia
| | - Kimberley Biggs
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Glenn F King
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Linlin Ma
- Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD 4111, Australia.
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222
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Johannesen KM, Nikanorova N, Marjanovic D, Pavbro A, Larsen LHG, Rubboli G, Møller RS. Utility of genetic testing for therapeutic decision-making in adults with epilepsy. Epilepsia 2020; 61:1234-1239. [PMID: 32427350 DOI: 10.1111/epi.16533] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 04/18/2020] [Accepted: 04/21/2020] [Indexed: 12/24/2022]
Abstract
OBJECTIVE Genetic testing has become a routine part of the diagnostic workup in children with early onset epilepsies. In the present study, we sought to investigate a cohort of adult patients with epilepsy, to determinate the diagnostic yield and explore the gain of personalized treatment approaches in adult patients. METHODS Two hundred patients (age span = 18-80 years) referred for diagnostic gene panel testing at the Danish Epilepsy Center were included. The vast majority (91%) suffered from comorbid intellectual disability. The medical records of genetically diagnosed patients were mined for data on epilepsy syndrome, cognition, treatment changes, and seizure outcome following the genetic diagnosis. RESULTS We found a genetic diagnosis in 46 of 200 (23%) patients. SCN1A, KCNT1, and STXBP1 accounted for the greatest number of positive findings (48%). More rare genetic findings included SLC2A1, ATP6A1V, HNRNPU, MEF2C, and IRF2BPL. Gene-specific treatment changes were initiated in 11 of 46 (17%) patients (one with SLC2A1, 10 with SCN1A) following the genetic diagnosis. Ten patients improved, with seizure reduction and/or increased alertness and general well-being. SIGNIFICANCE With this study, we show that routine diagnostic testing is highly relevant in adults with epilepsy. The diagnostic yield is similar to previously reported pediatric cohorts, and the genetic findings can be useful for therapeutic decision-making, which may lead to better seizure control, ultimately improving quality of life.
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Affiliation(s)
- Katrine M Johannesen
- Department of Epilepsy Genetics and Personalized Treatment, Danish Epilepsy Center, Dianalund, Denmark.,Department of Regional Health Research, University of Southern Denmark, Odense, Denmark
| | - Natalya Nikanorova
- Department of Epilepsy Genetics and Personalized Treatment, Danish Epilepsy Center, Dianalund, Denmark
| | | | - Agnieszka Pavbro
- Department of Neurology, Danish Epilepsy Center, Dianalund, Denmark
| | | | - Guido Rubboli
- Department of Epilepsy Genetics and Personalized Treatment, Danish Epilepsy Center, Dianalund, Denmark.,University of Copenhagen, Copenhagen, Denmark
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Treatment, Danish Epilepsy Center, Dianalund, Denmark.,Department of Regional Health Research, University of Southern Denmark, Odense, Denmark
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223
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Miao P, Tang S, Ye J, Wang J, Lou Y, Zhang B, Xu X, Chen X, Li Y, Feng J. Electrophysiological features: The next precise step for SCN2A developmental epileptic encephalopathy. Mol Genet Genomic Med 2020; 8:e1250. [PMID: 32400968 PMCID: PMC7336724 DOI: 10.1002/mgg3.1250] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 03/01/2020] [Accepted: 03/05/2020] [Indexed: 12/19/2022] Open
Abstract
Background To investigate the relationships among phenotypes, genotypes, and funotypes of SCN2A‐related developmental epileptic encephalopathy (DEE). Methods We enrolled five DEE patients with five de novo variants of the SCN2A. Functional analysis and pharmacological features of Nav1.2 channel protein expressed in HEK293T cells were characterized by whole‐cell patch‐clamp recording. Results The phenotypes of c.4712T>C(p. I1571T), c.2995G>A(p.E999K), and c.4015A>G(p. N1339D) variants showed similar characteristics, including early seizure onset with severe to profound intellectual disability. Electrophysiological recordings revealed a hyperpolarizing shift in the voltage dependence of the activation curve and smaller recovery time constants of fast‐inactivation than in wild type, indicating a prominent gain of function (GOF). Moreover, pharmacological electrophysiology showed that phenytoin inhibited over a 70% peak current and was more effective than oxcarbazepine and carbamazepine. In contrast, c.4972C>T (p.P1658S) and c.5317G>A (p.A1773T) led to loss of function (LOF) changes, showing reduced current density and enhanced fast inactivation. Both showed seizure onset after 3 months of age with moderate development delay. Interestingly, we discovered that choreoathetosis was a specific phenotype feature. Conclusion These findings provided the insights into the phenotype–genotype–funotype relationships of SCN2A‐related DEE. The preliminary evaluation using the distinct hints of GOF and LOF helped plan the treatment, and the next precise step should be electrophysiological study.
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Affiliation(s)
- Pu Miao
- Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Siyang Tang
- Children's Hospital and Department of Biophysics, National Clinical Research Center for Child Health, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Jia Ye
- Children's Hospital and Department of Biophysics, National Clinical Research Center for Child Health, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Jianda Wang
- Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yuting Lou
- Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Bijun Zhang
- Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaoxiao Xu
- Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaoquan Chen
- Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yuezhou Li
- Children's Hospital and Department of Biophysics, National Clinical Research Center for Child Health, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Jianhua Feng
- Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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224
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Muller GK. The neonatal SCN2A mutant channel mimics adult channel properties. J Gen Physiol 2020; 152:151655. [PMID: 32291436 PMCID: PMC7201879 DOI: 10.1085/jgp.201912468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Grace K Muller
- Johns Hopkins University School of Medicine, Baltimore, MD
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225
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Tang S, Addis L, Smith A, Topp SD, Pendziwiat M, Mei D, Parker A, Agrawal S, Hughes E, Lascelles K, Williams RE, Fallon P, Robinson R, Cross HJ, Hedderly T, Eltze C, Kerr T, Desurkar A, Hussain N, Kinali M, Bagnasco I, Vassallo G, Whitehouse W, Goyal S, Absoud M, Møller RS, Helbig I, Weber YG, Marini C, Guerrini R, Simpson MA, Pal DK. Phenotypic and genetic spectrum of epilepsy with myoclonic atonic seizures. Epilepsia 2020; 61:995-1007. [PMID: 32469098 DOI: 10.1111/epi.16508] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 02/24/2020] [Accepted: 03/27/2020] [Indexed: 12/30/2022]
Abstract
OBJECTIVE We aimed to describe the extent of neurodevelopmental impairments and identify the genetic etiologies in a large cohort of patients with epilepsy with myoclonic atonic seizures (MAE). METHODS We deeply phenotyped MAE patients for epilepsy features, intellectual disability, autism spectrum disorder, and attention-deficit/hyperactivity disorder using standardized neuropsychological instruments. We performed exome analysis (whole exome sequencing) filtered on epilepsy and neuropsychiatric gene sets to identify genetic etiologies. RESULTS We analyzed 101 patients with MAE (70% male). The median age of seizure onset was 34 months (range = 6-72 months). The main seizure types were myoclonic atonic or atonic in 100%, generalized tonic-clonic in 72%, myoclonic in 69%, absence in 60%, and tonic seizures in 19% of patients. We observed intellectual disability in 62% of patients, with extremely low adaptive behavioral scores in 69%. In addition, 24% exhibited symptoms of autism and 37% exhibited attention-deficit/hyperactivity symptoms. We discovered pathogenic variants in 12 (14%) of 85 patients, including five previously published patients. These were pathogenic genetic variants in SYNGAP1 (n = 3), KIAA2022 (n = 2), and SLC6A1 (n = 2), as well as KCNA2, SCN2A, STX1B, KCNB1, and MECP2 (n = 1 each). We also identified three new candidate genes, ASH1L, CHD4, and SMARCA2 in one patient each. SIGNIFICANCE MAE is associated with significant neurodevelopmental impairment. MAE is genetically heterogeneous, and we identified a pathogenic genetic etiology in 14% of this cohort by exome analysis. These findings suggest that MAE is a manifestation of several etiologies rather than a discrete syndromic entity.
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Affiliation(s)
- Shan Tang
- Evelina London Children's Hospital, London, UK
- Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, UK
| | - Laura Addis
- Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, UK
- Eli Lilly and Company, Erl Wood, Surrey, UK
| | - Anna Smith
- Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, UK
| | - Simon D Topp
- Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, UK
| | - Manuela Pendziwiat
- Clinic for Neuropediatrics, Schleswig-Holstein University Clinics, Kiel, Germany
| | - Davide Mei
- Meyer Children's Hospital, University of Florence, Florence, Italy
| | | | - Shakti Agrawal
- Birmingham Children's Hospital National Health Service Foundation Trust, Birmingham, UK
| | - Elaine Hughes
- Evelina London Children's Hospital, London, UK
- King's College Hospital, London, UK
| | | | | | - Penny Fallon
- St George's National Health Service Health Care Trust, London, UK
| | - Robert Robinson
- Great Ormond Street Hospital for Children National Health Service Trust, London, UK
| | - Helen J Cross
- Great Ormond Street Hospital for Children National Health Service Trust, London, UK
- Clinical Neurosciences, UCL - Institute of Child Health, London, UK
| | | | - Christin Eltze
- Great Ormond Street Hospital for Children National Health Service Trust, London, UK
| | - Tim Kerr
- St George's National Health Service Health Care Trust, London, UK
| | - Archana Desurkar
- Sheffield Children's National Health Service Foundation Trust, Sheffield, UK
| | - Nahin Hussain
- University Hospital of Leicester National Health Service Trust, Leicester, UK
| | - Maria Kinali
- Chelsea and Westminster Hospital National Health Service Foundation Trust, London, UK
| | - Irene Bagnasco
- Child Neurology and Psychiatry Unit, Martini Hospital, Turin, Italy
| | | | | | - Sushma Goyal
- Evelina London Children's Hospital, London, UK
- King's College Hospital, London, UK
| | | | | | - Ingo Helbig
- Clinic for Neuropediatrics, Schleswig-Holstein University Clinics, Kiel, Germany
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
- Epilepsy NeuroGenetics Initiative, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
- Department of Biomedical and Health Informatics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Yvonne G Weber
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, Tübingen, Germany
- Department of Neurosurgery, University of Tübingen, Tübingen, Germany
| | - Carla Marini
- Meyer Children's Hospital, University of Florence, Florence, Italy
| | - Renzo Guerrini
- Meyer Children's Hospital, University of Florence, Florence, Italy
| | - Michael A Simpson
- Division of Genetics and Molecular Medicine, King's College London, London, UK
| | - Deb K Pal
- Evelina London Children's Hospital, London, UK
- Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, UK
- King's College Hospital, London, UK
- Medical Research Council Centre for Neurodevelopmental Disorders, King's College London, London, UK
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226
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Hedrich UBS, Lauxmann S, Lerche H. SCN2A channelopathies: Mechanisms and models. Epilepsia 2020; 60 Suppl 3:S68-S76. [PMID: 31904120 DOI: 10.1111/epi.14731] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 03/21/2019] [Indexed: 01/01/2023]
Abstract
Variants in the SCN2A gene, encoding the voltage-gated sodium channel NaV 1.2, cause a variety of neuropsychiatric syndromes with different severity ranging from self-limiting epilepsies with early onset to developmental and epileptic encephalopathy with early or late onset and intellectual disability (ID), as well as ID or autism without seizures. Functional analysis of channel defects demonstrated a genotype-phenotype correlation and suggested effective treatment options for one group of affected patients carrying gain-of-function variants. Here, we sum up the functional mechanisms underlying different phenotypes of patients with SCN2A channelopathies and present currently available models that can help in understanding SCN2A-related disorders.
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Affiliation(s)
- Ulrike B S Hedrich
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Stephan Lauxmann
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
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227
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Wolff M, Brunklaus A, Zuberi SM. Phenotypic spectrum and genetics of SCN2A-related disorders, treatment options, and outcomes in epilepsy and beyond. Epilepsia 2020; 60 Suppl 3:S59-S67. [PMID: 31904126 DOI: 10.1111/epi.14935] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 04/12/2019] [Accepted: 04/12/2019] [Indexed: 12/25/2022]
Abstract
Pathogenic variants in the SCN2A gene are associated with a variety of neurodevelopmental phenotypes, defined in recent years through multicenter collaboration. Phenotypes include benign (self-limited) neonatal and infantile epilepsy and more severe developmental and epileptic encephalopathies also presenting in early infancy. There is increasing evidence that an important phenotype linked to the gene is autism and intellectual disability without epilepsy or with rare seizures in later childhood. Other associations of SCN2A include the movement disorders chorea and episodic ataxia. It is likely that as genetic testing enters mainstream practice that new phenotypic associations will be identified. Some missense, gain of function variants tend to present in early infancy with epilepsy, whereas other missense or truncating, loss of function variants present with later-onset epilepsies or intellectual disability only. Knowledge of both mutation type and functional consequences can guide precision therapy. Sodium channel blockers may be effective antiepileptic medications in gain of function, neonatal and infantile presentations.
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Affiliation(s)
- Markus Wolff
- Pediatric Neurology, Vivantes Hospital Neukoelln, Berlin, Germany
| | - Andreas Brunklaus
- Paediatric Neurosciences Research Group, Royal Hospital for Children & School of Medicine, University of Glasgow, Glasgow, UK
| | - Sameer M Zuberi
- Paediatric Neurosciences Research Group, Royal Hospital for Children & School of Medicine, University of Glasgow, Glasgow, UK
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228
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Auvin S, Avbersek A, Bast T, Chiron C, Guerrini R, Kaminski RM, Lagae L, Muglia P, Cross JH. Drug Development for Rare Paediatric Epilepsies: Current State and Future Directions. Drugs 2020; 79:1917-1935. [PMID: 31734883 DOI: 10.1007/s40265-019-01223-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Rare diseases provide a challenge in the evaluation of new therapies. However, orphan drug development is of increasing interest because of the legislation enabling facilitated support by regulatory agencies through scientific advice, and the protection of the molecules with orphan designation. In the landscape of the rare epilepsies, very few syndromes, namely Dravet syndrome, Lennox-Gastaut syndrome and West syndrome, have been subject to orphan drug development. Despite orphan designations for rare epilepsies having dramatically increased in the past 10 years, the number of approved drugs remains limited and restricted to a handful of epilepsy syndromes. In this paper, we describe the current state of orphan drug development for rare epilepsies. We identified a large number of compounds currently under investigation, but mostly in the same rare epilepsy syndromes as in the past. A rationale for further development in rare epilepsies could be based on the match between the drug mechanisms of action and the knowledge of the causative gene mutation or by evidence from animal models. In case of the absence of strong pathophysiological hypotheses, exploratory/basket clinical studies could be helpful to identify a subpopulation that may benefit from the new drug. We provide some suggestions for future improvements in orphan drug development such as promoting paediatric drug investigations, better evaluation of the incidence and the prevalence, together with the natural history data, and the development of new primary outcomes.
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Affiliation(s)
- Stéphane Auvin
- PROTECT, INSERM U1141, Université de Paris, Paris, France. .,Service de Neurologie Pédiatrique, AP-HP, Hôpital Universitaire Robert-Debré, 48, Boulevard Sérurier, 75935, Paris Cedex 19, France.
| | | | - Thomas Bast
- The Kork Epilepsy Center, Kehl-Kork, Germany.,Medical Faculty of the University of Freiburg, Freiburg, Germany
| | - Catherine Chiron
- PROTECT, INSERM U1141, Université de Paris, Paris, France.,Service de Neurologie Pédiatrique, AP-HP, Hôpital Necker-Enfanst Malades, Paris, France
| | - Renzo Guerrini
- Neuroscience Department, Children's Hospital Anna Meyer-University of Florence, Florence, Italy
| | - Rafal M Kaminski
- UCB Pharma, Braine-l'Alleud, Belgium.,Roche Pharma Research and Early Development (pRED), Roche Innovation Center, Basel, Switzerland
| | - Lieven Lagae
- Department Development and Regeneration, Section Paediatric Neurology, University Hospitals, University of Leuven, Leuven, Belgium
| | | | - J Helen Cross
- UCL NIHR BRC Great Ormond Street Institute of Child Health, London, UK
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229
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Maljevic S, Keren B, Aung YH, Forster IC, Mignot C, Buratti J, Lafitte A, Freihuber C, Rodan LH, Bergin A, Hubert L, Poirier K, Munnich A, Besmond C, Hauser N, Miller R, McWalter K, Nabbout R, Héron D, Leguern E, Depienne C, Petrou S, Nava C. Novel GABRA2 variants in epileptic encephalopathy and intellectual disability with seizures. Brain 2020; 142:e15. [PMID: 31032849 DOI: 10.1093/brain/awz079] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Snezana Maljevic
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia
| | - Boris Keren
- APHP, Hôpital Pitié-Salpêtrière, Département de Génétique, Centre de Reference Déficience Intellectuelle de Causes Rares, GRC UPMC «Déficience Intellectuelle et Autisme», Paris, France
| | - Ye Htet Aung
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia
| | - Ian C Forster
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia
| | - Cyril Mignot
- APHP, Hôpital Pitié-Salpêtrière, Département de Génétique, Centre de Reference Déficience Intellectuelle de Causes Rares, GRC UPMC «Déficience Intellectuelle et Autisme», Paris, France.,Sorbonne Universités, Institut du Cerveau et de la Moelle épinière, ICM, Inserm U1127, CNRS UMR 7225, F-75013, Paris, France
| | - Julien Buratti
- APHP, Hôpital Pitié-Salpêtrière, Département de Génétique, Centre de Reference Déficience Intellectuelle de Causes Rares, GRC UPMC «Déficience Intellectuelle et Autisme», Paris, France
| | - Aurélie Lafitte
- APHP, Hôpital Pitié-Salpêtrière, Département de Génétique, Centre de Reference Déficience Intellectuelle de Causes Rares, GRC UPMC «Déficience Intellectuelle et Autisme», Paris, France
| | - Cécile Freihuber
- AP-HP, Hôpital Trousseau, Service de Neuropédiatrie, Paris, France
| | - Lance H Rodan
- Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.,Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ann Bergin
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Laurence Hubert
- INSERM UMR 1163, Translational Genetics Lab., Paris-Descartes University, Imagine Institute, Paris, France
| | - Karine Poirier
- INSERM UMR 1163, Translational Genetics Lab., Paris-Descartes University, Imagine Institute, Paris, France
| | - Arnold Munnich
- INSERM UMR 1163, Translational Genetics Lab., Paris-Descartes University, Imagine Institute, Paris, France
| | - Claude Besmond
- INSERM UMR 1163, Translational Genetics Lab., Paris-Descartes University, Imagine Institute, Paris, France
| | - Natalie Hauser
- Inova Health System, Inova Translational Medicine Institute, Falls Church, VA, USA
| | - Rebecca Miller
- Inova Health System, Inova Translational Medicine Institute, Falls Church, VA, USA
| | | | - Rima Nabbout
- APHP, Hôpital Necker Enfants Malades, Centre de référence épilepsies rares, Service de Neurologie pédiatrique, Paris, France
| | - Delphine Héron
- APHP, Hôpital Pitié-Salpêtrière, Département de Génétique, Centre de Reference Déficience Intellectuelle de Causes Rares, GRC UPMC «Déficience Intellectuelle et Autisme», Paris, France
| | - Eric Leguern
- APHP, Hôpital Pitié-Salpêtrière, Département de Génétique, Centre de Reference Déficience Intellectuelle de Causes Rares, GRC UPMC «Déficience Intellectuelle et Autisme», Paris, France.,Sorbonne Universités, Institut du Cerveau et de la Moelle épinière, ICM, Inserm U1127, CNRS UMR 7225, F-75013, Paris, France
| | - Christel Depienne
- Sorbonne Universités, Institut du Cerveau et de la Moelle épinière, ICM, Inserm U1127, CNRS UMR 7225, F-75013, Paris, France.,Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Steven Petrou
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia
| | - Caroline Nava
- APHP, Hôpital Pitié-Salpêtrière, Département de Génétique, Centre de Reference Déficience Intellectuelle de Causes Rares, GRC UPMC «Déficience Intellectuelle et Autisme», Paris, France.,Sorbonne Universités, Institut du Cerveau et de la Moelle épinière, ICM, Inserm U1127, CNRS UMR 7225, F-75013, Paris, France
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230
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Kruth KA, Grisolano TM, Ahern CA, Williams AJ. SCN2A channelopathies in the autism spectrum of neuropsychiatric disorders: a role for pluripotent stem cells? Mol Autism 2020; 11:23. [PMID: 32264956 PMCID: PMC7140374 DOI: 10.1186/s13229-020-00330-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 03/25/2020] [Indexed: 12/12/2022] Open
Abstract
Efforts to identify the causes of autism spectrum disorders have highlighted the importance of both genetics and environment, but the lack of human models for many of these disorders limits researchers’ attempts to understand the mechanisms of disease and to develop new treatments. Induced pluripotent stem cells offer the opportunity to study specific genetic and environmental risk factors, but the heterogeneity of donor genetics may obscure important findings. Diseases associated with unusually high rates of autism, such as SCN2A syndromes, provide an opportunity to study specific mutations with high effect sizes in a human genetic context and may reveal biological insights applicable to more common forms of autism. Loss-of-function mutations in the SCN2A gene, which encodes the voltage-gated sodium channel NaV1.2, are associated with autism rates up to 50%. Here, we review the findings from experimental models of SCN2A syndromes, including mouse and human cell studies, highlighting the potential role for patient-derived induced pluripotent stem cell technology to identify the molecular and cellular substrates of autism.
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Affiliation(s)
- Karina A Kruth
- Department of Psychiatry, Iowa Neuroscience Institute, University of Iowa, 169 Newton Rd, 2326 PBDB, Iowa City, IA, 52242, USA
| | - Tierney M Grisolano
- Department of Molecular Physiology and Biophysics, Iowa Neuroscience Institute, University of Iowa, 169 Newton Rd, 2312 PBDB, Iowa City, IA, 52242, USA
| | - Christopher A Ahern
- Department of Molecular Physiology and Biophysics, Iowa Neuroscience Institute, University of Iowa, 169 Newton Rd, 2312 PBDB, Iowa City, IA, 52242, USA
| | - Aislinn J Williams
- Department of Psychiatry, Iowa Neuroscience Institute, University of Iowa, 169 Newton Rd, 2326 PBDB, Iowa City, IA, 52242, USA.
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231
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Abstract
Epilepsy includes a number of medical conditions with recurrent seizures as common denominator. The large number of different syndromes and seizure types as well as the highly variable inter-individual response to the therapies makes management of this condition often challenging. In the last two decades, a genetic etiology has been revealed in more than half of all epilepsies and single gene defects in ion channels or neurotransmitter receptors have been associated with most inherited forms of epilepsy, including some focal and lesional forms as well as specific epileptic developmental encephalopathies. Several genetic tests are now available, including targeted assays up to revolutionary tools that have made sequencing of all coding (whole exome) and non-coding (whole genome) regions of the human genome possible. These recent technological advances have also driven genetic discovery in epilepsy and increased our understanding of the molecular mechanisms of many epileptic disorders, eventually providing targets for precision medicine in some syndromes, such as Dravet syndrome, pyroxidine-dependent epilepsy, and glucose transporter 1 deficiency. However, these examples represent a relatively small subset of all types of epilepsy, and to date, precision medicine in epilepsy has primarily focused on seizure control, and other clinical aspects, such as neurodevelopmental and neuropsychiatric comorbidities, have yet been possible to address. We herein summarize the most recent advances in genetic testing and provide up-to-date approaches for the choice of the correct test for some epileptic disorders and tailored treatments that are already applicable in some monogenic epilepsies. In the next years, the most probably scenario is that epilepsy treatment will be very different from the currently almost empirical approach, eventually with a "precision medicine" approach applicable on a large scale.
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Affiliation(s)
- Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto "G. Gaslini", Genoa, Italy.
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Via Gaslini 5, 16148, Genoa, Italy.
| | - Berge A Minassian
- Department of Pediatrics Division of Neurology, University of Texas Southwestern, Dallas, Texas, USA
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232
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Identification of common genetic markers of paroxysmal neurological disorders using a network analysis approach. Neurol Sci 2020; 41:851-857. [DOI: 10.1007/s10072-019-04113-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 10/15/2019] [Indexed: 01/11/2023]
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233
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Mason ER, Cummins TR. Differential Inhibition of Human Nav1.2 Resurgent and Persistent Sodium Currents by Cannabidiol and GS967. Int J Mol Sci 2020; 21:ijms21072454. [PMID: 32244818 PMCID: PMC7177867 DOI: 10.3390/ijms21072454] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/27/2020] [Accepted: 03/28/2020] [Indexed: 12/24/2022] Open
Abstract
Many epilepsy patients are refractory to conventional antiepileptic drugs. Resurgent and persistent currents can be enhanced by epilepsy mutations in the Nav1.2 channel, but conventional antiepileptic drugs inhibit normal transient currents through these channels, along with aberrant resurgent and persistent currents that are enhanced by Nav1.2 epilepsy mutations. Pharmacotherapies that specifically target aberrant resurgent and/or persistent currents would likely have fewer unwanted side effects and be effective in many patients with refractory epilepsy. This study investigated the effects of cannbidiol (CBD) and GS967 (each at 1 μM) on transient, resurgent, and persistent currents in human embryonic kidney (HEK) cells stably expressing wild-type hNav1.2 channels. We found that CBD preferentially inhibits resurgent currents over transient currents in this paradigm; and that GS967 preferentially inhibits persistent currents over transient currents. Therefore, CBD and GS967 may represent a new class of more targeted and effective antiepileptic drugs.
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Affiliation(s)
- Emily R. Mason
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, IUPUI campus, Indianapolis, IN 46202, USA
- Correspondence:
| | - Theodore R. Cummins
- Department of Biology, Purdue School of Science, IUPUI campus, Indianapolis, IN 46202, USA;
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234
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Lee S, Kim SH, Kim B, Lee ST, Choi JR, Kim HD, Lee JS, Kang HC. Genetic diagnosis and clinical characteristics by etiological classification in early-onset epileptic encephalopathy with burst suppression pattern. Epilepsy Res 2020; 163:106323. [PMID: 32247221 DOI: 10.1016/j.eplepsyres.2020.106323] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 03/01/2020] [Accepted: 03/20/2020] [Indexed: 01/17/2023]
Abstract
BACKGROUND Early-onset epileptic encephalopathies with burst suppression (EOEE-BS) are a group of neonatal epileptic syndromes characterized by intractable epilepsy and severe psychomotor delay with structural and metabolic factors accounting for major etiologies. However, recent advances in gene sequencing have identified that genetic factors might also play a significant role in the development of EOEE-BS. Herein, we used various genetic tests to identify pathogenic genetic variants in EOEE-BS irrespective of structural malformations and analyzed the clinical features associated with each different etiology. METHODS A total of 48 patients with EOEE-BS were included. Except for patients with severe hypoxic damage, patients with structural malformations were included in our patient cohort. Clinical features of the patients were reviewed, and etiological diagnoses were made based on several genetic tests, metabolic studies, and radiological findings. RESULT A genetic diagnosis was made in 31 (64.6 %) patients, with the most commonly diagnosed gene being STXBP1 (n = 13, 27.1 %), followed by KCNQ2 (n = 5, 10.4 %), SCN2A (n = 5, 10.4 %), DEPDC5 (n = 3, 6.3 %), CASK (n = 1, 2.1 %), CDKL5 (n = 1, 2.1 %), GNAO1 (n = 1, 2.1 %), SLC6A8 (n = 1, 2.1 %), and LIS1 deletion (n = 1, 2.1 %). Other than the classification of epilepsy syndrome, no clinical features were associated with the genetically diagnosed group. Among eight patients with structural malformations, genetic diagnosis was achieved in five (62.5 %), and those patients had pathogenic mutations in DEPDC5 and CASK or LIS1 deletion, indicating the significance of gene sequencing irrespective of structural abnormalities. Treatment responses to a variety of medications and the ketogenic diet differed by etiology, and surgical resection proved to be effective in patients with cortical dysplasia. CONCLUSION Genetic etiologies are an important factor in EOEE-BS irrespective of structural malformations and the treatment options may differ by etiology.
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Affiliation(s)
- Sangbo Lee
- Division of Pediatric Neurology, Epilepsy Research Institute, Severance Children's Hospital, Department of Pediatrics, Yonsei University College of Medicine, Yonsei-ro 50-1, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Se Hee Kim
- Division of Pediatric Neurology, Epilepsy Research Institute, Severance Children's Hospital, Department of Pediatrics, Yonsei University College of Medicine, Yonsei-ro 50-1, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Borahm Kim
- Department of Laboratory Medicine, Severance Hospital, Yonsei University College of Medicine, Yonsei-ro 50-1, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Seung-Tae Lee
- Department of Laboratory Medicine, Severance Hospital, Yonsei University College of Medicine, Yonsei-ro 50-1, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Jong Rak Choi
- Department of Laboratory Medicine, Severance Hospital, Yonsei University College of Medicine, Yonsei-ro 50-1, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Heung Dong Kim
- Division of Pediatric Neurology, Epilepsy Research Institute, Severance Children's Hospital, Department of Pediatrics, Yonsei University College of Medicine, Yonsei-ro 50-1, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Joon Soo Lee
- Division of Pediatric Neurology, Epilepsy Research Institute, Severance Children's Hospital, Department of Pediatrics, Yonsei University College of Medicine, Yonsei-ro 50-1, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Hoon-Chul Kang
- Division of Pediatric Neurology, Epilepsy Research Institute, Severance Children's Hospital, Department of Pediatrics, Yonsei University College of Medicine, Yonsei-ro 50-1, Seodaemun-gu, Seoul, 03722, Republic of Korea.
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235
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Abstract
PURPOSE OF REVIEW Although differentiating neonatal-onset epilepsies from acute symptomatic neonatal seizures has been increasingly recognized as crucial, existing guidelines, and recommendations on EEG monitoring are mainly based on acute symptomatic seizures, especially secondary to hypoxic-ischemic encephalopathy. We aimed to narratively review current knowledge on neonatal-onset epilepsies of genetic, metabolic, and structural non-acquired origin, with special emphasis on EEG features and monitoring. RECENT FINDINGS A wide range of rare conditions are increasingly described, reducing undiagnosed cases. Although distinguishing features are identifiable in some, how to best monitor and detect less described etiologies is still an issue. A comprehensive approach considering onset, seizure evolution, ictal semiology, clinical, laboratory, EEG, and neuroimaging data is key to diagnosis. Phenotypic variability prevents precise recommendations, but a solid, consistent method moving from existing published guidelines helps in correctly assessing these newborns in order to provide better care, especially in view of expanding precision therapies.
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236
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Matthews E, Balestrini S, Sisodiya SM, Hanna MG. Muscle and brain sodium channelopathies: genetic causes, clinical phenotypes, and management approaches. THE LANCET CHILD & ADOLESCENT HEALTH 2020; 4:536-547. [PMID: 32142633 DOI: 10.1016/s2352-4642(19)30425-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 10/29/2019] [Accepted: 12/12/2019] [Indexed: 01/26/2023]
Abstract
Voltage-gated sodium channels are essential for excitability of skeletal muscle fibres and neurons. An increasing number of disabling or fatal paediatric neurological disorders linked to mutations of voltage-gated sodium channel genes are recognised. Muscle phenotypes include episodic paralysis, myotonia, neonatal hypotonia, respiratory compromise, laryngospasm or stridor, congenital myasthenia, and myopathy. Evidence suggests a possible link between sodium channel dysfunction and sudden infant death. Increasingly recognised phenotypes of brain sodium channelopathies include several epilepsy disorders and complex encephalopathies. Together, these early-onset muscle and brain phenotypes have a substantial morbidity and a considerable mortality. Important advances in understanding the pathophysiological mechanisms underlying these channelopathies have helped to identify effective targeted therapies. The availability of effective treatments underlines the importance of increasing clinical awareness and the need to achieve a precise genetic diagnosis. In this Review, we describe the expanded range of phenotypes of muscle and brain sodium channelopathies and the underlying knowledge regarding mechanisms of sodium channel dysfunction. We also outline a diagnostic approach and review the available treatment options.
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Affiliation(s)
- Emma Matthews
- Department of Neuromuscular Diseases, Medical Research Council Centre for Neuromuscular Diseases, University College London Queen Square Institute of Neurology, London, UK; National Hospital for Neurology and Neurosurgery, University College London Hospitals National Health Service Foundation Trust, London, UK.
| | - Simona Balestrini
- Department of Clinical and Experimental Epilepsy, University College London Queen Square Institute of Neurology, London, UK; Chalfont Centre for Epilepsy, Buckinghamshire, UK; National Hospital for Neurology and Neurosurgery, University College London Hospitals National Health Service Foundation Trust, London, UK
| | - Sanjay M Sisodiya
- Department of Clinical and Experimental Epilepsy, University College London Queen Square Institute of Neurology, London, UK; Chalfont Centre for Epilepsy, Buckinghamshire, UK; National Hospital for Neurology and Neurosurgery, University College London Hospitals National Health Service Foundation Trust, London, UK
| | - Michael G Hanna
- Department of Neuromuscular Diseases, Medical Research Council Centre for Neuromuscular Diseases, University College London Queen Square Institute of Neurology, London, UK; National Hospital for Neurology and Neurosurgery, University College London Hospitals National Health Service Foundation Trust, London, UK
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237
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Brunklaus A, Du J, Steckler F, Ghanty II, Johannesen KM, Fenger CD, Schorge S, Baez-Nieto D, Wang HR, Allen A, Pan JQ, Lerche H, Heyne H, Symonds JD, Zuberi SM, Sanders S, Sheidley BR, Craiu D, Olson HE, Weckhuysen S, DeJonge P, Helbig I, Van Esch H, Busa T, Milh M, Isidor B, Depienne C, Poduri A, Campbell AJ, Dimidschstein J, Møller RS, Lal D. Biological concepts in human sodium channel epilepsies and their relevance in clinical practice. Epilepsia 2020; 61:387-399. [PMID: 32090326 DOI: 10.1111/epi.16438] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 01/06/2020] [Accepted: 01/06/2020] [Indexed: 01/07/2023]
Abstract
OBJECTIVE Voltage-gated sodium channels (SCNs) share similar amino acid sequence, structure, and function. Genetic variants in the four human brain-expressed SCN genes SCN1A/2A/3A/8A have been associated with heterogeneous epilepsy phenotypes and neurodevelopmental disorders. To better understand the biology of seizure susceptibility in SCN-related epilepsies, our aim was to determine similarities and differences between sodium channel disorders, allowing us to develop a broader perspective on precision treatment than on an individual gene level alone. METHODS We analyzed genotype-phenotype correlations in large SCN-patient cohorts and applied variant constraint analysis to identify severe sodium channel disease. We examined temporal patterns of human SCN expression and correlated functional data from in vitro studies with clinical phenotypes across different sodium channel disorders. RESULTS Comparing 865 epilepsy patients (504 SCN1A, 140 SCN2A, 171 SCN8A, four SCN3A, 46 copy number variation [CNV] cases) and analysis of 114 functional studies allowed us to identify common patterns of presentation. All four epilepsy-associated SCN genes demonstrated significant constraint in both protein truncating and missense variation when compared to other SCN genes. We observed that age at seizure onset is related to SCN gene expression over time. Individuals with gain-of-function SCN2A/3A/8A missense variants or CNV duplications share similar characteristics, most frequently present with early onset epilepsy (<3 months), and demonstrate good response to sodium channel blockers (SCBs). Direct comparison of corresponding SCN variants across different SCN subtypes illustrates that the functional effects of variants in corresponding channel locations are similar; however, their clinical manifestation differs, depending on their role in different types of neurons in which they are expressed. SIGNIFICANCE Variant function and location within one channel can serve as a surrogate for variant effects across related sodium channels. Taking a broader view on precision treatment suggests that in those patients with a suspected underlying genetic epilepsy presenting with neonatal or early onset seizures (<3 months), SCBs should be considered.
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Affiliation(s)
- Andreas Brunklaus
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, UK.,School of Medicine, University of Glasgow, Glasgow, UK
| | - Juanjiangmeng Du
- Cologne Center for Genomics, University of Cologne, University Hospital Cologne, Cologne, Germany
| | - Felix Steckler
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, UK.,School of Medicine, University of Glasgow, Glasgow, UK
| | - Ismael I Ghanty
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, UK.,School of Medicine, University of Glasgow, Glasgow, UK
| | - Katrine M Johannesen
- Deparment of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center Filadelfia, Dianalund, Denmark.,Institute for Regional Health Services, University of Southern Denmark, Odense, Denmark
| | - Christina Dühring Fenger
- Deparment of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center Filadelfia, Dianalund, Denmark.,Amplexa Genetics, Odense, Denmark
| | - Stephanie Schorge
- Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, UK.,School of Pharmacy, University College London, London, UK
| | - David Baez-Nieto
- Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts
| | - Hao-Ran Wang
- Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts
| | - Andrew Allen
- Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts
| | - Jen Q Pan
- Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Germany
| | - Henrike Heyne
- Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts.,Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, Massachusetts.,Institute for Molecular Medicine Finland, University of Helsinki, Helsinki, Finland
| | - Joseph D Symonds
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, UK.,School of Medicine, University of Glasgow, Glasgow, UK
| | - Sameer M Zuberi
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, UK.,School of Medicine, University of Glasgow, Glasgow, UK
| | - Stephan Sanders
- Department of Psychiatry, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California
| | - Beth R Sheidley
- Epilepsy Genetics Program, Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Boston, Massachusetts
| | - Dana Craiu
- Carol Davila University of Medicine, Department of Clinical Neurosciences, Pediatric Neurology Discipline, Bucharest, Romania.,Alexandru Obregia Hospital, Pediatric Neurology Clinic, Bucharest, Romania
| | - Heather E Olson
- Epilepsy Genetics Program, Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Boston, Massachusetts
| | - Sarah Weckhuysen
- Neurogenetics Group, Center for Molecular Neurology, VIB, Antwerp, Belgium.,Laboratory of Neurogenetics, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.,Department of Neurology, University Hospital Antwerp, Antwerp, Belgium
| | - Peter DeJonge
- Neurogenetics Group, Center for Molecular Neurology, VIB, Antwerp, Belgium.,Laboratory of Neurogenetics, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.,Department of Neurology, University Hospital Antwerp, Antwerp, Belgium
| | - Ingo Helbig
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Epilepsy NeuroGenetics Initiative, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Department of Biomedical and Health Informatics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Neuropediatrics, University of Kiel, Kiel, Germany
| | - Hilde Van Esch
- Department of Human Genetics and Center for Human Genetics, Laboratory for Genetics of Cognition, University Hospitals Leuven, Leuven, Belgium
| | - Tiffany Busa
- Genetics Department, Timone Enfants University Hospital Center, Public Assistance-Marseille Hospitals, Marseille, France
| | - Matthieu Milh
- Medical Genetics and Functional Genomics, National Institute of Health and Medical Research, Mixed Unit of Research S910, Aix-Marseille University, Marseille, France.,Hematology Laboratory, Le Mans Hospital Center, Le Mans, France
| | - Bertrand Isidor
- Medical Genetics Department, Nantes University Hospital Center, Nantes, France
| | - Christel Depienne
- Institute of Human Genetics, Essen University Hospital, Essen, Germany.,Brain and Spinal Cord Institute, National Institute of Health and Medical Research, Unit 1127, National Center for Scientific Research, Mixed Unit of Research 7225, Sorbonne Universities, Pierre and Marie Curie University, Mixed Unit of Research S 1127, Brain & Spine Institute, Paris, France
| | - Annapurna Poduri
- Epilepsy Genetics Program, Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Boston, Massachusetts.,Harvard Medical School, Boston, Massachusetts
| | | | - Jordane Dimidschstein
- Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts
| | - Rikke S Møller
- Deparment of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center Filadelfia, Dianalund, Denmark.,Institute for Regional Health Services, University of Southern Denmark, Odense, Denmark
| | - Dennis Lal
- Cologne Center for Genomics, University of Cologne, University Hospital Cologne, Cologne, Germany.,Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts.,Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, Massachusetts.,Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, Ohio.,Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
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238
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Cárdenas-Rodríguez N, Carmona-Aparicio L, Pérez-Lozano DL, Ortega-Cuellar D, Gómez-Manzo S, Ignacio-Mejía I. Genetic variations associated with pharmacoresistant epilepsy (Review). Mol Med Rep 2020; 21:1685-1701. [PMID: 32319641 PMCID: PMC7057824 DOI: 10.3892/mmr.2020.10999] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 01/16/2020] [Indexed: 12/13/2022] Open
Abstract
Epilepsy is a common, serious neurological disorder worldwide. Although this disease can be successfully treated in most cases, not all patients respond favorably to medical treatments, which can lead to pharmacoresistant epilepsy. Drug-resistant epilepsy can be caused by a number of mechanisms that may involve environmental and genetic factors, as well as disease- and drug-related factors. In recent years, numerous studies have demonstrated that genetic variation is involved in the drug resistance of epilepsy, especially genetic variations found in drug resistance-related genes, including the voltage-dependent sodium and potassium channels genes, and the metabolizer of endogenous and xenobiotic substances genes. The present review aimed to highlight the genetic variants that are involved in the regulation of drug resistance in epilepsy; a comprehensive understanding of the role of genetic variation in drug resistance will help us develop improved strategies to regulate drug resistance efficiently and determine the pathophysiological processes that underlie this common human neurological disease.
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Affiliation(s)
- Noemí Cárdenas-Rodríguez
- Laboratory of Neuroscience, National Institute of Pediatrics, Ministry of Health, Coyoacán, Mexico City 04530, Mexico
| | - Liliana Carmona-Aparicio
- Laboratory of Neuroscience, National Institute of Pediatrics, Ministry of Health, Coyoacán, Mexico City 04530, Mexico
| | - Diana L Pérez-Lozano
- Laboratory of Neuroscience, National Institute of Pediatrics, Ministry of Health, Coyoacán, Mexico City 04530, Mexico
| | - Daniel Ortega-Cuellar
- Laboratory of Experimental Nutrition, National Institute of Pediatrics, Ministry of Health, Coyoacán, Mexico City 04530, Mexico
| | - Saúl Gómez-Manzo
- Laboratory of Genetic Biochemistry, National Institute of Pediatrics, Ministry of Health, Coyoacán, Mexico City 04530, Mexico
| | - Iván Ignacio-Mejía
- Laboratory of Translational Medicine, Military School of Health Graduates, Lomas de Sotelo, Militar, Mexico City 11200, Mexico
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239
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Rare genetic susceptibility variants assessment in autism spectrum disorder: detection rate and practical use. Transl Psychiatry 2020; 10:77. [PMID: 32094338 PMCID: PMC7039996 DOI: 10.1038/s41398-020-0760-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 12/10/2019] [Accepted: 01/10/2020] [Indexed: 12/21/2022] Open
Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental disorder with a strong genetic component whose knowledge evolves quickly. Next-generation sequencing is the only effective technology to deal with the high genetic heterogeneity of ASD in a clinical setting. However, rigorous criteria to classify rare genetic variants conferring ASD susceptibility are currently lacking. We have performed whole-exome sequencing to identify both nucleotide variants and copy number variants (CNVs) in 253 ASD patients, including 68 patients with intellectual disability (ID) and 90 diagnosed as Asperger syndrome. Using explicit criteria to classify both susceptibility genes and susceptibility variants we prioritized 217 genes belonging to the following categories: syndromic genes, genes with an excess of de novo protein truncating variants and genes targeted by rare CNVs. We obtained a susceptibility variant detection rate of 19.7% (95% CI: [15-25.2%]). The rate for CNVs was 7.1% (95% CI: [4.3-11%]) and 12.6% (95% CI: [8.8-17.4%]) for nucleotide variants. The highest rate (30.1%, 95% CI: [20.2-43.2%]) was obtained in the ASD + ID subgroup. A strong contributor for at risk nucleotide variants was the recently identified set of genes (n = 81) harboring an excess of de novo protein truncating variants. Since there is currently no evidence that the genes targeted here are necessary and sufficient to cause ASD, we recommend to avoid the term "causative of ASD" when delivering the information about a variant to a family and to use instead the term "genetic susceptibility factor contributing to ASD".
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240
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Smith RS, Walsh CA. Ion Channel Functions in Early Brain Development. Trends Neurosci 2020; 43:103-114. [PMID: 31959360 PMCID: PMC7092371 DOI: 10.1016/j.tins.2019.12.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 12/08/2019] [Accepted: 12/10/2019] [Indexed: 12/12/2022]
Abstract
During prenatal brain development, ion channels are ubiquitous across several cell types, including progenitor cells and migrating neurons but their function has not been clear. In the past, ion channel dysfunction has been primarily studied in the context of postnatal, differentiated neurons that fire action potentials - notably ion channels mutated in the epilepsies - yet data now support a surprising role in prenatal human brain disorders as well. Modern gene discovery approaches have identified defective ion channels in individuals with cerebral cortex malformations, which reflect abnormalities in early-to-middle stages of embryonic development (prior to ubiquitous action potentials). These human genetics studies and recent in utero animal modeling work suggest that precise control of ionic flux (calcium, sodium, and potassium) contributes to in utero developmental processes such as neural proliferation, migration, and differentiation.
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Affiliation(s)
- Richard S Smith
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, and Howard Hughes Medical Institute, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
| | - Christopher A Walsh
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, and Howard Hughes Medical Institute, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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241
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Helbig I, Ellis CA. Personalized medicine in genetic epilepsies - possibilities, challenges, and new frontiers. Neuropharmacology 2020; 172:107970. [PMID: 32413583 DOI: 10.1016/j.neuropharm.2020.107970] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 01/05/2020] [Accepted: 01/16/2020] [Indexed: 12/13/2022]
Abstract
Identifying the optimal treatment based on specific characteristics of each patient is the main promise of precision medicine. In the field of epilepsy, the identification of more than 100 causative genes provides the enticing possibility of treatments targeted to specific disease etiologies. These conditions include classical examples, such as the use of vitamin B6 in antiquitin deficiency or the ketogenic diet in GLUT1 deficiency, where the disease mechanism can be directly addressed by the selection of a specific therapeutic compound. For epilepsies caused by channelopathies there have been advances in understanding how the selection of existing medications can be targeted to the functional consequences of genetic alterations. We discuss the examples of the use of sodium channel blockers such as phenytoin and oxcarbazepine in the sodium channelopathies, quinidine in KCNT1-related epilepsies, and strategies in GRIN-related epilepsies as examples of epilepsy precision medicine. Assessing the clinical response to targeted treatments of these conditions has been complicated by genetic and phenotypic heterogeneity, as well as by various neurological and non-neurological comorbidities. Moving forward, the development of standardized outcome measures will be critical to successful precision medicine trials in complex and heterogeneous disorders like the epilepsies. Finally, we address new frontiers in epilepsy precision medicine, including the need to match the growing volume of genetic data with high-throughput functional assays to assess the functional consequences of genetic variants and the ability to extract clinical data at large scale from electronic medical records and apply quantitative methods based on standardized phenotyping language.
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Affiliation(s)
- Ingo Helbig
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA; The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, USA; Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA; Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, 19104, USA.
| | - Colin A Ellis
- The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, USA; Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA; Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, 19104, USA
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242
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Reynolds C, King MD, Gorman KM. The phenotypic spectrum of SCN2A-related epilepsy. Eur J Paediatr Neurol 2020; 24:117-122. [PMID: 31924505 DOI: 10.1016/j.ejpn.2019.12.016] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 12/06/2019] [Indexed: 10/25/2022]
Abstract
Pathogenic variants in SCN2A are reported in a spectrum of neurodevelopmental disorders including developmental and epileptic encephalopathies, benign familial neonatal-infantile seizures, episodic ataxia, and autism spectrum disorder and intellectual disability with and without seizures. To date, more than 300 patients with SCN2A variants have been published, the majority presenting with epilepsy. Large cohort studies and variant-specific electrophysiology, have enabled the delineation of different SCN2A-epilepsy phenotypes, phenotype-genotype correlations, prediction of pharmacosensitivity to sodium channel blockers and long-term prognostication for clinicians and families. Herein, we summarise the core phenotypes of SCN2A-related epilepsy, genotype-phenotype correlations, response to medication and future research.
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Affiliation(s)
- Claire Reynolds
- Department of Neurology and Clinical Neurophysiology, Children's Health Ireland at Temple Street, Dublin 1, Ireland
| | - Mary D King
- Department of Neurology and Clinical Neurophysiology, Children's Health Ireland at Temple Street, Dublin 1, Ireland; School of Medicine and Medical Sciences, University College Dublin, Dublin 4, Ireland
| | - Kathleen M Gorman
- Department of Neurology and Clinical Neurophysiology, Children's Health Ireland at Temple Street, Dublin 1, Ireland; School of Medicine and Medical Sciences, University College Dublin, Dublin 4, Ireland.
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243
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Scheffer IE, Liao J. Deciphering the concepts behind "Epileptic encephalopathy" and "Developmental and epileptic encephalopathy". Eur J Paediatr Neurol 2020; 24:11-14. [PMID: 31926847 DOI: 10.1016/j.ejpn.2019.12.023] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 12/23/2019] [Indexed: 02/08/2023]
Abstract
The recent introduction of the term 'developmental and epileptic encephalopathy' by the International League Against Epilepsy has added another conceptual layer to understanding the most severe group of epilepsies. An epileptic encephalopathy is defined by the presence of frequent epileptiform activity that impacts adversely on development, typically causing slowing or regression of developmental skills, and usually associated with frequent seizures. Many of the epileptic encephalopathies are now known to have an identifiable molecular genetic basis. The term 'developmental' was introduced as there are multiple facets leading to developmental impairment in affected individuals. The underlying genetic cause often results in developmental delay in its own right, with the epileptic encephalopathy further adversely affecting development. Treatment of the epileptic encephalopathy may improve developmental progress, so early recognition and active management are essential to improve developmental outcomes. Equally, understanding that the genetic aetiology independently leads to developmental impairment means that precision therapies need to be holistic in addressing the devastating consequences of this group of diseases.
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Affiliation(s)
- Ingrid E Scheffer
- Department of Medicine and Paediatrics, The University of Melbourne, Austin Health and Royal Children's Hospital, Florey Institute and Murdoch Children's Research Institute, Melbourne, Australia.
| | - Jianxiang Liao
- Epilepsy Center, Shenzhen Children's Hospital, Shenzhen, Guangdong Province, China
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244
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Du J, Simmons S, Brunklaus A, Adiconis X, Hession CC, Fu Z, Li Y, Shema R, Møller RS, Barak B, Feng G, Meisler M, Sanders S, Lerche H, Campbell AJ, McCarroll S, Levin JZ, Lal D. Differential excitatory vs inhibitory SCN expression at single cell level regulates brain sodium channel function in neurodevelopmental disorders. Eur J Paediatr Neurol 2020; 24:129-133. [PMID: 31928904 DOI: 10.1016/j.ejpn.2019.12.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 12/18/2019] [Indexed: 10/25/2022]
Abstract
The four voltage-gated sodium channels SCN1/2/3/8A have been associated with heterogeneous types of developmental disorders, each presenting with disease specific temporal and cell type specific gene expression. Using single-cell RNA sequencing transcriptomic data from humans and mice, we observe that SCN1A is predominantly expressed in inhibitory neurons. In contrast, SCN2/3/8A are profoundly expressed in excitatory neurons with SCN2/3A starting prenatally, followed by SCN1/8A neonatally. In contrast to previous observations from low resolution RNA screens, we observe that all four genes are expressed in both excitatory and inhibitory neurons, however, exhibit differential expression strength. These findings provide molecular evidence, at single-cell resolution, to support the hypothesis that the excitatory/inhibitory (E/I) neuronal expression ratios of sodium channels are important regulatory mechanisms underlying brain homeostasis and neurological diseases. Modulating the E/I expression balance within cell types of sodium channels could serve as a potential strategy to develop targeted treatment for NaV-associated neuronal developmental disorders.
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Affiliation(s)
- Juanjiangmeng Du
- Cologne Center for Genomics, University of Cologne, University Hospital Cologne, Cologne, Germany
| | - Sean Simmons
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Analytic and Translational Genetics Unit, Massachusetts General Hospital, Cambridge, MA, USA
| | - Andreas Brunklaus
- The Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, UK; School of Medicine, University of Glasgow, Glasgow, UK.
| | - Xian Adiconis
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Cynthia C Hession
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Zhanyan Fu
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Yinqing Li
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Reut Shema
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center, Dianalund, Denmark; Institute for Regional Health Services, University of Southern Denmark, Odense, Denmark
| | - Boaz Barak
- McGovern Institute for Brain Research and Department of Brain & Cognitive Sciences, MIT, Cambridge, MA, USA
| | - Guoping Feng
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA; McGovern Institute for Brain Research and Department of Brain & Cognitive Sciences, MIT, Cambridge, MA, USA
| | - Miriam Meisler
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA; Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Stephan Sanders
- Department of Psychiatry, UCSF Weill Institute for Neurosciences, University of California, San Francisco, CA, USA
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Arthur J Campbell
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Steven McCarroll
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Joshua Z Levin
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Dennis Lal
- Cologne Center for Genomics, University of Cologne, University Hospital Cologne, Cologne, Germany; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA; Analytic and Translational Genetics Unit, Massachusetts General Hospital, Cambridge, MA, USA; Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA; Genomic Medicine Institute, Lerner Research Institute Cleveland Clinic, Cleveland, OH, USA.
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245
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Antiepileptic therapy approaches in KCNQ2 related epilepsy: A systematic review. Eur J Med Genet 2020; 63:103628. [DOI: 10.1016/j.ejmg.2019.02.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 02/04/2019] [Accepted: 02/10/2019] [Indexed: 12/12/2022]
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246
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Hoelz H, Herdl C, Gerstl L, Tacke M, Vill K, von Stuelpnagel C, Rost I, Hoertnagel K, Abicht A, Hollizeck S, Larsen LHG, Borggraefe I. Impact on Clinical Decision Making of Next-Generation Sequencing in Pediatric Epilepsy in a Tertiary Epilepsy Referral Center. Clin EEG Neurosci 2020; 51:61-69. [PMID: 31554424 DOI: 10.1177/1550059419876518] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Background. Next-generation sequencing (NGS) describes new powerful techniques of nucleic acid analysis, which allow not only disease gene identification diagnostics but also applications for transcriptome/methylation analysis and meta-genomics. NGS helps identify many monogenic epilepsy syndromes. Pediatric epilepsy patients can be tested using NGS epilepsy panels to diagnose them, thereby influencing treatment choices. The primary objective of this study was to evaluate the impact of genetic testing on clinical decision making in pediatric epilepsy patients. Methods. We completed a single-center retrospective cohort study of 91 patients (43 male) aged 19 years or less undergoing NGS with epilepsy panels differing in size ranging from 5 to 434 genes from October 2013 to September 2017. Results. During a mean time of 3.6 years between symptom onset and genetic testing, subjects most frequently showed epileptic encephalopathy (40%), focal epilepsy (33%), and generalized epilepsy (18%). In 16 patients (18% of the study population), "pathogenic" or "likely pathogenic" results according to ACMG criteria were found. Ten of the 16 patients (63%) experienced changes in clinical management regarding their medication and avoidance of further diagnostic evaluation, that is, presurgical evaluation. Conclusion. NGS epilepsy panels contribute to the diagnosis of pediatric epilepsy patients and may change their clinical management with regard to both preventing unnecessary and potentially harmful diagnostic procedures and management. Thus, the present data support the early implementation in order to adopt clinical management in selected cases and prevent further invasive investigations. Given the relatively small sample size and heterogeneous panels a larger prospective study with more homogeneous panels would be helpful to further determine the impact of NGS on clinical decision making.
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Affiliation(s)
- Hannes Hoelz
- Department of Pediatric Neurology, Developmental Medicine and Social Pediatrics, Dr von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
| | - Christian Herdl
- Department of Pediatric Neurology, Developmental Medicine and Social Pediatrics, Dr von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
| | - Lucia Gerstl
- Department of Pediatric Neurology, Developmental Medicine and Social Pediatrics, Dr von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
| | - Moritz Tacke
- Department of Pediatric Neurology, Developmental Medicine and Social Pediatrics, Dr von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
| | - Katharina Vill
- Department of Pediatric Neurology, Developmental Medicine and Social Pediatrics, Dr von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
| | - Celina von Stuelpnagel
- Department of Pediatric Neurology, Developmental Medicine and Social Pediatrics, Dr von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany.,Paracelsus Medical University, Salzburg, Austria
| | - Imma Rost
- Zentrum für Humangenetik und Laboratoriumsdiagnostik Dr. Klein Dr. Rost und Kollegen, Martinsried, Germany
| | | | - Angela Abicht
- Friedrich-Baur-Institute, Department of Neurology, Ludwig-Maximilians-University, Munich, Germany.,Medical Genetics Center-MGZ, Munich, Germany
| | - Sebastian Hollizeck
- Department of Pediatrics, Dr. von Hauner Children's Hospital, Department of Pediatrics, Ludwig-Maximilians-University, Munich, Germany
| | | | - Ingo Borggraefe
- Department of Pediatric Neurology, Developmental Medicine and Social Pediatrics, Dr von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany.,Epilepsy Center (Pediatric Section), Ludwig-Maximilians-University, Munich, Germany
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247
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Recent advances in treatment of epilepsy-related sodium channelopathies. Eur J Paediatr Neurol 2020; 24:123-128. [PMID: 31889633 DOI: 10.1016/j.ejpn.2019.12.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 12/06/2019] [Indexed: 11/22/2022]
Abstract
Voltage-gated sodium channels (VGSCs) play a crucial role in generation of action potentials. Pathogenic variants in the five human brain expressed VGSC genes, SCN1A, SCN2A, SCN3A, SCN8A and SCN1B have been associated with a spectrum of epilepsy phenotypes and neurodevelopmental disorders. In the last decade, next generation sequencing techniques have revolutionized the way we diagnose these channelopathies, which is paving the way towards precision medicine. Knowing the functional effect (Loss-of-function versus Gain-of-function) of a variant is not only important for understanding the underlying pathophysiology, but it is particularly crucial to orient therapeutic decisions. Here we provide a review of the literature dealing with treatment options in epilepsy-related sodium channelopathies, including the current and emerging medications.
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248
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Bartolini E, Campostrini R, Kiferle L, Pradella S, Rosati E, Chinthapalli K, Palumbo P. Epilepsy and brain channelopathies from infancy to adulthood. Neurol Sci 2019; 41:749-761. [PMID: 31838630 DOI: 10.1007/s10072-019-04190-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 12/06/2019] [Indexed: 01/04/2023]
Abstract
Genetic brain channelopathies result from inherited or de novo mutations of genes encoding ion channel subunits within the central nervous system. Most neurological channelopathies arise in childhood with paroxysmal or episodic symptoms, likely because of a transient impairment of homeostatic mechanisms regulating membrane excitability, and the prototypical expression of this impairment is epilepsy. Migraine, episodic ataxia and alternating hemiplegia can also occur, as well as chronic phenotypes, such as spinocerebellar ataxias, intellectual disability and autism spectrum disorder. Voltage-gated and ligand-gated channels may be involved. In most cases, a single gene may be associated with a phenotypical spectrum that shows variable expressivity. Different clinical features may arise at different ages and the adult phenotype may be remarkably modified from the syndrome onset in childhood or adolescence. Recognizing the prominent phenotypical traits of brain channelopathies is essential to perform appropriate diagnostic investigations and to provide the better care not only in the paediatric setting but also for adult patients and their caregivers. Herein, we provide an overview of genetic brain channelopathies associated with epilepsy, highlight the different molecular mechanisms and describe the different clinical characteristics which may prompt the clinician to suspect specific syndromes and to possibly establish tailored treatments.
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Affiliation(s)
- Emanuele Bartolini
- USL Centro Toscana, Neurology Unit, Nuovo Ospedale Santo Stefano, Via Suor Niccolina Infermiera 20, 59100, Prato, Italy.
| | - Roberto Campostrini
- USL Centro Toscana, Neurology Unit, Nuovo Ospedale Santo Stefano, Via Suor Niccolina Infermiera 20, 59100, Prato, Italy
| | - Lorenzo Kiferle
- USL Centro Toscana, Neurology Unit, Nuovo Ospedale Santo Stefano, Via Suor Niccolina Infermiera 20, 59100, Prato, Italy
| | - Silvia Pradella
- USL Centro Toscana, Neurology Unit, Nuovo Ospedale Santo Stefano, Via Suor Niccolina Infermiera 20, 59100, Prato, Italy
| | - Eleonora Rosati
- USL Centro Toscana, Neurology Unit, Nuovo Ospedale Santo Stefano, Via Suor Niccolina Infermiera 20, 59100, Prato, Italy
| | | | - Pasquale Palumbo
- USL Centro Toscana, Neurology Unit, Nuovo Ospedale Santo Stefano, Via Suor Niccolina Infermiera 20, 59100, Prato, Italy
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249
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Customized multigene panels in epilepsy: the best things come in small packages. Neurogenetics 2019; 21:1-18. [PMID: 31834528 DOI: 10.1007/s10048-019-00598-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 11/12/2019] [Indexed: 12/13/2022]
Abstract
Over the past 10 years, the increasingly important role played by next-generation sequencing panels in the genetic diagnosis of epilepsy has led to a growing list of gene variants and a plethora of new scientific data. To date, however, there is still no consensus on what constitutes the "ideal panel design," or on the most rational criteria for selecting the best candidates for gene-panel analysis, even though both might optimize the cost-benefit ratio and the diagnostic efficiency of customized gene panels. Even though more and more laboratories are adopting whole-exome sequencing as a first-tier diagnostic approach, interpreting, "in silico," a set of epilepsy-related genes remains difficult. In the light of these considerations, we performed a systematic review of the targeted gene panels for epilepsy already reported in the available scientific literature, with a view to identifying the best criteria for selecting patients for gene-panel analysis, and the best way to design an "ideal," gold-standard panel that includes all genes with an established role in epilepsy pathogenesis, as well as those that might help to guide decisions regarding specific medical interventions and treatments. Our analyses suggest that the usefulness and diagnostic power of customized gene panels for epilepsy may be greatest when these panels are confined to rationally selected, relatively small, pools of genes, and applied in more carefully selected epilepsy patients (those with complex forms of epilepsy). A panel containing 64 genes, which includes the 45 genes harboring a significant number of pathogenic variants identified in previous literature, the 32 clinically actionable genes, and the 21 ILAE (International League Against Epilepsy) recommended genes, may represent an "ideal" core set likely able to provide the highest diagnostic efficiency and cost-effectiveness and facilitate gene prioritization when testing patients with whole-exome/whole-genome sequencing.
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250
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Gardella E, Møller RS. Phenotypic and genetic spectrum of
SCN
8A
‐related disorders, treatment options, and outcomes. Epilepsia 2019; 60 Suppl 3:S77-S85. [DOI: 10.1111/epi.16319] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 07/29/2019] [Indexed: 02/06/2023]
Affiliation(s)
- Elena Gardella
- Danish Epilepsy Center Dianalund Denmark
- Institute for Regional Health Services University of Southern Denmark Odense Denmark
| | - Rikke S. Møller
- Danish Epilepsy Center Dianalund Denmark
- Institute for Regional Health Services University of Southern Denmark Odense Denmark
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