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Li B, Zhu X, Zhao D, Li Y, Yang Y, Li J, Bi C, Zhang X. igRNA Prediction and Selection AI Models (igRNA-PS) for Bystander-less ABE Base Editing. J Mol Biol 2024; 436:168714. [PMID: 39029887 DOI: 10.1016/j.jmb.2024.168714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 06/28/2024] [Accepted: 07/13/2024] [Indexed: 07/21/2024]
Abstract
CRISPR derived base editing techniques tend to edit multiple bases in the targeted region, which impedes precise reversion of disease-associated single nucleotide variations (SNVs). We designed an imperfect gRNA (igRNA) editing strategy to achieve bystander-less single-base editing. To predict the performance and provide ready-to-use igRNAs, we employed a high-throughput method to edit 5000 loci, each with approximate 19 systematically designed ABE igRNAs. Through deep learning of the relationship of editing efficiency, original gRNA sequence and igRNA sequence, AI models were constructed and tested, designated igRNA Prediction and Selection AI models (igRNA-PS). The models have three functions, First, they can identify the major editing site from the bystanders on a gRNA protospacer with a near 90% accuracy. second, a modified single-base editing efficiency (SBE), considering both single-base editing efficiency and product purity, can be predicted for any given igRNAs. Third, for an editing locus, a set of 64 igRNAs derived from a gRNA can be generated, evaluated through igRNA-PS to select for the best performer, and provided to the user. In this work, we overcome one of the most significant obstacles of base editors, and provide a convenient and efficient approach for single-base bystander-less ABE base editing.
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Affiliation(s)
- Bo Li
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300000, China; National Center of Technology Innovation for Synthetic Biology, Tianjin 300000, China
| | - Xiagu Zhu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300000, China; National Center of Technology Innovation for Synthetic Biology, Tianjin 300000, China; College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300222, China
| | - Dongdong Zhao
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300000, China; National Center of Technology Innovation for Synthetic Biology, Tianjin 300000, China
| | - Yaqiu Li
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300000, China; National Center of Technology Innovation for Synthetic Biology, Tianjin 300000, China
| | - Yuanzhao Yang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300000, China; National Center of Technology Innovation for Synthetic Biology, Tianjin 300000, China; College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300222, China
| | - Ju Li
- College of Life Science, Tianjin Normal University, Tianjin, China
| | - Changhao Bi
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300000, China; National Center of Technology Innovation for Synthetic Biology, Tianjin 300000, China.
| | - Xueli Zhang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300000, China; National Center of Technology Innovation for Synthetic Biology, Tianjin 300000, China.
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Badura-Stronka M, Wołyńska K, Winczewska-Wiktor A, Marcinkowska J, Karolewska D, Tomkowiak-Kędzia D, Piechota M, Przyborska M, Kochalska N, Steinborn B. Validation of targeted next-generation sequencing panels in a cohort of Polish patients with epilepsy: assessing variable performance across clinical endophenotypes and uncovering novel genetic variants. Front Neurol 2024; 14:1316933. [PMID: 38328757 PMCID: PMC10849089 DOI: 10.3389/fneur.2023.1316933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 12/26/2023] [Indexed: 02/09/2024] Open
Abstract
Introduction Targeted Next-Generation Sequencing Panels (TNGSP) have become a standard in global clinical practice. Instead of questioning the necessity of next-generation sequencing in epilepsy patients, contemporary large-scale research focuses on factors such as the size of TNGSP, the comparative advantages of exome or genome-wide sequencing over TNGSP, and the impact of clinical, electrophysiological, and demographic variables on genetic test performance. This study aims to elucidate the demographic and clinical factors influencing the performance of TNGSP in 138 Polish patients with epilepsy, recognizing the pivotal role of genetic testing in guiding patient management and therapy. Methods A retrospective analysis was conducted on patients from a genetic clinic in Poznań, Poland, who underwent commercial gene panel studies at Invitae Corporation (USA) between 2020 and 2022. Patient groups were defined based on the age of onset of the first epileptic seizures, seizure type, gender, fever dependence of seizures, presence of intellectual disability or developmental delay, abnormalities in MRI, and the presence of dysmorphic features or congenital malformations. Seizure classification followed the 2017 ILAE criteria. Results Among the 138 patients, 30 (21.7%) exhibited a pathogenic or likely pathogenic variant, with a distribution of 20.7% in males and 22.5% in females. Diagnostic performance correlated with the patient's age at the onset of the first seizure and the type of seizure. Predominant variants were identified in the SCN1A, PRRT2, CDKL5, DEPDC5, TSC2, and SLC2A1 genes. Additionally, 12 genes (CACNA1A, SCN2A, GRIN2A, KCNQ2, CHD2, DYNC1H1, NEXMIF, SCN1B, DDX3X, EEF1A2, NPRL3, UBE3A) exhibited single instances of damage. Notably, novel variants were discovered in DEPDC5, SCN1A, TSC2, CDKL5, NPRL3, DYNC1H1, CHD2, and DDX3X. Discussion Identified variants were present in genes previously recognized in both European and non-European populations. A thorough examination of Variants of Uncertain Significance (VUSs), specifically focusing on gene copy number changes, may unveil more extensive chromosomal aberrations. The relatively frequent occurrence of pathological variants in X chromosome-linked genes in girls warrants further investigation, challenging the prevailing notion of male predominance in X-linked epilepsy.
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Affiliation(s)
- Magdalena Badura-Stronka
- Chair and Department of Medical Genetics, Poznan University of Medical Sciences, Poznań, Poland
- Centers for Medical Genetics GENESIS, Poznań, Poland
| | - Katarzyna Wołyńska
- Chair and Department of Medical Genetics, Poznan University of Medical Sciences, Poznań, Poland
| | - Anna Winczewska-Wiktor
- Chair and Department of Developmental Neurology, Poznan University of Medical Sciences, Poznań, Poland
| | - Justyna Marcinkowska
- Chair and Department of Informatics and Statistics, Poznan University of Medical Sciences, Poznań, Poland
| | | | | | | | | | | | - Barbara Steinborn
- Chair and Department of Developmental Neurology, Poznan University of Medical Sciences, Poznań, Poland
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Doorn N. Unraveling Dravet Syndrome: Exploring the complex effects of sodium channel mutations on neuronal networks. Sci Prog 2024; 107:368504231225076. [PMID: 38373395 PMCID: PMC10878221 DOI: 10.1177/00368504231225076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024]
Abstract
Dravet Syndrome (DS) is a severe developmental epileptic encephalopathy with frequent intractable seizures accompanied by cognitive impairment, often caused by pathogenic variants in SCN1A encoding sodium channel NaV1.1. Recent research utilizing in vitro patient-derived neuronal networks and accompanying in silico models uncovered that not just sodium-but also potassium-and synaptic currents were impaired in DS networks. Here, we explore the implications of these findings for three questions that remain elusive in DS: How do sodium channel impairments result in epilepsy? How can identical variants lead to varying phenotypes? What mechanisms underlie the developmental delay in DS patients? We speculate that impaired potassium currents might be a secondary effect to NaV1.1 mutations and could result in hyperexcitable neurons and epileptic networks. Moreover, we reason that homeostatic plasticity is actively engaged in DS networks, possibly affecting the phenotype and impairing learning and development when driven to extremes.
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Affiliation(s)
- Nina Doorn
- Department of Clinical Neurophysiology, University of Twente, Enschede, The Netherlands
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Borowicz-Reutt K, Czernia J, Krawczyk M. Genetic Background of Epilepsy and Antiepileptic Treatments. Int J Mol Sci 2023; 24:16280. [PMID: 38003469 PMCID: PMC10671416 DOI: 10.3390/ijms242216280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 11/01/2023] [Accepted: 11/08/2023] [Indexed: 11/26/2023] Open
Abstract
Advanced identification of the gene mutations causing epilepsy syndromes is expected to translate into faster diagnosis and more effective treatment of these conditions. Over the last 5 years, approximately 40 clinical trials on the treatment of genetic epilepsies have been conducted. As a result, some medications that are not regular antiseizure drugs (e.g., soticlestat, fenfluramine, or ganaxolone) have been introduced to the treatment of drug-resistant seizures in Dravet, Lennox-Gastaut, maternally inherited chromosome 15q11.2-q13.1 duplication (Dup 15q) syndromes, and protocadherin 19 (PCDH 19)-clusterig epilepsy. And although the effects of soticlestat, fenfluramine, and ganaxolone are described as promising, they do not significantly affect the course of the mentioned epilepsy syndromes. Importantly, each of these syndromes is related to mutations in several genes. On the other hand, several mutations can occur within one gene, and different gene variants may be manifested in different disease phenotypes. This complex pattern of inheritance contributes to rather poor genotype-phenotype correlations. Hence, the detection of a specific mutation is not synonymous with a precise diagnosis of a specific syndrome. Bearing in mind that seizures develop as a consequence of the predominance of excitatory over inhibitory processes, it seems reasonable that mutations in genes encoding sodium and potassium channels, as well as glutamatergic and gamma-aminobutyric (GABA) receptors, play a role in the pathogenesis of epilepsy. In some cases, different pathogenic variants of the same gene can result in opposite functional effects, determining the effectiveness of therapy with certain medications. For instance, seizures related to gain-of-function (GoF) mutations in genes encoding sodium channels can be successfully treated with sodium channel blockers. On the contrary, the same drugs may aggravate seizures related to loss-of-function (LoF) variants of the same genes. Hence, knowledge of gene mutation-treatment response relationships facilitates more favorable selection of drugs for anticonvulsant therapy.
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Affiliation(s)
- Kinga Borowicz-Reutt
- Independent Unit of Experimental Neuropathophysiology, Department of Toxicology, Medical University of Lublin, Jaczewskiego 8b, 20-090 Lublin, Poland; (J.C.); (M.K.)
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Wen F, Tan Z, Huang D, Jiang Y, Xiang J. LncRNA PVT1 Promotes Neuronal Cell Apoptosis and Neuroinflammation by Regulating miR-488-3p/FOXD3/SCN2A Axis in Epilepsy. Neurochem Res 2023; 48:895-908. [PMID: 36378391 DOI: 10.1007/s11064-022-03801-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 09/08/2022] [Accepted: 10/18/2022] [Indexed: 11/16/2022]
Abstract
It is vital to understand the mechanism of epilepsy onset and development. Dysregulated lncRNAs are closely associated with epilepsy. Our work probed the role of lncRNA PVT1/miR-488-3p/FOXD3/SCN2A axis in epilepsy. The mRNA and protein expressions were assessed using qRT-PCR and western blot. MTT assay and TUNEL staining were conducted to assess cell viability and apoptosis, respectively. TNFα, IL-1β and IL-6 levels were analyzed using ELISA. LDH level was tested by Assay Kit. The binding relationship between PVT1, miR-488-3p and FOXD3 were verified using dual luciferase reporter gene assay. The epilepsy model of rats was established by lithium-pilocarpine injection. Nissl staining was performed to evaluate neuronal damage. PVT1 was markedly upregulated in epilepsy model cells. Knockdown of PVT1 increased the viability, while repressed the apoptosis and inflammatory cytokines secretion as well as LDH level in epilepsy cell model. MiR-488-3p alleviated neuronal injury and neuroinflammation in model cells. MiR-488-3p functioned as the direct target of PVT1, and its inhibition neutralized the effects of PVT1 silencing on neuronal cell injury and neuroinflammation in model cells. Furthermore, miR-488-3p inhibited neuronal cell injury and neuroinflammation in model cells by regulating FOXD3/SCN2A pathway. Finally, animal experiments proved that PVT1 promoted epilepsy-induced neuronal cell injury and neuroinflammation by regulating miR-488-3p-mediated FOXD3/SCN2A pathway. PVT1 promoted neuronal cell injury and inflammatory response in epilepsy via inhibiting miR-488-3p and further regulating FOXD3/SCN2A pathway.
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Affiliation(s)
- Fang Wen
- Department of Neurology, The Second Xiangya Hospital of Central South University, Changsha, 410011, Hunan, People's Republic of China
| | - Zhigang Tan
- Department of Neurosurgery, The Second Xiangya Hospital of Central South University, No. 139, Renmin Road, Changsha, 410011, Hunan, People's Republic of China
| | - Dezhi Huang
- Department of Neurosurgery, The Second Xiangya Hospital of Central South University, No. 139, Renmin Road, Changsha, 410011, Hunan, People's Republic of China
| | - Yugang Jiang
- Department of Neurosurgery, The Second Xiangya Hospital of Central South University, No. 139, Renmin Road, Changsha, 410011, Hunan, People's Republic of China
| | - Jun Xiang
- Department of Neurosurgery, The Second Xiangya Hospital of Central South University, No. 139, Renmin Road, Changsha, 410011, Hunan, People's Republic of China.
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Türkyılmaz A, Tekin E, Yaralı O, Çebi AH. Genetic Landscape of SCN1A Variants in a Turkish Cohort with GEFS+ Spectrum and Dravet Syndrome. Mol Syndromol 2022; 13:270-281. [PMID: 36158059 PMCID: PMC9421706 DOI: 10.1159/000521330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 12/03/2021] [Indexed: 01/03/2023] Open
Abstract
Introduction The α subunit of voltage-gated sodium channels in mammals is encoded by 9 different genes, and variations in the SCN1A, SCN2A, SCN3A, and SCN8A genes highly expressed in the CNS have been associated with epilepsy phenotypes. This study aimed at investigating the frequency of SCN1A gene variations in Dravet syndrome (DS) and GEFS+ spectrum phenotype cases and discussing the molecular results in the context of genotype-phenotype correlation. Methods Fifteen patients diagnosed with DS and 54 patients meeting the GEFS+ spectrum criteria were included in this study. All patients were evaluated by next-generation sequencing and multiplex ligation-dependent probe amplification using an SCN1A gene commercial kit. Results A total of 17 different variants were detected in 18 index cases (26%), of which 7 were novel variations (p.M1R, p.M147T, p.I767L, p.N1391Ifs*5, p.R1886G, p.E1915G, p.R1933Q). Of the 18 cases with variation in the SCN1A gene, 12 had DS and 6 had GEFS+ phenotype. The variations were de novo in all DS cases and in 1 case with a GEFS+ phenotype; in 5 GEFS+ cases, the variant was inherited from the affected parent. Discussion This study contributes to the variation spectrum in cases with DS and GEFS+ phenotype with the novel variants detected. SCN1A genetic analysis can help in determining whether antiseizure medication should be selected or avoided in cases with variations. The elucidation of the molecular etiology makes it possible to provide the family with effective genetic counseling for future pregnancies.
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Affiliation(s)
- Ayberk Türkyılmaz
- Department of Medical Genetics, Faculty of Medicine, Karadeniz Technical University, Trabzon, Turkey,*Ayberk Türkyılmaz,
| | - Emine Tekin
- Department of Pediatric Neurology, Faculty of Medicine, Giresun University, Giresun, Turkey
| | - Oğuzhan Yaralı
- Clinic of Medical Genetics, Erzurum Training and Research Hospital, Erzurum, Turkey
| | - Alper Han Çebi
- Department of Medical Genetics, Faculty of Medicine, Karadeniz Technical University, Trabzon, Turkey
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7
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Genetics and gene therapy in Dravet syndrome. Epilepsy Behav 2022; 131:108043. [PMID: 34053869 DOI: 10.1016/j.yebeh.2021.108043] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 05/02/2021] [Accepted: 05/02/2021] [Indexed: 12/17/2022]
Abstract
Dravet syndrome is a well-established electro-clinical condition first described in 1978. A main genetic cause was identified with the discovery of a loss-of-function SCN1A variant in 2001. Mechanisms underlying the phenotypic variations have subsequently been a main topic of research. Various genetic modifiers of clinical severities have been elucidated through many rigorous studies on genotype-phenotype correlations and the recent advances in next generation sequencing technology. Furthermore, a deeper understanding of the regulation of gene expression and remarkable progress on genome-editing technology using the CRISPR-Cas9 system provide significant opportunities to overcome hurdles of gene therapy, such as enhancing NaV1.1 expression. This article reviews the current understanding of genetic pathology and the status of research toward the development of gene therapy for Dravet syndrome. This article is part of the Special Issue "Severe Infantile Epilepsies".
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Shao E, Chang CW, Li Z, Yu X, Ho K, Zhang M, Wang X, Simms J, Lo I, Speckart J, Holtzman J, Yu GQ, Roberson ED, Mucke L. TAU ablation in excitatory neurons and postnatal TAU knockdown reduce epilepsy, SUDEP, and autism behaviors in a Dravet syndrome model. Sci Transl Med 2022; 14:eabm5527. [PMID: 35476595 DOI: 10.1126/scitranslmed.abm5527] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Intracellular accumulation of TAU aggregates is a hallmark of several neurodegenerative diseases. However, global genetic reduction of TAU is beneficial also in models of other brain disorders that lack such TAU pathology, suggesting a pathogenic role of nonaggregated TAU. Here, conditional ablation of TAU in excitatory, but not inhibitory, neurons reduced epilepsy, sudden unexpected death in epilepsy, overactivation of the phosphoinositide 3-kinase-AKT-mammalian target of rapamycin pathway, brain overgrowth (megalencephaly), and autism-like behaviors in a mouse model of Dravet syndrome, a severe epileptic encephalopathy of early childhood. Furthermore, treatment with a TAU-lowering antisense oligonucleotide, initiated on postnatal day 10, had similar therapeutic effects in this mouse model. Our findings suggest that excitatory neurons are the critical cell type in which TAU has to be reduced to counteract brain dysfunctions associated with Dravet syndrome and that overall cerebral TAU reduction could have similar benefits, even when initiated postnatally.
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Affiliation(s)
- Eric Shao
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Che-Wei Chang
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Zhiyong Li
- Alzheimer's Disease Center, Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Xinxing Yu
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Kaitlyn Ho
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Michelle Zhang
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Xin Wang
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Jeffrey Simms
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Iris Lo
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Jessica Speckart
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Julia Holtzman
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Gui-Qiu Yu
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Erik D Roberson
- Alzheimer's Disease Center, Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Lennart Mucke
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA.,Department of Neurology and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA
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Wang JY, Tang B, Sheng WX, Hua LD, Zeng Y, Fan CX, Deng WY, Gao MM, Zhu WW, He N, Su T. Clinical and Functional Features of Epilepsy-Associated In-Frame Deletion Variants in SCN1A. Front Mol Neurosci 2022; 15:828846. [PMID: 35359575 PMCID: PMC8964123 DOI: 10.3389/fnmol.2022.828846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Accepted: 02/21/2022] [Indexed: 11/13/2022] Open
Abstract
Objective Naturally occurring in-frame deletion is a unique type of genetic variations, causing the loss of one or more amino acids of proteins. A number of in-frame deletion variants in an epilepsy-associated gene SCN1A, encoding voltage gated sodium channel alpha unit 1.1 (Nav1.1), have been reported in public database. In contrast to the missense and truncation variants, the in-frame deletions in SCN1A remains largely uncharacterized. Methods We summarized the basic information of forty-four SCN1A in-frame deletion variants and performed further analysis on six variants identified in our cases with epilepsy. Mutants of the six in-frame deletions and one truncating variant used as comparison were generated and co-transfected with beta-1 and -2 subunits in tsA201 cells, followed by patch clamp recordings. Results Reviewing all the in-frame deletions showed that they spread over the entire Nav1.1 protein, without obvious “hot spots.” The dominant type (54%) was single residue loss. There was no obvious relationship between the length or locations of deletions and their clinical phenotypes. The six in-frame deletions were two single residue deletions (p.M400del and p.I1772del), one microdeletion (p.S128_F130del) and three macrodeletions (p.T303_R322del, p.T160_Y202del, and p.V1335_V1428del). They scatter and affect different functional domains, including transmembrane helices, pore region, and P-loop. Electrophysiological recordings revealed no measurable sodium current in all of the six mutants. In contrast, the truncating mutant p.M1619Ifs*7 that loses a long stretch of peptides retains partial function. Significance The complete loss-of-function in these shortened, abnormal mutants indicates that Nav1.1 protein is a highly accurate structure, and many of the residues have no redundancy to ion conductance. In-frame deletions caused particularly deleterious effect on protein function possibly due to the disruption of ordered residues.
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Affiliation(s)
- Jing-Yang Wang
- Institute of Neuroscience, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Key Laboratory of Neurogenetics and Channelopathies, Ministry of Education of China, Guangzhou, China
- Department of Neurology, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Bin Tang
- Institute of Neuroscience, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Key Laboratory of Neurogenetics and Channelopathies, Ministry of Education of China, Guangzhou, China
| | - Wen-Xiang Sheng
- Institute of Neuroscience, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Key Laboratory of Neurogenetics and Channelopathies, Ministry of Education of China, Guangzhou, China
| | - Li-Dong Hua
- Translational Medicine Center, Maternal and Child Health Research Institute, Guangdong Women and Children’s Hospital, Guangzhou, China
| | - Yang Zeng
- Institute of Neuroscience, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Key Laboratory of Neurogenetics and Channelopathies, Ministry of Education of China, Guangzhou, China
| | - Cui-Xia Fan
- Institute of Neuroscience, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Key Laboratory of Neurogenetics and Channelopathies, Ministry of Education of China, Guangzhou, China
| | - Wei-Yi Deng
- Institute of Neuroscience, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Key Laboratory of Neurogenetics and Channelopathies, Ministry of Education of China, Guangzhou, China
| | - Mei-Mei Gao
- Institute of Neuroscience, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Key Laboratory of Neurogenetics and Channelopathies, Ministry of Education of China, Guangzhou, China
| | - Wei-Wen Zhu
- Department of Neurology, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Na He
- Department of Neurology, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Tao Su
- Institute of Neuroscience, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Key Laboratory of Neurogenetics and Channelopathies, Ministry of Education of China, Guangzhou, China
- *Correspondence: Tao Su,
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Naseer MI, Abdulkareem AA, Rasool M, Algahtani H, Muthaffar OY, Pushparaj PN. Whole-Exome Sequencing Identifies Novel SCN1A and CACNB4 Genes Mutations in the Cohort of Saudi Patients With Epilepsy. Front Pediatr 2022; 10:919996. [PMID: 35813387 PMCID: PMC9257097 DOI: 10.3389/fped.2022.919996] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 05/25/2022] [Indexed: 12/14/2022] Open
Abstract
Epilepsy is a neurological disorder described as recurrent seizures mild to severe convulsions along with conscious loss. There are many different genetic anomalies or non-genetic conditions that affect the brain and cause epilepsy. The exact cause of epilepsy is unknown so far. In this study, whole-exome sequencing showed a family having novel missense variant c.1603C>T, p. Arg535Cys in exon 10 of Sodium Voltage-Gated Channel Alpha Subunit 1 (SCN1A) gene. Moreover, targeted Sanger sequencing analysis showed c.1212A>G p.Val404Ile in SCN1A gene in 10 unrelated patients and a mutation in Calcium Voltage-Gated Channel Auxiliary Subunit Beta 4 gene where one base pair insertion of "G" c.78_79insG, p.Asp27Glyfs*26 in the exon 3 in three different patients were observed from the cohort of 25 epileptic sporadic cases. The insertion changes the amino acid sequence leading to a frameshift mutation. Here, we have described, for the first time, three novel mutations that may be associated with epilepsy in the Saudi population. The study not only help us to identify the exact cause of genetic variations causing epilepsy whereas but it would also eventually enable us to establish a database to provide a foundation for understanding the critical genomic regions to control epilepsy in Saudi patients.
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Affiliation(s)
- Muhammad Imran Naseer
- Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Angham Abdulrhman Abdulkareem
- Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Mahmood Rasool
- Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Hussein Algahtani
- King Abdulaziz Medical City, King Saud Bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia
| | - Osama Yousef Muthaffar
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Peter Natesan Pushparaj
- Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
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Application of Thermodynamics and Protein–Protein Interaction Network Topology for Discovery of Potential New Treatments for Temporal Lobe Epilepsy. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11178059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In this paper, we propose a bioinformatics-based method, which introduces thermodynamic measures and topological characteristics aimed to identify potential drug targets for pharmaco-resistant epileptic patients. We apply the Gibbs homology analysis to the protein–protein interaction network characteristic of temporal lobe epilepsy. With the identification of key proteins involved in the disease, particularly a number of ribosomal proteins, an assessment of their inhibitors is the next logical step. The results of our work offer a direction for future development of prospective therapeutic solutions for epilepsy patients, especially those who are not responding to the current standard of care.
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Gowda VK, Battina M, Vegda H, Srinivasan VM, Chikara SK, Mishra A, Shivappa SK, Benakappa N. Cohort of Phenotype, Genotype, and Outcome of SCN Developmental and Epileptic Encephalopathies from Southern Part of India. J Pediatr Genet 2021; 12:32-41. [PMID: 36684540 PMCID: PMC9848768 DOI: 10.1055/s-0041-1731020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 04/03/2021] [Indexed: 01/25/2023]
Abstract
The SCN encephalopathies are one of the rare early childhood intractable epileptic encephalopathies associated with pleomorphic seizures, cognitive decline, motor, and behavioral abnormalities that begin in early infancy. There is a dearth of data on phenotype and genotype of SCN encephalopathies from the Indian subcontinent, hence we are reporting clinical and molecular profile and outcome of SCN developmental and epileptic encephalopathies. This is a retrospective chart review of SCN developmental and epileptic encephalopathies in a tertiary care center, Bangalore, India between January 2015 and March 2020. All children with clinical features of SCN developmental and epileptic encephalopathies and confirmed with pathogenic variants were included. A total of 50 cases of SCN developmental and epileptic encephalopathies were analyzed, 31 of them were male and the mean age of presentation was 7.8 months. Precipitating factors for the first episode of seizure were fever and vaccination accounting for 33 and 8 children, respectively. Forty (80%) children had prolonged seizures and 15 (30%) had epileptic spasms. All children had a normal birth history and normal development before the onset of seizures, which was followed by developmental delay and regression. Thirty (60%) children had behavioral difficulties, notable hyperactivity, and autistic features. Neuroimaging and the initial electroencephalogram (EEG) were normal in all patients. The mean age of abnormal EEG was 14 months. The various subtypes of SCN variants were SCN1A in 31 children followed by SCN2A and SCN9A in eight children each and SCN1B in three children. Frameshift and nonsense mutations were associated with more severe phenotype and poor outcome compared with missense mutations. Thirty-four patients partially responded to treatment and the rest were refractory. The results of genetic testing were used to guide treatment; sodium channel blocking antiepileptic drugs were discontinued in 15 patients and sodium channel blocking agents were started in 3 patients with partial response. Three out of four children on stiripentol had a partial response. The SCN developmental and epileptic encephalopathies can present with epileptic spasms in addition to other types of seizures. Epileptic spasms are more common in nonsense and frameshift mutations. The outcome is poor in children with epileptic spasms compared with those without epileptic spasms. Genetic testing helps to select antiepileptic drugs that lead to seizure reduction.
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Affiliation(s)
- Vykuntaraju K. Gowda
- Department of Pediatric Neurology, Indira Gandhi Institute of Child Health, Bengaluru, Karnataka, India,Address for correspondence Vykuntaraju K. Gowda, DM Department of Pediatric Neurology, Indira Gandhi Institute of Child HealthNear NIMHANS, Bengaluru, Karnataka 560029India
| | - Manojna Battina
- Department of Pediatric Neurology, Indira Gandhi Institute of Child Health, Bengaluru, Karnataka, India
| | - Hemadri Vegda
- Department of Pediatric Neurology, Indira Gandhi Institute of Child Health, Bengaluru, Karnataka, India
| | - Varunvenkat M. Srinivasan
- Department of Pediatric Neurology, Indira Gandhi Institute of Child Health, Bengaluru, Karnataka, India
| | - Surendra K. Chikara
- Department of Molecular Genetics, Bione, Brigade IRV Center, Bangalore, Karnataka, India
| | - Adrija Mishra
- Department of Molecular Genetics, Bione, Brigade IRV Center, Bangalore, Karnataka, India
| | - Sanjay K. Shivappa
- Department of Pediatrics, Indira Gandhi Institute of Child Health, Bengaluru, Karnataka, India
| | - Naveen Benakappa
- Department of Pediatrics, Indira Gandhi Institute of Child Health, Bengaluru, Karnataka, India
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Sullo F, Pasquetti E, Patanè F, Lo Bianco M, Marino SD, Polizzi A, Falsaperla R, Ruggieri M, Zanghì A, Praticò AD. SCN1A and Its Related Epileptic Phenotypes. JOURNAL OF PEDIATRIC NEUROLOGY 2021. [DOI: 10.1055/s-0041-1727260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
AbstractEpilepsy is one of the most common neurological disorders, with a lifetime incidence of 1 in 26. Approximately two-thirds of epilepsy has a substantial genetic component in its etiology. As a result, simultaneous screening for mutations in multiple genes and performing whole exome sequencing (WES) are becoming very frequent in the clinical evaluation of children with epilepsy. In this setting, mutations in voltage-gated sodium channel (SCN) α-subunit genes are the most commonly identified cause of epilepsy, with sodium channel genes (i.e., SCN1A, SCN2A, SCN8A) being the most frequently identified causative genes. SCN1A mutations result in a wide spectrum of epilepsy phenotypes ranging from simple febrile seizures to Dravet syndrome, a severe epileptic encephalopathy. In case of mutation of SCN1A, it is also possible to observe behavioral alterations, such as impulsivity, inattentiveness, and distractibility, which can be framed in an attention deficit hyperactivity disorder (ADHD) like phenotype. Despite more than 1,200 SCN1A mutations being reported, it is not possible to assess a clear phenotype–genotype correlations. Treatment remains a challenge and seizure control is often partial and transitory.
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Affiliation(s)
- Federica Sullo
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Elisa Pasquetti
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Francesca Patanè
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Manuela Lo Bianco
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Simona D. Marino
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
| | - Agata Polizzi
- Chair of Pediatrics, Department of Educational Sciences, University of Catania, Catania, Italy
| | - Raffaele Falsaperla
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
- Unit of Neonatal Intensive Care and Neonatology, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
| | - Martino Ruggieri
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Antonio Zanghì
- Department of Medical and Surgical Sciences and Advanced Technology “G.F. Ingrassia,” University of Catania, Catania, Italy
| | - Andrea D. Praticò
- Unit of Rare Diseases of the Nervous System in Childhood, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
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14
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Hirose S, Tanaka Y, Shibata M, Kimura Y, Ishikawa M, Higurashi N, Yamamoto T, Ichise E, Chiyonobu T, Ishii A. Application of induced pluripotent stem cells in epilepsy. Mol Cell Neurosci 2020; 108:103535. [DOI: 10.1016/j.mcn.2020.103535] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 07/10/2020] [Accepted: 07/31/2020] [Indexed: 02/06/2023] Open
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15
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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: 61] [Impact Index Per Article: 15.3] [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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16
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Symonds JD, McTague A. Epilepsy and developmental disorders: Next generation sequencing in the clinic. Eur J Paediatr Neurol 2020; 24:15-23. [PMID: 31882278 DOI: 10.1016/j.ejpn.2019.12.008] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 12/06/2019] [Indexed: 01/07/2023]
Abstract
BACKGROUND The advent of Next Generation Sequencing (NGS) has led to a redefining of the genetic landscape of the epilepsies. Hundreds of single gene epilepsies have been described. Genes associated with epilepsy involve diverse processes. Now a substantial proportion of individuals with epilepsy can receive a high definition molecular genetic diagnosis. METHODS In this review we update the current genetic landscape of the epilepsies and categorise the major functional groupings of epilepsy-associated genes. We describe currently available genetic testing approaches. We perform a literature review of NGS studies and review the factors which determine yield in cohorts undergoing testing. We identify factors associated with positive genetic diagnosis and consider the utility of genetic testing in terms of treatment selection as well as more qualitative aspects of care. FINDINGS Epilepsy-associated genes can be grouped into five broad functional categories: ion transport; cell growth and differentiation; regulation of synaptic processes; transport and metabolism of small molecules within and between cells; and regulation of gene transcription and translation. Early onset of seizures, drug-resistance, and developmental comorbidity are associated with higher diagnostic yield. The most commonly implicated genes in NGS studies to date, in order, are SCN1A, KCNQ2, CDKL5, SCN2A, and STXBP1. In unselected infantile cohorts PRRT2, a gene associated with self-limited epilepsy, is frequently implicated. Genetic diagnosis provides utility in terms of treatment choice closing the diagnostic odyssey, avoiding unnecessary further testing, and informing future reproductive decisions. CONCLUSIONS Genetic testing has become a first line test in epilepsy. As techniques improve and understanding advances, its utility is set to increase. Genetic diagnosis, particularly in early onset developmental and epileptic encephalopathies, influences treatment choice in a significant proportion of patients. The realistic prospect of gene therapy is a cause for optimism.
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Affiliation(s)
- Joseph D Symonds
- Paediatric Neuroscience Research Group, Royal Hospital for Children, Glasgow, G51 4TF, UK; Medical Veterinary and Life Sciences, University of Glasgow, G12 8QQ, UK.
| | - Amy McTague
- Institute of Child Health, University Collge London, 30 Guilford St, Holborn, London WC1N 1EH, UK
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17
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Gertler TS, Calhoun J, Laux L. A single-center, retrospective analysis of genotype-phenotype correlations in children with Dravet syndrome. Seizure 2019; 75:1-6. [PMID: 31864146 DOI: 10.1016/j.seizure.2019.12.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 11/25/2019] [Accepted: 12/11/2019] [Indexed: 12/31/2022] Open
Abstract
PURPOSE Dravet syndrome is an early-onset epileptic encephalopathy caused most often by loss-of-function SCN1A variants. Following recognition of its genetic basis and unique clinical features, Dravet syndrome has become one of the most well-studied genetic epilepsies. We sought to evaluate the genetic diversity and correlative seizure phenotype, comorbidities, and response to antiepileptic therapies of patients with clinically-diagnosed Dravet syndrome seen in a tertiary care center. The goal of this study was to examine genotype-phenotype correlations and to ascertain if specific antiepileptic therapies may be more effective on the basis of genetic test result alone. METHOD Retrospective chart review of demographics, comorbidities, seizure types, and responses to antiepileptic therapies of all patients (n = 137) with a clinical diagnosis of Dravet syndrome seen at Lurie Children's Hospital of Chicago from 2008 to 2016. RESULTS Of the 96% of Dravet syndrome patients with pathogenic SCN1A variants subdivided by missense or truncating variant, there was no difference in clinical presentation. Response to antiepileptic therapies did not differ by genotype with regard to medication class. CONCLUSIONS This is the largest cohort of Dravet patients from within the US to report medication response with respect to genotype. Missense variants in SCN1A were most common in the voltage-sensor and pore domains. All patients were most likely to respond to the recommended medication triad compared to other antiepileptic therapies.
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Affiliation(s)
- Tracy S Gertler
- Division of Neurology, Department of Pediatrics, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, IL 60611, USA; Pharmacology Department, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
| | - Jeffrey Calhoun
- Neurology Department, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Linda Laux
- Division of Neurology, Department of Pediatrics, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, IL 60611, USA
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18
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Fernández-Marmiesse A, Roca I, Díaz-Flores F, Cantarín V, Pérez-Poyato MS, Fontalba A, Laranjeira F, Quintans S, Moldovan O, Felgueroso B, Rodríguez-Pedreira M, Simón R, Camacho A, Quijada P, Ibanez-Mico S, Domingno MR, Benito C, Calvo R, Pérez-Cejas A, Carrasco ML, Ramos F, Couce ML, Ruiz-Falcó ML, Gutierrez-Solana L, Martínez-Atienza M. Rare Variants in 48 Genes Account for 42% of Cases of Epilepsy With or Without Neurodevelopmental Delay in 246 Pediatric Patients. Front Neurosci 2019; 13:1135. [PMID: 31780880 PMCID: PMC6856296 DOI: 10.3389/fnins.2019.01135] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 10/08/2019] [Indexed: 12/21/2022] Open
Abstract
In order to characterize the genetic architecture of epilepsy in a pediatric population from the Iberian Peninsula (including the Canary Islands), we conducted targeted exome sequencing of 246 patients with infantile-onset seizures with or without neurodevelopmental delay. We detected 107 variants in 48 different genes, which were implicated in neuronal excitability, neurodevelopment, synaptic transmission, and metabolic pathways. In 104 cases (42%) we detected variant(s) that we classified as pathogenic or likely pathogenic. Of the 48 mutated genes, 32 were dominant, 8 recessive and 8 X-linked. Of the patients for whom family studies could be performed and in whom pathogenic variants were identified in dominant or X-linked genes, 82% carried de novo mutations. The involvement of small copy number variations (CNVs) is 9%. The use of progressively updated custom panels with high mean vertical coverage enabled establishment of a definitive diagnosis in a large proportion of cases (42%) and detection of CNVs (even duplications) with high fidelity. In 10.5% of patients we detected associations that are pending confirmation via functional and/or familial studies. Our findings had important consequences for the clinical management of the probands, since a large proportion of the cohort had been clinically misdiagnosed, and their families were subsequently able to avail of genetic counseling. In some cases, a more appropriate treatment was selected for the patient in question, or an inappropriate treatment discontinued. Our findings suggest the existence of modifier genes that may explain the incomplete penetrance of some epilepsy-related genes. We discuss possible reasons for non-diagnosis and future research directions. Further studies will be required to uncover the roles of structural variants, epimutations, and oligogenic inheritance in epilepsy, thereby providing a more complete molecular picture of this disease. In summary, given the broad phenotypic spectrum of most epilepsy-related genes, efficient genomic tools like the targeted exome sequencing panel described here are essential for early diagnosis and treatment, and should be implemented as first-tier diagnostic tools for children with epilepsy without a clear etiologic basis.
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Affiliation(s)
- Ana Fernández-Marmiesse
- Unit for the Diagnosis and Treatment of Congenital Metabolic Diseases, Clinical University Hospital of Santiago de Compostela, Health Research Institute of Santiago de Compostela, Santiago de Compostela, Spain.,Genomes & Disease Group, Molecular Medicine and Chronic Diseases Research Centre (CiMUS), Santiago de Compostela University-IDIS, Santiago de Compostela, Spain
| | - Iria Roca
- Unit for the Diagnosis and Treatment of Congenital Metabolic Diseases, Clinical University Hospital of Santiago de Compostela, Health Research Institute of Santiago de Compostela, Santiago de Compostela, Spain.,Genomes & Disease Group, Molecular Medicine and Chronic Diseases Research Centre (CiMUS), Santiago de Compostela University-IDIS, Santiago de Compostela, Spain
| | - Felícitas Díaz-Flores
- Molecular Genetics Unit, Clinical University Hospital of Canarias, Santa Cruz de Tenerife, Spain
| | - Verónica Cantarín
- Neuropediatrics Unit, Niño Jesús Clinical University Hospital, Madrid, Spain
| | | | - Ana Fontalba
- Genetics Unit, Marqués de Valdecilla Clinical University Hospital, Santander, Spain
| | - Francisco Laranjeira
- Centro de Genética Médica Jacinto Magalhães, Centro Hospitalar Do Porto, Porto, Portugal
| | - Sofia Quintans
- Neuropediatrics Unit, Santa María Hospital, Lisbon, Portugal
| | - Oana Moldovan
- Genetics Unit, Santa María Hospital, Lisbon, Portugal
| | - Blanca Felgueroso
- Neuropediatrics Unit, Teresa Herrera Child's Hospital, A Coruña, Spain
| | | | - Rogelio Simón
- Neuropediatrics Unit, 12 de Octubre Clinical University Hospital, Madrid, Spain
| | - Ana Camacho
- Neuropediatrics Unit, 12 de Octubre Clinical University Hospital, Madrid, Spain.,Department of Medicine, Complutense University of Madrid, Madrid, Spain
| | - Pilar Quijada
- Metabolic Disorders Unit, 12 de Octubre Clinical University Hospital, Madrid, Spain
| | - Salvador Ibanez-Mico
- Neuropediatrics Unit, Virgen de la Arrixaca Clinical University Hospital, Murcia, Spain
| | - Mª Rosario Domingno
- Neuropediatrics Unit, Virgen de la Arrixaca Clinical University Hospital, Murcia, Spain
| | - Carmen Benito
- Genetics Unit, Clinical University Hospital of Málaga, Málaga, Spain
| | - Rocío Calvo
- Neuropediatrics Unit, Clinical University Hospital of Málaga, Málaga, Spain
| | - Antonia Pérez-Cejas
- Molecular Genetics Unit, Clinical University Hospital of Canarias, Santa Cruz de Tenerife, Spain
| | - Mª Llanos Carrasco
- Neuropediatrics Unit, Clinical University Hospital Severo Ochoa, Leganés, Madrid, Spain
| | - Feliciano Ramos
- Clinical Genetics Unit, Pediatrics, Clinical University Hospital of Zaragoza, Zaragoza, Spain
| | - Mª Luz Couce
- Unit for the Diagnosis and Treatment of Congenital Metabolic Diseases, Clinical University Hospital of Santiago de Compostela, Health Research Institute of Santiago de Compostela, Santiago de Compostela, Spain
| | - Mª Luz Ruiz-Falcó
- Neuropediatrics Unit, Niño Jesús Clinical University Hospital, Madrid, Spain
| | | | - Margarita Martínez-Atienza
- Genomes & Disease Group, Molecular Medicine and Chronic Diseases Research Centre (CiMUS), Santiago de Compostela University-IDIS, Santiago de Compostela, Spain.,Molecular Genetics Unit, Clinical University Hospital of Canarias, Santa Cruz de Tenerife, Spain.,Molecular Genetics Unit, Virgen de las Nieves Clinical University Hospital, Granada, Spain
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19
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The MAP1B Binding Domain of Na v1.6 Is Required for Stable Expression at the Axon Initial Segment. J Neurosci 2019; 39:4238-4251. [PMID: 30914445 DOI: 10.1523/jneurosci.2771-18.2019] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 03/14/2019] [Accepted: 03/17/2019] [Indexed: 12/22/2022] Open
Abstract
Nav1.6 (SCN8A) is a major voltage-gated sodium channel in the mammalian CNS, and is highly concentrated at the axon initial segment (AIS). As previously demonstrated, the microtubule associated protein MAP1B binds the cytoplasmic N terminus of Nav1.6, and this interaction is disrupted by the mutation p.VAVP(77-80)AAAA. We now demonstrate that this mutation results in WT expression levels on the somatic surface but reduced surface expression at the AIS of cultured rat embryonic hippocampal neurons from both sexes. The mutation of the MAP1B binding domain did not impair vesicular trafficking and preferential delivery of Nav1.6 to the AIS; nor was the diffusion of AIS inserted channels altered relative to WT. However, the reduced AIS surface expression of the MAP1B mutant was restored to WT levels by inhibiting endocytosis with Dynasore, indicating that compartment-specific endocytosis was responsible for the lack of AIS accumulation. Interestingly, the lack of AIS targeting resulted in an elevated percentage of persistent current, suggesting that this late current originates predominantly in the soma. No differences in the voltage dependence of activation or inactivation were detected in the MAP1B binding mutant relative to WT channel. We hypothesize that MAP1B binding to the WT Nav1.6 masks an endocytic motif, thus allowing long-term stability on the AIS surface. This work identifies a critical and important new role for MAP1B in the regulation of neuronal excitability and adds to our understanding of AIS maintenance and plasticity, in addition to identifying new target residues for pathogenic mutations of SCN8A SIGNIFICANCE STATEMENT Nav1.6 is a major voltage-gated sodium channel in human brain, where it regulates neuronal activity due to its localization at the axon initial segment (AIS). Nav1.6 mutations cause epilepsy, intellectual disability, and movement disorders. In the present work, we show that loss of interaction with MAP1B within the Nav1.6 N terminus reduces the steady-state abundance of Nav1.6 at the AIS. The effect is due to increased Nav1.6 endocytosis at this neuronal compartment rather than a failure of forward trafficking to the AIS. This work confirms a new biological role of MAP1B in the regulation of sodium channel localization and will contribute to future analysis of patient mutations in the cytoplasmic N terminus of Nav1.6.
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20
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Dravet Syndrome in Lebanon: First Report on Cases with SCN1A Mutations. Case Rep Med 2019; 2019:5270503. [PMID: 30805006 PMCID: PMC6360541 DOI: 10.1155/2019/5270503] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 12/28/2018] [Accepted: 01/03/2019] [Indexed: 11/18/2022] Open
Abstract
Dravet syndrome, also known as severe myoclonic epilepsy in infancy, is a rare disease characterized by the appearance of different types of seizures in a healthy baby, triggered by various factors and stressful events. We report 8 Lebanese cases referred for molecular analysis of the SCN1A gene. Results were positive in 7 cases and revealed de novo variants at the heterozygous state in different exons of the gene for all except one, where the variant was intronic. Four variants were novel. Confirmation of Dravet syndrome is important for a better follow-up and treatment, preventing the occurrence of status epilepticus and severe neurological deterioration.
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21
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Shen H, Liu D, Wu K, Lei J, Yan N. Structures of human Na v1.7 channel in complex with auxiliary subunits and animal toxins. Science 2019; 363:1303-1308. [PMID: 30765606 DOI: 10.1126/science.aaw2493] [Citation(s) in RCA: 288] [Impact Index Per Article: 57.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Accepted: 01/29/2019] [Indexed: 12/18/2022]
Abstract
Voltage-gated sodium channel Nav1.7 represents a promising target for pain relief. Here we report the cryo-electron microscopy structures of the human Nav1.7-β1-β2 complex bound to two combinations of pore blockers and gating modifier toxins (GMTs), tetrodotoxin with protoxin-II and saxitoxin with huwentoxin-IV, both determined at overall resolutions of 3.2 angstroms. The two structures are nearly identical except for minor shifts of voltage-sensing domain II (VSDII), whose S3-S4 linker accommodates the two GMTs in a similar manner. One additional protoxin-II sits on top of the S3-S4 linker in VSDIV The structures may represent an inactivated state with all four VSDs "up" and the intracellular gate closed. The structures illuminate the path toward mechanistic understanding of the function and disease of Nav1.7 and establish the foundation for structure-aided development of analgesics.
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Affiliation(s)
- Huaizong Shen
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China
| | - Dongliang Liu
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China
| | - Kun Wu
- Medical Research Center, Beijing Key Laboratory of Cardiopulmonary Cerebral Resuscitation, Beijing Chao-Yang Hospital, Capital Medical University, Beijing 100020, China
| | - Jianlin Lei
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China.,Technology Center for Protein Sciences, Ministry of Education Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Nieng Yan
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China. .,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China
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22
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Tunçer GÖ, Teber S, Albayrak P, Kutluk MG, Deda G. A case of Dravet Syndrome with a newly defined mutation in the SCN1A gene. Turk Arch Pediatr 2018; 53:259-262. [PMID: 30872930 DOI: 10.5152/turkpediatriars.2018.4197] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 02/03/2017] [Indexed: 01/03/2023]
Abstract
Dravet syndrome is a catastrophic progressive epileptic syndrome. De novo loss of function mutations on the SCN1A gene coding voltage-gated sodium channels are responsible. Disruption of the triggering of hippocampal GABAergic interneurons is assumed as the cause of fall in the seizure threshold. A ten-year-old boy first presented at age 10 months with febrile-clonic seizures, which began when he was aged 8 months. Electroencephalography was found as normal. Phenobarbital was initiated because of long-lasting seizures. However, his seizures continued and the therapy was replaced with valproic acid. On follow-up, different antiepileptics were used, which were stopped due to inefficiency or adverse effects. SCN1A gene analysis was performed and a heterozygous c.4018delC mutation was identified. This new frame-shift mutation resulting from an early stop-codon is thought to be the cause of the disease. Finally, he was prescribed valproic acid and stiripentol. For patients with fever-triggered, treatment-resistant seizures, and delayed psychomotor development, Dravet syndrome should be considered. Genetic diagnosis is important for treatment and follow-up.
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Affiliation(s)
- Gökçen Öz Tunçer
- Department of Pediatrics, Division of Pediatric Neurology, Ankara University School of Medicine, Ankara, Turkey
| | - Serap Teber
- Department of Pediatrics, Division of Pediatric Neurology, Ankara University School of Medicine, Ankara, Turkey
| | - Pelin Albayrak
- Department of Pediatrics, Division of Pediatric Neurology, Ankara University School of Medicine, Ankara, Turkey
| | - Muhammet Gültekin Kutluk
- Department of Pediatrics, Division of Pediatric Neurology, Ankara University School of Medicine, Ankara, Turkey
| | - Gülhis Deda
- Department of Pediatrics, Division of Pediatric Neurology, Ankara University School of Medicine, Ankara, Turkey
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23
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Liu J, Tong L, Song S, Niu Y, Li J, Wu X, Zhang J, Zai CC, Luo F, Wu J, Li H, Wong AHC, Sun R, Liu F, Li B. Novel and de novo mutations in pediatric refractory epilepsy. Mol Brain 2018; 11:48. [PMID: 30185235 PMCID: PMC6125990 DOI: 10.1186/s13041-018-0392-5] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 08/27/2018] [Indexed: 12/19/2022] Open
Abstract
Pediatric refractory epilepsy is a broad phenotypic spectrum with great genetic heterogeneity. Next-generation sequencing (NGS) combined with Sanger sequencing could help to understand the genetic diversity and underlying disease mechanisms in pediatric epilepsy. Here, we report sequencing results from a cohort of 172 refractory epilepsy patients aged 0-14 years. The pathogenicity of identified variants was evaluated in accordance with the American College of Medical Genetics and Genomics (ACMG) criteria. We identified 43 pathogenic or likely pathogenic variants in 40 patients (23.3%). Among these variants, 74.4% mutations (32/43) were de novo and 60.5% mutations (26/43) were novel. Patients with onset age of seizures ≤12 months had higher yields of deleterious variants compared to those with onset age of seizures > 12 months (P = 0.006). Variants in ion channel genes accounted for the greatest functional gene category (55.8%), with SCN1A coming first (16/43). 81.25% (13/16) of SCN1A mutations were de novo and 68.8% (11/16) were novel in Dravet syndrome. Pathogenic or likely pathogenic variants were found in the KCNQ2, STXBP1, SCN2A genes in Ohtahara syndrome. Novel deleterious variants were also found in West syndrome, Doose syndrome and glucose transporter type 1 deficiency syndrome patients. One de novo MECP2 mutation were found in a Rett syndrome patient. TSC1/TSC2 variants were found in 60% patients with tuberous sclerosis complex patients. Other novel mutations detected in unclassified epilepsy patients involve the SCN8A, CACNA1A, GABRB3, GABRA1, IQSEC2, TSC1, VRK2, ATP1A2, PCDH19, SLC9A6 and CHD2 genes. Our study provides novel insights into the genetic origins of pediatric epilepsy and represents a starting-point for further investigations into the molecular pathophysiology of pediatric epilepsy that could eventually lead to better treatments.
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Affiliation(s)
- Jing Liu
- Department of Pediatrics, Qilu Hospital of Shandong University, Jinan, Shandong, People's Republic of China.,Shandong University, Jinan, Shandong, People's Republic of China
| | - Lili Tong
- Department of Pediatrics, Qilu Hospital of Shandong University, Jinan, Shandong, People's Republic of China.,Shandong University, Jinan, Shandong, People's Republic of China
| | - Shuangshuang Song
- Qilu Children's hospital of Shandong University, Jinan, Shandong, People's Republic of China
| | - Yue Niu
- Department of Pediatrics, Qilu Hospital of Shandong University, Jinan, Shandong, People's Republic of China.,Shandong University, Jinan, Shandong, People's Republic of China
| | - Jun Li
- Department of Pediatrics, Qilu Hospital of Shandong University, Jinan, Shandong, People's Republic of China.,Shandong University, Jinan, Shandong, People's Republic of China
| | - Xiu Wu
- Department of Pediatrics, Qilu Hospital of Shandong University, Jinan, Shandong, People's Republic of China.,Shandong University, Jinan, Shandong, People's Republic of China
| | - Jie Zhang
- MyGenostics Inc., Beijing, People's Republic of China
| | - Clement C Zai
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, University of Toronto, Toronto, ON, Canada
| | - Fang Luo
- MyGenostics Inc., Beijing, People's Republic of China
| | - Jian Wu
- MyGenostics Inc., Beijing, People's Republic of China
| | - Haiyin Li
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, University of Toronto, Toronto, ON, Canada
| | - Albert H C Wong
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, University of Toronto, Toronto, ON, Canada
| | - Ruopeng Sun
- Department of Pediatrics, Qilu Hospital of Shandong University, Jinan, Shandong, People's Republic of China.,Shandong University, Jinan, Shandong, People's Republic of China
| | - Fang Liu
- Shandong University, Jinan, Shandong, People's Republic of China.,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, University of Toronto, Toronto, ON, Canada
| | - Baomin Li
- Department of Pediatrics, Qilu Hospital of Shandong University, Jinan, Shandong, People's Republic of China. .,Shandong University, Jinan, Shandong, People's Republic of China.
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24
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Griffin A, Hamling KR, Hong S, Anvar M, Lee LP, Baraban SC. Preclinical Animal Models for Dravet Syndrome: Seizure Phenotypes, Comorbidities and Drug Screening. Front Pharmacol 2018; 9:573. [PMID: 29915537 PMCID: PMC5994396 DOI: 10.3389/fphar.2018.00573] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 05/14/2018] [Indexed: 12/18/2022] Open
Abstract
Epilepsy is a common chronic neurological disease affecting almost 3 million people in the United States and 50 million people worldwide. Despite availability of more than two dozen FDA-approved anti-epileptic drugs (AEDs), one-third of patients fail to receive adequate seizure control. Specifically, pediatric genetic epilepsies are often the most severe, debilitating and pharmaco-resistant forms of epilepsy. Epileptic syndromes share a common symptom of unprovoked seizures. While some epilepsies/forms of epilepsy are the result of acquired insults such as head trauma, febrile seizure, or viral infection, others have a genetic basis. The discovery of epilepsy associated genes suggests varied underlying pathologies and opens the door for development of new "personalized" treatment options for each genetic epilepsy. Among these, Dravet syndrome (DS) has received substantial attention for both the pre-clinical and early clinical development of novel therapeutics. Despite these advances, there is no FDA-approved treatment for DS. Over 80% of patients diagnosed with DS carry a de novo mutation within the voltage-gated sodium channel gene SCN1A and these patients suffer with drug resistant and life-threatening seizures. Here we will review the preclinical animal models for DS featuring inactivation of SCN1A (including zebrafish and mice) with an emphasis on seizure phenotypes and behavioral comorbidities. Because many drugs fail somewhere between initial preclinical discovery and clinical trials, it is equally important that we understand how these models respond to known AEDs. As such, we will also review the available literature and recent drug screening efforts using these models with a focus on assay protocols and predictive pharmacological profiles. Validation of these preclinical models is a critical step in our efforts to efficiently discover new therapies for these patients. The behavioral and electrophysiological drug screening assays in zebrafish will be discussed in detail including specific examples from our laboratory using a zebrafish scn1 mutant and a summary of the nearly 3000 drugs screened to date. As the discovery and development phase rapidly moves from the lab-to-the-clinic for DS, it is hoped that this preclinical strategy offers a platform for how to approach any genetic epilepsy.
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Affiliation(s)
- Aliesha Griffin
- Epilepsy Research Laboratory Department of Neurological Surgery and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, United States
| | - Kyla R Hamling
- Epilepsy Research Laboratory Department of Neurological Surgery and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, United States
| | - SoonGweon Hong
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, United States
| | - Mana Anvar
- Epilepsy Research Laboratory Department of Neurological Surgery and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, United States
| | - Luke P Lee
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, United States
| | - Scott C Baraban
- Epilepsy Research Laboratory Department of Neurological Surgery and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, United States
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25
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Abstract
Dravet syndrome (DS) is a medically refractory epilepsy that onsets in the first year of life with prolonged seizures, often triggered by fever. Over time, patients develop other seizure types (myoclonic, atypical absences, drops), intellectual disability, crouch gait and other co-morbidities (sleep problems, autonomic dysfunction). Complete seizure control is generally not achievable with current therapies, and the goals of treatment are to balance reduction of seizure burden with adverse effects of therapies. Treatment of co-morbidities must also be addressed, as they have a significant impact on the quality of life of patients with DS. Seizures are typically worsened with sodium-channel agents. Accepted first-line agents include clobazam and valproic acid, although these rarely provide adequate seizure control. Benefit has also been noted with stiripentol, topiramate, levetiracetam, the ketogenic diet and vagal nerve stimulation. Several agents presently in development, specifically fenfluramine and cannabidiol, have shown efficacy in clinical trials. Status epilepticus is a recurring problem for patients with DS, particularly in their early childhood years. All patients should be prescribed a home rescue therapy (usually a benzodiazepine) but should also have a written seizure action plan that outlines when rescue should be given and further steps to take in the local hospital if the seizure persists despite home rescue therapy.
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26
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Zhou P, He N, Zhang JW, Lin ZJ, Wang J, Yan LM, Meng H, Tang B, Li BM, Liu XR, Shi YW, Zhai QX, Yi YH, Liao WP. Novel mutations and phenotypes of epilepsy-associated genes in epileptic encephalopathies. GENES BRAIN AND BEHAVIOR 2018; 17:e12456. [PMID: 29314583 DOI: 10.1111/gbb.12456] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 12/13/2017] [Accepted: 12/30/2017] [Indexed: 12/30/2022]
Abstract
Epileptic encephalopathies are severe epilepsy disorders with strong genetic bases. We performed targeted next-generation sequencing (NGS) in 70 patients with epileptic encephalopathies. The likely pathogenicity of variants in candidate genes was evaluated by American College of Medical Genetics and Genomics (ACMG) scoring taken together with the accepted clinical presentation. Thirty-three candidate variants were detected after population filtration and computational prediction. According to ACMG, 21 candidate variants, including 18 de novo variants, were assessed to be pathogenic/likely pathogenic with clinical concordance. Twelve variants were initially assessed as uncertain significance by ACMG, among which 3 were considered causative and 3 others were considered possibly causative after analysis of clinical concordance. In total, 24 variants were identified as putatively causative, among which 19 were novel findings. SCN1A mutations were identified in 50% of patients with Dravet syndrome. TSC1/TSC2 mutations were detected in 66.7% of patients with tuberous sclerosis. STXBP1 mutations were the main findings in patients with West syndrome. Mutations in SCN2A, KCNT1, KCNQ2 and CLCN4 were identified in patients with epileptic infantile with migrating focal seizures; among them, KCNQ2 and CLCN4 were first identified as potential causative genes. Only one CHD2 mutation was detected in patients with Lennox-Gastaut syndrome. This study highlighted the utility of targeted NGS in genetic diagnoses of epileptic encephalopathies and a comprehensive evaluation of the pathogenicity of variants based on ACMG scoring and assessment of clinical concordance. Epileptic encephalopathies differ in genetic causes, and the genotype-phenotype correlations would provide insights into the underlying pathogenic mechanisms.
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Affiliation(s)
- P Zhou
- Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Institute of Neuroscience, Guangzhou, China.,Key Laboratory of Neurogenetics, Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - N He
- Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Institute of Neuroscience, Guangzhou, China.,Key Laboratory of Neurogenetics, Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - J-W Zhang
- Department of Pediatrics, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Z-J Lin
- Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Institute of Neuroscience, Guangzhou, China.,Key Laboratory of Neurogenetics, Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - J Wang
- Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Institute of Neuroscience, Guangzhou, China.,Key Laboratory of Neurogenetics, Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - L-M Yan
- Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Institute of Neuroscience, Guangzhou, China.,Key Laboratory of Neurogenetics, Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - H Meng
- Department of Neurology, The First Affiliated Hospital of Jinan University, Guangzhou, China.,Clinical Neuroscience Institute, Jinan University, Guangzhou, China
| | - B Tang
- Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Institute of Neuroscience, Guangzhou, China.,Key Laboratory of Neurogenetics, Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - B-M Li
- Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Institute of Neuroscience, Guangzhou, China.,Key Laboratory of Neurogenetics, Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - X-R Liu
- Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Institute of Neuroscience, Guangzhou, China.,Key Laboratory of Neurogenetics, Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Y-W Shi
- Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Institute of Neuroscience, Guangzhou, China.,Key Laboratory of Neurogenetics, Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Q-X Zhai
- Department of Pediatrics, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Y-H Yi
- Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Institute of Neuroscience, Guangzhou, China.,Key Laboratory of Neurogenetics, Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - W-P Liao
- Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Institute of Neuroscience, Guangzhou, China.,Key Laboratory of Neurogenetics, Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
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27
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Nakayama T, Ishii A, Yoshida T, Nasu H, Shimojima K, Yamamoto T, Kure S, Hirose S. Somatic mosaic deletions involving SCN1A
cause Dravet syndrome. Am J Med Genet A 2018; 176:657-662. [DOI: 10.1002/ajmg.a.38596] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 10/09/2017] [Accepted: 12/07/2017] [Indexed: 12/19/2022]
Affiliation(s)
- Tojo Nakayama
- Department of Pediatrics; Tohoku University School of Medicine; Sendai Japan
| | - Atsushi Ishii
- Department of Pediatrics; School of Medicine; Fukuoka University; Fukuoka Japan
- Central Research Institute for the Molecular Pathomechanisms of Epilepsy; Fukuoka University; Fukuoka Japan
| | - Takeshi Yoshida
- Department of Pediatrics; Kyoto University Graduate School of Medicine; Kyoto Japan
| | - Hirosato Nasu
- National Epilepsy Center; Shizuoka Institute of Epilepsy and Neurological Disorders; Shizuoka Japan
| | - Keiko Shimojima
- Tokyo Women's Medical University Institute for Integrated Medical Sciences; Tokyo Japan
| | - Toshiyuki Yamamoto
- Tokyo Women's Medical University Institute for Integrated Medical Sciences; Tokyo Japan
| | - Shigeo Kure
- Department of Pediatrics; Tohoku University School of Medicine; Sendai Japan
| | - Shinichi Hirose
- Department of Pediatrics; School of Medicine; Fukuoka University; Fukuoka Japan
- Central Research Institute for the Molecular Pathomechanisms of Epilepsy; Fukuoka University; Fukuoka Japan
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28
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Xiang J, Wen F, Zhang L, Zhou Y. FOXD3 inhibits SCN2A gene transcription in intractable epilepsy cell models. Exp Neurol 2017; 302:14-21. [PMID: 29288635 DOI: 10.1016/j.expneurol.2017.12.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 12/20/2017] [Accepted: 12/26/2017] [Indexed: 12/28/2022]
Abstract
The expression of sodium voltage-gated channel alpha subunit 2 (SCN2A) is closely related to the development of epilepsy. This study investigated regulatory element of the SCN2A gene involved in epilepsy. An intractable epilepsy cell model was constructed using hippocampal primary neurons and the SH-SY5Y cell line. SCN2A protein and gene expression in cells as well as the level of lactic acid dehydrogenase (LDH) in the cell culture supernatants was detected. Potential regulatory factors of SCN2A and its upstream regulatory elements were identified using the dual-luciferase reporter assay. Finally, the role of the hypothetical transcription factor in epilepsy was examined by using its small interfering RNA (siRNA). Results found that levels of LDH and expression of the hypothetical transcription factor, Forkhead box D3 (FOXD3), was both increased in the model cells, whereas that of SCN2A was decreased. The results of dual-luciferase reporter assays revealed that an upstream region of SCN2A gene spanning from nucleotides -1617 to -1470 was a transcription factor binding region and a trans-acting factor role of FOXD3 was identified in the core region (GGCAAAATTAT). Then the FOXD3 binding site was further verified by the chromatin immunoprecipitation (ChIP) assay and electrophoretic mobility shift assay (EMSA). After SH-SY5Y cells were transfected with FOXD3 siRNA, the release of LDH into culture supernatants and the LDH expression levels in cells were significantly decreased. SCN2A expression in model cells was increased by knockdown of FOXD3. Therefore, this study demonstrated that FOXD3 is a trans-acting factor of SCN2A, and this mechanism may play a role in cell injury after epilepsy.
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Affiliation(s)
- Jun Xiang
- Department of Neurosurgery, The Second Xiang-Ya Hospital of Central South University, Changsha 410011, Hunan Province, China.
| | - Fang Wen
- Neurology Electroencephalogram Room of Neurology Department, The Second Xiang-Ya Hospital of Central South University, Changsha 410011, Hunan Province, China
| | - Lingyun Zhang
- Department of Neurosurgery, The Second Xiang-Ya Hospital of Central South University, Changsha 410011, Hunan Province, China
| | - Yu Zhou
- Department of Neurosurgery, The Second Xiang-Ya Hospital of Central South University, Changsha 410011, Hunan Province, China
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29
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Sula A, Wallace BA. Interpreting the functional role of a novel interaction motif in prokaryotic sodium channels. J Gen Physiol 2017; 149:613-622. [PMID: 28522439 PMCID: PMC5460950 DOI: 10.1085/jgp.201611740] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 05/01/2017] [Indexed: 01/17/2023] Open
Abstract
Sula and Wallace explore evidence supporting a role for a novel interaction motif in the gating of prokaryotic sodium channels. Voltage-gated sodium channels enable the translocation of sodium ions across cell membranes and play crucial roles in electrical signaling by initiating the action potential. In humans, mutations in sodium channels give rise to several neurological and cardiovascular diseases, and hence they are targets for pharmaceutical drug developments. Prokaryotic sodium channel crystal structures have provided detailed views of sodium channels, which by homology have suggested potentially important functionally related structural features in human sodium channels. A new crystal structure of a full-length prokaryotic channel, NavMs, in a conformation we proposed to represent the open, activated state, has revealed a novel interaction motif associated with channel opening. This motif is associated with disease when mutated in human sodium channels and plays an important and dynamic role in our new model for channel activation.
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Affiliation(s)
- Altin Sula
- Institute of Structural and Molecular Biology, Birkbeck College, University of London, London, England, UK
| | - B A Wallace
- Institute of Structural and Molecular Biology, Birkbeck College, University of London, London, England, UK
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30
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Parrini E, Marini C, Mei D, Galuppi A, Cellini E, Pucatti D, Chiti L, Rutigliano D, Bianchini C, Virdò S, De Vita D, Bigoni S, Barba C, Mari F, Montomoli M, Pisano T, Rosati A, Guerrini R. Diagnostic Targeted Resequencing in 349 Patients with Drug-Resistant Pediatric Epilepsies Identifies Causative Mutations in 30 Different Genes. Hum Mutat 2016; 38:216-225. [DOI: 10.1002/humu.23149] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 11/13/2016] [Indexed: 12/17/2022]
Affiliation(s)
- Elena Parrini
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Carla Marini
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Davide Mei
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Anna Galuppi
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Elena Cellini
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Daniela Pucatti
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Laura Chiti
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Domenico Rutigliano
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Claudia Bianchini
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Simona Virdò
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Dalila De Vita
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Stefania Bigoni
- UOL of Medical Genetics; Ferrara University Hospital; Ferrara Italy
| | - Carmen Barba
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Francesco Mari
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Martino Montomoli
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Tiziana Pisano
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Anna Rosati
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
| | - Renzo Guerrini
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department; A Meyer Children's Hospital; University of Florence; Florence Italy
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31
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Møller RS, Larsen LHG, Johannesen KM, Talvik I, Talvik T, Vaher U, Miranda MJ, Farooq M, Nielsen JEK, Svendsen LL, Kjelgaard DB, Linnet KM, Hao Q, Uldall P, Frangu M, Tommerup N, Baig SM, Abdullah U, Born AP, Gellert P, Nikanorova M, Olofsson K, Jepsen B, Marjanovic D, Al-Zehhawi LIK, Peñalva SJ, Krag-Olsen B, Brusgaard K, Hjalgrim H, Rubboli G, Pal DK, Dahl HA. Gene Panel Testing in Epileptic Encephalopathies and Familial Epilepsies. Mol Syndromol 2016; 7:210-219. [PMID: 27781031 DOI: 10.1159/000448369] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
In recent years, several genes have been causally associated with epilepsy. However, making a genetic diagnosis in a patient can still be difficult, since extensive phenotypic and genetic heterogeneity has been observed in many monogenic epilepsies. This study aimed to analyze the genetic basis of a wide spectrum of epilepsies with age of onset spanning from the neonatal period to adulthood. A gene panel targeting 46 epilepsy genes was used on a cohort of 216 patients consecutively referred for panel testing. The patients had a range of different epilepsies from benign neonatal seizures to epileptic encephalopathies (EEs). Potentially causative variants were evaluated by literature and database searches, submitted to bioinformatic prediction algorithms, and validated by Sanger sequencing. If possible, parents were included for segregation analysis. We identified a presumed disease-causing variant in 49 (23%) of the 216 patients. The variants were found in 19 different genes including SCN1A, STXBP1, CDKL5, SCN2A, SCN8A, GABRA1, KCNA2, and STX1B. Patients with neonatal-onset epilepsies had the highest rate of positive findings (57%). The overall yield for patients with EEs was 32%, compared to 17% among patients with generalized epilepsies and 16% in patients with focal or multifocal epilepsies. By the use of a gene panel consisting of 46 epilepsy genes, we were able to find a disease-causing genetic variation in 23% of the analyzed patients. The highest yield was found among patients with neonatal-onset epilepsies and EEs.
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Affiliation(s)
- Rikke S Møller
- Danish Epilepsy Centre, University of Southern Denmark, Denmark; Institute for Regional Health Services, University of Southern Denmark, Denmark
| | | | - Katrine M Johannesen
- Danish Epilepsy Centre, University of Southern Denmark, Denmark; Institute for Regional Health Services, University of Southern Denmark, Denmark
| | - Inga Talvik
- Tallinn Children's Hospital, Tallinn, Estonia; Tartu University Hospital, Children's Clinic, Tartu, Estonia
| | - Tiina Talvik
- Tartu University Hospital, Children's Clinic, Tartu, Estonia; Department of Paediatrics, University of Tartu, Tartu, Estonia
| | - Ulvi Vaher
- Tartu University Hospital, Children's Clinic, Tartu, Estonia; Department of Paediatrics, University of Tartu, Tartu, Estonia
| | - Maria J Miranda
- Department of Pediatrics, Pediatric Neurology, Herlev University Hospital, Copenhagen University, Herlev, Denmark
| | - Muhammad Farooq
- Department of Cellular and Molecular Medicine, Wilhelm Johannsen Centre for Functional Genome Research, University of Copenhagen, Copenhagen, Denmark; Human Molecular Genetics Laboratory, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE)-PIEAS, Faisalabad, Pakistan
| | - Jens E K Nielsen
- Department of Clinical Medicine, Section of Gynaecology, Obstetrics and Paediatrics, Roskilde Hospital, Roskilde, Denmark
| | | | | | - Karen M Linnet
- Department of Pediatrics, Aarhus University Hospital, Aarhus, Denmark
| | - Qin Hao
- Amplexa Genetics, Odense, Denmark
| | - Peter Uldall
- Danish Epilepsy Centre, University of Southern Denmark, Denmark
| | - Mimoza Frangu
- Department of Pediatrics, Holbæk Hospital, Holbæk, Denmark
| | - Niels Tommerup
- Department of Cellular and Molecular Medicine, Wilhelm Johannsen Centre for Functional Genome Research, University of Copenhagen, Copenhagen, Denmark
| | - Shahid M Baig
- Human Molecular Genetics Laboratory, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE)-PIEAS, Faisalabad, Pakistan
| | - Uzma Abdullah
- Department of Cellular and Molecular Medicine, Wilhelm Johannsen Centre for Functional Genome Research, University of Copenhagen, Copenhagen, Denmark; Human Molecular Genetics Laboratory, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE)-PIEAS, Faisalabad, Pakistan
| | - Alfred P Born
- Department of Paediatrics, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Pia Gellert
- Danish Epilepsy Centre, University of Southern Denmark, Denmark
| | - Marina Nikanorova
- Danish Epilepsy Centre, University of Southern Denmark, Denmark; Institute for Regional Health Services, University of Southern Denmark, Denmark
| | - Kern Olofsson
- Danish Epilepsy Centre, University of Southern Denmark, Denmark
| | - Birgit Jepsen
- Danish Epilepsy Centre, University of Southern Denmark, Denmark
| | | | - Lana I K Al-Zehhawi
- Department of Clinical Genetics, Aarhus University Hospital, Aarhus, Denmark
| | | | - Bente Krag-Olsen
- Department of Pediatrics, Aarhus University Hospital, Aarhus, Denmark
| | | | - Helle Hjalgrim
- Danish Epilepsy Centre, University of Southern Denmark, Denmark; Institute for Regional Health Services, University of Southern Denmark, Denmark
| | - Guido Rubboli
- Danish Epilepsy Centre, Filadelfia, Dianalund, Denmark
| | - Deb K Pal
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
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Cognitive-behavioral profiles in teenagers with Dravet syndrome. Brain Dev 2016; 38:554-62. [PMID: 26797655 DOI: 10.1016/j.braindev.2015.12.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 12/19/2015] [Accepted: 12/28/2015] [Indexed: 11/21/2022]
Abstract
AIM To investigate behavior and cognitive performances of teenage patients with Dravet syndrome (DS). METHODS We enrolled 20 teenage patients (12 females and 8 males) with DS, followed in the Child Neurology Unit of the Catholic University (Rome). Patients underwent a full clinical examination including behavioral and cognitive assessments (respectively, CBCL and Wechsler scales). RESULTS All patients showed behavior disorders and mental retardation, mild in six cases, moderate in seven and severe in the remaining seven. Among mildly retarded patients visual function, particularly visuo-motor abilities resulted mostly impaired in Wechsler subtests, whereas verbal skills were relatively preserved. In contrast, a general cognitive impairment was observed in moderately and severely retarded patients. CONCLUSIONS Our teenage patients with DS compared with other series at different ages (young childhood, adulthood) suggest a progressivity of neurological and neuropsychological signs. A visuomotor default and a relative preservation of verbal skills, like what has been found in previous reports of younger patients, are still evident in mildly impaired cases. Therefore, the progression over time of these cases toward a generalized impairment may be suggested, but only longitudinal studies can confirm it. There was a possible responsibility of some epileptic disorders in worsening the neuropsychological outcome (early myoclonic seizures and atypical absences, as well as persistent EEG background slowness in the last 3years).
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Shi XY, Tomonoh Y, Wang WZ, Ishii A, Higurashi N, Kurahashi H, Kaneko S, Hirose S. Efficacy of antiepileptic drugs for the treatment of Dravet syndrome with different genotypes. Brain Dev 2016; 38:40-6. [PMID: 26183863 DOI: 10.1016/j.braindev.2015.06.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 06/28/2015] [Accepted: 06/30/2015] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Evaluation of the efficacy of antiepileptic drugs (AEDs) used in the treatment of Dravet syndrome (DS) with different genotypes. METHODS Patients with DS were recruited from different tertiary hospitals. Using a direct sequencing method and Multiplex Ligation-Dependent Probe Amplification (MLPA), genetic abnormalities were assessed within the exons and flanking introns of SCN1A gene, which encodes the α1 subunit of neuronal sodium channels. Patients were divided into SCN1A-positive and SCN1A-negative groups according to the results of genetic tests. Medical records, including detailed treatment information, were surveyed to compare the effect of different AEDs on clonic or tonic-clonic seizures (GTCS). Efficacy variable was responder rate with regard to seizure reduction. RESULTS One hundred and sixty of 276 (57.97%) patients had mutation in SCN1A gene (only 128 of them had provided detailed medical records). Among the 116 patients without SCN1A mutations, 87 had provided detailed medical records. Both older AEDs (valproate, phenobarbital, bromide, carbamazepine, clonazepam, and clobazam) and newer AEDs such as zonisamide were used in these patients. Valproate was the most frequently used AED (86.72% in the SCN1A-positive group, 78.16% in the SCN1A-negative group), with 52.25% and 41.18% responder rates in SCN1A-positive and SCN1A-negative patients, respectively (P=0.15). Bromide was used in 40.63% of the SCN1A-positive patients and 20.69% of the SCN1A-negative patients, and its responder rates were 71.15% and 94.44% in SCN1A-positive and SCN1A-negative patients, respectively (P=0.05). Efficacy rates of clonazepam, clobazam, phenobarbital, and zonisamide ranged from 30% to 50%, and these rates were not correlated with different genotypes (P>0.05). Carbamazepine had either no effect or aggravated seizures in all SCN1A-positive patients. SIGNIFICANCE Bromide is most effective and is a well-tolerated drug among DS patients, especially among SCN1A-negative patients. Carbamazepine should be avoided in patients with SCN1A mutations.
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Affiliation(s)
- Xiu-Yu Shi
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan; Central Research Institute for the Molecular Pathomechanisms of Epilepsy, Fukuoka University, Fukuoka, Japan; Department of Pediatrics, Chinese PLA General Hospital, Beijing, China
| | - Yuko Tomonoh
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan; Central Research Institute for the Molecular Pathomechanisms of Epilepsy, Fukuoka University, Fukuoka, Japan
| | - Wen-Ze Wang
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan; Central Research Institute for the Molecular Pathomechanisms of Epilepsy, Fukuoka University, Fukuoka, Japan; Department of Pathology, Peking Union Medical College Hospital, Chinese Academy of Medical Science, Beijing, China
| | - Atsushi Ishii
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan; Central Research Institute for the Molecular Pathomechanisms of Epilepsy, Fukuoka University, Fukuoka, Japan
| | - Norimichi Higurashi
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan; Central Research Institute for the Molecular Pathomechanisms of Epilepsy, Fukuoka University, Fukuoka, Japan; Department of Pediatrics, Jikei University School of Medicine, Tokyo, Japan
| | - Hirokazu Kurahashi
- Department of Pediatric Neurology, Central Hospital of Aichi Welfare Center for Persons with Developmental Disabilities, Kasugai, Japan
| | - Sunao Kaneko
- Department of Neuropsychiatry, School of Medicine, Hirosaki University, Hirosaki, Japan
| | - Shinichi Hirose
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan; Central Research Institute for the Molecular Pathomechanisms of Epilepsy, Fukuoka University, Fukuoka, Japan.
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Wu YW, Sullivan J, McDaniel SS, Meisler MH, Walsh EM, Li SX, Kuzniewicz MW. Incidence of Dravet Syndrome in a US Population. Pediatrics 2015; 136:e1310-5. [PMID: 26438699 PMCID: PMC4621800 DOI: 10.1542/peds.2015-1807] [Citation(s) in RCA: 157] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/12/2015] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE De novo mutations of the gene sodium channel 1α (SCN1A) are the major cause of Dravet syndrome, an infantile epileptic encephalopathy. US incidence of DS has been estimated at 1 in 40 000, but no US epidemiologic studies have been performed since the advent of genetic testing. METHODS In a retrospective, population-based cohort of all infants born at Kaiser Permanente Northern California during 2007-2010, we electronically identified patients who received ≥2 seizure diagnoses before age 12 months and who were also prescribed anticonvulsants at 24 months. A child neurologist reviewed records to identify infants who met 4 of 5 criteria for clinical Dravet syndrome: normal development before seizure onset; ≥2 seizures before age 12 months; myoclonic, hemiclonic, or generalized tonic-clonic seizures; ≥2 seizures lasting >10 minutes; and refractory seizures after age 2 years. SCN1A gene sequencing was performed as part of routine clinical care. RESULTS Eight infants met the study criteria for clinical Dravet syndrome, yielding an incidence of 1 per 15 700. Six of these infants (incidence of 1 per 20 900) had a de novo SCN1A missense mutation that is likely to be pathogenic. One infant had an inherited SCN1A variant that is unlikely to be pathogenic. All 8 experienced febrile seizures, and 6 had prolonged seizures lasting >10 minutes by age 1 year. CONCLUSIONS Dravet syndrome due to an SCN1A mutation is twice as common in the United States as previously thought. Genetic testing should be considered in children with ≥2 prolonged febrile seizures by 1 year of age.
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Affiliation(s)
- Yvonne W. Wu
- Departments of Neurology and,Pediatrics, University of California, San Francisco, San Francisco, California
| | - Joseph Sullivan
- Departments of Neurology and,Pediatrics, University of California, San Francisco, San Francisco, California
| | | | - Miriam H. Meisler
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan
| | | | | | - Michael W. Kuzniewicz
- Research, and,Neonatology, Kaiser Permanente Northern California, Oakland, California; and
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Tuncer FN, Gormez Z, Calik M, Altiokka Uzun G, Sagiroglu MS, Yuceturk B, Yuksel B, Baykan B, Bebek N, Iscan A, Ugur Iseri SA, Ozbek U. A clinical variant in SCN1A inherited from a mosaic father cosegregates with a novel variant to cause Dravet syndrome in a consanguineous family. Epilepsy Res 2015; 113:5-10. [DOI: 10.1016/j.eplepsyres.2015.02.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 02/12/2015] [Accepted: 02/27/2015] [Indexed: 11/26/2022]
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Guala A, Peruzzi C, Gennaro E, Pennese L, Danesino C. Maternal germinal mosaicism forSCN1Ain sibs with a mild form of Dravet syndrome. Am J Med Genet A 2015; 167A:1165-7. [DOI: 10.1002/ajmg.a.36990] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 01/04/2015] [Indexed: 11/06/2022]
Affiliation(s)
- Andrea Guala
- SOC Pediatria; Ospedale Castelli; Verbania Italy
| | | | - Elena Gennaro
- Laboratorio di Genetica Umana; E.O. Ospedali Galliera; Genova Italy
| | - Loredana Pennese
- Laboratorio di Genetica Umana; E.O. Ospedali Galliera; Genova Italy
| | - Cesare Danesino
- Dipartimento di Medicina Molecolare; University of Pavia, and IRCCS S. Matteo; Pavia Italy
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Bayat A, Hjalgrim H, Møller RS. The incidence of SCN1A-related Dravet syndrome in Denmark is 1:22,000: a population-based study from 2004 to 2009. Epilepsia 2015; 56:e36-9. [PMID: 25778844 DOI: 10.1111/epi.12927] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/28/2014] [Indexed: 12/20/2022]
Abstract
Dravet syndrome is a severe infantile-onset epileptic encephalopathy associated with mutations in the sodium channel alpha-1 subunit gene SCN1A. We aimed to describe the incidence of Dravet syndrome in the Danish population. Based on a 6-year birth cohort from 2004 to 2009, we propose an incidence of 1:22,000, which is higher than what has been established earlier. We identified 17 cases with SCN1A mutation-positive Dravet syndrome. Fifteen patients were found, by conventional Sanger sequencing. Two additional patients with clinical Dravet syndrome, but without a detectable SCN1A mutation by Sanger sequencing, were diagnosed with a SCN1A mutation after using a targeted next-generation sequencing gene panel.
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Affiliation(s)
- Allan Bayat
- Department of Clinical Genetics, Copenhagen University Hospital, Copenhagen, Denmark
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Lateef TM, Johann-Liang R, Kaulas H, Hasan R, Williams K, Caserta V, Nelson KB. Seizures, encephalopathy, and vaccines: experience in the National Vaccine Injury Compensation Program. J Pediatr 2015; 166:576-81. [PMID: 25477158 DOI: 10.1016/j.jpeds.2014.10.054] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 09/12/2014] [Accepted: 10/22/2014] [Indexed: 10/24/2022]
Abstract
OBJECTIVES To describe the demographic and clinical characteristics of children for whom claims were filed with the National Vaccine Injury Compensation Program (VICP) alleging seizure disorder and/or encephalopathy as a vaccine injury. STUDY DESIGN The National VICP within the Department of Health and Human Services compensates individuals who develop medical problems associated with a covered immunization. We retrospectively reviewed medical records of children younger than 2 years of age with seizures and/or encephalopathy allegedly caused by an immunization, where a claim was filed in the VICP between 1995 through 2005. RESULTS The VICP retrieved 165 claims that had sufficient clinical information for review. Approximately 80% of these alleged an injury associated with whole-cell diphtheria, pertussis (whooping cough), and tetanus or tetanus, diphtheria toxoids, and acellular pertussis vaccine. Pre-existing seizures were found in 13% and abnormal findings on a neurologic examination before the alleged vaccine injury in 10%. A final diagnostic impression of seizure disorder was established in 69%, of whom 17% (28 patients) had myoclonic epilepsy, including possible severe myoclonic epilepsy of infancy. Specific conditions not caused by immunization, such as tuberous sclerosis and cerebral dysgenesis, were identified in 16% of subjects. CONCLUSION A significant number of children with alleged vaccine injury had pre-existing neurologic or neurodevelopmental abnormalities. Among those developing chronic epilepsy, many had clinical features suggesting genetically determined epilepsy. Future studies that include genotyping may allow more specific therapy and prognostication, and enhance public confidence in vaccination.
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Affiliation(s)
- Tarannum M Lateef
- Department of Neurology, Children's National Medical Center and George Washington University School of Medicine, Washington, DC.
| | - Rosemary Johann-Liang
- Division of Vaccine Injury Compensation, Department of Health and Human Services, Rockville, MD
| | - Himanshu Kaulas
- Department of Neurology, Children's National Medical Center and George Washington University School of Medicine, Washington, DC
| | - Rakibul Hasan
- Department of Neurology, Children's National Medical Center and George Washington University School of Medicine, Washington, DC
| | - Karen Williams
- Division of Vaccine Injury Compensation, Department of Health and Human Services, Rockville, MD
| | - Vito Caserta
- Division of Vaccine Injury Compensation, Department of Health and Human Services, Rockville, MD
| | - Karin B Nelson
- Department of Neurology, Children's National Medical Center and George Washington University School of Medicine, Washington, DC; National Institute of Neurologic Disorders and Stroke, National Institutes of Health, Bethesda, MD
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Kouga T, Shimbo H, Iai M, Yamashita S, Ishii A, Ihara Y, Hirose S, Yamakawa K, Osaka H. Effect of CYP2C19 polymorphisms on stiripentol administration in Japanese cases of Dravet syndrome. Brain Dev 2015; 37:243-9. [PMID: 24819914 DOI: 10.1016/j.braindev.2014.04.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 03/31/2014] [Accepted: 04/08/2014] [Indexed: 10/25/2022]
Abstract
OBJECTIVE The objective of this study was to investigate stiripentol (STP) administration in cases of Dravet syndrome (DS) by comparing CYP2C19 allelic polymorphisms with the clinical effects of STP, including plasma concentrations of concomitant drugs and adverse effects of STP. MATERIALS AND METHODS Eleven cases of DS cases were included. Demographic and clinical characteristics of the cases (age at the study period, body weight, mean dose and plasma concentration of valproate acid (VPA)/clobazam (CLB) off and on STP, mean plasma concentration of norclobazam (N-CLB) off and on STP, degree of seizure reduction, and adverse effects of STP) were examined with each CYP2C19 polymorphism. RESULTS There were 3 cases of DS with wild type, 6 with intermediate type, and 2 with poor type of CYP2C19 polymorphisms. The N-CLB concentration/CLB dose ratio and N-CLB/CLB concentration ratio off STP were significantly higher in poor metabolizers. Three (37%) of 8 cases showed no effectiveness of STP regardless of the N-CLB concentration increase, and 1 (33%) of 3 cases showed effectiveness of STP regardless of N-CLB concentration decrease. In total, 6 (54%) of 11 cases with DS had >50% reduction in seizure frequency without significant differences in CYP2C19 polymorphisms. CONCLUSION This study demonstrated an effect of CYP2C19 polymorphisms on STP administration in Japanese cases of DS. There were cases of seizure reduction regardless of N-CLB concentration decrease on STP, which suggests a significant anti-convulsant action of STP. N-CLB concentration decrease on STP was observed in 1 case with ketogenic diet and 2 cases with (∗)3 allelic polymorphisms of CYP2C19.
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Affiliation(s)
- Takeshi Kouga
- Division of Neurology, Kanagawa Children's Medical Center, Yokohama, Japan
| | - Hiroko Shimbo
- Division of Neurology, Kanagawa Children's Medical Center, Yokohama, Japan
| | - Mizue Iai
- Division of Neurology, Kanagawa Children's Medical Center, Yokohama, Japan
| | - Sumimasa Yamashita
- Division of Neurology, Kanagawa Children's Medical Center, Yokohama, Japan
| | - Atsushi Ishii
- Departments of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan; Central Research Institute for the Pathomechanisms of Epilepsy, Fukuoka University, Fukuoka, Japan
| | - Yukiko Ihara
- Departments of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan
| | - Shinichi Hirose
- Departments of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan; Central Research Institute for the Pathomechanisms of Epilepsy, Fukuoka University, Fukuoka, Japan
| | - Kazuhiro Yamakawa
- Laboratory for Neurogenetics, RIKEN Brain Science Institute, Saitama, Japan
| | - Hitoshi Osaka
- Division of Neurology, Kanagawa Children's Medical Center, Yokohama, Japan; Department of Pediatrics, Jichi Medical University, Shimotsuke, Japan.
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Abstract
Voltage-gated sodium channels initiate action potentials in brain neurons, mutations in sodium channels cause inherited forms of epilepsy, and sodium channel blockers-along with other classes of drugs-are used in therapy of epilepsy. A mammalian voltage-gated sodium channel is a complex containing a large, pore-forming α subunit and one or two smaller β subunits. Extensive structure-function studies have revealed many aspects of the molecular basis for sodium channel structure, and X-ray crystallography of ancestral bacterial sodium channels has given insight into their three-dimensional structure. Mutations in sodium channel α and β subunits are responsible for genetic epilepsy syndromes with a wide range of severity, including generalized epilepsy with febrile seizures plus (GEFS+), Dravet syndrome, and benign familial neonatal-infantile seizures. These seizure syndromes are treated with antiepileptic drugs that offer differing degrees of success. The recent advances in understanding of disease mechanisms and sodium channel structure promise to yield improved therapeutic approaches.
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Affiliation(s)
- William A Catterall
- Department of Pharmacology, University of Washington, Seattle, Washington 98195-7280;
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41
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Xu X, Zhang Y, Sun H, Liu X, Yang X, Xiong H, Jiang Y, Bao X, Wang S, Yang Z, Wu Y, Qin J, Lin Q, Wu X. Early clinical features and diagnosis of Dravet syndrome in 138 Chinese patients with SCN1A mutations. Brain Dev 2014; 36:676-81. [PMID: 24168886 DOI: 10.1016/j.braindev.2013.10.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2013] [Revised: 08/23/2013] [Accepted: 10/09/2013] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To summarize the early clinical features of Dravet syndrome (DS) patients with SCN1A gene mutations before the age of one. METHODS SCN1A gene mutation screening was performed by PCR-DNA sequencing and multiple ligation-dependent probe amplication (MLPA). The early clinical features of DS patients with SCN1A mutations were reviewed with attention to the seizures induced by fever and other precipitating factors before the first year of life. RESULTS The clinical data of 138 DS patients with SCN1A gene mutations were reviewed. The median seizure onset age was 5.3 months. Ninety-nine patients (71.7%) experienced seizures with duration more than 15 min in the first year of life. Two or more seizures induced by fever within 24h or the same febrile illness were observed in 93 patients (67.4%). 111 patients (80.4%) had hemi-clonic and (or) focal seizures. Seizures had been triggered by fever of low degree (T<38 °C) in 62.3% (86/138) before the first year of life. Vaccine-related seizures were observed in 34.8% (48/138). Seizures in 22.5% (31/138) of patients were triggered by hot bath. Carbamazepine, oxcarbazepine, lamotrigine, phenobarbital and phenytoin showed either no effect or exacerbating the seizures in our group. CONCLUSION The seizure onset age in DS patients was earlier than that was in common febrile seizures. When a baby exhibits two or more features of complex febrile seizures in the first year of life, a diagnosis of DS should be considered, and SCN1A gene mutation screening should be performed as early as possible. Early diagnosis of DS will help clinicians more effectively prescribe antiepileptic drugs for stronger prognosis.
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Affiliation(s)
- Xiaojing Xu
- Department of Pediatrics, Peking University First Hospital, China
| | - Yuehua Zhang
- Department of Pediatrics, Peking University First Hospital, China.
| | - Huihui Sun
- Department of Pediatrics, Beijing Ji Shui Tan Hospital, China
| | - Xiaoyan Liu
- Department of Pediatrics, Peking University First Hospital, China
| | - Xiaoling Yang
- Department of Pediatrics, Peking University First Hospital, China
| | - Hui Xiong
- Department of Pediatrics, Peking University First Hospital, China
| | - Yuwu Jiang
- Department of Pediatrics, Peking University First Hospital, China
| | - Xinhua Bao
- Department of Pediatrics, Peking University First Hospital, China
| | - Shuang Wang
- Department of Pediatrics, Peking University First Hospital, China
| | - Zhixian Yang
- Department of Pediatrics, Peking University First Hospital, China
| | - Ye Wu
- Department of Pediatrics, Peking University First Hospital, China
| | - Jiong Qin
- Department of Pediatrics, Peking University First Hospital, China
| | - Qing Lin
- Department of Pediatrics, Peking University First Hospital, China
| | - Xiru Wu
- Department of Pediatrics, Peking University First Hospital, China
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Kaneko S, Yoshida S, Kanai K, Yasui-Furukori N, Iwasa H. Development of individualized medicine for epilepsy based on genetic information. Expert Rev Clin Pharmacol 2014; 1:661-81. [DOI: 10.1586/17512433.1.5.661] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Abstract
Epilepsy affects almost 1% of the population, and yet the pathophysiology of this disorder is unknown in the majority of the cases. Recently, a number of mutations in different genes were identified, mostly in cases of familial epilepsy with a Mendelian mode of inheritance. The majority of these genes code for voltage- or ligand-gated ion channels. Interestingly, not only generalized epilepsies, but also focal epilepsies were shown to be caused by mutated genes, which in some cases are expressed ubiquitously in the brain. This review will focus on the monogenic familial epilepsies and the clinical and molecular aspects of these diseases.
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Affiliation(s)
- Danielle M Andrade
- University of Toronto, Division of Neurology, Krembil Neuroscience Centre, Toronto Western Hospital, Toronto, Canada.
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44
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Ishii A, Kanaumi T, Sohda M, Misumi Y, Zhang B, Kakinuma N, Haga Y, Watanabe K, Takeda S, Okada M, Ueno S, Kaneko S, Takashima S, Hirose S. Association of nonsense mutation in GABRG2 with abnormal trafficking of GABAA receptors in severe epilepsy. Epilepsy Res 2014; 108:420-32. [PMID: 24480790 DOI: 10.1016/j.eplepsyres.2013.12.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 12/07/2013] [Accepted: 12/16/2013] [Indexed: 11/29/2022]
Abstract
Mutations in GABRG2, which encodes the γ2 subunit of GABAA receptors, can cause both genetic epilepsy with febrile seizures plus (GEFS+) and Dravet syndrome. Most GABRG2 truncating mutations associated with Dravet syndrome result in premature termination codons (PTCs) and are stably translated into mutant proteins with potential dominant-negative effects. This study involved search for mutations in candidate genes for Dravet syndrome, namely SCN1A, 2A, 1B, 2B, GABRA1, B2, and G2. A heterozygous nonsense mutation (c.118C>T, p.Q40X) in GABRG2 was identified in dizygotic twin girls with Dravet syndrome and their apparently healthy father. Electrophysiological studies with the reconstituted GABAA receptors in HEK cells showed reduced GABA-induced currents when mutated γ2 DNA was cotransfected with wild-type α1 and β2 subunits. In this case, immunohistochemistry using antibodies to the α1 and γ2 subunits of GABAA receptor showed granular staining in the soma. In addition, microinjection of mutated γ2 subunit cDNA into HEK cells severely inhibited intracellular trafficking of GABAA receptor subunits α1 and β2, and retention of these proteins in the endoplasmic reticulum. The mutated γ2 subunit-expressing neurons also showed impaired axonal transport of the α1 and β2 subunits. Our findings suggested that different phenotypes of epilepsy, e.g., GEFS+ and Dravet syndrome (which share similar abnormalities in causative genes) are likely due to impaired axonal transport associated with the dominant-negative effects of GABRG2.
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Affiliation(s)
- Atsushi Ishii
- Department of Pediatrics, Fukuoka University, Fukuoka, Japan; Central Research Institute for the Molecular Pathomechanisms of Epilepsy, Fukuoka University, Fukuoka, Japan
| | - Takeshi Kanaumi
- Department of Pediatrics, Fukuoka University, Fukuoka, Japan; Central Research Institute for the Molecular Pathomechanisms of Epilepsy, Fukuoka University, Fukuoka, Japan
| | - Miwa Sohda
- Division of Oral Biochemistry, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Yoshio Misumi
- Department of Cell Biology, Fukuoka University, Fukuoka, Japan
| | - Bo Zhang
- Department of Biochemistry, Fukuoka University, Fukuoka, Japan
| | - Naoto Kakinuma
- Department of Anatomy and Cell Biology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo, Japan
| | - Yoshiko Haga
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Kazuyoshi Watanabe
- Faculty of Health and Medical Sciences, Aichi Shukutoku University, Nagakute, Japan
| | - Sen Takeda
- Department of Anatomy and Cell Biology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo, Japan
| | - Motohiro Okada
- Division of Neuroscience, Graduate School of Medicine, Mie University, Tsu, Japan
| | - Shinya Ueno
- Rehabilitation Medicine, Institute of Brain Science, Japan
| | - Sunao Kaneko
- Department of Neuropsychiatry, Hirosaki University, Hirosaki, Japan; North Tohoku Epilepsy Center, Minato Hospital, Hachinohe, Japan
| | - Sachio Takashima
- Yanagawa Institute for Developmental Disabilities, Child Neurology, International University of Health and Welfare, Yanagawa, Japan
| | - Shinichi Hirose
- Department of Pediatrics, Fukuoka University, Fukuoka, Japan; Central Research Institute for the Molecular Pathomechanisms of Epilepsy, Fukuoka University, Fukuoka, Japan.
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45
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Kim YO, Bellows S, McMahon JM, Iona X, Damiano J, Dibbens L, Kelley K, Gill D, Cross JH, Berkovic SF, Scheffer IE. Atypical multifocal Dravet syndrome lacks generalized seizures and may show later cognitive decline. Dev Med Child Neurol 2014; 56:85-90. [PMID: 24328833 DOI: 10.1111/dmcn.12322] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/02/2013] [Indexed: 12/01/2022]
Abstract
AIM To show that atypical multifocal Dravet syndrome is a recognizable, electroclinical syndrome associated with sodium channel gene (SCN1A) mutations that readily escapes diagnosis owing to later cognitive decline and tonic seizures. METHOD Eight patients underwent electroclinical characterization. SCN1A was sequenced and copy number variations sought by multiplex ligation-dependent probe amplification. RESULTS All patients were female (age range at assessment 5-26y) with median seizure onset at 6.5 months (range 4-19mo). The initial seizure was brief in seven and status epilepticus only occurred in one; three were febrile. Focal seizures occurred in four patients and bilateral convulsion in the other four. All patients developed multiple focal seizure types and bilateral convulsions, with seizure clusters in six. The most common focal seizure semiology (six out of eight) comprised unilateral clonic activity. Five also had focal or asymmetric tonic seizures. Rare or transient myoclonic seizures occurred in six individuals, often triggered by specific antiepileptic drugs. Developmental slowing occurred in all: six between 3 years and 8 years, and two around 1 year 6 months. Cognitive outcome varied from severe to mild intellectual disability. Multifocal epileptiform discharges were seen on electroencephalography. Seven out of eight patients had SCN1A mutations. INTERPRETATION Atypical, multifocal Dravet syndrome with SCN1A mutations may not be recognized because of later cognitive decline and frequent tonic seizures.
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Affiliation(s)
- Young Ok Kim
- Epilepsy Research Centre, Department of Medicine, The University of Melbourne, Austin Health, Melbourne, Australia; Department of Paediatrics, School of Medicine, Chonnam National University, Gwangju, Korea
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Steinlein OK. Mechanisms underlying epilepsies associated with sodium channel mutations. PROGRESS IN BRAIN RESEARCH 2014; 213:97-111. [DOI: 10.1016/b978-0-444-63326-2.00005-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Weiss MM, Van der Zwaag B, Jongbloed JDH, Vogel MJ, Brüggenwirth HT, Lekanne Deprez RH, Mook O, Ruivenkamp CAL, van Slegtenhorst MA, van den Wijngaard A, Waisfisz Q, Nelen MR, van der Stoep N. Best Practice Guidelines for the Use of Next-Generation Sequencing Applications in Genome Diagnostics: A National Collaborative Study of Dutch Genome Diagnostic Laboratories. Hum Mutat 2013; 34:1313-21. [DOI: 10.1002/humu.22368] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Accepted: 06/05/2013] [Indexed: 11/09/2022]
Affiliation(s)
- Marjan M. Weiss
- Department of Clinical Genetics; VU University Medical Centre; Amsterdam; The Netherlands
| | - Bert Van der Zwaag
- Department of Medical Genetics; University Medical Centre Utrecht; Utrecht; The Netherlands
| | - Jan D. H. Jongbloed
- Department of Genetics; University Medical Centre Groningen; Groningen; The Netherlands
| | - Maartje J. Vogel
- Department of Medical Genetics; University Medical Centre Utrecht; Utrecht; The Netherlands
| | | | | | - Olaf Mook
- Department of Clinical Genetics; Academic Medical Centre; Amsterdam; The Netherlands
| | | | | | - Arthur van den Wijngaard
- Department of Clinical Genetics; University Medical Centre Maastricht; Maastricht; The Netherlands
| | - Quinten Waisfisz
- Department of Clinical Genetics; VU University Medical Centre; Amsterdam; The Netherlands
| | - Marcel R. Nelen
- Department of Human Genetics; Radboud University Nijmegen Medical Centre; Nijmegen; The Netherlands
| | - Nienke van der Stoep
- Department of Clinical Genetics; Leiden University Medical Centre; Leiden; The Netherlands
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48
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The SCN1A gene variants and epileptic encephalopathies. J Hum Genet 2013; 58:573-80. [PMID: 23884151 DOI: 10.1038/jhg.2013.77] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 06/24/2013] [Accepted: 07/03/2013] [Indexed: 02/02/2023]
Abstract
The voltage-gated sodium channels are fundamental units that evoke the action potential in excitable cells such as neurons. These channels are integral membrane proteins typically consisting of one α-subunit, which forms the larger central pore of the channel, and two smaller auxiliary β-subunits, which modulate the channel functions. Genetic alterations in the SCN1A gene coding for the α-subunit of the neuronal voltage-gated sodium ion channel, type 1 (NaV 1.1), is associated with a spectrum of seizure-related disorders in human, ranging from a relatively milder form of febrile seizures to a more severe epileptic condition known as the Dravet syndrome. Among the epilepsy genes, the SCN1A gene perhaps known to have the largest number of disease-associated alleles. Here we present a meta-analysis on the SCN1A gene variants and provide comprehensive information on epilepsy-associated gene variants, their frequency, the predicted effect on the protein, the ethnicity of the affected along with the inheritance pattern and the associated epileptic phenotype. We also summarize our current understanding on the pathophysiology of the SCN1A gene defects, disease mechanism, genetic modifiers and their clinical and diagnostic relevance.
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49
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Ishii A, Yasumoto S, Ihara Y, Inoue T, Fujita T, Nakamura N, Ohfu M, Yamashita Y, Takatsuka H, Taga T, Miyata R, Ito M, Tsuchiya H, Matsuoka T, Kitao T, Murakami K, Lee WT, Kaneko S, Hirose S. Genetic analysis of PRRT2 for benign infantile epilepsy, infantile convulsions with choreoathetosis syndrome, and benign convulsions with mild gastroenteritis. Brain Dev 2013; 35:524-30. [PMID: 23073245 DOI: 10.1016/j.braindev.2012.09.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 09/05/2012] [Accepted: 09/11/2012] [Indexed: 11/18/2022]
Abstract
PURPOSE PRRT2 mutations were recently identified in benign familial infantile epilepsy (BFIE) and infantile convulsions with paroxysmal choreoathetosis (ICCA) but no abnormalities have so far been identified in their phenotypically similar seizure disorder of benign convulsions with mild gastroenteritis (CwG), while mutations in KCNQ2 and KCNQ3 have been recognized in benign familial neonatal epilepsy (BFNE). The aim of this study was to identify PRRT2 mutations in infantile convulsions in Asian families with BFIE and ICCA, CwG and BFNE. METHODS We recruited 26 unrelated Japanese affected with either BFIE or non-familial benign infantile seizures and their families, including three families with ICCA. A total of 17 Japanese and Taiwanese with CwG, 50 Japanese with BFNE and 96 healthy volunteers were also recruited. Mutations of PRRT2 were sought using direct sequencing. RESULTS Heterozygous truncation mutation (c.649dupC) was identified in 15 of 26 individuals with benign infantile epilepsy (52.1%). All three families of ICCA harbored the same mutation (100%). Another novel mutation (c.1012+2dupT) was found in the proband of a family with BFIE. However, no PRRT2 mutation was found in either CwG or BFNE. CONCLUSIONS The results confirm that c.649dupC, a truncating mutation of PRRT2, is a hotspot mutation resulting in BFIE or ICCA regardless of the ethnic background. In contrast, PRRT2 mutations do not seem to be associated with CwG or BFNE. Screening for PRRT2 mutation might be useful in early-stage differentiation of BFIE from CwG.
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Affiliation(s)
- Atsushi Ishii
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan
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Higurashi N, Uchida T, Lossin C, Misumi Y, Okada Y, Akamatsu W, Imaizumi Y, Zhang B, Nabeshima K, Mori MX, Katsurabayashi S, Shirasaka Y, Okano H, Hirose S. A human Dravet syndrome model from patient induced pluripotent stem cells. Mol Brain 2013; 6:19. [PMID: 23639079 PMCID: PMC3655893 DOI: 10.1186/1756-6606-6-19] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 04/03/2013] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Dravet syndrome is a devastating infantile-onset epilepsy syndrome with cognitive deficits and autistic traits caused by genetic alterations in SCN1A gene encoding the α-subunit of the voltage-gated sodium channel Na(v)1.1. Disease modeling using patient-derived induced pluripotent stem cells (iPSCs) can be a powerful tool to reproduce this syndrome's human pathology. However, no such effort has been reported to date. We here report a cellular model for DS that utilizes patient-derived iPSCs. RESULTS We generated iPSCs from a Dravet syndrome patient with a c.4933C>T substitution in SCN1A, which is predicted to result in truncation in the fourth homologous domain of the protein (p.R1645*). Neurons derived from these iPSCs were primarily GABAergic (>50%), although glutamatergic neurons were observed as a minor population (<1%). Current-clamp analyses revealed significant impairment in action potential generation when strong depolarizing currents were injected. CONCLUSIONS Our results indicate a functional decline in Dravet neurons, especially in the GABAergic subtype, which supports previous findings in murine disease models, where loss-of-function in GABAergic inhibition appears to be a main driver in epileptogenesis. Our data indicate that patient-derived iPSCs may serve as a new and powerful research platform for genetic disorders, including the epilepsies.
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Affiliation(s)
- Norimichi Higurashi
- Department of Pediatrics, School of Medicine, Fukuoka University, 45-1, 7-chome, Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan
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