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Dwivedi R, Kaushik M, Tripathi M, Dada R, Tiwari P. Unraveling the genetic basis of epilepsy: Recent advances and implications for diagnosis and treatment. Brain Res 2024; 1843:149120. [PMID: 39032529 DOI: 10.1016/j.brainres.2024.149120] [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: 05/20/2024] [Revised: 07/05/2024] [Accepted: 07/08/2024] [Indexed: 07/23/2024]
Abstract
Epilepsy, affecting approximately 1% of the global population, manifests as recurring seizures and is heavily influenced by genetic factors. Recent advancements in genetic technologies have revolutionized our understanding of epilepsy's genetic landscape. Key studies, such as the discovery of mutations in ion channels (e.g., SCN1A and SCN2A), neurotransmitter receptors (e.g., GABRA1), and synaptic proteins (e.g., SYNGAP1, KCNQ2), have illuminated critical pathways underlying epilepsy susceptibility and pathogenesis. Genome-wide association studies (GWAS) have identified specific genetic variations linked to epilepsy risk, such as variants near SCN1A and PCDH7, enhancing diagnostic accuracy and enabling personalized treatment strategies. Moreover, epigenetic mechanisms, including DNA methylation (e.g., MBD5), histone modifications (e.g., HDACs), and non-coding RNAs (e.g., miR-134), play pivotal roles in altering gene expression and synaptic plasticity, contributing to epileptogenesis. These discoveries offer promising avenues for therapeutic interventions aimed at improving outcomes for epilepsy patients. Genetic testing has become essential in clinical practice, facilitating precise diagnosis and tailored management approaches based on individual genetic profiles. Furthermore, insights into epigenetic regulation suggest novel therapeutic targets for developing more effective epilepsy treatments. In summary, this review highlights significant progress in understanding the genetic and epigenetic foundations of epilepsy. By integrating findings from key studies and specifying genes involved in epigenetic modifications, we underscore the potential for advanced therapeutic strategies in this complex neurological disorder, emphasizing the importance of personalized medicine approaches in epilepsy management.
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Affiliation(s)
- Rekha Dwivedi
- Department of Neurology, All India Institute of Medical Sciences (AIIMS), New Delhi 110029, India
| | - Meenakshi Kaushik
- Department of Anatomy, All India Institute of Medical Sciences (AIIMS), New Delhi 110029, India
| | - Manjari Tripathi
- Department of Neurology, All India Institute of Medical Sciences (AIIMS), New Delhi 110029, India
| | - Rima Dada
- Department of Anatomy, All India Institute of Medical Sciences (AIIMS), New Delhi 110029, India
| | - Prabhakar Tiwari
- Department of Anatomy, All India Institute of Medical Sciences (AIIMS), New Delhi 110029, India.
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2
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Dong R, Jin R, Zhang H, Zhang H, Xue M, Li Y, Zhang K, Lv Y, Li X, Liu Y, Gai Z. Genotypic and phenotypic characteristics of sodium channel-associated epilepsy in Chinese population. J Hum Genet 2024:10.1038/s10038-024-01257-2. [PMID: 38880818 DOI: 10.1038/s10038-024-01257-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 04/27/2024] [Accepted: 04/30/2024] [Indexed: 06/18/2024]
Abstract
Variants in voltage-gated sodium channel (VGSC) genes are implicated in seizures, epilepsy, and neurodevelopmental disorders, constituting a significant aspect of hereditary epilepsy in the Chinese population. Through retrospective analysis utilizing next-generation sequencing (NGS), we examined the genotypes and phenotypes of VGSC-related epilepsy cases from a cohort of 691 epilepsy subjects. Our findings revealed that 5.1% of subjects harbored VGSC variants, specifically 22 with SCN1A, 9 with SCN2A, 1 with SCN8A, and 3 with SCN1B variants; no SCN3A variants were detected. Among these, 14 variants were previously reported, while 21 were newly identified. SCN1A variant carriers predominantly presented with Dravet Syndrome (DS) and Genetic Epilepsy with Febrile Seizures Plus (GEFS + ), featuring a heightened sensitivity to fever-induced seizures. Statistically significant disparities emerged between the SCN1A-DS and SCN1A-GEFS+ groups concerning seizure onset and genetic diagnosis age, incidence of status epilepticus, mental retardation, anti-seizure medication (ASM) responsiveness, and familial history. Notably, subjects with SCN1A variants affecting the protein's pore region experienced more frequent cluster seizures. All SCN2A variants were of de novo origin, and 88.9% of individuals with SCN2A variations exhibited cluster seizures. This research reveals a significant association between variations in VGSC-related genes and the clinical phenotype diversity of epilepsy subjects in China, emphasizing the pivotal role of NGS screening in establishing accurate disease diagnoses and guiding the selection of ASM.
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Affiliation(s)
- Rui Dong
- Pediatric Research Institute, Children's Hospital Affiliated to Shandong University (Jinan Children's Hospital), Jinan, China
- Shandong Provincial Clinical Research Center for Children's Health and Disease, Jinan, China
| | - Ruifeng Jin
- Shandong Provincial Clinical Research Center for Children's Health and Disease, Jinan, China
- Department of neurology, Children's Hospital Affiliated to Shandong University (Jinan Children's Hospital), Jinan, China
| | - Hongwei Zhang
- Shandong Provincial Clinical Research Center for Children's Health and Disease, Jinan, China
- Department of neurology, Children's Hospital Affiliated to Shandong University (Jinan Children's Hospital), Jinan, China
| | - Haiyan Zhang
- Pediatric Research Institute, Children's Hospital Affiliated to Shandong University (Jinan Children's Hospital), Jinan, China
- Shandong Provincial Clinical Research Center for Children's Health and Disease, Jinan, China
| | - Min Xue
- Pediatric Research Institute, Children's Hospital Affiliated to Shandong University (Jinan Children's Hospital), Jinan, China
- Shandong Provincial Clinical Research Center for Children's Health and Disease, Jinan, China
| | - Yue Li
- Pediatric Research Institute, Children's Hospital Affiliated to Shandong University (Jinan Children's Hospital), Jinan, China
- Shandong Provincial Clinical Research Center for Children's Health and Disease, Jinan, China
| | - Kaihui Zhang
- Pediatric Research Institute, Children's Hospital Affiliated to Shandong University (Jinan Children's Hospital), Jinan, China
- Shandong Provincial Clinical Research Center for Children's Health and Disease, Jinan, China
| | - Yuqiang Lv
- Pediatric Research Institute, Children's Hospital Affiliated to Shandong University (Jinan Children's Hospital), Jinan, China
- Shandong Provincial Clinical Research Center for Children's Health and Disease, Jinan, China
| | - Xiaoying Li
- Shandong Provincial Clinical Research Center for Children's Health and Disease, Jinan, China.
- Neonatology department, Children's Hospital Affiliated to Shandong University (Jinan Children's Hospital), Jinan, China.
| | - Yi Liu
- Pediatric Research Institute, Children's Hospital Affiliated to Shandong University (Jinan Children's Hospital), Jinan, China.
- Shandong Provincial Clinical Research Center for Children's Health and Disease, Jinan, China.
| | - Zhongtao Gai
- Pediatric Research Institute, Children's Hospital Affiliated to Shandong University (Jinan Children's Hospital), Jinan, China
- Shandong Provincial Clinical Research Center for Children's Health and Disease, Jinan, China
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3
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Veltra D, Theodorou V, Katsalouli M, Vorgia P, Niotakis G, Tsaprouni T, Pons R, Kosma K, Kampouraki A, Tsoutsou I, Makrythanasis P, Kekou K, Traeger-Synodinos J, Sofocleous C. SCN1A Channels a Wide Range of Epileptic Phenotypes: Report of Novel and Known Variants with Variable Presentations. Int J Mol Sci 2024; 25:5644. [PMID: 38891831 PMCID: PMC11171476 DOI: 10.3390/ijms25115644] [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: 04/03/2024] [Revised: 05/15/2024] [Accepted: 05/18/2024] [Indexed: 06/21/2024] Open
Abstract
SCN1A, the gene encoding for the Nav1.1 channel, exhibits dominant interneuron-specific expression, whereby variants disrupting the channel's function affect the initiation and propagation of action potentials and neuronal excitability causing various types of epilepsy. Dravet syndrome (DS), the first described clinical presentation of SCN1A channelopathy, is characterized by severe myoclonic epilepsy in infancy (SMEI). Variants' characteristics and other genetic or epigenetic factors lead to extreme clinical heterogeneity, ranging from non-epileptic conditions to developmental and epileptic encephalopathy (DEE). This current study reports on findings from 343 patients referred by physicians in hospitals and tertiary care centers in Greece between 2017 and 2023. Positive family history for specific neurologic disorders was disclosed in 89 cases and the one common clinical feature was the onset of seizures, at a mean age of 17 months (range from birth to 15 years old). Most patients were specifically referred for SCN1A investigation (Sanger Sequencing and MLPA) and only five for next generation sequencing. Twenty-six SCN1A variants were detected, including nine novel causative variants (c.4567A>Τ, c.5564C>A, c.2176+2T>C, c.3646G>C, c.4331C>A, c.1130_1131delGAinsAC, c.1574_1580delCTGAGGA, c.4620A>G and c.5462A>C), and are herein presented, along with subsequent genotype-phenotype associations. The identification of novel variants complements SCN1A databases extending our expertise on genetic counseling and patient and family management including gene-based personalized interventions.
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Affiliation(s)
- Danai Veltra
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, St. Sophia’s Children’s Hospital, 11527 Athens, Greece; (D.V.); (K.K.); (A.K.); (I.T.); (P.M.); (K.K.); (J.T.-S.)
- Research University Institute for the Study and Prevention of Genetic and Malignant Disease of Childhood, National and Kapodistrian University of Athens, St. Sophia’s Children’s Hospital, 11527 Athens, Greece
| | - Virginia Theodorou
- Pediatric Neurology Department, St. Sophia’s Children’s Hospital, 11527 Athens, Greece; (V.T.); (M.K.)
| | - Marina Katsalouli
- Pediatric Neurology Department, St. Sophia’s Children’s Hospital, 11527 Athens, Greece; (V.T.); (M.K.)
| | - Pelagia Vorgia
- Agrifood and Life Sciences Institute, Hellenic Mediterranean University, 71410 Heraklion, Greece;
| | - Georgios Niotakis
- Pediatric Neurology Department, Venizelion Hospital, 71409 Heraklion, Greece;
| | | | - Roser Pons
- First Department of Pediatrics, Medical School, National and Kapodistrian University of Athens, St. Sophia’s Children’s Hospital, 11527 Athens, Greece;
| | - Konstantina Kosma
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, St. Sophia’s Children’s Hospital, 11527 Athens, Greece; (D.V.); (K.K.); (A.K.); (I.T.); (P.M.); (K.K.); (J.T.-S.)
| | - Afroditi Kampouraki
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, St. Sophia’s Children’s Hospital, 11527 Athens, Greece; (D.V.); (K.K.); (A.K.); (I.T.); (P.M.); (K.K.); (J.T.-S.)
| | - Irene Tsoutsou
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, St. Sophia’s Children’s Hospital, 11527 Athens, Greece; (D.V.); (K.K.); (A.K.); (I.T.); (P.M.); (K.K.); (J.T.-S.)
| | - Periklis Makrythanasis
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, St. Sophia’s Children’s Hospital, 11527 Athens, Greece; (D.V.); (K.K.); (A.K.); (I.T.); (P.M.); (K.K.); (J.T.-S.)
- Department of Genetic Medicine and Development, Medical School, University of Geneva, 1211 Geneva, Switzerland
- Biomedical Research Foundation of the Academy of Athens, 11527 Athens, Greece
| | - Kyriaki Kekou
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, St. Sophia’s Children’s Hospital, 11527 Athens, Greece; (D.V.); (K.K.); (A.K.); (I.T.); (P.M.); (K.K.); (J.T.-S.)
| | - Joanne Traeger-Synodinos
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, St. Sophia’s Children’s Hospital, 11527 Athens, Greece; (D.V.); (K.K.); (A.K.); (I.T.); (P.M.); (K.K.); (J.T.-S.)
| | - Christalena Sofocleous
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, St. Sophia’s Children’s Hospital, 11527 Athens, Greece; (D.V.); (K.K.); (A.K.); (I.T.); (P.M.); (K.K.); (J.T.-S.)
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Chen GT, Nair G, Osorio AJ, Holley SM, Ghassemzadeh K, Gonzalez J, Lu C, Sanjana NE, Cepeda C, Geschwind DH. Enhancer-targeted CRISPR-Activation Rescues Haploinsufficient Autism Susceptibility Genes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.13.584921. [PMID: 38559217 PMCID: PMC10980046 DOI: 10.1101/2024.03.13.584921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Autism Spectrum Disorder (ASD) is a highly heritable condition with diverse clinical presentations. Approximately 20% of ASD's genetic susceptibility is imparted by de novo mutations of major effect, most of which cause haploinsufficiency. We mapped enhancers of two high confidence autism genes - CHD8 and SCN2A and used CRISPR-based gene activation (CRISPR-A) in hPSC-derived excitatory neurons and cerebral forebrain organoids to correct the effects of haploinsufficiency, taking advantage of the presence of a wildtype allele of each gene and endogenous gene regulation. We found that CRISPR-A induced a sustained increase in CHD8 and SCN2A expression in treated neurons and organoids, with rescue of gene expression levels and mutation-associated phenotypes, including gene expression and physiology. These data support gene activation via targeting enhancers of haploinsufficient genes, as a therapeutic intervention in ASD and other neurodevelopmental disorders.
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Ding K, Gong Y, Cheng C, Li X, Zhu Y, Gao X, Li Y, Yuan C, Liu Z, Jiang W, Chen C, Yao LH. Expression and electrophysiological characteristics of VGSC during mouse myoblasts differentiation. Cell Signal 2024; 113:110970. [PMID: 37967692 DOI: 10.1016/j.cellsig.2023.110970] [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: 10/09/2023] [Revised: 10/31/2023] [Accepted: 11/12/2023] [Indexed: 11/17/2023]
Abstract
Voltage-gated sodium channels (VGSC) are essential for triggering and relaying action potentials (AP), which perform critical functions in a variety of physiological processes, such as controlling muscle contractions and facilitating the release of neurotransmitters. In this study, we used a mouse C2C12 cell differentiation model to study the molecular expression and channel dynamics of VGSC and to investigate the exact role of VGSC in the development of muscle regeneration. Immunofluorescence, Real-time quantitative polymerase chain reaction, Western blot, and whole-cell patch clamp were employed for this purpose in mouse myoblasts. The findings revealed an increase in intracellular sodium concentration, NaV1.4 gene expression, and protein expression with the progress of differentiation (days 0, 1, 3, 5 and 7). Furthermore, VGSC dynamics exhibit the following characteristics: ① The increase of sodium current (INa); ② The decrease in the activation threshold and the voltage trigger maximum of INa; ③ A positive shift in the steady-state inactivation curve; ④ The recovery of INa during repolarization is delayed, the activity-dependent decay rate of INa was accelerated, and the proportionate amount of the fraction of activated channels was reduced. Based on these results, it is postulated that the activation threshold of AP could be decreased, and the refractory period could be extended with the extension of differentiation duration, which may contribute to muscle contraction. Taken together, VGSC provides a theoretical and empirical basis for exploring potential targets for neuromuscular diseases and other therapeutic muscle regeneration dysfunctions.
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Affiliation(s)
- Kaizhi Ding
- School of Life Science, Jiangxi Science & Technology Normal University, Nanchang, Jiangxi 330013, PR China
| | - Yanchun Gong
- School of Life Science, Jiangxi Science & Technology Normal University, Nanchang, Jiangxi 330013, PR China
| | - Chunfang Cheng
- School of Life Science, Jiangxi Science & Technology Normal University, Nanchang, Jiangxi 330013, PR China; School of Physical Education and Health, Jiangxi Science & Technology Normal University, Nanchang, Jiangxi 330013, PR China
| | - Xiaonuo Li
- School of Life Science, Jiangxi Science & Technology Normal University, Nanchang, Jiangxi 330013, PR China
| | - Yuanjie Zhu
- School of Life Science, Jiangxi Science & Technology Normal University, Nanchang, Jiangxi 330013, PR China
| | - Xiaofei Gao
- School of Life Science, Jiangxi Science & Technology Normal University, Nanchang, Jiangxi 330013, PR China
| | - Yuhua Li
- School of Life Science, Jiangxi Science & Technology Normal University, Nanchang, Jiangxi 330013, PR China
| | - Chunhua Yuan
- School of Physical Education and Health, Jiangxi Science & Technology Normal University, Nanchang, Jiangxi 330013, PR China
| | - Zhibing Liu
- School of Physical Education and Health, Jiangxi Science & Technology Normal University, Nanchang, Jiangxi 330013, PR China
| | - Wei Jiang
- Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi 330006, PR China
| | - Chong Chen
- School of Life Science, Jiangxi Science & Technology Normal University, Nanchang, Jiangxi 330013, PR China; School of Physical Education and Health, Jiangxi Science & Technology Normal University, Nanchang, Jiangxi 330013, PR China; NHC Key Laboratory of Diagnosis and Treatment on Brain Functional Diseases, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, PR China.
| | - Li-Hua Yao
- School of Life Science, Jiangxi Science & Technology Normal University, Nanchang, Jiangxi 330013, PR China; School of Physical Education and Health, Jiangxi Science & Technology Normal University, Nanchang, Jiangxi 330013, PR China.
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6
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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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Rusina E, Simonti M, Duprat F, Cestèle S, Mantegazza M. Voltage-gated sodium channels in genetic epilepsy: up and down of excitability. J Neurochem 2023. [PMID: 37654020 DOI: 10.1111/jnc.15947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 08/11/2023] [Accepted: 08/13/2023] [Indexed: 09/02/2023]
Abstract
The past two decades have witnessed a wide range of studies investigating genetic variants of voltage-gated sodium (NaV ) channels, which are involved in a broad spectrum of diseases, including several types of epilepsy. We have reviewed here phenotypes and pathological mechanisms of genetic epilepsies caused by variants in NaV α and β subunits, as well as of some relevant interacting proteins (FGF12/FHF1, PRRT2, and Ankyrin-G). Notably, variants of all these genes can induce either gain- or loss-of-function of NaV leading to either neuronal hyperexcitability or hypoexcitability. We present the results of functional studies obtained with different experimental models, highlighting that they should be interpreted considering the features of the experimental system used. These systems are models, but they have allowed us to better understand pathophysiological issues, ameliorate diagnostics, orientate genetic counseling, and select/develop therapies within a precision medicine framework. These studies have also allowed us to gain insights into the physiological roles of different NaV channels and of the cells that express them. Overall, our review shows the progress that has been made, but also the need for further studies on aspects that have not yet been clarified. Finally, we conclude by highlighting some significant themes of general interest that can be gleaned from the results of the work of the last two decades.
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Affiliation(s)
- Evgeniia Rusina
- University Cote d'Azur, Valbonne-Sophia Antipolis, France
- CNRS UMR 7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
| | - Martina Simonti
- University Cote d'Azur, Valbonne-Sophia Antipolis, France
- CNRS UMR 7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
| | - Fabrice Duprat
- University Cote d'Azur, Valbonne-Sophia Antipolis, France
- CNRS UMR 7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
- Inserm, Valbonne-Sophia Antipolis, France
| | - Sandrine Cestèle
- University Cote d'Azur, Valbonne-Sophia Antipolis, France
- CNRS UMR 7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
| | - Massimo Mantegazza
- University Cote d'Azur, Valbonne-Sophia Antipolis, France
- CNRS UMR 7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
- Inserm, Valbonne-Sophia Antipolis, France
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Asadi-Pooya AA. Precision Medicine in Epilepsy Management; GET Application (Gene, Epilepsy, Treatment). Clin Neuropharmacol 2023; 46:95-97. [PMID: 37191562 DOI: 10.1097/wnf.0000000000000549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
Abstract
OBJECTIVES The aim was to develop a prototype of an application (app) that identifies the significance of discovered genes for further consideration in the treatment plan of patients with epilepsy (precision medicine). METHODS MEDLINE was systematically searched for related publications from inception to April 1, 2022. The following search strategy was implemented (title/abstract): "epilepsy" AND "precision" AND "medicine." The following data were extracted: genes, phenotypes associated with those genes, and the recommended treatments. Two other databases were searched to cross-check the retrieved data and add to the data: https://www.genecards.org and https://medlineplus.gov/genetics. Also, the original articles of the identified genes were retrieved. Genes with specific treatment strategies (ie, any specific drug to be selected or to be avoided and also any other specific therapies [eg, diets, supplements, etc]) were selected. RESULTS A database of 93 genes, which are associated with various epilepsy syndromes and for which specific treatment strategies have been suggested, was developed. CONCLUSIONS A Web-based app (a search engine) was developed accordingly that is freely available at http://get.yektaparnian.ir/, GET (Gene, Epilepsy, Treatment). When a patient comes to the clinic with a genetic diagnosis and a specific gene is identified, the physician enters the gene name into the search box, and the app shows whether this genetic epilepsy needs a specific treatment. This endeavor would benefit from input by experts in the field, and the Web site should be developed more comprehensively.
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Affiliation(s)
- Ali A Asadi-Pooya
- Shiraz University of Medical Sciences, Shiraz, Iran; and Thomas Jefferson University, Philadelphia, PA
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9
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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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Lin JJ, Meletti S, Vaudano AE, Lin KL. Developmental and epileptic encephalopathies: Is prognosis related to different epileptic network dysfunctions? Epilepsy Behav 2022; 131:107654. [PMID: 33349540 DOI: 10.1016/j.yebeh.2020.107654] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/17/2020] [Accepted: 11/18/2020] [Indexed: 11/19/2022]
Abstract
Developmental and epileptic encephalopathies are a group of rare, severe epilepsies, which are characterized by refractory seizures starting in infancy or childhood and developmental delay or regression. Developmental changes might be independent of epilepsy. However, interictal epileptic activity and seizures can further deteriorate cognition and behavior. Recently, the concept of developmental and epileptic encephalopathies has moved from the lesions associated with epileptic encephalopathies toward the epileptic network dysfunctions on the functioning of the brain. Early recognition and differentiation of patients with developmental and epileptic encephalopathies is important, as precision therapies need to be holistic to address the often devastating symptoms. In this review, we discuss the evolution of the concept of developmental and epileptic encephalopathies in recent years, as well as the current understanding of the genetic basis of developmental and epileptic encephalopathies. Finally, we will discuss the role of epileptic network dysfunctions on prognosis for these severe conditions.
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Affiliation(s)
- Jainn-Jim Lin
- Division of Pediatric Critical Care and Pediatric Neurocritical Care Center, Chang Gung Children's Hospital and Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, Taiwan; Graduate Institute of Clinical Medical Sciences, Chang Gung University, College of Medicine, Taoyuan, Taiwan; Division of Pediatric Neurology, Chang Gung Children's Hospital and Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, Taiwan; Department of Respiratory Therapy, Chang Gung Children's Hospital and Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, Taiwan; Study Group for Intensive and Integrated Care of Pediatric Central Nervous System (iCNS Group), Chang Gung Children's Hospital, Taoyuan, Taiwan
| | - Stefano Meletti
- Division of Neurology, University Hospital of Modena, Modena, Italy; Department of Biomedical, Metabolic and Neural Science, University of Modena and Reggio Emilia, Modena, Italy
| | - Anna Elisabetta Vaudano
- Division of Neurology, University Hospital of Modena, Modena, Italy; Department of Biomedical, Metabolic and Neural Science, University of Modena and Reggio Emilia, Modena, Italy
| | - Kuang-Lin Lin
- Division of Pediatric Neurology, Chang Gung Children's Hospital and Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, Taiwan; Study Group for Intensive and Integrated Care of Pediatric Central Nervous System (iCNS Group), Chang Gung Children's Hospital, Taoyuan, Taiwan.
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11
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Caefer DM, Phan NQ, Liddle JC, Balsbaugh JL, O'Shea JP, Tzingounis AV, Schwartz D. The Okur-Chung Neurodevelopmental Syndrome Mutation CK2 K198R Leads to a Rewiring of Kinase Specificity. Front Mol Biosci 2022; 9:850661. [PMID: 35517865 PMCID: PMC9062000 DOI: 10.3389/fmolb.2022.850661] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Accepted: 03/22/2022] [Indexed: 11/13/2022] Open
Abstract
Okur-Chung Neurodevelopmental Syndrome (OCNDS) is caused by heterozygous mutations to the CSNK2A1 gene, which encodes the alpha subunit of protein kinase CK2. The most frequently occurring mutation is lysine 198 to arginine (K198R). To investigate the impact of this mutation, we first generated a high-resolution phosphorylation motif of CK2WT, including the first characterization of specificity for tyrosine phosphorylation activity. A second high resolution motif representing CK2K198R substrate specificity was also generated. Here we report the impact of the OCNDS associated CK2K198R mutation. Contrary to prior speculation, the mutation does not result in a complete loss of function, but rather shifts the substrate specificity of the kinase. Broadly speaking the mutation leads to 1) a decreased preference for acidic residues in the +1 position, 2) a decreased preference for threonine phosphorylation, 3) an increased preference for tyrosine phosphorylation, and 4) an alteration of the tyrosine phosphorylation specificity motif. To further investigate the result of this mutation we have developed a probability-based scoring method, allowing us to predict shifts in phosphorylation in the K198R mutant relative to the wild type kinase. As an initial step we have applied the methodology to the set of axonally localized ion channels in an effort to uncover potential alterations of the phosphoproteome associated with the OCNDS disease condition.
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Affiliation(s)
- Danielle M Caefer
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, United States
| | - Nhat Q Phan
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, United States
| | - Jennifer C Liddle
- Center for Open Research Resources and Equipment, Proteomics and Metabolomics Facility, University of Connecticut, Storrs, CT, United States
| | - Jeremy L Balsbaugh
- Center for Open Research Resources and Equipment, Proteomics and Metabolomics Facility, University of Connecticut, Storrs, CT, United States
| | - Joseph P O'Shea
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, United States
| | - Anastasios V Tzingounis
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, United States
| | - Daniel Schwartz
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, United States
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12
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Hieu NLT, Thu NTM, Ngan LTA, Van LTK, Huy DP, Linh PTT, Mai NTQ, Hien HTD, Hang DTT. Genetic analysis using targeted exome sequencing of 53 Vietnamese children with developmental and epileptic encephalopathies. Am J Med Genet A 2022; 188:2048-2060. [PMID: 35365919 DOI: 10.1002/ajmg.a.62741] [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: 08/15/2021] [Revised: 01/14/2022] [Accepted: 03/13/2022] [Indexed: 11/07/2022]
Abstract
Developmental and epileptic encephalopathies (DEE) refers to a group of rare and severe neurodevelopmental disorders where genetic etiologies can play a major role. This study aimed to elucidate the genetic etiologies of a cohort of 53 Vietnamese patients with DEE. All patients were classified into known electroclinical syndromes where possible. Exome sequencing (ES) followed by a targeted analysis on 294 DEE-related genes was then performed. Patients with identified causative variants were followed for 6 months to determine the impact of genetic testing on their treatment. The diagnostic yield was 38.0% (20/53), which was significantly higher in the earlier onset group (<12 months) than in the later onset group (≥12 months). The 19 identified variants belonged to 11 genes with various cellular functions. Genes encoding ion channels especially sodium voltage-gated channel were the most frequently involved. Most variants were missense variants and located in key protein functional domains. Four variants were novel and four had been reported previously but in different phenotypes. Within 6 months of further follow-up, treatment changes were applied for six patients based on the identified disease-causing variants, with five patients showing a positive impact. This is the first study in Vietnam to analyze the genetics of DEE. This study confirms the strong involvement of genetic etiologies in DEE, especially early onset DEE. The study also contributes to clarify the genotype-phenotype correlations of DEE and highlights the efficacy of targeted ES in the diagnosis and treatment of DEE.
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Affiliation(s)
- Nguyen Le Trung Hieu
- Neurology Department, Children Hospital 2, Ho Chi Minh City, Vietnam.,University of Medicine and Pharmacy, Ho Chi Minh City, Vietnam
| | | | - Le Tran Anh Ngan
- Neurology Department, Children Hospital 2, Ho Chi Minh City, Vietnam
| | - Le Thi Khanh Van
- Neurology Department, Children Hospital 2, Ho Chi Minh City, Vietnam
| | - Do Phuoc Huy
- Medical Genetics Institute, Ho Chi Minh City, Vietnam
| | - Pham Thi Truc Linh
- Functional Genomic Unit, DNA Medical Technology Company, Ho Chi Minh City, Vietnam
| | - Nguyen Thi Quynh Mai
- Research Center for Genetics and Reproductive Health, School of Medicine, Vietnam National University, Ho Chi Minh City, Vietnam
| | - Huynh Thi Dieu Hien
- Research Center for Genetics and Reproductive Health, School of Medicine, Vietnam National University, Ho Chi Minh City, Vietnam
| | - Do Thi Thu Hang
- Research Center for Genetics and Reproductive Health, School of Medicine, Vietnam National University, Ho Chi Minh City, Vietnam
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13
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Wong JC, Butler KM, Shapiro L, Thelin JT, Mattison KA, Garber KB, Goldenberg PC, Kubendran S, Schaefer GB, Escayg A. Pathogenic in-Frame Variants in SCN8A: Expanding the Genetic Landscape of SCN8A-Associated Disease. Front Pharmacol 2021; 12:748415. [PMID: 34867351 PMCID: PMC8635767 DOI: 10.3389/fphar.2021.748415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 10/21/2021] [Indexed: 01/11/2023] Open
Abstract
Numerous SCN8A mutations have been identified, of which, the majority are de novo missense variants. Most mutations result in epileptic encephalopathy; however, some are associated with less severe phenotypes. Mouse models generated by knock-in of human missense SCN8A mutations exhibit seizures and a range of behavioral abnormalities. To date, there are only a few Scn8a mouse models with in-frame deletions or insertions, and notably, none of these mouse lines exhibit increased seizure susceptibility. In the current study, we report the generation and characterization of two Scn8a mouse models (ΔIRL/+ and ΔVIR/+) carrying overlapping in-frame deletions within the voltage sensor of domain 4 (DIVS4). Both mouse lines show increased seizure susceptibility and infrequent spontaneous seizures. We also describe two unrelated patients with the same in-frame SCN8A deletion in the DIV S5-S6 pore region, highlighting the clinical relevance of this class of mutations.
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Affiliation(s)
- Jennifer C Wong
- Department of Human Genetics, Emory University, Atlanta, GA, United States
| | - Kameryn M Butler
- Department of Human Genetics, Emory University, Atlanta, GA, United States.,Greenwood Genetic Center, Greenwood, SC, United States
| | - Lindsey Shapiro
- Department of Human Genetics, Emory University, Atlanta, GA, United States
| | - Jacquelyn T Thelin
- Department of Human Genetics, Emory University, Atlanta, GA, United States
| | - Kari A Mattison
- Department of Human Genetics, Emory University, Atlanta, GA, United States
| | - Kathryn B Garber
- Department of Human Genetics, Emory University, Atlanta, GA, United States
| | - Paula C Goldenberg
- Department of Pediatrics and Medical Genetics, Harvard Medical School, Boston, MA, United States
| | - Shobana Kubendran
- Department of Pediatrics, Kansas University School of Medicine-Wichita, Wichita, KS, United States
| | - G Bradley Schaefer
- University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Andrew Escayg
- Department of Human Genetics, Emory University, Atlanta, GA, United States
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14
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Salinas V, Martínez N, Maturo JP, Rodriguez-Quiroga SA, Zavala L, Medina N, Amartino H, Sfaello I, Agosta G, Serafín EM, Morón DG, Kauffman MA, Vega P. Clinical next generation sequencing in developmental and epileptic encephalopathies: Diagnostic relevance of data re-analysis and variants re-interpretation. Eur J Med Genet 2021; 64:104363. [PMID: 34673242 DOI: 10.1016/j.ejmg.2021.104363] [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: 12/11/2020] [Revised: 09/24/2021] [Accepted: 10/08/2021] [Indexed: 11/26/2022]
Abstract
Developmental and epileptic encephalopathies (DEE) are complex pediatric epilepsies, in which heterogeneous pathogenic factors play an important role. Next-generation-sequencing based tools have shown excellent effectiveness. The constant increase in the number of new genotype-phenotype associations suggests the periodic need for re-interpretation and re-analysis of genetic studies without positive results. In this study, we report the diagnostic utility of targeted gene panel sequencing and whole exome sequencing in 55 Argentine subjects with DEE, focusing on the utility of re-interpretation and re-analysis of undetermined and negative genetic diagnoses. The new information in biomedical literature and databases was used for the re-interpretation. For re-analysis, sequencing data processing was repeated using updated bioinformatics tools. Initially, pathogenic variants were detected in 21 subjects (38%). After an average time of 29 months, 25% of the subjects without a genetic diagnosis were re-categorized as diagnosed. Finally, the overall diagnostic yield increased to 53% (29 subjects). In consequence of the re-interpretation and re-analysis, we identified novel variants in the genes: CHD2, COL4A1, FOXG1, GABRA1, GRIN2B, HNRNPU, KCNQ2, MECP2, PCDH19, SCN1A, SCN2A, SCN8A, SLC6A1, STXBP1 and WWOX. Our results expand the diagnostic yield of this subgroup of infantile and childhood seizures and demonstrate the importance of re-evaluation of genetic tests in subjects without an identified causative etiology.
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Affiliation(s)
- Valeria Salinas
- Neurogenetics Unit, Hospital JM Ramos Mejía, Buenos Aires, Argentina; Precision Medicine and Clinical Genomics Group, Translational Medicine Research Institute-CONICET, Faculty of Biomedical Sciences, Universidad Austral, Buenos Aires, Argentina.
| | - Nerina Martínez
- Neurogenetics Unit, Hospital JM Ramos Mejía, Buenos Aires, Argentina.
| | - Josefina Pérez Maturo
- Neurogenetics Unit, Hospital JM Ramos Mejía, Buenos Aires, Argentina; Precision Medicine and Clinical Genomics Group, Translational Medicine Research Institute-CONICET, Faculty of Biomedical Sciences, Universidad Austral, Buenos Aires, Argentina.
| | | | - Lucia Zavala
- Neurogenetics Unit, Hospital JM Ramos Mejía, Buenos Aires, Argentina.
| | - Nancy Medina
- Neurogenetics Unit, Hospital JM Ramos Mejía, Buenos Aires, Argentina.
| | - Hernán Amartino
- Paediatric Neurology Unit, Hospital Universitario Austral, Buenos Aires, Argentina.
| | - Ignacio Sfaello
- CETES, Instituto de Neurología Infanto-Juvenil, Córdoba, Argentina.
| | - Guillermo Agosta
- Paediatric Neurology Unit, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina.
| | | | | | - Marcelo A Kauffman
- Neurogenetics Unit, Hospital JM Ramos Mejía, Buenos Aires, Argentina; Precision Medicine and Clinical Genomics Group, Translational Medicine Research Institute-CONICET, Faculty of Biomedical Sciences, Universidad Austral, Buenos Aires, Argentina.
| | - Patricia Vega
- Neurogenetics Unit, Hospital JM Ramos Mejía, Buenos Aires, Argentina.
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15
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Wang D, Jiang Y, Hong S, Ma J, Liao S, Cheng M, Li T, Jiang L. Prognostic factors for the recurrence of afebrile seizures after benign convulsions associated with mild gastroenteritis. Epilepsia 2021; 62:3068-3075. [PMID: 34668572 DOI: 10.1111/epi.17102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 10/02/2021] [Accepted: 10/05/2021] [Indexed: 12/01/2022]
Abstract
OBJECTIVE The overall prognosis of benign convulsions associated with mild gastroenteritis (CwG) is favorable, and the incidence of afebrile seizure recurrence with or without gastroenteritis (ASwGI and ASwoGI, respectively) is low. In this study we investigated the prognostic factors associated with afebrile seizure (AS) relapse after the first CwG episode. METHODS A hospital-based cohort with an initial CwG episode from January 2012 to October 2019 was followed for at least 19 months. The relapse types were divided into ASwGI and ASwoGI. Logistic regression analysis was performed to identify the independent prognostic factors for the recurrence of AS after the initial CwG episode. Furthermore, the clinical characteristics between ASwGI and ASwoGI were compared. RESULTS Among the 868 patients enrolled, 67 (7.7%) experienced a second AS and 71% (48/67) showed gastroenteritis-associated recurrence. Except for five patients with subsequent epilepsy (0.6%), only eight (0.9%) experienced three seizure episodes. The independent predictive factors for the subsequent recurrence of AS were age less than 18 months at onset (odds ratio [OR]: 2.93, 95% confidence interval [CI]: 1.53-5.63), repeated seizures over 24 h (OR: 4.09, 95% CI: 2.19-7.65), and absence of fever (OR: 2.33, 95% CI: 1.26-4.33) during the first CwG episode. The probability of recurrence of AS for those with one, two, and three predictive factors was 3.23%, 13.35%, and 22.85%, respectively. In addition, the age at onset was significantly lower in the ASwoGI group than in the ASwGI group during the first episode (p < .05). SIGNIFICANCE The risk of AS relapse after the initial CwG episode is low, and the majority of patients presented with gastroenteritis. The risk can be predicted by age at onset, repeated seizures over 24 h, and absence of fever during the first CwG episode.
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Affiliation(s)
- Duan Wang
- Department of Neurology, Children's Hospital of Chongqing Medical University(CHCMU), Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, National Clinical Research Center for Child Health and Disorders, Chongqing, China
| | - Yu Jiang
- Department of Neurology, Children's Hospital of Chongqing Medical University(CHCMU), Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, National Clinical Research Center for Child Health and Disorders, Chongqing, China
| | - Siqi Hong
- Department of Neurology, Children's Hospital of Chongqing Medical University(CHCMU), Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, National Clinical Research Center for Child Health and Disorders, Chongqing, China
| | - Jiannan Ma
- Department of Neurology, Children's Hospital of Chongqing Medical University(CHCMU), Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, National Clinical Research Center for Child Health and Disorders, Chongqing, China
| | - Shuang Liao
- Department of Neurology, Children's Hospital of Chongqing Medical University(CHCMU), Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, National Clinical Research Center for Child Health and Disorders, Chongqing, China
| | - Min Cheng
- Department of Neurology, Children's Hospital of Chongqing Medical University(CHCMU), Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, National Clinical Research Center for Child Health and Disorders, Chongqing, China
| | - Tingsong Li
- Ministry of Education Key Laboratory of Child Development and Disorders, International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, National Clinical Research Center for Child Health and Disorders, Chongqing, China.,Department of Rehabilitation, CHCMU, Chongqing, China
| | - Li Jiang
- Department of Neurology, Children's Hospital of Chongqing Medical University(CHCMU), Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, National Clinical Research Center for Child Health and Disorders, Chongqing, China
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16
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Abstract
Genetic testing has yielded major advances in our understanding of the causes of epilepsy. Seizures remain resistant to treatment in a significant proportion of cases, particularly in severe, childhood-onset epilepsy, the patient population in which an underlying causative genetic variant is most likely to be identified. A genetic diagnosis can be explanatory as to etiology, and, in some cases, might suggest a therapeutic approach; yet, a clear path from genetic diagnosis to treatment remains unclear in most cases. Here, we discuss theoretical considerations behind the attempted use of small molecules for the treatment of genetic epilepsies, which is but one among various approaches currently under development. We explore a few salient examples and consider the future of the small molecule approach for genetic epilepsies. We conclude that significant additional work is required to understand how genetic variation leads to dysfunction of epilepsy-associated protein targets, and how this impacts the function of diverse subtypes of neurons embedded within distributed brain circuits to yield epilepsy and epilepsy-associated comorbidities. A syndrome- or even variant-specific approach may be required to achieve progress. Advances in the field will require improved methods for large-scale target validation, compound identification and optimization, and the development of accurate model systems that reflect the core features of human epilepsy syndromes, as well as novel approaches towards clinical trials of such compounds in small rare disease cohorts.
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Affiliation(s)
- Ethan M Goldberg
- Department of Pediatrics, Division of Neurology, Abramson Research Center, The Epilepsy Neurogenetics Initiative, The Children's Hospital of Philadelphia, Abramson Research Center Room 502A, 19104, Philadelphia, PA, USA.
- Departments of Neurology and Neuroscience, The University of Pennsylvania Perelman School of Medicine, 19104, Philadelphia, PA, USA.
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17
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Brunklaus A. No evidence that SCN9A variants are associated with epilepsy. Seizure 2021; 91:172-173. [PMID: 34171626 DOI: 10.1016/j.seizure.2021.05.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 05/31/2021] [Indexed: 11/18/2022] Open
Affiliation(s)
- A Brunklaus
- The Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, United Kingdom; Institute of Health and Wellbeing, University of Glasgow, Glasgow, United Kingdom.
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18
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Miao P, Tang S, Ye J, Tang J, Wang J, Zheng C, Li Y, Feng J. Differential Functional Changes of Nav1.2 Channel Causing SCN2A-Related Epilepsy and Status Epilepticus During Slow Sleep. Front Neurol 2021; 12:653517. [PMID: 34093402 PMCID: PMC8170409 DOI: 10.3389/fneur.2021.653517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 03/24/2021] [Indexed: 11/13/2022] Open
Abstract
Background: Nav1.2 encoded by the SCN2A gene is a brain-expressed voltage-gated sodium channel known to be associated with neurodevelopment disorders ranging from benign familial neonatal infantile seizures (BFIS) to developmental and epileptic encephalopathy (DEE) and autism spectrum disorder. Interestingly, status epilepticus during slow sleep (ESES), which aggravates cognitive impairment, has been found in SCN2A-related epilepsy. However, the functional features and the relationship between SCN2A and ESES have not been researched. Method: We herein investigated the functional consequences of an unpublished de novo V911A and the other two published variants in patients with SCN2A-related disorder and ESES by whole-cell patch-clamp studies in transfected HEK293T cells. Results: The unpublished V911A and published K1933M variants detected in patients with DEE exhibited a profound gain-of-functional (GOF) change. Another published BFIS variant S863F significantly reduced current density as a loss-of-functional (LOF) change. The refractory epilepsy in the patient with V911A was controlled by using the precise treatment of oxcarbazepine (OXC) since the age of 3 months. ESES was found at 18 months during the seizure-free period. We finally chose an aggressive treatment for eliminating ESES by using methylprednisolone combined with levetiracetam and nitrazepam instead of the precise treatment of OXC. Conclusion: Both GOF and LOF variants in the SCN2A gene can lead to ESES among the phenotypes of DEE and BFIS. We should monitor the electroencephalogram regularly in the patients with SCN2A-related epilepsy even during their seizure-free period.
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Affiliation(s)
- Pu Miao
- Pediatric Department, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Siyang Tang
- National Health Center and Chinese Academy of Medical Sciences Key Laboratory of Medical Neurobiology, National Clinical Research Center for Child Health, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jia Ye
- National Health Center and Chinese Academy of Medical Sciences Key Laboratory of Medical Neurobiology, National Clinical Research Center for Child Health, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jihong Tang
- Department of Neurology, Children's Hospital of Soochow University, Suzhou, China
| | - Jianda Wang
- Pediatric Department, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Chaoguang Zheng
- Pediatric Department, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yuezhou Li
- National Health Center and Chinese Academy of Medical Sciences Key Laboratory of Medical Neurobiology, National Clinical Research Center for Child Health, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jianhua Feng
- Pediatric Department, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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19
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Ithal D, Sukumaran SK, Bhattacharjee D, Vemula A, Nadella R, Mahadevan J, Sud R, Viswanath B, Purushottam M, Jain S. Exome hits demystified: The next frontier. Asian J Psychiatr 2021; 59:102640. [PMID: 33892377 DOI: 10.1016/j.ajp.2021.102640] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 03/26/2021] [Indexed: 12/13/2022]
Abstract
Severe mental illnesses such as schizophrenia and bipolar disorder have complex inheritance patterns, involving both common and rare variants. Whole exome sequencing is a promising approach to find out the rare genetic variants. We had previously reported several rare variants in multiplex families with severe mental illnesses. The current article tries to summarise the biological processes and pattern of expression of genes harbouring the aforementioned variants, linking them to known clinical manifestations through a methodical narrative review. Of the 28 genes considered for this review from 7 families with multiple affected individuals, 6 genes are implicated in various neuropsychiatric manifestations including some variations in the brain morphology assessed by magnetic resonance imaging. Another 15 genes, though associated with neuropsychiatric manifestations, did not have established brain morphological changes whereas the remaining 7 genes did not have any previously recorded neuropsychiatric manifestations at all. Wnt/b-catenin signaling pathway was associated with 6 of these genes and PI3K/AKT, calcium signaling, ERK, RhoA and notch signaling pathways had at least 2 gene associations. We present a comprehensive review of biological and clinical knowledge about the genes previously reported in multiplex families with severe mental illness. A 'disease in dish approach' can be helpful to further explore the fundamental mechanisms.
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Affiliation(s)
- Dhruva Ithal
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
| | - Salil K Sukumaran
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
| | - Debanjan Bhattacharjee
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
| | - Alekhya Vemula
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
| | - Ravi Nadella
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
| | - Jayant Mahadevan
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
| | - Reeteka Sud
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
| | - Biju Viswanath
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
| | - Meera Purushottam
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India.
| | - Sanjeev Jain
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
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20
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Aledo-Serrano Á, Gómez-Iglesias P, Toledano R, Garcia-Peñas JJ, Garcia-Morales I, Anciones C, Soto-Insuga V, Benke TA, Del Pino I, Gil-Nagel A. Sodium channel blockers for the treatment of epilepsy in CDKL5 deficiency disorder: Findings from a multicenter cohort. Epilepsy Behav 2021; 118:107946. [PMID: 33848848 DOI: 10.1016/j.yebeh.2021.107946] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 03/21/2021] [Accepted: 03/21/2021] [Indexed: 12/15/2022]
Abstract
OBJECTIVE This study was aimed to analyze the effectiveness of sodium channel blockers (SCBs) in CDKL5 deficiency disorder (CDD)-related epilepsy. METHODS A retrospective, observational study was performed, including patients with CDD diagnosis evaluated between 2016 and 2019 at three tertiary Epilepsy Centers. Demographic, electroclinical and genetic features, as well as ASM treatments and their outcomes were analyzed, with special focus on SCBs. RESULTS Twenty-one patients evaluated at three tertiary Epilepsy Centers were included, of which 19 presented with epilepsy (90.5%); all had pathogenic mutations of CDKL5. Six patients (31.6%) were classified as SCB responders (more than 50% reduction), four being currently seizure free (mean seizure-free period of 8 years). Most frequent SCB drugs were oxcarbazepine (OXC), carbamazepine (CBZ), and lacosamide (LCM). None of them presented relevant adverse events. In contrast, three patients showed seizure aggravation in the non-responder group. When comparing both groups, responders had statistically significant younger age at SCB treatment and epilepsy onset, higher proportion of focal epileptiform activity and less frequent history of West syndrome. CONCLUSIONS The results of this study indicate that treatment with SCBs might be effective and safe in a subset of patients with CDD-related epilepsy.
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Affiliation(s)
- Ángel Aledo-Serrano
- Epilepsy Program. Neurology Department, Ruber Internacional Hospital, Madrid, Spain; Epilepsy Unit. Neuroscience Department, Corachan Clinic, Barcelona, Spain.
| | | | - Rafael Toledano
- Epilepsy Program. Neurology Department, Ruber Internacional Hospital, Madrid, Spain; Epilepsy Unit, Neurology Department, Ramon y Cajal University Hospital, Madrid, Spain
| | - Juan Jose Garcia-Peñas
- Department of Pediatric Neurology, Niño Jesus University Children's Hospital, Madrid, Spain
| | - Irene Garcia-Morales
- Epilepsy Program. Neurology Department, Ruber Internacional Hospital, Madrid, Spain; Epilepsy Unit. Neurology Department, Clínico San Carlos University Hospital, Madrid, Spain
| | - Carla Anciones
- Epilepsy Program. Neurology Department, Ruber Internacional Hospital, Madrid, Spain
| | - Victor Soto-Insuga
- Department of Pediatric Neurology, Niño Jesus University Children's Hospital, Madrid, Spain
| | - Timothy A Benke
- Departments of Pediatrics, Neurology, and Pharmacology, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, CO, United States
| | - Isabel Del Pino
- Principe Felipe Research Center (Centro de Investigación Principe Felipe, CIPF), Valencia, Spain
| | - Antonio Gil-Nagel
- Epilepsy Program. Neurology Department, Ruber Internacional Hospital, Madrid, Spain
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21
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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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22
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Jones LB, Peters CH, Rosch RE, Owers M, Hughes E, Pal DK, Ruben PC. The L1624Q Variant in SCN1A Causes Familial Epilepsy Through a Mixed Gain and Loss of Channel Function. Front Pharmacol 2021; 12:788192. [PMID: 34925043 PMCID: PMC8675213 DOI: 10.3389/fphar.2021.788192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 11/17/2021] [Indexed: 11/13/2022] Open
Abstract
Variants of the SCN1A gene encoding the neuronal voltage-gated sodium channel NaV1.1 cause over 85% of all cases of Dravet syndrome, a severe and often pharmacoresistent epileptic encephalopathy with mostly infantile onset. But with the increased availability of genetic testing for patients with epilepsy, variants in SCN1A have now also been described in a range of other epilepsy phenotypes. The vast majority of these epilepsy-associated variants are de novo, and most are either nonsense variants that truncate the channel or missense variants that are presumed to cause loss of channel function. However, biophysical analysis has revealed a significant subset of missense mutations that result in increased excitability, further complicating approaches to precision pharmacotherapy for patients with SCN1A variants and epilepsy. We describe clinical and biophysical data of a familial SCN1A variant encoding the NaV1.1 L1624Q mutant. This substitution is located on the extracellular linker between S3 and S4 of Domain IV of NaV1.1 and is a rare case of a familial SCN1A variant causing an autosomal dominant frontal lobe epilepsy. We expressed wild-type (WT) and L1642Q channels in CHO cells. Using patch-clamp to characterize channel properties at several temperatures, we show that the L1624Q variant increases persistent current, accelerates fast inactivation onset and decreases current density. While SCN1A-associated epilepsy is typically considered a loss-of-function disease, our results put L1624Q into a growing set of mixed gain and loss-of-function variants in SCN1A responsible for epilepsy.
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Affiliation(s)
- Laura B Jones
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Colin H Peters
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Richard E Rosch
- MRC Centre for Neurodevelopmental Disorders, King's College London, London, United Kingdom.,Department of Paediatric Neurology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
| | - Maxine Owers
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Elaine Hughes
- Department of Paediatric Neurosciences, King's College Hospital, London, United Kingdom.,Department of Paediatric Neurosciences, Evelina London Children's Hospital, London, United Kingdom
| | - Deb K Pal
- MRC Centre for Neurodevelopmental Disorders, King's College London, London, United Kingdom.,Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, United Kingdom
| | - Peter C Ruben
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
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23
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Turner TJ, Zourray C, Schorge S, Lignani G. Recent advances in gene therapy for neurodevelopmental disorders with epilepsy. J Neurochem 2020; 157:229-262. [PMID: 32880951 PMCID: PMC8436749 DOI: 10.1111/jnc.15168] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 08/18/2020] [Accepted: 08/20/2020] [Indexed: 12/14/2022]
Abstract
Neurodevelopmental disorders can be caused by mutations in neuronal genes fundamental to brain development. These disorders have severe symptoms ranging from intellectually disability, social and cognitive impairments, and a subset are strongly linked with epilepsy. In this review, we focus on those neurodevelopmental disorders that are frequently characterized by the presence of epilepsy (NDD + E). We loosely group the genes linked to NDD + E with different neuronal functions: transcriptional regulation, intrinsic excitability and synaptic transmission. All these genes have in common a pivotal role in defining the brain architecture and function during early development, and when their function is altered, symptoms can present in the first stages of human life. The relationship with epilepsy is complex. In some NDD + E, epilepsy is a comorbidity and in others seizures appear to be the main cause of the pathology, suggesting that either structural changes (NDD) or neuronal communication (E) can lead to these disorders. Furthermore, grouping the genes that cause NDD + E, we review the uses and limitations of current models of the different disorders, and how different gene therapy strategies are being developed to treat them. We highlight where gene replacement may not be a treatment option, and where innovative therapeutic tools, such as CRISPR‐based gene editing, and new avenues of delivery are required. In general this group of genetically defined disorders, supported increasing knowledge of the mechanisms leading to neurological dysfunction serve as an excellent collection for illustrating the translational potential of gene therapy, including newly emerging tools.
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Affiliation(s)
- Thomas J Turner
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Clara Zourray
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK.,Department of Pharmacology, UCL School of Pharmacy, London, UK
| | | | - Gabriele Lignani
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
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24
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Takai A, Yamaguchi M, Yoshida H, Chiyonobu T. Investigating Developmental and Epileptic Encephalopathy Using Drosophila melanogaster. Int J Mol Sci 2020; 21:ijms21176442. [PMID: 32899411 PMCID: PMC7503973 DOI: 10.3390/ijms21176442] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 08/30/2020] [Accepted: 09/01/2020] [Indexed: 12/16/2022] Open
Abstract
Developmental and epileptic encephalopathies (DEEs) are the spectrum of severe epilepsies characterized by early-onset, refractory seizures occurring in the context of developmental regression or plateauing. Early infantile epileptic encephalopathy (EIEE) is one of the earliest forms of DEE, manifesting as frequent epileptic spasms and characteristic electroencephalogram findings in early infancy. In recent years, next-generation sequencing approaches have identified a number of monogenic determinants underlying DEE. In the case of EIEE, 85 genes have been registered in Online Mendelian Inheritance in Man as causative genes. Model organisms are indispensable tools for understanding the in vivo roles of the newly identified causative genes. In this review, we first present an overview of epilepsy and its genetic etiology, especially focusing on EIEE and then briefly summarize epilepsy research using animal and patient-derived induced pluripotent stem cell (iPSC) models. The Drosophila model, which is characterized by easy gene manipulation, a short generation time, low cost and fewer ethical restrictions when designing experiments, is optimal for understanding the genetics of DEE. We therefore highlight studies with Drosophila models for EIEE and discuss the future development of their practical use.
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Affiliation(s)
- Akari Takai
- Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan;
| | - Masamitsu Yamaguchi
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 603-8585, Japan; (M.Y.); (H.Y.)
- Kansai Gakken Laboratory, Kankyo Eisei Yakuhin Co. Ltd., Kyoto 619-0237, Japan
| | - Hideki Yoshida
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 603-8585, Japan; (M.Y.); (H.Y.)
| | - Tomohiro Chiyonobu
- Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan;
- Correspondence:
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