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Ng ACH, Chahine M, Scantlebury MH, Appendino JP. Channelopathies in epilepsy: an overview of clinical presentations, pathogenic mechanisms, and therapeutic insights. J Neurol 2024; 271:3063-3094. [PMID: 38607431 DOI: 10.1007/s00415-024-12352-x] [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: 03/17/2024] [Revised: 03/24/2024] [Accepted: 03/25/2024] [Indexed: 04/13/2024]
Abstract
Pathogenic variants in genes encoding ion channels are causal for various pediatric and adult neurological conditions. In particular, several epilepsy syndromes have been identified to be caused by specific channelopathies. These encompass a spectrum from self-limited epilepsies to developmental and epileptic encephalopathies spanning genetic and acquired causes. Several of these channelopathies have exquisite responses to specific antiseizure medications (ASMs), while others ASMs may prove ineffective or even worsen seizures. Some channelopathies demonstrate phenotypic pleiotropy and can cause other neurological conditions outside of epilepsy. This review aims to provide a comprehensive exploration of the pathophysiology of seizure generation, ion channels implicated in epilepsy, and several genetic epilepsies due to ion channel dysfunction. We outline the clinical presentation, pathogenesis, and the current state of basic science and clinical research for these channelopathies. In addition, we briefly look at potential precision therapy approaches emerging for these disorders.
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Affiliation(s)
- Andy Cheuk-Him Ng
- Clinical Neuroscience and Pediatric Neurology, Department of Pediatrics, Cumming School of Medicine, Alberta Children's Hospital, University of Calgary, 28 Oki Drive NW, Calgary, AB, T3B 6A8, Canada
- Division of Neurology, Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta and Stollery Children's Hospital, Edmonton, AB, Canada
| | - Mohamed Chahine
- Department of Medicine, Faculty of Medicine, Université Laval, Quebec City, QC, Canada
- CERVO, Brain Research Centre, Quebec City, Canada
| | - Morris H Scantlebury
- Clinical Neuroscience and Pediatric Neurology, Department of Pediatrics, Cumming School of Medicine, Alberta Children's Hospital, University of Calgary, 28 Oki Drive NW, Calgary, AB, T3B 6A8, Canada
- Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Calgary, Canada
| | - Juan P Appendino
- Clinical Neuroscience and Pediatric Neurology, Department of Pediatrics, Cumming School of Medicine, Alberta Children's Hospital, University of Calgary, 28 Oki Drive NW, Calgary, AB, T3B 6A8, Canada.
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Poliquin S, Nwosu G, Randhave K, Shen W, Flamm C, Kang JQ. Modulating Endoplasmic Reticulum Chaperones and Mutant Protein Degradation in GABRG2(Q390X) Associated with Genetic Epilepsy with Febrile Seizures Plus and Dravet Syndrome. Int J Mol Sci 2024; 25:4601. [PMID: 38731820 PMCID: PMC11083348 DOI: 10.3390/ijms25094601] [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: 03/04/2024] [Revised: 04/10/2024] [Accepted: 04/17/2024] [Indexed: 05/13/2024] Open
Abstract
A significant number of patients with genetic epilepsy do not obtain seizure freedom, despite developments in new antiseizure drugs, suggesting a need for novel therapeutic approaches. Many genetic epilepsies are associated with misfolded mutant proteins, including GABRG2(Q390X)-associated Dravet syndrome, which we have previously shown to result in intracellular accumulation of mutant GABAA receptor γ2(Q390X) subunit protein. Thus, a potentially promising therapeutic approach is modulation of proteostasis, such as increasing endoplasmic reticulum (ER)-associated degradation (ERAD). To that end, we have here identified an ERAD-associated E3 ubiquitin ligase, HRD1, among other ubiquitin ligases, as a strong modulator of wildtype and mutant γ2 subunit expression. Overexpressing HRD1 or knockdown of HRD1 dose-dependently reduced the γ2(Q390X) subunit. Additionally, we show that zonisamide (ZNS)-an antiseizure drug reported to upregulate HRD1-reduces seizures in the Gabrg2+/Q390X mouse. We propose that a possible mechanism for this effect is a partial rescue of surface trafficking of GABAA receptors, which are otherwise sequestered in the ER due to the dominant-negative effect of the γ2(Q390X) subunit. Furthermore, this partial rescue was not due to changes in ER chaperones BiP and calnexin, as total expression of these chaperones was unchanged in γ2(Q390X) models. Our results here suggest that leveraging the endogenous ERAD pathway may present a potential method to degrade neurotoxic mutant proteins like the γ2(Q390X) subunit. We also demonstrate a pharmacological means of regulating proteostasis, as ZNS alters protein trafficking, providing further support for the use of proteostasis regulators for the treatment of genetic epilepsies.
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Affiliation(s)
- Sarah Poliquin
- Neuroscience Graduate Program, Vanderbilt University, Nashville, TN 37232, USA;
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232, USA;
| | - Gerald Nwosu
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232, USA;
- Department of Neuroscience and Pharmacology, Meharry Medical College, Nashville, TN 37208, USA
- Department of Neurology, Vanderbilt University Medical Center, 465 21st Ave South, Nashville, TN 37232, USA; (K.R.); (W.S.); (C.F.)
| | - Karishma Randhave
- Department of Neurology, Vanderbilt University Medical Center, 465 21st Ave South, Nashville, TN 37232, USA; (K.R.); (W.S.); (C.F.)
| | - Wangzhen Shen
- Department of Neurology, Vanderbilt University Medical Center, 465 21st Ave South, Nashville, TN 37232, USA; (K.R.); (W.S.); (C.F.)
| | - Carson Flamm
- Department of Neurology, Vanderbilt University Medical Center, 465 21st Ave South, Nashville, TN 37232, USA; (K.R.); (W.S.); (C.F.)
| | - Jing-Qiong Kang
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232, USA;
- Department of Neurology, Vanderbilt University Medical Center, 465 21st Ave South, Nashville, TN 37232, USA; (K.R.); (W.S.); (C.F.)
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
- Vanderbilt Kennedy Center of Human Development, Vanderbilt University, Nashville, TN 37232, USA
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Wu J, Zhao M, Jin YC, Li M, Yu KX, Yu HB. Schisandrin B, a dual positive allosteric modulator of GABA A and glycine receptors, alleviates seizures in multiple mouse models. Acta Pharmacol Sin 2024; 45:465-479. [PMID: 38017298 PMCID: PMC10834591 DOI: 10.1038/s41401-023-01195-3] [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: 07/26/2023] [Accepted: 11/09/2023] [Indexed: 11/30/2023] Open
Abstract
Epilepsy is a prevalent and severe neurological disorder and approximately 30% of patients are resistant to existing medications. It is of utmost importance to develop alternative therapies to treat epilepsy. Schisandrin B (SchB) is a major bioactive constituent of Schisandra chinensis (Turcz.) Baill and has multiple neuroprotective effects, sedative and hypnotic activities. In this study, we investigated the antiseizure effect of SchB in various mouse models of seizure and explored the underlying mechanisms. Pentylenetetrazole (PTZ), strychnine (STR), and pilocarpine-induced mouse seizure models were established. We showed that injection of SchB (10, 30, 60 mg/kg, i.p.) dose-dependently delayed the onset of generalized tonic-clonic seizures (GTCS), reduced the incidence of GTCS and mortality in PTZ and STR models. Meanwhile, injection of SchB (30 mg/kg, i.p.) exhibited therapeutic potential in pilocarpine-induced status epilepticus model, which was considered as a drug-resistant model. In whole-cell recording from CHO/HEK-239 cells stably expressing recombinant human GABAA receptors (GABAARs) and glycine receptors (GlyRs) and cultured hippocampal neurons, co-application of SchB dose-dependently enhanced GABA or glycine-induced current with EC50 values at around 5 μM, and application of SchB (10 μM) alone did not activate the channels in the absence of GABA or glycine. Furthermore, SchB (10 μM) eliminated both PTZ-induced inhibition on GABA-induced current (IGABA) and strychnine (STR)-induced inhibition on glycine-induced current (Iglycine). Moreover, SchB (10 μM) efficiently rescued the impaired GABAARs associated with genetic epilepsies. In addition, the homologous mutants in both GlyRs-α1(S267Q) and GABAARs-α1(S297Q)β2(N289S)γ2L receptors by site-directed mutagenesis tests abolished SchB-induced potentiation of IGABA and Iglycine. In conclusion, we have identified SchB as a natural positive allosteric modulator of GABAARs and GlyRs, supporting its potential as alternative therapies for epilepsy.
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Affiliation(s)
- Jun Wu
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Miao Zhao
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Yu-Chen Jin
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Min Li
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Ke-Xin Yu
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Hai-Bo Yu
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China.
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Mortensen M, Xu Y, Shehata MA, Krall J, Ernst M, Frølund B, Smart TG. Pregnenolone sulfate analogues differentially modulate GABA A receptor closed/desensitised states. Br J Pharmacol 2023; 180:2482-2499. [PMID: 37194503 PMCID: PMC10952582 DOI: 10.1111/bph.16143] [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: 06/07/2021] [Revised: 02/07/2023] [Accepted: 05/05/2023] [Indexed: 05/18/2023] Open
Abstract
BACKGROUND AND PURPOSE GABAA receptors are regulated by numerous classes of allosteric modulators. However, regulation of receptor macroscopic desensitisation remains largely unexplored and may offer new therapeutic opportunities. Here, we report the emerging potential for modulating desensitisation with analogues of the endogenous inhibitory neurosteroid, pregnenolone sulfate. EXPERIMENTAL APPROACH New pregnenolone sulfate analogues were synthesised incorporating various heterocyclic substitutions located at the C-21 position on ring D. The pharmacological profiles of these compounds were assessed using electrophysiology and recombinant GABAA receptors together with mutagenesis, molecular dynamics simulations, structural modelling and kinetic simulations. KEY RESULTS All seven analogues retained a negative allosteric modulatory capability whilst exhibiting diverse potencies. Interestingly, we observed differential effects on GABA current decay by compounds incorporating either a six- (compound 5) or five-membered heterocyclic ring (compound 6) on C-21, which was independent of their potencies as inhibitors. We propose that differences in molecular charges, and the targeted binding of analogues to specific states of the GABAA receptor, are the most likely cause of the distinctive functional profiles. CONCLUSIONS AND IMPLICATIONS Our findings reveal that heterocyclic addition to inhibitory neurosteroids not only affected their potency and macroscopic efficacy but also affected innate receptor mechanisms that underlie desensitisation. Acute modulation of macroscopic desensitisation will determine the degree and duration of GABA inhibition, which are vital for the integration of neural circuit activity. Discovery of this form of modulation could present an opportunity for next-generation GABAA receptor drug design and development.
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Affiliation(s)
- Martin Mortensen
- Department of Neuroscience, Physiology and PharmacologyUniversity College LondonLondonUK
| | - Yue Xu
- Department of Drug Design and Pharmacology, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Mohamed A. Shehata
- Department of Drug Design and Pharmacology, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Jacob Krall
- Department of Drug Design and Pharmacology, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
- Present address:
Xellia Pharmaceuticals ApSCopenhagenDenmark
| | - Margot Ernst
- Department of Pathology of the Nervous System, Center for Brain ResearchMedical University of ViennaViennaAustria
| | - Bente Frølund
- Department of Drug Design and Pharmacology, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Trevor G. Smart
- Department of Neuroscience, Physiology and PharmacologyUniversity College LondonLondonUK
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5
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Absalom NL, Lin SXN, Liao VWY, Chua HC, Møller RS, Chebib M, Ahring PK. GABA A receptors in epilepsy: Elucidating phenotypic divergence through functional analysis of genetic variants. J Neurochem 2023. [PMID: 37621067 DOI: 10.1111/jnc.15932] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 07/27/2023] [Accepted: 08/01/2023] [Indexed: 08/26/2023]
Abstract
Normal brain function requires a tightly regulated balance between excitatory and inhibitory neurotransmissions. γ-Aminobutyric acid type A (GABAA ) receptors represent the major class of inhibitory ion channels in the mammalian brain. Dysregulation of these receptors and/or their associated pathways is strongly implicated in the pathophysiology of epilepsy. To date, hundreds of different GABAA receptor subunit variants have been associated with epilepsy, making them a prominent cause of genetically linked epilepsy. While identifying these genetic variants is crucial for accurate diagnosis and effective genetic counselling, it does not necessarily lead to improved personalised treatment options. This is because the identification of a variant does not reveal how the function of GABAA receptors is affected. Genetic variants in GABAA receptor subunits can cause complex changes to receptor properties resulting in various degrees of gain-of-function, loss-of-function or a combination of both. Understanding how variants affect the function of GABAA receptors therefore represents an important first step in the ongoing development of precision therapies. Furthermore, it is important to ensure that functional data are produced using methodologies that allow genetic variants to be classified using clinical guidelines such as those developed by the American College of Medical Genetics and Genomics. This article will review the current knowledge in the field and provide recommendations for future functional analysis of genetic GABAA receptor variants.
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Affiliation(s)
- Nathan L Absalom
- School of Science, University of Western Sydney, Sydney, New South Wales, Australia
- Brain and Mind Centre, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Susan X N Lin
- Brain and Mind Centre, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Vivian W Y Liao
- Brain and Mind Centre, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Han C Chua
- Brain and Mind Centre, Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Medicine, The Danish Epilepsy Centre, Filadelfia, Dianalund, Denmark
- Department of Regional Health Research, University of Southern Denmark, Odense, Denmark
| | - Mary Chebib
- Brain and Mind Centre, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Philip K Ahring
- Brain and Mind Centre, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
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Yi Y, Zhong C, Wei-wei H. The long-term neurodevelopmental outcomes of febrile seizures and underlying mechanisms. Front Cell Dev Biol 2023; 11:1186050. [PMID: 37305674 PMCID: PMC10248510 DOI: 10.3389/fcell.2023.1186050] [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: 03/14/2023] [Accepted: 05/16/2023] [Indexed: 06/13/2023] Open
Abstract
Febrile seizures (FSs) are convulsions caused by a sudden increase in body temperature during a fever. FSs are one of the commonest presentations in young children, occurring in up to 4% of children between the ages of about 6 months and 5 years old. FSs not only endanger children's health, cause panic and anxiety to families, but also have many adverse consequences. Both clinical and animal studies show that FSs have detrimental effects on neurodevelopment, that cause attention deficit hyperactivity disorder (ADHD), increased susceptibility to epilepsy, hippocampal sclerosis and cognitive decline during adulthood. However, the mechanisms of FSs in developmental abnormalities and disease occurrence during adulthood have not been determined. This article provides an overview of the association of FSs with neurodevelopmental outcomes, outlining both the underlying mechanisms and the possible appropriate clinical biomarkers, from histological changes to cellular molecular mechanisms. The hippocampus is the brain region most significantly altered after FSs, but the motor cortex and subcortical white matter may also be involved in the development disorders induced by FSs. The occurrence of multiple diseases after FSs may share common mechanisms, and the long-term role of inflammation and γ-aminobutyric acid (GABA) system are currently well studied.
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Affiliation(s)
- You Yi
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Chen Zhong
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Zhejiang Chinese Medical University, Hangzhou, China
| | - Hu Wei-wei
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
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7
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Liang W, Wang J, Sui J, Yun F, Shen Y, Zhou J, Wu Y, Shen D, Zhang Q. Inflammation as a target for the treatment of fever-associated epilepsy in zebrafish larvae. Int Immunopharmacol 2023; 116:109802. [PMID: 36738682 DOI: 10.1016/j.intimp.2023.109802] [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: 11/22/2022] [Revised: 01/16/2023] [Accepted: 01/25/2023] [Indexed: 02/05/2023]
Abstract
Inflammation is considered to be involved in epileptogenesis. However, the relationship between fever and inflammation as well as the mechanisms of fever in the occurrence and development of childhood epilepsy need further investigation. Here, we described an in vivo model of hyperthermia-induced seizures in zebrafish larvae with pentylenetetrazole (PTZ) exposure. Hyperthermia increased the susceptibility to seizure and the production of pro-inflammatory factors in PTZ-induced zebrafish larvae. As mutations in GABRG2 have been associated with fever-associated epilepsy, we used a Tg(hGABRG2F343L) zebrafish model expressing mutant human GABRG2(F343L) to further investigate the involvement of inflammation in fever-induced seizures. Our data indicated that hyperthermia also increased the locomotor activity in Tg(hGABRG2F343L) zebrafish larvae. Although the production of pro-inflammatory factors was upregulated by GABRG2 mutation, hyperthermia did not change the production of pro-inflammatory factors significantly. Lipopolysaccharide (LPS) stimulation was sufficient to increase the locomotor activity in zebrafish larvae, suggesting that inflammation contributed to fever-associated epilepsy. The expression of GABRG2 was increased with PTZ induction, especially at a higher temperature. Moreover, inhibition of inflammation by dexamethasone (DEX) reduced the excitability of zebrafish larvae, especially at a higher temperature. Finally, in vitro experiments proved that LPS stimulation increased the production of IL-1β and IL-6 in GABRG2(F343L) transfected cells. Collectively, our study demonstrated that neuroinflammation was induced in febrile seizures, and the increased expression of IL-1β and IL-6 might be responsible for epileptogenesis. The vicious cycle between fever and inflammation might induce seizure onset, and anti-inflammatory strategies might be a potential treatment for fever-associated epilepsy.
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Affiliation(s)
- Wenpeng Liang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Nantong University, Nantong, China
| | - Jie Wang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Nantong University, Nantong, China
| | - Jiahui Sui
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Nantong University, Nantong, China
| | - Feng Yun
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Nantong University, Nantong, China
| | - Yuntian Shen
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Nantong University, Nantong, China
| | - Jing Zhou
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Nantong University, Nantong, China
| | - Youjia Wu
- Department of Pediatrics, Affiliated Hospital of Nantong University, Nantong, China
| | - Dingding Shen
- Department of Neurology & Collaborative Innovation Center for Brain Science, Ruijin Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China.
| | - Qi Zhang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Nantong University, Nantong, China.
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8
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Hernandez CC, Shen Y, Hu N, Shen W, Narayanan V, Ramsey K, He W, Zou L, Macdonald RL. GABRG2 Variants Associated with Febrile Seizures. Biomolecules 2023; 13:414. [PMID: 36979350 PMCID: PMC10046037 DOI: 10.3390/biom13030414] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Revised: 02/13/2023] [Accepted: 02/17/2023] [Indexed: 02/24/2023] Open
Abstract
Febrile seizures (FS) are the most common form of epilepsy in children between six months and five years of age. FS is a self-limited type of fever-related seizure. However, complicated prolonged FS can lead to complex partial epilepsy. We found that among the GABAA receptor subunit (GABR) genes, most variants associated with FS are harbored in the γ2 subunit (GABRG2). Here, we characterized the effects of eight variants in the GABAA receptor γ2 subunit on receptor biogenesis and channel function. Two-thirds of the GABRG2 variants followed the expected autosomal dominant inheritance in FS and occurred as missense and nonsense variants. The remaining one-third appeared as de novo in the affected probands and occurred only as missense variants. The loss of GABAA receptor function and dominant negative effect on GABAA receptor biogenesis likely caused the FS phenotype. In general, variants in the GABRG2 result in a broad spectrum of phenotypic severity, ranging from asymptomatic, FS, genetic epilepsy with febrile seizures plus (GEFS+), and Dravet syndrome individuals. The data presented here support the link between FS, epilepsy, and GABRG2 variants, shedding light on the relationship between the variant topological occurrence and disease severity.
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Affiliation(s)
- Ciria C. Hernandez
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yanwen Shen
- Department of Pediatrics, Seventh Medical Center of Chinese PLA General Hospital, Beijing 100010, China
| | - Ningning Hu
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Wangzhen Shen
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Vinodh Narayanan
- Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, AZ 85004, USA
| | - Keri Ramsey
- Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, AZ 85004, USA
| | - Wen He
- Department of Pediatrics, Seventh Medical Center of Chinese PLA General Hospital, Beijing 100010, China
| | - Liping Zou
- Department of Pediatrics, Seventh Medical Center of Chinese PLA General Hospital, Beijing 100010, China
| | - Robert L. Macdonald
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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9
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Leng X, Zhang T, Guan Y, Tang M. Genotype and phenotype analysis of epilepsy caused by ADGRV1 mutations in Chinese children. Seizure 2022; 103:108-114. [DOI: 10.1016/j.seizure.2022.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 11/07/2022] [Accepted: 11/10/2022] [Indexed: 11/13/2022] Open
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10
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Hong H, Lu X, Wu C, Chen J, Chen C, Zhang J, Huang C, Cui Z. A review for the pharmacological effects of paeoniflorin in the nervous system. Front Pharmacol 2022; 13:898955. [PMID: 36046834 PMCID: PMC9420976 DOI: 10.3389/fphar.2022.898955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 07/22/2022] [Indexed: 11/29/2022] Open
Abstract
Paeoniflorin, a terpenoid glycoside compound extracted from Paeonia lactiflora Pall, shows preventive and therapeutic effects in various types of nervous system disorders. However, to date, no comprehensive knowledge on the pharmacological effects of paeoniflorin on the nervous system is available online. Clarification of this issue may be useful for the development of paeoniflorin as a new drug for the treatment of nervous system disorders. To this end, the authors summarize the pharmacological aspects of paeoniflorin and its possible mechanisms, such as restoration of mitochondrial function; inhibition of neuroinflammation, oxidative stress, and cellular apoptosis; activation of adenosine A1 receptor, cAMP response element-binding protein (CREB) and extracellular signal-regulated kinase 1/2 (ERK1/2); or enhancement of brain-derived neurotrophic factor and serotonin function, in the prevention of disorders such as cerebral ischemia, subarachnoid hemorrhage, vascular dementia, Alzheimer's disease, Parkinson's disease, depression, post-traumatic syndrome disorder, and epilepsy, by reviewing the previously published literature.
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Affiliation(s)
- Hongxiang Hong
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong, Jiangsu, China
| | - Xu Lu
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, Jiangsu, China
| | - Chunshuai Wu
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong, Jiangsu, China
| | - Jiajia Chen
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong, Jiangsu, China
| | - Chu Chen
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong, Jiangsu, China
| | - Jinlong Zhang
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong, Jiangsu, China
| | - Chao Huang
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, Jiangsu, China
| | - Zhiming Cui
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong, Jiangsu, China
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11
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Koko M, Motelow JE, Stanley KE, Bobbili DR, Dhindsa RS, May P. Association of ultra-rare coding variants with genetic generalized epilepsy: A case-control whole exome sequencing study. Epilepsia 2022; 63:723-735. [PMID: 35032048 PMCID: PMC8891088 DOI: 10.1111/epi.17166] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 12/29/2021] [Accepted: 12/29/2021] [Indexed: 01/18/2023]
Abstract
OBJECTIVE We aimed to identify genes associated with genetic generalized epilepsy (GGE) by combining large cohorts enriched with individuals with a positive family history. Secondarily, we set out to compare the association of genes independently with familial and sporadic GGE. METHODS We performed a case-control whole exome sequencing study in unrelated individuals of European descent diagnosed with GGE (previously recruited and sequenced through multiple international collaborations) and ancestry-matched controls. The association of ultra-rare variants (URVs; in 18 834 protein-coding genes) with epilepsy was examined in 1928 individuals with GGE (vs. 8578 controls), then separately in 945 individuals with familial GGE (vs. 8626 controls), and finally in 1005 individuals with sporadic GGE (vs. 8621 controls). We additionally examined the association of URVs with familial and sporadic GGE in two gene sets important for inhibitory signaling (19 genes encoding γ-aminobutyric acid type A [GABAA ] receptors, 113 genes representing the GABAergic pathway). RESULTS GABRG2 was associated with GGE (p = 1.8 × 10-5 ), approaching study-wide significance in familial GGE (p = 3.0 × 10-6 ), whereas no gene approached a significant association with sporadic GGE. Deleterious URVs in the most intolerant subgenic regions in genes encoding GABAA receptors were associated with familial GGE (odds ratio [OR] = 3.9, 95% confidence interval [CI] = 1.9-7.8, false discovery rate [FDR]-adjusted p = .0024), whereas their association with sporadic GGE had marginally lower odds (OR = 3.1, 95% CI = 1.3-6.7, FDR-adjusted p = .022). URVs in GABAergic pathway genes were associated with familial GGE (OR = 1.8, 95% CI = 1.3-2.5, FDR-adjusted p = .0024) but not with sporadic GGE (OR = 1.3, 95% CI = .9-1.9, FDR-adjusted p = .19). SIGNIFICANCE URVs in GABRG2 are likely an important risk factor for familial GGE. The association of gene sets of GABAergic signaling with familial GGE is more prominent than with sporadic GGE.
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Affiliation(s)
- Mahmoud Koko
- Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany
| | - Joshua E. Motelow
- Institute for Genomic Medicine, Columbia University, 10032 New York, USA
| | - Kate E. Stanley
- Institute for Genomic Medicine, Columbia University, 10032 New York, USA
| | - Dheeraj R. Bobbili
- Luxembourg Centre for Systems Biomedicine, University Luxembourg, 4367 Belvaux, Luxembourg
| | - Ryan S. Dhindsa
- Institute for Genomic Medicine, Columbia University, 10032 New York, USA
| | - Patrick May
- Luxembourg Centre for Systems Biomedicine, University Luxembourg, 4367 Belvaux, Luxembourg
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Belelli D, Hales TG, Lambert JJ, Luscher B, Olsen R, Peters JA, Rudolph U, Sieghart W. GABA A receptors in GtoPdb v.2021.3. IUPHAR/BPS GUIDE TO PHARMACOLOGY CITE 2021; 2021. [PMID: 35005623 DOI: 10.2218/gtopdb/f72/2021.3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The GABAA receptor is a ligand-gated ion channel of the Cys-loop family that includes the nicotinic acetylcholine, 5-HT3 and strychnine-sensitive glycine receptors. GABAA receptor-mediated inhibition within the CNS occurs by fast synaptic transmission, sustained tonic inhibition and temporally intermediate events that have been termed 'GABAA, slow' [45]. GABAA receptors exist as pentamers of 4TM subunits that form an intrinsic anion selective channel. Sequences of six α, three β, three γ, one δ, three ρ, one ε, one π and one θ GABAA receptor subunits have been reported in mammals [278, 235, 236, 283]. The π-subunit is restricted to reproductive tissue. Alternatively spliced versions of many subunits exist (e.g. α4- and α6- (both not functional) α5-, β2-, β3- and γ2), along with RNA editing of the α3 subunit [71]. The three ρ-subunits, (ρ1-3) function as either homo- or hetero-oligomeric assemblies [359, 50]. Receptors formed from ρ-subunits, because of their distinctive pharmacology that includes insensitivity to bicuculline, benzodiazepines and barbiturates, have sometimes been termed GABAC receptors [359], but they are classified as GABA A receptors by NC-IUPHAR on the basis of structural and functional criteria [16, 235, 236]. Many GABAA receptor subtypes contain α-, β- and γ-subunits with the likely stoichiometry 2α.2β.1γ [168, 235]. It is thought that the majority of GABAA receptors harbour a single type of α- and β - subunit variant. The α1β2γ2 hetero-oligomer constitutes the largest population of GABAA receptors in the CNS, followed by the α2β3γ2 and α3β3γ2 isoforms. Receptors that incorporate the α4- α5-or α 6-subunit, or the β1-, γ1-, γ3-, δ-, ε- and θ-subunits, are less numerous, but they may nonetheless serve important functions. For example, extrasynaptically located receptors that contain α6- and δ-subunits in cerebellar granule cells, or an α4- and δ-subunit in dentate gyrus granule cells and thalamic neurones, mediate a tonic current that is important for neuronal excitability in response to ambient concentrations of GABA [209, 272, 83, 19, 288]. GABA binding occurs at the β+/α- subunit interface and the homologous γ+/α- subunits interface creates the benzodiazepine site. A second site for benzodiazepine binding has recently been postulated to occur at the α+/β- interface ([254]; reviewed by [282]). The particular α-and γ-subunit isoforms exhibit marked effects on recognition and/or efficacy at the benzodiazepine site. Thus, receptors incorporating either α4- or α6-subunits are not recognised by 'classical' benzodiazepines, such as flunitrazepam (but see [356]). The trafficking, cell surface expression, internalisation and function of GABAA receptors and their subunits are discussed in detail in several recent reviews [52, 140, 188, 316] but one point worthy of note is that receptors incorporating the γ2 subunit (except when associated with α5) cluster at the postsynaptic membrane (but may distribute dynamically between synaptic and extrasynaptic locations), whereas as those incorporating the δ subunit appear to be exclusively extrasynaptic. NC-IUPHAR [16, 235, 3, 2] class the GABAA receptors according to their subunit structure, pharmacology and receptor function. Currently, eleven native GABAA receptors are classed as conclusively identified (i.e., α1β2γ2, α1βγ2, α3βγ2, α4βγ2, α4β2δ, α4β3δ, α5βγ2, α6βγ2, α6β2δ, α6β3δ and ρ) with further receptor isoforms occurring with high probability, or only tentatively [235, 236]. It is beyond the scope of this Guide to discuss the pharmacology of individual GABAA receptor isoforms in detail; such information can be gleaned in the reviews [16, 95, 168, 173, 143, 278, 216, 235, 236] and [9, 10]. Agents that discriminate between α-subunit isoforms are noted in the table and additional agents that demonstrate selectivity between receptor isoforms, for example via β-subunit selectivity, are indicated in the text below. The distinctive agonist and antagonist pharmacology of ρ receptors is summarised in the table and additional aspects are reviewed in [359, 50, 145, 223]. Several high-resolution cryo-electron microscopy structures have been described in which the full-length human α1β3γ2L GABAA receptor in lipid nanodiscs is bound to the channel-blocker picrotoxin, the competitive antagonist bicuculline, the agonist GABA (γ-aminobutyric acid), and the classical benzodiazepines alprazolam and diazepam [198].
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Abstract
BACKGROUND Febrile seizures occurring in a child older than one month during an episode of fever affect 2-4% of children in Great Britain and the United States and recur in 30%. Rapid-acting antiepileptics and antipyretics given during subsequent fever episodes have been used to avoid the adverse effects of continuous antiepileptic drugs. This is an updated version of a Cochrane Review previously published in 2017. OBJECTIVES To evaluate primarily the effectiveness and safety of antiepileptic and antipyretic drugs used prophylactically to treat children with febrile seizures; and also to evaluate any other drug intervention where there is a sound biological rationale for its use. SEARCH METHODS For the latest update we searched the following databases on 3 February 2020: Cochrane Register of Studies (CRS Web), MEDLINE (Ovid, 1946 to 31 January 2020). CRS Web includes randomised or quasi-randomised controlled trials from PubMed, Embase, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform (ICTRP), the Cochrane Central Register of Controlled Trials (CENTRAL), and the specialised registers of Cochrane Review Groups including the Cochrane Epilepsy Group. We imposed no language restrictions and contacted researchers to identify continuing or unpublished studies. SELECTION CRITERIA Trials using randomised or quasi-randomised participant allocation that compared the use of antiepileptics, antipyretics or recognised Central Nervous System active agents with each other, placebo, or no treatment. DATA COLLECTION AND ANALYSIS For the original review, two review authors independently applied predefined criteria to select trials for inclusion and extracted the predefined relevant data, recording methods for randomisation, blinding, and exclusions. For the 2016 update, a third review author checked all original inclusions, data analyses, and updated the search. For the 2020 update, one review author updated the search and performed the data analysis following a peer-review process with the original review authors. We assessed seizure recurrence at 6, 12, 18, 24, 36, 48 months, and where data were available at age 5 to 6 years along with recorded adverse effects. We evaluated the presence of publication bias using funnel plots. MAIN RESULTS We included 42 articles describing 32 randomised trials, with 4431 randomised participants used in the analysis of this review. We analysed 15 interventions of continuous or intermittent prophylaxis and their control treatments. Methodological quality was moderate to poor in most studies. We found no significant benefit for intermittent phenobarbital, phenytoin, valproate, pyridoxine, ibuprofen, or zinc sulfate versus placebo or no treatment; nor for diclofenac versus placebo followed by ibuprofen, paracetamol, or placebo; nor for continuous phenobarbital versus diazepam, intermittent rectal diazepam versus intermittent valproate, or oral diazepam versus clobazam. There was a significant reduction of recurrent febrile seizures with intermittent diazepam versus placebo or no treatment at six months (risk ratio (RR) 0.64, 95% confidence interval (CI) 0.48 to 0.85; 6 studies, 1151 participants; moderate-certainty evidence), 12 months (RR 0.69, 95% CI 0.56 to 0.84; 8 studies, 1416 participants; moderate-certainty evidence), 18 months (RR 0.37, 95% CI 0.23 to 0.60; 1 study, 289 participants; low-certainty evidence), 24 months (RR 0.73, 95% CI 0.56 to 0.95; 4 studies, 739 participants; high-certainty evidence), 36 months (RR 0.58, 95% CI 0.40 to 0.85; 1 study, 139 participants; low-certainty evidence), 48 months (RR 0.36, 95% CI 0.15 to 0.89; 1 study, 110 participants; moderate-certainty evidence), with no benefit at 60 to 72 months (RR 0.08, 95% CI 0.00 to 1.31; 1 study, 60 participants; very low-certainty evidence). Phenobarbital versus placebo or no treatment reduced seizures at six months (RR 0.59, 95% CI 0.42 to 0.83; 6 studies, 833 participants; moderate-certainty evidence), 12 months (RR 0.54, 95% CI 0.42 to 0.70; 7 studies, 807 participants; low-certainty evidence), and 24 months (RR 0.69, 95% CI 0.53 to 0.89; 3 studies, 533 participants; moderate-certainty evidence), but not at 18 months (RR 0.77, 95% CI 0.56 to 1.05; 2 studies, 264 participants) or 60 to 72 months follow-up (RR 1.50, 95% CI 0.61 to 3.69; 1 study, 60 participants; very low-certainty evidence). Intermittent clobazam compared to placebo at six months resulted in a RR of 0.36 (95% CI 0.20 to 0.64; 1 study, 60 participants; low-certainty evidence), an effect found against an extremely high (83.3%) recurrence rate in the controls, a result that needs replication. When compared to intermittent diazepam, intermittent oral melatonin did not significantly reduce seizures at six months (RR 0.45, 95% CI 0.18 to 1.15; 1 study, 60 participants; very-low certainty evidence). When compared to placebo, intermittent oral levetiracetam significantly reduced recurrent seizures at 12 months (RR 0.27, 95% CI 0.15 to 0.52; 1 study, 115 participants; very low-certainty evidence). The recording of adverse effects was variable. Two studies reported lower comprehension scores in phenobarbital-treated children. Adverse effects were recorded in up to 30% of children in the phenobarbital-treated groups and 36% in benzodiazepine-treated groups. We found evidence of publication bias in the meta-analyses of comparisons for phenobarbital versus placebo (seven studies) at 12 months but not at six months (six studies); and valproate versus placebo (four studies) at 12 months. There were too few studies to identify publication bias for the other comparisons. The methodological quality of most of the included studies was low or very low. Methods of randomisation and allocation concealment often did not meet current standards, and 'treatment versus no treatment' was more commonly seen than 'treatment versus placebo', leading to obvious risks of bias. AUTHORS' CONCLUSIONS: We found reduced recurrence rates for intermittent diazepam and continuous phenobarbital, with adverse effects in up to 30% of children. The apparent benefit for clobazam treatment in one trial needs to be replicated. Levetiracetam also shows benefit with a good safety profile; however, further study is required. Given the benign nature of recurrent febrile seizures, and the high prevalence of adverse effects of these drugs, parents and families should be supported with adequate contact details of medical services and information on recurrence, first aid management, and, most importantly, the benign nature of the phenomenon.
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Affiliation(s)
- Martin Offringa
- Child Health Evaluative Sciences, Hospital for Sick Children, Toronto, Canada
| | - Richard Newton
- Department of Paediatric Neurology, Royal Manchester Children's Hospital, Manchester, UK
| | - Sarah J Nevitt
- Department of Health Data Science, University of Liverpool, Liverpool, UK
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Neocortex- and hippocampus-specific deletion of Gabrg2 causes temperature-dependent seizures in mice. Cell Death Dis 2021; 12:553. [PMID: 34050134 PMCID: PMC8163876 DOI: 10.1038/s41419-021-03846-x] [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: 02/12/2021] [Accepted: 05/17/2021] [Indexed: 02/04/2023]
Abstract
Mutations in the GABRG2 gene encoding the γ-aminobutyric acid (GABA) A receptor gamma 2 subunit are associated with genetic epilepsy with febrile seizures plus, febrile seizures plus, febrile seizures, and other symptoms of epilepsy. However, the mechanisms underlying Gabrg2-mediated febrile seizures are poorly understood. Here, we used the Cre/loxP system to generate conditional knockout (CKO) mice with deficient Gabrg2 in the hippocampus and neocortex. Heterozygous CKO mice (Gabrg2fl/wtCre+) exhibited temperature-dependent myoclonic jerks, generalised tonic-clonic seizures, increased anxiety-like symptoms, and a predisposition to induce seizures. Cortical electroencephalography showed the hyperexcitability in response to temperature elevation in Gabrg2fl/wtCre+ mice, but not in wild-type mice. Gabrg2fl/wtCre+ mice exhibited spontaneous seizures and susceptibility to temperature-induced seizures. Loss of neurons were observed in cortical layers V-VI and hippocampus of Gabrg2fl/wtCre+ mice. Furthermore, the latency of temperature- or pentylenetetrazol-induced seizures were significantly decreased in Gabrg2fl/wtCre+ mice compared with wild-type mice. In summary, Gabrg2fl/wtCre+ mice with Gabrg2 deletion in the neocortex and hippocampus reproduce many features of febrile seizures and therefore provide a novel model to further understand this syndrome at the cellular and molecular level.
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Han JY, Lee HJ, Lee YM, Park J. Identification of Missense ADGRV1 Mutation as a Candidate Genetic Cause of Familial Febrile Seizure 4. CHILDREN (BASEL, SWITZERLAND) 2020; 7:children7090144. [PMID: 32962041 PMCID: PMC7552766 DOI: 10.3390/children7090144] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 09/04/2020] [Accepted: 09/10/2020] [Indexed: 01/03/2023]
Abstract
Febrile seizure (FS) is related to a febrile illness (temperature > 38 °C) not caused by an infection of central nervous system, without neurologic deficits in children aged 6–60 months. The family study implied a polygenic model in the families of proband(s) with single FS, however in families with repeated FS, inheritance was matched to autosomal dominance with reduced disease penetrance. A 20 month-old girl showed recurrent FS and afebrile seizures without developmental delay or intellectual disability. The seizures disappeared after 60 months without anti-seizure medication. The 35 year-old proband’s mother also experienced five episodes of simple FS and two episodes of unprovoked seizures before 5 years old. Targeted exome sequencing was conducted along with epilepsy/seizure-associated gene-filtering to identify the candidate causative mutation. As a result, a heterozygous c.2039A>G of the ADGRV1 gene leading to a codon change of aspartic acid to glycine at the position 680 (rs547076322) was identified. This protein’s glycine residue is highly conserved, and its allele frequency is 0.00002827 in the gnomAD population database. ADGRV1 mutation may have an influential role in the occurrence of genetic epilepsies, especially those with febrile and afebrile seizures. Further investigation of ADGRV1 mutations is needed to prove that it is a significant susceptible gene for febrile and/or afebrile seizures in early childhood.
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Affiliation(s)
- Ji Yoon Han
- Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea;
| | - Hyun Joo Lee
- Departments of Pediatrics, Yonsei University College of Medicine, Seoul 06273, Korea;
| | - Young-Mock Lee
- Departments of Pediatrics, Yonsei University College of Medicine, Seoul 06273, Korea;
- Correspondence: (Y.-M.L.); (J.P.); Tel.: +82-2-2019-3354 (Y.-M.L.); +82-42-220-9799 (J.P.); Fax: +82-2-3261-9473 (Y.-M.L.); +82-42-220-9915 (J.P.)
| | - Joonhong Park
- Department of Laboratory Medicine, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
- Department of Laboratory Medicine, Jeonbuk National University Medical School and Hospital, Jeonju 54907, Korea
- Correspondence: (Y.-M.L.); (J.P.); Tel.: +82-2-2019-3354 (Y.-M.L.); +82-42-220-9799 (J.P.); Fax: +82-2-3261-9473 (Y.-M.L.); +82-42-220-9915 (J.P.)
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Differential Coassembly of α1-GABA ARs Associated with Epileptic Encephalopathy. J Neurosci 2020; 40:5518-5530. [PMID: 32513829 DOI: 10.1523/jneurosci.2748-19.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 05/05/2020] [Accepted: 05/06/2020] [Indexed: 01/18/2023] Open
Abstract
GABAA receptors (GABAARs) are profoundly important for controlling neuronal excitability. Spontaneous and familial mutations to these receptors feature prominently in excitability disorders and neurodevelopmental deficits following disruption to GABA-mediated inhibition. Recent genotyping of an individual with severe epilepsy and Williams-Beuren syndrome identified a frameshifting de novo variant in a major GABAAR gene, GABRA1 This truncated the α1 subunit between the third and fourth transmembrane domains and introduced 24 new residues forming the mature protein, α1Lys374Serfs*25 Cell surface expression of mutant murine GABAARs is severely impaired compared with WT, due to retention in the endoplasmic reticulum. Mutant receptors were differentially coexpressed with β3, but not with β2, subunits in mammalian cells. Reduced surface expression was reflected by smaller IPSCs, which may underlie the induction of seizures. The mutant does not have a dominant-negative effect on native neuronal GABAAR expression since GABA current density was unaffected in hippocampal neurons, although mutant receptors exhibited limited GABA sensitivity. To date, the underlying mechanism is unique for epileptogenic variants and involves differential β subunit expression of GABAAR populations, which profoundly affected receptor function and synaptic inhibition.SIGNIFICANCE STATEMENT GABAARs are critical for controlling neural network excitability. They are ubiquitously distributed throughout the brain, and their dysfunction underlies many neurologic disorders, especially epilepsy. Here we report the characterization of an α1-GABAAR variant that results in severe epilepsy. The underlying mechanism is structurally unusual, with the loss of part of the α1 subunit transmembrane domain and part-replacement with nonsense residues. This led to compromised and differential α1 subunit cell surface expression with β subunits resulting in severely reduced synaptic inhibition. Our study reveals that disease-inducing variants can affect GABAAR structure, and consequently subunit assembly and cell surface expression, critically impacting on the efficacy of synaptic inhibition, a property that will orchestrate the extent and duration of neuronal excitability.
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GABRG2 Deletion Linked to Genetic Epilepsy with Febrile Seizures Plus Affects the Expression of GABA A Receptor Subunits and Other Genes at Different Temperatures. Neuroscience 2020; 438:116-136. [PMID: 32418750 DOI: 10.1016/j.neuroscience.2020.04.049] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 04/29/2020] [Accepted: 04/30/2020] [Indexed: 12/11/2022]
Abstract
Mutations in γ-aminobutyric acid A receptor (GABAA) subunits and sodium channel genes, especially GABRG2 and SCN1A, have been reported to be associated with febrile seizures (FS) and genetic epilepsy with febrile seizures plus (GEFS+). GEFS+ is a well-known family of epileptic syndrome with autosomal dominant inheritance in children. Its most common phenotypes are febrile seizures often with accessory afebrile generalized tonic-clonic seizures, febrile seizures plus (FS+), severe epileptic encephalopathy, as well as other types of generalized or localization-related seizures. However, the pathogenesis of febrile seizures remains largely unknown. Here, we generated a GABRG2 gene knockout cell line (HT22GABRG2KO) by applying the CRISPR/Cas9-mediated genomic deletion in HT-22 mouse hippocampal neuronal cell line to explore the function of GABRG2 in vitro. With mRNA-seq, we found significant changes in the expression profiles of several epilepsy-related genes when GABRG2 was knockout, some of them showing temperature-induced changes as well. Kyoto Encyclopedia Gene and Genomic (KEGG) analysis revealed a significant alteration in the MAPK and PI3K-Akt signaling pathways. We also observed an up-regulation of the matrix metalloproteinases (MMPs) family after GABRG2 knockout. Furthermore, the significant decrease in expression of GABRA1 and CACNA1A (but not others) with an increase in temperature is a novel finding. In summary, mutations in the GABAA receptor can lead to a decrease in numbers of receptors, which may cause the impairment of GABAergic pathway signaling. This data has been the first time to reveal that GABRG2 mutations would affect the function of other genes, and based on this finding we hope this work would also provide a new direction for the research of GABRG2 in GEFS+. It also may provide a molecular basis for the severity of epilepsy, and guide the clinical medication for the treatment of the epilepsy focused on the function on GABAA receptors, which, might be a new strategy for genetic diagnosis and targeted treatment of epilepsy.
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Zhang T, Chen M, Zhu A, Zhang X, Fang T. Novel mutation of SCN9A gene causing generalized epilepsy with febrile seizures plus in a Chinese family. Neurol Sci 2020; 41:1913-1917. [PMID: 32062735 PMCID: PMC7359139 DOI: 10.1007/s10072-020-04284-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 02/03/2020] [Indexed: 12/28/2022]
Abstract
Generalized epilepsy with febrile seizures plus (GEFS+) is a complex familial epilepsy syndrome. It is mainly caused by mutations in SCN1A gene, encoding type 1 voltage-gated sodium channel α-subunit (NaV1.1), and GABRA1 gene, encoding the α1 subunit of the γ-aminobutyric acid type A (GABAA) receptor, while seldom related with SCN9A gene, encoding the voltage-gated sodium channel NaV1.7. In this study, we investigated a Chinese family with an autosomal dominant form of GEFS+. DNA sequencing of the whole coding region revealed a novel heterozygous nucleotide substitution (c.5873A>G) causing a missense mutation (p.Y1958C). This mutation was predicted to be deleterious by three different bioinformatics programs (The polyphen2, SIFT, and MutationTaster). Our finding reports a novel likely pathogenic SCN9A Y1958C heterozygous mutation in a Chinese family with GEFS+ and provides additional supports that SCN9A variants may be associated with human epilepsies.
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Affiliation(s)
- Tian Zhang
- Department of Pediatrics, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui, China.,Department of Pediatrics, Anhui Provincial Hospital Affiliated to Anhui Medical University, Hefei, 230001, Anhui, China
| | - Mingwu Chen
- Department of Pediatrics, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui, China. .,Department of Pediatrics, Anhui Provincial Hospital Affiliated to Anhui Medical University, Hefei, 230001, Anhui, China.
| | - Angang Zhu
- Department of Pediatrics, Anhui Provincial Hospital, Wannan Medical College, Wuhu, 241002, Anhui, China
| | - Xiaoguang Zhang
- Department of Pediatrics, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui, China.,Department of Pediatrics, Anhui Provincial Hospital Affiliated to Anhui Medical University, Hefei, 230001, Anhui, China
| | - Tao Fang
- Department of Pediatrics, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui, China
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Pathophysiology of and therapeutic options for a GABRA1 variant linked to epileptic encephalopathy. Mol Brain 2019; 12:92. [PMID: 31707987 PMCID: PMC6842544 DOI: 10.1186/s13041-019-0513-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 10/14/2019] [Indexed: 01/07/2023] Open
Abstract
We report the identification of a de novo GABRA1 (R214C) variant in a child with epileptic encephalopathy (EE), describe its functional characterization and pathophysiology, and evaluate its potential therapeutic options. The GABRA1 (R214C) variant was identified using whole exome sequencing, and the pathogenic effect of this mutation was investigated by comparing wild-type (WT) α1 and R214C α1 GABAA receptor-expressing HEK cells. GABA-evoked currents in these cells were recorded using whole-cell, outside-out macro-patch and cell-attached single-channel patch-clamp recordings. Changes to surface and total protein expression levels of WT α1 and R214C α1 were quantified using surface biotinylation assay and western blotting, respectively. Finally, potential therapeutic options were explored by determining the effects of modulators, including diazepam, insulin, and verapamil, on channel gating and receptor trafficking of WT and R214C GABAA receptors. We found that the GABRA1 (R214C) variant decreased whole-cell GABA-evoked currents by reducing single channel open time and both surface and total GABAA receptor expression levels. The GABA-evoked currents in R214C GABAA receptors could only be partially restored with benzodiazepine (diazepam) and insulin. However, verapamil treatment for 24 h fully restored the function of R214C mutant receptors, primarily by increasing channel open time. We conclude that the GABRA1 (R214C) variant reduces channel activity and surface expression of mutant receptors, thereby contributing to the pathogenesis of genetic EE. The functional restoration by verapamil suggests that it is a potentially new therapeutic option for patients with the R214C variant and highlights the value of precision medicine in the treatment of genetic EEs.
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Hixson KM, Cogswell M, Brooks-Kayal AR, Russek SJ. Evidence for a non-canonical JAK/STAT signaling pathway in the synthesis of the brain's major ion channels and neurotransmitter receptors. BMC Genomics 2019; 20:677. [PMID: 31455240 PMCID: PMC6712773 DOI: 10.1186/s12864-019-6033-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 08/15/2019] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Brain-derived neurotrophic factor (BDNF) is a major signaling molecule that the brain uses to control a vast network of intracellular cascades fundamental to properties of learning and memory, and cognition. While much is known about BDNF signaling in the healthy nervous system where it controls the mitogen activated protein kinase (MAPK) and cyclic-AMP pathways, less is known about its role in multiple brain disorders where it contributes to the dysregulated neuroplasticity seen in epilepsy and traumatic brain injury (TBI). We previously found that neurons respond to prolonged BDNF exposure (both in vivo (in models of epilepsy and TBI) and in vitro (in BDNF treated primary neuronal cultures)) by activating the Janus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) signaling pathway. This pathway is best known for its association with inflammatory cytokines in non-neuronal cells. RESULTS Here, using deep RNA-sequencing of neurons exposed to BDNF in the presence and absence of well characterized JAK/STAT inhibitors, and without non-neuronal cells, we determine the BDNF transcriptome that is specifically regulated by agents that inhibit JAK/STAT signaling. Surprisingly, the BDNF-induced JAK/STAT transcriptome contains ion channels and neurotransmitter receptors coming from all the major classes expressed in the brain, along with key modulators of synaptic plasticity, neurogenesis, and axonal remodeling. Analysis of this dataset has revealed a unique non-canonical mechanism of JAK/STATs in neurons as differential gene expression mediated by STAT3 is not solely dependent upon phosphorylation at residue 705 and may involve a BDNF-induced interaction of STAT3 with Heterochromatin Protein 1 alpha (HP1α). CONCLUSIONS These findings suggest that the neuronal BDNF-induced JAK/STAT pathway involves more than STAT3 phosphorylation at 705, providing the first evidence for a non-canonical mechanism that may involve HP1α. Our analysis reveals that JAK/STAT signaling regulates many of the genes associated with epilepsy syndromes where BDNF levels are markedly elevated. Uncovering the mechanism of this novel form of BDNF signaling in the brain may provide a new direction for epilepsy therapeutics and open a window into the complex mechanisms of STAT3 transcriptional regulation in neurological disease.
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Affiliation(s)
- Kathryn M. Hixson
- Laboratory of Translational Epilepsy, Department of Pharmacology & Experimental Therapeutics, Boston University School of Medicine (BUSM), Boston, USA
- Graduate Program for Neuroscience (GPN), Boston University (BU), Boston, USA
| | - Meaghan Cogswell
- Laboratory of Translational Epilepsy, Department of Pharmacology & Experimental Therapeutics, Boston University School of Medicine (BUSM), Boston, USA
| | - Amy R. Brooks-Kayal
- Department of Pediatric Neurology, University of Colorado Anschutz Medical Campus, Aurora, USA
| | - Shelley J. Russek
- Laboratory of Translational Epilepsy, Department of Pharmacology & Experimental Therapeutics, Boston University School of Medicine (BUSM), Boston, USA
- Graduate Program for Neuroscience (GPN), Boston University (BU), Boston, USA
- Department of Biology, Boston University (BU), Boston, USA
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21
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Kipnis PA, Sullivan BJ, Kadam SD. Sex-Dependent Signaling Pathways Underlying Seizure Susceptibility and the Role of Chloride Cotransporters. Cells 2019; 8:cells8050448. [PMID: 31085988 PMCID: PMC6562404 DOI: 10.3390/cells8050448] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/04/2019] [Accepted: 05/09/2019] [Indexed: 12/18/2022] Open
Abstract
Seizure incidence, severity, and antiseizure medication (ASM) efficacy varies between males and females. Differences in sex-dependent signaling pathways that determine network excitability may be responsible. The identification and validation of sex-dependent molecular mechanisms that influence seizure susceptibility is an emerging focus of neuroscience research. The electroneutral cation-chloride cotransporters (CCCs) of the SLC12A gene family utilize Na+-K+-ATPase generated electrochemical gradients to transport chloride into or out of neurons. CCCs regulate neuronal chloride gradients, cell volume, and have a strong influence over the electrical response to the inhibitory neurotransmitter GABA. Acquired or genetic causes of CCCs dysfunction have been linked to seizures during early postnatal development, epileptogenesis, and refractoriness to ASMs. A growing number of studies suggest that the developmental expression of CCCs, such as KCC2, is sex-dependent. This review will summarize the reports of sexual dimorphism in epileptology while focusing on the role of chloride cotransporters and their associated modulators that can influence seizure susceptibility.
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Affiliation(s)
- Pavel A Kipnis
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA.
| | - Brennan J Sullivan
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA.
| | - Shilpa D Kadam
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA.
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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22
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Hernandez CC, Macdonald RL. A structural look at GABA A receptor mutations linked to epilepsy syndromes. Brain Res 2019; 1714:234-247. [PMID: 30851244 DOI: 10.1016/j.brainres.2019.03.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 02/25/2019] [Accepted: 03/06/2019] [Indexed: 12/12/2022]
Abstract
Understanding the genetic variation in GABAA receptor subunit genes (GABRs), GABRA1-6, GABRB1-3, GABRG1-3 and GABRD, in individuals affected by epilepsy may improve the diagnosis and treatment of epilepsy syndromes through identification of disease-associated variants. However, the lack of functional analysis and validation of many novel and previously reported familial and de novo mutations have made it challenging to address meaningful gene associations with epilepsy syndromes. GABAA receptors belong to the Cys-loop receptor family. Even though GABAA receptor mutant residues are widespread among different GABRs, their frequent occurrence in important structural domains that share common functional features suggests associations between structure and function.
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Affiliation(s)
- Ciria C Hernandez
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA.
| | - Robert L Macdonald
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
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23
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Abstract
Several aspects of thermoregulation play a role in epilepsy. Circuitries involved in thermoregulation are affected by seizures and epilepsy, hyperthermia may be both cause and result of seizures, and hypothermia may prevent or abort seizures. Autonomic manifestations of seizures including thermoregulatory disturbances are common in a variety of clinical epilepsy syndromes. Experimental hyperthermia has been studied extensively, predominantly to investigate febrile seizures of childhood. In particular prolonged or complex febrile seizures have been associated with the later development of epilepsy in adulthood and the pathophysiology of how febrile seizures cause epilepsy is of tremendous interest. Febrile seizures represent an opportunity to potentially intervene early in life in susceptible individuals and affect epileptogenesis. The pathophysiologic underpinnings of how hyperthermia induces seizures and how this in turn results in epilepsy are controversial, but likely involve multiple factors. Both glutamatergic and GABAergic neurotransmission is affected, and numerous mutations in genes encoding ion channels have been identified. Cytokines such as interleukin-1β have been implicated in febrile seizures as well as susceptibility to provoked seizures later in life. Hyperthermia is a common feature of generalized convulsive status epilepticus, but may also be seen with nonconvulsive seizures, indicating involvement of thermoregulatory centers.
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Affiliation(s)
- Sebastian Pollandt
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, United States.
| | - Thomas P Bleck
- Departments of Neurological Sciences, Neurosurgery, Medicine, and Anesthesiology, Rush Medical College, Chicago, IL, United States; Clinical Neurophysiology Laboratory, Rush University Medical Center, Chicago, IL, United States
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24
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Wong SQ, Jones A, Dodd S, Grimes D, Barclay JW, Marson AG, Cunliffe VT, Burgoyne RD, Sills GJ, Morgan A. A Caenorhabditis elegans assay of seizure-like activity optimised for identifying antiepileptic drugs and their mechanisms of action. J Neurosci Methods 2018; 309:132-142. [PMID: 30189284 PMCID: PMC6200019 DOI: 10.1016/j.jneumeth.2018.09.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 08/14/2018] [Accepted: 09/02/2018] [Indexed: 11/28/2022]
Abstract
Worms with mutant GABAA receptors exhibit convulsions upon exposure to pentylenetetrazol. Convulsions are prevented by the approved anti-epileptic drug, ethosuximide. C. elegans model is a higher throughput, ethical alternative to rodent seizure models.
Background Epilepsy affects around 1% of people, but existing antiepileptic drugs (AEDs) only offer symptomatic relief and are ineffective in approximately 30% of patients. Hence, new AEDs are sorely needed. However, a major bottleneck is the low-throughput nature of early-stage AED screens in conventional rodent models. This process could potentially be expedited by using simpler invertebrate systems, such as the nematode Caenorhabditis elegans. New method Head-bobbing convulsions were previously reported to be inducible by pentylenetetrazol (PTZ) in C. elegans with loss-of-function mutations in unc-49, which encodes a GABAA receptor. Given that epilepsy-linked mutations in human GABAA receptors are well documented, this could represent a clinically-relevant system for early-stage AED screens. However, the original agar plate-based assay is unsuited to large-scale screening and has not been validated for identifying AEDs. Therefore, we established an alternative streamlined, higher-throughput approach whereby mutants were treated with PTZ and AEDs via liquid-based incubation. Results Convulsions induced within minutes of PTZ exposure in unc-49 mutants were strongly inhibited by the established AED ethosuximide. This protective activity was independent of ethosuximide’s suggested target, the T-type calcium channel, as a null mutation in the worm cca-1 ortholog did not affect ethosuximide’s anticonvulsant action. Comparison with existing method Our streamlined assay is AED-validated, feasible for higher throughput compound screens, and can facilitate insights into AED mechanisms of action. Conclusions Based on an epilepsy-associated genetic background, this C. elegans unc-49 model of seizure-like activity presents an ethical, higher throughput alternative to conventional rodent seizure models for initial AED screens.
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Affiliation(s)
- Shi Quan Wong
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK.
| | - Alistair Jones
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK.
| | - Steven Dodd
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK.
| | - Douglas Grimes
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK.
| | - Jeff W Barclay
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK.
| | - Anthony G Marson
- Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK.
| | - Vincent T Cunliffe
- Department of Biomedical Science, University of Sheffield, Sheffield, UK.
| | - Robert D Burgoyne
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK.
| | - Graeme J Sills
- Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK.
| | - Alan Morgan
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK.
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25
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Hines RM, Maric HM, Hines DJ, Modgil A, Panzanelli P, Nakamura Y, Nathanson AJ, Cross A, Deeb T, Brandon NJ, Davies P, Fritschy JM, Schindelin H, Moss SJ. Developmental seizures and mortality result from reducing GABA A receptor α2-subunit interaction with collybistin. Nat Commun 2018; 9:3130. [PMID: 30087324 PMCID: PMC6081406 DOI: 10.1038/s41467-018-05481-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 07/05/2018] [Indexed: 01/08/2023] Open
Abstract
Fast inhibitory synaptic transmission is mediated by γ-aminobutyric acid type A receptors (GABAARs) that are enriched at functionally diverse synapses via mechanisms that remain unclear. Using isothermal titration calorimetry and complementary methods we demonstrate an exclusive low micromolar binding of collybistin to the α2-subunit of GABAARs. To explore the biological relevance of collybistin-α2-subunit selectivity, we generate mice with a mutation in the α2-subunit-collybistin binding region (Gabra2-1). The mutation results in loss of a distinct subset of inhibitory synapses and decreased amplitude of inhibitory synaptic currents. Gabra2-1 mice have a striking phenotype characterized by increased susceptibility to seizures and early mortality. Surviving Gabra2-1 mice show anxiety and elevations in electroencephalogram δ power, which are ameliorated by treatment with the α2/α3-selective positive modulator, AZD7325. Taken together, our results demonstrate an α2-subunit selective binding of collybistin, which plays a key role in patterned brain activity, particularly during development.
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Affiliation(s)
- Rochelle M Hines
- Department of Neuroscience, Tufts University School of Medicine, Boston, 02111, MA, USA.
- Department of Psychology, University of Nevada Las Vegas, Las Vegas, 89154, Ne, USA.
| | - Hans Michael Maric
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, D-97080, Germany
- Department of Biotechnology and Biophysics, Biocenter, University of Würzburg, Würzburg, D-97080, Germany
| | - Dustin J Hines
- Department of Neuroscience, Tufts University School of Medicine, Boston, 02111, MA, USA
- Department of Psychology, University of Nevada Las Vegas, Las Vegas, 89154, Ne, USA
| | - Amit Modgil
- Department of Neuroscience, Tufts University School of Medicine, Boston, 02111, MA, USA
| | - Patrizia Panzanelli
- Department of Neuroscience Rita Levi Montalcini, University of Turin, Turin, 10126, Italy
| | - Yasuko Nakamura
- Department of Neuroscience, Tufts University School of Medicine, Boston, 02111, MA, USA
| | - Anna J Nathanson
- Department of Neuroscience, Tufts University School of Medicine, Boston, 02111, MA, USA
| | - Alan Cross
- AstraZeneca Neuroscience iMED, Biotech Unit, Boston, 02451, MA, USA
| | - Tarek Deeb
- Department of Neuroscience, Tufts University School of Medicine, Boston, 02111, MA, USA
- AstraZeneca Tufts Laboratory for Basic and Translational Neuroscience, Boston, 02111, MA, USA
| | - Nicholas J Brandon
- AstraZeneca Neuroscience iMED, Biotech Unit, Boston, 02451, MA, USA
- AstraZeneca Tufts Laboratory for Basic and Translational Neuroscience, Boston, 02111, MA, USA
| | - Paul Davies
- Department of Neuroscience, Tufts University School of Medicine, Boston, 02111, MA, USA
| | - Jean-Marc Fritschy
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, 8057, Switzerland
- Center for Neuroscience Zurich, University of Zurich and ETH Zurich, Zurich, 8057, Switzerland
| | - Hermann Schindelin
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, D-97080, Germany
| | - Stephen J Moss
- Department of Neuroscience, Tufts University School of Medicine, Boston, 02111, MA, USA.
- AstraZeneca Tufts Laboratory for Basic and Translational Neuroscience, Boston, 02111, MA, USA.
- Department of Neuroscience, Physiology and Pharmacology, University College, London, WC1E 6BT, UK.
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26
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Abstract
Fever-associated seizures or epilepsy (FASE) is primarily characterised by the occurrence of a seizure or epilepsy usually accompanied by a fever. It is common in infants and children, and generally includes febrile seizures (FS), febrile seizures plus (FS+), Dravet syndrome (DS) and genetic epilepsy with febrile seizures plus (GEFSP). The aetiology of FASE is unclear. Genetic factors may play crucial roles in FASE. Mutations in certain genes may cause a wide spectrum of phenotypical overlap ranging from isolated FS, FS+ and GEFSP to DS. Synapse-associated proteins, postsynaptic GABAA receptor, and sodium channels play important roles in synaptic transmission. Mutations in these genes may involve in the pathogenesis of FASE. Elevated temperature promotes synaptic vesicle (SV) recycling and enlarges SV size, which may enhance synaptic transmission and contribute to FASE occurring. This review provides an overview of the loci, genes, underlying pathogenesis and the fever-inducing effect of FASE. It may provide a more comprehensive understanding of pathogenesis and contribute to the clinical diagnosis of FASE.
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27
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Durisic N, Keramidas A, Dixon CL, Lynch JW. SAHA (Vorinostat) Corrects Inhibitory Synaptic Deficits Caused by Missense Epilepsy Mutations to the GABA A Receptor γ2 Subunit. Front Mol Neurosci 2018; 11:89. [PMID: 29628874 PMCID: PMC5876238 DOI: 10.3389/fnmol.2018.00089] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 03/06/2018] [Indexed: 11/22/2022] Open
Abstract
The GABAA receptor (GABAAR) α1 subunit A295D epilepsy mutation reduces the surface expression of α1A295Dβ2γ2 GABAARs via ER-associated protein degradation. Suberanilohydroxamic acid (SAHA, also known as Vorinostat) was recently shown to correct the misfolding of α1A295D subunits and thereby enhance the functional surface expression of α1A295Dβ2γ2 GABAARs. Here we investigated whether SAHA can also restore the surface expression of γ2 GABAAR subunits that incorporate epilepsy mutations (N40S, R43Q, P44S, R138G) known to reduce surface expression via ER-associated protein degradation. As a control, we also investigated the γ2K289M epilepsy mutation that impairs gating without reducing surface expression. Effects of mutations were evaluated on inhibitory postsynaptic currents (IPSCs) mediated by the major synaptic α1β2γ2 GABAAR isoform. Recordings were performed in neuron-HEK293 cell artificial synapses to minimise contamination by GABAARs of undefined subunit composition. Transfection with α1β2γ2N40S, α1β2γ2R43Q, α1β2γ2P44S and α1β2γ2R138G subunits produced IPSCs with decay times slower than those of unmutated α1β2γ2 GABAARs due to the low expression of mutant γ2 subunits and the correspondingly high expression of slow-decaying α1β2 GABAARs. SAHA pre-treatment significantly accelerated the decay time constants of IPSCs consistent with the upregulation of mutant γ2 subunit expression. This increase in surface expression was confirmed by immunohistochemistry. SAHA had no effect on either the IPSC kinetics or surface expression levels of α1β2γ2K289M GABAARs, confirming its specificity for ER-retained mutant γ2 subunits. We also found that α1β2γ2K289M GABAARs and SAHA-treated α1β2γ2R43Q, α1β2γ2P44S and α1β2γ2R138G GABAARs all mediated IPSCs that decayed at significantly faster rates than wild type receptors as temperature was increased from 22 to 40°C. This may help explain why these mutations cause febrile seizures (FS). Given that SAHA is approved by therapeutic regulatory agencies for human use, we propose that it may be worth investigating as a treatment for epilepsies caused by the N40S, R43Q, P44S and R138G mutations. Although SAHA has already been proposed as a therapeutic for patients harbouring the α1A295D epilepsy mutation, the present study extends its potential utility to a new subunit and four new mutations.
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Affiliation(s)
- Nela Durisic
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Angelo Keramidas
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Christine L Dixon
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Joseph W Lynch
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
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Ye M, Yang J, Tian C, Zhu Q, Yin L, Jiang S, Yang M, Shu Y. Differential roles of Na V1.2 and Na V1.6 in regulating neuronal excitability at febrile temperature and distinct contributions to febrile seizures. Sci Rep 2018; 8:753. [PMID: 29335582 PMCID: PMC5768682 DOI: 10.1038/s41598-017-17344-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 11/20/2017] [Indexed: 01/25/2023] Open
Abstract
Dysregulation of voltage-gated sodium channels (VGSCs) is associated with multiple clinical disorders, including febrile seizures (FS). The contribution of different sodium channel subtypes to environmentally triggered seizures is not well understood. Here we demonstrate that somatic and axonal sodium channels primarily mediated through NaV1.2 and NaV1.6 subtypes, respectively, behave differentially at FT, and might play distinct roles in FS generation. In contrast to sodium channels on the main axonal trunk, somatic ones are more resistant to inactivation and display significantly augmented currents, faster gating rates and kinetics of recovery from inactivation at FT, features that promote neuronal excitabilities. Pharmacological inhibition of NaV1.2 by Phrixotoxin-3 (PTx3) suppressed FT-induced neuronal hyperexcitability in brain slice, while up-regulation of NaV1.2 as in NaV1.6 knockout mice showed an opposite effect. Consistently, NaV1.6 knockout mice were more susceptible to FS, exhibiting much lower temperature threshold and shorter onset latency than wildtype mice. Neuron modeling further suggests that NaV1.2 is the major subtype mediating FT-induced neuronal hyperexcitability, and predicts potential outcomes of alterations in sodium channel subtype composition. Together, these data reveal a role of native NaV1.2 on neuronal excitability at FT and its important contribution to FS pathogenesis.
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Affiliation(s)
- Mingyu Ye
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.
| | - Jun Yang
- State Key Laboratory of Cognitive Neuroscience and Learning, School of Brain and Cognitive Sciences, the Collaborative Innovation Center for Brain Science, Beijing Normal University, Beijing, China
| | - Cuiping Tian
- iHuman Institute, ShanghaiTech University, Shanghai, China
| | - Qiyu Zhu
- Brain Institute, College of Pharmaceutical Sciences, Capital Medical University, Beijing, China
| | - Luping Yin
- State Key Laboratory of Cognitive Neuroscience and Learning, School of Brain and Cognitive Sciences, the Collaborative Innovation Center for Brain Science, Beijing Normal University, Beijing, China
| | - Shan Jiang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Mingpo Yang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Yousheng Shu
- State Key Laboratory of Cognitive Neuroscience and Learning, School of Brain and Cognitive Sciences, the Collaborative Innovation Center for Brain Science, Beijing Normal University, Beijing, China.
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29
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Oyrer J, Maljevic S, Scheffer IE, Berkovic SF, Petrou S, Reid CA. Ion Channels in Genetic Epilepsy: From Genes and Mechanisms to Disease-Targeted Therapies. Pharmacol Rev 2018; 70:142-173. [PMID: 29263209 DOI: 10.1124/pr.117.014456] [Citation(s) in RCA: 163] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 10/02/2017] [Indexed: 12/19/2022] Open
Abstract
Epilepsy is a common and serious neurologic disease with a strong genetic component. Genetic studies have identified an increasing collection of disease-causing genes. The impact of these genetic discoveries is wide reaching-from precise diagnosis and classification of syndromes to the discovery and validation of new drug targets and the development of disease-targeted therapeutic strategies. About 25% of genes identified in epilepsy encode ion channels. Much of our understanding of disease mechanisms comes from work focused on this class of protein. In this study, we review the genetic, molecular, and physiologic evidence supporting the pathogenic role of a number of different voltage- and ligand-activated ion channels in genetic epilepsy. We also review proposed disease mechanisms for each ion channel and highlight targeted therapeutic strategies.
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Affiliation(s)
- Julia Oyrer
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Snezana Maljevic
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Ingrid E Scheffer
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Samuel F Berkovic
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Steven Petrou
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Christopher A Reid
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
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30
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Butilă AT, Zazgyva A, Sin AI, Szabo ER, Tilinca MC. GABRG2 C588T gene polymorphisms might be a predictive genetic marker of febrile seizures and generalized recurrent seizures: a case-control study in a Romanian pediatric population. Arch Med Sci 2018; 14:157-166. [PMID: 29379546 PMCID: PMC5778423 DOI: 10.5114/aoms.2016.63739] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 08/14/2016] [Indexed: 02/06/2023] Open
Abstract
INTRODUCTION This case-control study aimed to assess two single nucleotide polymorphisms of the gene encoding the GABRG2 protein - GABRG2 (3145 G>A) and GABRG2 rs 211037 Asn196Asn (C588T) - in a cohort of pediatric patients from Romania, and evaluate their possible impact on drug-resistant forms of generalized epilepsy and recurrent febrile seizures. MATERIAL AND METHODS One hundred and fourteen children with idiopathic generalized epilepsy (group 1) or febrile seizures (group 2) were compared to 153 controls. Peripheral blood samples were assessed using polymerase chain reaction-restriction fragment length polymorphism analysis, with results interpreted based on the disappearance of a restriction site in the C allele (122 bp) compared to the T allele (100 bp + 22 bp). RESULTS A significant association was found with the TT homozygous genotype and T allele for both febrile seizures and epilepsy for the C588T locus, while GABRG2 G>A 3145 showed no significant association with any type of seizure. The TT homozygous genotype of GABRG2 Asn196Asn polymorphism was more frequent in patients with a history of febrile seizures (p = 0.0001), without a significant association identified for GABRG2-G>A 3145. Composite analysis showed associations with epilepsy for CC-AG (p = 0.02) and CT-AG (p = 0.007) with the CC-AA combination as reference. CONCLUSIONS C588T polymorphism of the GABRG2 gene might be a predictive genetic marker in triggering febrile convulsions. GABRG2 rs211037 TT homozygotes and T allele variants have an increased risk for developing febrile seizures. Recurrent crises and repeated episodes of seizures are more frequent in the GABRG2 Asn196Asn TT genotype polymorphism, with a 45 and 8 times higher risk of developing idiopathic generalized epilepsy and recurrent febrile seizures, respectively.
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Affiliation(s)
- Anamaria Todoran Butilă
- Department of Genetics, University of Medicine and Pharmacy of Târgu-Mureş, Târgu-Mureş, Romania
| | - Ancuta Zazgyva
- Department of Cell and Molecular Biology, University of Medicine and Pharmacy of Târgu-Mureş, Târgu-Mureş, Romania
| | - Anca Ileana Sin
- Department of Cell and Molecular Biology, University of Medicine and Pharmacy of Târgu-Mureş, Târgu-Mureş, Romania
| | - Elisabeta Racoș Szabo
- Department of Psychiatry, University of Medicine and Pharmacy of Târgu-Mureş, Târgu-Mureş, Romania
| | - Mariana Cornelia Tilinca
- Department of Cell and Molecular Biology, University of Medicine and Pharmacy of Târgu-Mureş, Târgu-Mureş, Romania
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Chuang SH, Reddy DS. Genetic and Molecular Regulation of Extrasynaptic GABA-A Receptors in the Brain: Therapeutic Insights for Epilepsy. J Pharmacol Exp Ther 2017; 364:180-197. [PMID: 29142081 DOI: 10.1124/jpet.117.244673] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 11/13/2017] [Indexed: 12/18/2022] Open
Abstract
GABA-A receptors play a pivotal role in many brain diseases. Epilepsy is caused by acquired conditions and genetic defects in GABA receptor channels regulating neuronal excitability in the brain. The latter is referred to as GABA channelopathies. In the last two decades, major advances have been made in the genetics of epilepsy. The presence of specific GABAergic genetic abnormalities leading to some of the classic epileptic syndromes has been identified. Advances in molecular cloning and recombinant systems have helped characterize mutations in GABA-A receptor subunit genes in clinical neurology. GABA-A receptors are the prime targets for neurosteroids (NSs). However, GABA-A receptors are not static but undergo rapid changes in their number or composition in response to the neuroendocrine milieu. This review describes the recent advances in the genetic and neuroendocrine control of extrasynaptic and synaptic GABA-A receptors in epilepsy and its impact on neurologic conditions. It highlights the current knowledge of GABA genetics in epilepsy, with an emphasis on the neuroendocrine regulation of extrasynaptic GABA-A receptors in network excitability and seizure susceptibility. Recent advances in molecular regulation of extrasynaptic GABA-A receptor-mediated tonic inhibition are providing unique new therapeutic approaches for epilepsy, status epilepticus, and certain brain disorders. The discovery of an extrasynaptic molecular mechanism represents a milestone for developing novel therapies such as NS replacement therapy for catamenial epilepsy.
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Affiliation(s)
- Shu-Hui Chuang
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas
| | - Doodipala Samba Reddy
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas
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Kang JQ. Defects at the crossroads of GABAergic signaling in generalized genetic epilepsies. Epilepsy Res 2017; 137:9-18. [PMID: 28865303 DOI: 10.1016/j.eplepsyres.2017.08.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 08/14/2017] [Accepted: 08/22/2017] [Indexed: 12/16/2022]
Abstract
Seizure disorders are very common and affect 3% of the general population. The recurrent unprovoked seizures that are also called epilepsies are highly diverse as to both underlying genetic basis and clinic presentations. Recent genetic advances and sequencing technologies indicate that many epilepsies previously thought to be without known causes, or idiopathic generalized epilepsies (IGEs), are virtually genetic epilepsy as they are caused by genetic variations. IGEs are estimated to account for ∼15-20% of all epilepsies. Initially IGEs were primarily considered channelopathies, because the first genetic defects identified in IGEs involved ion channel genes. However, new findings indicate that mutations in many non ion channel genes are also involved in addition to those in ion channel genes. Interestingly, mutations in many genes associated with epilepsy affect GABAergic signaling, a major biological pathway in epilepsy. Additionally, many antiepileptic drugs work via enhancing GABAergic signaling. Hence, the review will focus on the mutations that impair GABAergic signaling and selectively discuss the newly identified STXBP1, PRRT2, and DNM1 in addition to those long-established epilepsy ion channel genes that also impair GABAergic signaling like SCN1A and GABAA receptor subunit genes. GABAergic signaling includes the pre- and post- synaptic mechanisms. Some mutations, such as STXBP1, PRRT2, DNM1, and SCN1A, impair GABAergic signaling mainly via pre-synaptic mechanisms while those mutations in GABAA receptor subunit genes impair GABAergic signaling via post-synaptic mechanisms. Nevertheless, these findings suggest impaired GABAergic signaling is a converging pathway of defects for many ion channel or non ion channel mutations associated with genetic epilepsies.
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Affiliation(s)
- Jing-Qiong Kang
- Departments of Neurology, Vanderbilt University Medical Center, Nashville, TN, 37232-8552, USA; Affiliated Hospital of Nantong University, Jiangsu, 226001, China; Vanderbilt Brain Institute, Vanderbilt Kennedy Center of Human Development, Vanderbilt University, Nashville, TN, 37232-8522, USA.
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Zhang YH, Burgess R, Malone JP, Glubb GC, Helbig KL, Vadlamudi L, Kivity S, Afawi Z, Bleasel A, Grattan-Smith P, Grinton BE, Bellows ST, Vears DF, Damiano JA, Goldberg-Stern H, Korczyn AD, Dibbens LM, Ruzzo EK, Hildebrand MS, Berkovic SF, Scheffer IE. Genetic epilepsy with febrile seizures plus: Refining the spectrum. Neurology 2017; 89:1210-1219. [PMID: 28842445 DOI: 10.1212/wnl.0000000000004384] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Accepted: 05/12/2017] [Indexed: 12/26/2022] Open
Abstract
OBJECTIVE Following our original description of generalized epilepsy with febrile seizures plus (GEFS+) in 1997, we analyze the phenotypic spectrum in 409 affected individuals in 60 families (31 new families) and expand the GEFS+ spectrum. METHODS We performed detailed electroclinical phenotyping on all available affected family members. Genetic analysis of known GEFS+ genes was carried out where possible. We compared our phenotypic and genetic data to those published in the literature over the last 19 years. RESULTS We identified new phenotypes within the GEFS+ spectrum: focal seizures without preceding febrile seizures (16/409 [4%]), classic genetic generalized epilepsies (22/409 [5%]), and afebrile generalized tonic-clonic seizures (9/409 [2%]). Febrile seizures remains the most frequent phenotype in GEFS+ (178/409 [44%]), followed by febrile seizures plus (111/409 [27%]). One third (50/163 [31%]) of GEFS+ families tested have a pathogenic variant in a known GEFS+ gene. CONCLUSION As 37/409 (9%) affected individuals have focal epilepsies, we suggest that GEFS+ be renamed genetic epilepsy with febrile seizures plus rather than generalized epilepsy with febrile seizures plus. The phenotypic overlap between GEFS+ and the classic generalized epilepsies is considerably greater than first thought. The clinical and molecular data suggest that the 2 major groups of generalized epilepsies share genetic determinants.
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Affiliation(s)
- Yue-Hua Zhang
- From the Epilepsy Research Centre, Department of Medicine (Y.-H.Z., R.B., J.P.M., G.C.G., K.L.H., L.V., B.E.G., S.T.B., D.F.V., J.A.D., M.S.H., S.F.B., I.E.S.), The University of Melbourne, Austin Health, Australia; Department of Pediatrics (Y.-H.Z.), Peking University First Hospital, Beijing, China; Department of Neurology (L.V.), The University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, Australia; Schneider Children's Medical Center of Israel (S.K., H.G.-S.), Petach Tikvah; Department of Neurology (Z.A.), Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel; Westmead Hospital (A.B.), New South Wales, Australia; Department of Neurology (P.G.-S.), Sydney Children's Hospital, Australia; Department of Neurology (A.D.K.), Tel Aviv University, Israel; Women's and Children's Hospital (L.M.D.), University of Adelaide, South Australia; Center for Neurobehavioral Genetics (E.K.R.), Semel Institute, David Geffen School of Medicine, University of California, Los Angeles; Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, Victoria; and The Florey Institute of Neurosciences and Mental Health (I.E.S.), Melbourne, Australia
| | - Rosemary Burgess
- From the Epilepsy Research Centre, Department of Medicine (Y.-H.Z., R.B., J.P.M., G.C.G., K.L.H., L.V., B.E.G., S.T.B., D.F.V., J.A.D., M.S.H., S.F.B., I.E.S.), The University of Melbourne, Austin Health, Australia; Department of Pediatrics (Y.-H.Z.), Peking University First Hospital, Beijing, China; Department of Neurology (L.V.), The University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, Australia; Schneider Children's Medical Center of Israel (S.K., H.G.-S.), Petach Tikvah; Department of Neurology (Z.A.), Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel; Westmead Hospital (A.B.), New South Wales, Australia; Department of Neurology (P.G.-S.), Sydney Children's Hospital, Australia; Department of Neurology (A.D.K.), Tel Aviv University, Israel; Women's and Children's Hospital (L.M.D.), University of Adelaide, South Australia; Center for Neurobehavioral Genetics (E.K.R.), Semel Institute, David Geffen School of Medicine, University of California, Los Angeles; Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, Victoria; and The Florey Institute of Neurosciences and Mental Health (I.E.S.), Melbourne, Australia
| | - Jodie P Malone
- From the Epilepsy Research Centre, Department of Medicine (Y.-H.Z., R.B., J.P.M., G.C.G., K.L.H., L.V., B.E.G., S.T.B., D.F.V., J.A.D., M.S.H., S.F.B., I.E.S.), The University of Melbourne, Austin Health, Australia; Department of Pediatrics (Y.-H.Z.), Peking University First Hospital, Beijing, China; Department of Neurology (L.V.), The University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, Australia; Schneider Children's Medical Center of Israel (S.K., H.G.-S.), Petach Tikvah; Department of Neurology (Z.A.), Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel; Westmead Hospital (A.B.), New South Wales, Australia; Department of Neurology (P.G.-S.), Sydney Children's Hospital, Australia; Department of Neurology (A.D.K.), Tel Aviv University, Israel; Women's and Children's Hospital (L.M.D.), University of Adelaide, South Australia; Center for Neurobehavioral Genetics (E.K.R.), Semel Institute, David Geffen School of Medicine, University of California, Los Angeles; Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, Victoria; and The Florey Institute of Neurosciences and Mental Health (I.E.S.), Melbourne, Australia
| | - Georgie C Glubb
- From the Epilepsy Research Centre, Department of Medicine (Y.-H.Z., R.B., J.P.M., G.C.G., K.L.H., L.V., B.E.G., S.T.B., D.F.V., J.A.D., M.S.H., S.F.B., I.E.S.), The University of Melbourne, Austin Health, Australia; Department of Pediatrics (Y.-H.Z.), Peking University First Hospital, Beijing, China; Department of Neurology (L.V.), The University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, Australia; Schneider Children's Medical Center of Israel (S.K., H.G.-S.), Petach Tikvah; Department of Neurology (Z.A.), Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel; Westmead Hospital (A.B.), New South Wales, Australia; Department of Neurology (P.G.-S.), Sydney Children's Hospital, Australia; Department of Neurology (A.D.K.), Tel Aviv University, Israel; Women's and Children's Hospital (L.M.D.), University of Adelaide, South Australia; Center for Neurobehavioral Genetics (E.K.R.), Semel Institute, David Geffen School of Medicine, University of California, Los Angeles; Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, Victoria; and The Florey Institute of Neurosciences and Mental Health (I.E.S.), Melbourne, Australia
| | - Katherine L Helbig
- From the Epilepsy Research Centre, Department of Medicine (Y.-H.Z., R.B., J.P.M., G.C.G., K.L.H., L.V., B.E.G., S.T.B., D.F.V., J.A.D., M.S.H., S.F.B., I.E.S.), The University of Melbourne, Austin Health, Australia; Department of Pediatrics (Y.-H.Z.), Peking University First Hospital, Beijing, China; Department of Neurology (L.V.), The University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, Australia; Schneider Children's Medical Center of Israel (S.K., H.G.-S.), Petach Tikvah; Department of Neurology (Z.A.), Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel; Westmead Hospital (A.B.), New South Wales, Australia; Department of Neurology (P.G.-S.), Sydney Children's Hospital, Australia; Department of Neurology (A.D.K.), Tel Aviv University, Israel; Women's and Children's Hospital (L.M.D.), University of Adelaide, South Australia; Center for Neurobehavioral Genetics (E.K.R.), Semel Institute, David Geffen School of Medicine, University of California, Los Angeles; Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, Victoria; and The Florey Institute of Neurosciences and Mental Health (I.E.S.), Melbourne, Australia
| | - Lata Vadlamudi
- From the Epilepsy Research Centre, Department of Medicine (Y.-H.Z., R.B., J.P.M., G.C.G., K.L.H., L.V., B.E.G., S.T.B., D.F.V., J.A.D., M.S.H., S.F.B., I.E.S.), The University of Melbourne, Austin Health, Australia; Department of Pediatrics (Y.-H.Z.), Peking University First Hospital, Beijing, China; Department of Neurology (L.V.), The University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, Australia; Schneider Children's Medical Center of Israel (S.K., H.G.-S.), Petach Tikvah; Department of Neurology (Z.A.), Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel; Westmead Hospital (A.B.), New South Wales, Australia; Department of Neurology (P.G.-S.), Sydney Children's Hospital, Australia; Department of Neurology (A.D.K.), Tel Aviv University, Israel; Women's and Children's Hospital (L.M.D.), University of Adelaide, South Australia; Center for Neurobehavioral Genetics (E.K.R.), Semel Institute, David Geffen School of Medicine, University of California, Los Angeles; Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, Victoria; and The Florey Institute of Neurosciences and Mental Health (I.E.S.), Melbourne, Australia
| | - Sara Kivity
- From the Epilepsy Research Centre, Department of Medicine (Y.-H.Z., R.B., J.P.M., G.C.G., K.L.H., L.V., B.E.G., S.T.B., D.F.V., J.A.D., M.S.H., S.F.B., I.E.S.), The University of Melbourne, Austin Health, Australia; Department of Pediatrics (Y.-H.Z.), Peking University First Hospital, Beijing, China; Department of Neurology (L.V.), The University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, Australia; Schneider Children's Medical Center of Israel (S.K., H.G.-S.), Petach Tikvah; Department of Neurology (Z.A.), Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel; Westmead Hospital (A.B.), New South Wales, Australia; Department of Neurology (P.G.-S.), Sydney Children's Hospital, Australia; Department of Neurology (A.D.K.), Tel Aviv University, Israel; Women's and Children's Hospital (L.M.D.), University of Adelaide, South Australia; Center for Neurobehavioral Genetics (E.K.R.), Semel Institute, David Geffen School of Medicine, University of California, Los Angeles; Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, Victoria; and The Florey Institute of Neurosciences and Mental Health (I.E.S.), Melbourne, Australia
| | - Zaid Afawi
- From the Epilepsy Research Centre, Department of Medicine (Y.-H.Z., R.B., J.P.M., G.C.G., K.L.H., L.V., B.E.G., S.T.B., D.F.V., J.A.D., M.S.H., S.F.B., I.E.S.), The University of Melbourne, Austin Health, Australia; Department of Pediatrics (Y.-H.Z.), Peking University First Hospital, Beijing, China; Department of Neurology (L.V.), The University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, Australia; Schneider Children's Medical Center of Israel (S.K., H.G.-S.), Petach Tikvah; Department of Neurology (Z.A.), Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel; Westmead Hospital (A.B.), New South Wales, Australia; Department of Neurology (P.G.-S.), Sydney Children's Hospital, Australia; Department of Neurology (A.D.K.), Tel Aviv University, Israel; Women's and Children's Hospital (L.M.D.), University of Adelaide, South Australia; Center for Neurobehavioral Genetics (E.K.R.), Semel Institute, David Geffen School of Medicine, University of California, Los Angeles; Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, Victoria; and The Florey Institute of Neurosciences and Mental Health (I.E.S.), Melbourne, Australia
| | - Andrew Bleasel
- From the Epilepsy Research Centre, Department of Medicine (Y.-H.Z., R.B., J.P.M., G.C.G., K.L.H., L.V., B.E.G., S.T.B., D.F.V., J.A.D., M.S.H., S.F.B., I.E.S.), The University of Melbourne, Austin Health, Australia; Department of Pediatrics (Y.-H.Z.), Peking University First Hospital, Beijing, China; Department of Neurology (L.V.), The University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, Australia; Schneider Children's Medical Center of Israel (S.K., H.G.-S.), Petach Tikvah; Department of Neurology (Z.A.), Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel; Westmead Hospital (A.B.), New South Wales, Australia; Department of Neurology (P.G.-S.), Sydney Children's Hospital, Australia; Department of Neurology (A.D.K.), Tel Aviv University, Israel; Women's and Children's Hospital (L.M.D.), University of Adelaide, South Australia; Center for Neurobehavioral Genetics (E.K.R.), Semel Institute, David Geffen School of Medicine, University of California, Los Angeles; Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, Victoria; and The Florey Institute of Neurosciences and Mental Health (I.E.S.), Melbourne, Australia
| | - Padraic Grattan-Smith
- From the Epilepsy Research Centre, Department of Medicine (Y.-H.Z., R.B., J.P.M., G.C.G., K.L.H., L.V., B.E.G., S.T.B., D.F.V., J.A.D., M.S.H., S.F.B., I.E.S.), The University of Melbourne, Austin Health, Australia; Department of Pediatrics (Y.-H.Z.), Peking University First Hospital, Beijing, China; Department of Neurology (L.V.), The University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, Australia; Schneider Children's Medical Center of Israel (S.K., H.G.-S.), Petach Tikvah; Department of Neurology (Z.A.), Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel; Westmead Hospital (A.B.), New South Wales, Australia; Department of Neurology (P.G.-S.), Sydney Children's Hospital, Australia; Department of Neurology (A.D.K.), Tel Aviv University, Israel; Women's and Children's Hospital (L.M.D.), University of Adelaide, South Australia; Center for Neurobehavioral Genetics (E.K.R.), Semel Institute, David Geffen School of Medicine, University of California, Los Angeles; Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, Victoria; and The Florey Institute of Neurosciences and Mental Health (I.E.S.), Melbourne, Australia
| | - Bronwyn E Grinton
- From the Epilepsy Research Centre, Department of Medicine (Y.-H.Z., R.B., J.P.M., G.C.G., K.L.H., L.V., B.E.G., S.T.B., D.F.V., J.A.D., M.S.H., S.F.B., I.E.S.), The University of Melbourne, Austin Health, Australia; Department of Pediatrics (Y.-H.Z.), Peking University First Hospital, Beijing, China; Department of Neurology (L.V.), The University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, Australia; Schneider Children's Medical Center of Israel (S.K., H.G.-S.), Petach Tikvah; Department of Neurology (Z.A.), Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel; Westmead Hospital (A.B.), New South Wales, Australia; Department of Neurology (P.G.-S.), Sydney Children's Hospital, Australia; Department of Neurology (A.D.K.), Tel Aviv University, Israel; Women's and Children's Hospital (L.M.D.), University of Adelaide, South Australia; Center for Neurobehavioral Genetics (E.K.R.), Semel Institute, David Geffen School of Medicine, University of California, Los Angeles; Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, Victoria; and The Florey Institute of Neurosciences and Mental Health (I.E.S.), Melbourne, Australia
| | - Susannah T Bellows
- From the Epilepsy Research Centre, Department of Medicine (Y.-H.Z., R.B., J.P.M., G.C.G., K.L.H., L.V., B.E.G., S.T.B., D.F.V., J.A.D., M.S.H., S.F.B., I.E.S.), The University of Melbourne, Austin Health, Australia; Department of Pediatrics (Y.-H.Z.), Peking University First Hospital, Beijing, China; Department of Neurology (L.V.), The University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, Australia; Schneider Children's Medical Center of Israel (S.K., H.G.-S.), Petach Tikvah; Department of Neurology (Z.A.), Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel; Westmead Hospital (A.B.), New South Wales, Australia; Department of Neurology (P.G.-S.), Sydney Children's Hospital, Australia; Department of Neurology (A.D.K.), Tel Aviv University, Israel; Women's and Children's Hospital (L.M.D.), University of Adelaide, South Australia; Center for Neurobehavioral Genetics (E.K.R.), Semel Institute, David Geffen School of Medicine, University of California, Los Angeles; Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, Victoria; and The Florey Institute of Neurosciences and Mental Health (I.E.S.), Melbourne, Australia
| | - Danya F Vears
- From the Epilepsy Research Centre, Department of Medicine (Y.-H.Z., R.B., J.P.M., G.C.G., K.L.H., L.V., B.E.G., S.T.B., D.F.V., J.A.D., M.S.H., S.F.B., I.E.S.), The University of Melbourne, Austin Health, Australia; Department of Pediatrics (Y.-H.Z.), Peking University First Hospital, Beijing, China; Department of Neurology (L.V.), The University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, Australia; Schneider Children's Medical Center of Israel (S.K., H.G.-S.), Petach Tikvah; Department of Neurology (Z.A.), Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel; Westmead Hospital (A.B.), New South Wales, Australia; Department of Neurology (P.G.-S.), Sydney Children's Hospital, Australia; Department of Neurology (A.D.K.), Tel Aviv University, Israel; Women's and Children's Hospital (L.M.D.), University of Adelaide, South Australia; Center for Neurobehavioral Genetics (E.K.R.), Semel Institute, David Geffen School of Medicine, University of California, Los Angeles; Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, Victoria; and The Florey Institute of Neurosciences and Mental Health (I.E.S.), Melbourne, Australia
| | - John A Damiano
- From the Epilepsy Research Centre, Department of Medicine (Y.-H.Z., R.B., J.P.M., G.C.G., K.L.H., L.V., B.E.G., S.T.B., D.F.V., J.A.D., M.S.H., S.F.B., I.E.S.), The University of Melbourne, Austin Health, Australia; Department of Pediatrics (Y.-H.Z.), Peking University First Hospital, Beijing, China; Department of Neurology (L.V.), The University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, Australia; Schneider Children's Medical Center of Israel (S.K., H.G.-S.), Petach Tikvah; Department of Neurology (Z.A.), Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel; Westmead Hospital (A.B.), New South Wales, Australia; Department of Neurology (P.G.-S.), Sydney Children's Hospital, Australia; Department of Neurology (A.D.K.), Tel Aviv University, Israel; Women's and Children's Hospital (L.M.D.), University of Adelaide, South Australia; Center for Neurobehavioral Genetics (E.K.R.), Semel Institute, David Geffen School of Medicine, University of California, Los Angeles; Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, Victoria; and The Florey Institute of Neurosciences and Mental Health (I.E.S.), Melbourne, Australia
| | - Hadassa Goldberg-Stern
- From the Epilepsy Research Centre, Department of Medicine (Y.-H.Z., R.B., J.P.M., G.C.G., K.L.H., L.V., B.E.G., S.T.B., D.F.V., J.A.D., M.S.H., S.F.B., I.E.S.), The University of Melbourne, Austin Health, Australia; Department of Pediatrics (Y.-H.Z.), Peking University First Hospital, Beijing, China; Department of Neurology (L.V.), The University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, Australia; Schneider Children's Medical Center of Israel (S.K., H.G.-S.), Petach Tikvah; Department of Neurology (Z.A.), Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel; Westmead Hospital (A.B.), New South Wales, Australia; Department of Neurology (P.G.-S.), Sydney Children's Hospital, Australia; Department of Neurology (A.D.K.), Tel Aviv University, Israel; Women's and Children's Hospital (L.M.D.), University of Adelaide, South Australia; Center for Neurobehavioral Genetics (E.K.R.), Semel Institute, David Geffen School of Medicine, University of California, Los Angeles; Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, Victoria; and The Florey Institute of Neurosciences and Mental Health (I.E.S.), Melbourne, Australia
| | - Amos D Korczyn
- From the Epilepsy Research Centre, Department of Medicine (Y.-H.Z., R.B., J.P.M., G.C.G., K.L.H., L.V., B.E.G., S.T.B., D.F.V., J.A.D., M.S.H., S.F.B., I.E.S.), The University of Melbourne, Austin Health, Australia; Department of Pediatrics (Y.-H.Z.), Peking University First Hospital, Beijing, China; Department of Neurology (L.V.), The University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, Australia; Schneider Children's Medical Center of Israel (S.K., H.G.-S.), Petach Tikvah; Department of Neurology (Z.A.), Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel; Westmead Hospital (A.B.), New South Wales, Australia; Department of Neurology (P.G.-S.), Sydney Children's Hospital, Australia; Department of Neurology (A.D.K.), Tel Aviv University, Israel; Women's and Children's Hospital (L.M.D.), University of Adelaide, South Australia; Center for Neurobehavioral Genetics (E.K.R.), Semel Institute, David Geffen School of Medicine, University of California, Los Angeles; Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, Victoria; and The Florey Institute of Neurosciences and Mental Health (I.E.S.), Melbourne, Australia
| | - Leanne M Dibbens
- From the Epilepsy Research Centre, Department of Medicine (Y.-H.Z., R.B., J.P.M., G.C.G., K.L.H., L.V., B.E.G., S.T.B., D.F.V., J.A.D., M.S.H., S.F.B., I.E.S.), The University of Melbourne, Austin Health, Australia; Department of Pediatrics (Y.-H.Z.), Peking University First Hospital, Beijing, China; Department of Neurology (L.V.), The University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, Australia; Schneider Children's Medical Center of Israel (S.K., H.G.-S.), Petach Tikvah; Department of Neurology (Z.A.), Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel; Westmead Hospital (A.B.), New South Wales, Australia; Department of Neurology (P.G.-S.), Sydney Children's Hospital, Australia; Department of Neurology (A.D.K.), Tel Aviv University, Israel; Women's and Children's Hospital (L.M.D.), University of Adelaide, South Australia; Center for Neurobehavioral Genetics (E.K.R.), Semel Institute, David Geffen School of Medicine, University of California, Los Angeles; Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, Victoria; and The Florey Institute of Neurosciences and Mental Health (I.E.S.), Melbourne, Australia
| | - Elizabeth K Ruzzo
- From the Epilepsy Research Centre, Department of Medicine (Y.-H.Z., R.B., J.P.M., G.C.G., K.L.H., L.V., B.E.G., S.T.B., D.F.V., J.A.D., M.S.H., S.F.B., I.E.S.), The University of Melbourne, Austin Health, Australia; Department of Pediatrics (Y.-H.Z.), Peking University First Hospital, Beijing, China; Department of Neurology (L.V.), The University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, Australia; Schneider Children's Medical Center of Israel (S.K., H.G.-S.), Petach Tikvah; Department of Neurology (Z.A.), Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel; Westmead Hospital (A.B.), New South Wales, Australia; Department of Neurology (P.G.-S.), Sydney Children's Hospital, Australia; Department of Neurology (A.D.K.), Tel Aviv University, Israel; Women's and Children's Hospital (L.M.D.), University of Adelaide, South Australia; Center for Neurobehavioral Genetics (E.K.R.), Semel Institute, David Geffen School of Medicine, University of California, Los Angeles; Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, Victoria; and The Florey Institute of Neurosciences and Mental Health (I.E.S.), Melbourne, Australia
| | - Michael S Hildebrand
- From the Epilepsy Research Centre, Department of Medicine (Y.-H.Z., R.B., J.P.M., G.C.G., K.L.H., L.V., B.E.G., S.T.B., D.F.V., J.A.D., M.S.H., S.F.B., I.E.S.), The University of Melbourne, Austin Health, Australia; Department of Pediatrics (Y.-H.Z.), Peking University First Hospital, Beijing, China; Department of Neurology (L.V.), The University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, Australia; Schneider Children's Medical Center of Israel (S.K., H.G.-S.), Petach Tikvah; Department of Neurology (Z.A.), Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel; Westmead Hospital (A.B.), New South Wales, Australia; Department of Neurology (P.G.-S.), Sydney Children's Hospital, Australia; Department of Neurology (A.D.K.), Tel Aviv University, Israel; Women's and Children's Hospital (L.M.D.), University of Adelaide, South Australia; Center for Neurobehavioral Genetics (E.K.R.), Semel Institute, David Geffen School of Medicine, University of California, Los Angeles; Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, Victoria; and The Florey Institute of Neurosciences and Mental Health (I.E.S.), Melbourne, Australia
| | - Samuel F Berkovic
- From the Epilepsy Research Centre, Department of Medicine (Y.-H.Z., R.B., J.P.M., G.C.G., K.L.H., L.V., B.E.G., S.T.B., D.F.V., J.A.D., M.S.H., S.F.B., I.E.S.), The University of Melbourne, Austin Health, Australia; Department of Pediatrics (Y.-H.Z.), Peking University First Hospital, Beijing, China; Department of Neurology (L.V.), The University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, Australia; Schneider Children's Medical Center of Israel (S.K., H.G.-S.), Petach Tikvah; Department of Neurology (Z.A.), Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel; Westmead Hospital (A.B.), New South Wales, Australia; Department of Neurology (P.G.-S.), Sydney Children's Hospital, Australia; Department of Neurology (A.D.K.), Tel Aviv University, Israel; Women's and Children's Hospital (L.M.D.), University of Adelaide, South Australia; Center for Neurobehavioral Genetics (E.K.R.), Semel Institute, David Geffen School of Medicine, University of California, Los Angeles; Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, Victoria; and The Florey Institute of Neurosciences and Mental Health (I.E.S.), Melbourne, Australia
| | - Ingrid E Scheffer
- From the Epilepsy Research Centre, Department of Medicine (Y.-H.Z., R.B., J.P.M., G.C.G., K.L.H., L.V., B.E.G., S.T.B., D.F.V., J.A.D., M.S.H., S.F.B., I.E.S.), The University of Melbourne, Austin Health, Australia; Department of Pediatrics (Y.-H.Z.), Peking University First Hospital, Beijing, China; Department of Neurology (L.V.), The University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, Australia; Schneider Children's Medical Center of Israel (S.K., H.G.-S.), Petach Tikvah; Department of Neurology (Z.A.), Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel; Westmead Hospital (A.B.), New South Wales, Australia; Department of Neurology (P.G.-S.), Sydney Children's Hospital, Australia; Department of Neurology (A.D.K.), Tel Aviv University, Israel; Women's and Children's Hospital (L.M.D.), University of Adelaide, South Australia; Center for Neurobehavioral Genetics (E.K.R.), Semel Institute, David Geffen School of Medicine, University of California, Los Angeles; Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, Victoria; and The Florey Institute of Neurosciences and Mental Health (I.E.S.), Melbourne, Australia.
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Kang JQ, Macdonald RL. Molecular Pathogenic Basis for GABRG2 Mutations Associated With a Spectrum of Epilepsy Syndromes, From Generalized Absence Epilepsy to Dravet Syndrome. JAMA Neurol 2017; 73:1009-16. [PMID: 27367160 DOI: 10.1001/jamaneurol.2016.0449] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
OBJECTIVE In this review article, we focus on the molecular pathogenic basis for genetic generalized epilepsies associated with mutations in the inhibitory γ-aminobutyric acid (GABAA) receptor γ2 subunit gene, GABRG2 (OMIM 137164), an established epilepsy gene. OBSERVATIONS The γ-aminobutyric acid (GABAA) receptor γ2 subunit gene, GABRG2, is abundantly expressed in the mammalian brain, and its encoded γ2 subunit is assembled into αβγ2 receptors, which are the major GABAA receptor isoforms in the brain. The γ2 subunits have a critical role in GABAA receptor trafficking and clustering at synapses. They reside inside the endoplasmic reticulum after synthesis, where they oligomerize with other binding partners, such as α and β subunits, and further assemble into pentameric receptors. Only correctly assembled receptors can traffic beyond the endoplasmic reticulum and reach the cell surface and synapses, where they conduct chloride ion current when activated by GABA. Mutations in GABRG2 have been associated with simple febrile seizures and with genetic epilepsy syndromes, including childhood absence epilepsy, generalized epilepsy with febrile seizures plus, and Dravet syndrome or severe myoclonic epilepsy in infancy. The mutations include missense, nonsense, and frameshift mutations, as well as splice-site and deletion mutations. The mutations have been identified in both coding and noncoding sequences like splice sites. In the coding sequence, these mutations are found in multiple locations, including the extracellular N-terminus, transmembrane domains, and transmembrane 3-transmembrane 4 intracellular loop. All of these mutations reduced channel function but to different extents and by diverse mechanisms, including nonsense-mediated messenger RNA decay, endoplasmic reticulum-associated protein degradation, dominant negative suppression of partnering subunits, mutant subunit aggregation causing cell stress and cell death, and gating defects. CONCLUSIONS AND RELEVANCE We conclude that the epilepsy phenotypic heterogeneity associated with GABRG2 mutations may be related to the extent of the reduction of GABAA receptor channel function and the differential dominant negative suppression, as well to toxicity related to the metabolism of mutant subunit proteins resulting from each mutant γ2 subunit, in addition to different genetic backgrounds.
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Affiliation(s)
- Jing-Qiong Kang
- Department of Neurology, Vanderbilt University, Nashville, Tennessee
| | - Robert L Macdonald
- Department of Neurology, Vanderbilt University, Nashville, Tennessee2Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee3Department of Pharmacology, Vanderbilt University, Nashville, Tennessee
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Ion Channel Genes and Epilepsy: Functional Alteration, Pathogenic Potential, and Mechanism of Epilepsy. Neurosci Bull 2017; 33:455-477. [PMID: 28488083 DOI: 10.1007/s12264-017-0134-1] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 02/20/2017] [Indexed: 01/29/2023] Open
Abstract
Ion channels are crucial in the generation and modulation of excitability in the nervous system and have been implicated in human epilepsy. Forty-one epilepsy-associated ion channel genes and their mutations are systematically reviewed. In this paper, we analyzed the genotypes, functional alterations (funotypes), and phenotypes of these mutations. Eleven genes featured loss-of-function mutations and six had gain-of-function mutations. Nine genes displayed diversified funotypes, among which a distinct funotype-phenotype correlation was found in SCN1A. These data suggest that the funotype is an essential consideration in evaluating the pathogenicity of mutations and a distinct funotype or funotype-phenotype correlation helps to define the pathogenic potential of a gene.
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Zou F, McWalter K, Schmidt L, Decker A, Picker JD, Lincoln S, Sweetser DA, Briere LC, Harini C, Marsh E, Medne L, Wang RY, Leydiker K, Mower A, Visser G, Cuppen I, van Gassen KL, van der Smagt J, Yousaf A, Tennison M, Shanmugham A, Butler E, Richard G, McKnight D. Expanding the phenotypic spectrum of GABRG2 variants: a recurrent GABRG2 missense variant associated with a severe phenotype. J Neurogenet 2017; 31:30-36. [PMID: 28460589 DOI: 10.1080/01677063.2017.1315417] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Pathogenic missense and truncating variants in the GABRG2 gene cause a spectrum of epilepsies, from Dravet syndrome to milder simple febrile seizures. In most cases, pathogenic missense variants in the GABRG2 gene segregate with a febrile seizure phenotype. In this case series, we report a recurrent, de novo missense variant (c0.316 G > A; p.A106T) in the GABRG2 gene that was identified in five unrelated individuals. These patients were described to have a more severe phenotype than previously reported for GABRG2 missense variants. Common features include variable early-onset seizures, significant motor and speech delays, intellectual disability, hypotonia, movement disorder, dysmorphic features and vision/ocular issues. Our report further explores a recurrent pathogenic missense variant within the GABRG2 variant family and broadens the spectrum of associated phenotypes for GABRG2-associated disorders.
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Affiliation(s)
| | | | | | | | - Jonathan D Picker
- b Division of Genetics and Genomics , Boston Children's Hospital , Boston , MA , USA
| | - Sharyn Lincoln
- b Division of Genetics and Genomics , Boston Children's Hospital , Boston , MA , USA.,c NIH Common Fund , Undiagnosed Diseases Network , Bethesda , MD , USA
| | - David A Sweetser
- c NIH Common Fund , Undiagnosed Diseases Network , Bethesda , MD , USA.,d Department of Medical Genetics , Massachusetts General Hospital for Children , Boston , MA , USA
| | - Lauren C Briere
- c NIH Common Fund , Undiagnosed Diseases Network , Bethesda , MD , USA.,d Department of Medical Genetics , Massachusetts General Hospital for Children , Boston , MA , USA
| | - Chellamani Harini
- e Division of Neurophysiology , Boston Children's Hospital , Boston , MA , USA
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- c NIH Common Fund , Undiagnosed Diseases Network , Bethesda , MD , USA
| | - Eric Marsh
- f Division of Child Neurology, Departments of Neurology and Pediatrics , Children's Hospital of Philadelphia , Philadelphia , PA , USA
| | - Livija Medne
- g Individualized Medical Genetics Center, Division of Human Genetics, Division of Neurology , The Children's Hospital of Philadelphia , Philadelphia , PA , USA
| | - Raymond Y Wang
- h Division of Metabolic Disorders , CHOC Children's Hospital , Orange , CA , USA
| | - Karen Leydiker
- h Division of Metabolic Disorders , CHOC Children's Hospital , Orange , CA , USA
| | - Andrew Mower
- i Neurology , CHOC Children's Hospital , Orange , CA , USA
| | - Gepke Visser
- j Wilhelmina Children's Hospital/University Medical Center , Utrecht , the Netherlands
| | - Inge Cuppen
- j Wilhelmina Children's Hospital/University Medical Center , Utrecht , the Netherlands
| | - Koen L van Gassen
- k Department of Genetics , University Medical Center Utrecht , Utrecht , the Netherlands
| | - Jasper van der Smagt
- k Department of Genetics , University Medical Center Utrecht , Utrecht , the Netherlands
| | - Adeel Yousaf
- l University of North Carolina at Chapel Hill , Chapel Hill , NC , USA
| | - Michael Tennison
- m University of North Carolina at Chapel Hill , Chapel Hill , NC , USA
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Warner TA, Liu Z, Macdonald RL, Kang JQ. Heat induced temperature dysregulation and seizures in Dravet Syndrome/GEFS+ Gabrg2 +/Q390X mice. Epilepsy Res 2017; 134:1-8. [PMID: 28505490 DOI: 10.1016/j.eplepsyres.2017.04.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 04/13/2017] [Accepted: 04/25/2017] [Indexed: 12/15/2022]
Abstract
It has been established that febrile seizures and its extended syndromes like generalized epilepsy with febrile seizures (FS) plus (GEFS+) and Dravet syndrome have been associated with mutations especially in SCN1A and GABRG2 genes. In patients, the onset of FS is likely due to the combined effect of temperature and inflammation in genetically vulnerable individuals because fever is often associated with infection. Much effort has been spent to understand the mechanisms underlying fever induction of seizures. In addition to the role of cytokines in FS, previous studies in Scn1a+/- knockout mice, a model of Dravet syndrome, indicated that temperature elevation alone could result in seizure generation, and the effect of elevated temperature inducing seizures was age-dependent. Here, we report the thermal effect in a different mouse model of Dravet syndrome, the Gabrg2+/Q390X knockin mouse. We demonstrated age-dependent dysregulated temperature control and that temperature elevation produced myoclonic jerks, generalized tonic clonic seizures (GTCSs) and heightened anxiety-like symptoms in Gabrg2+/Q390X mice. The study indicated that regardless of other inflammatory factors, brief heat alone increased brain excitability and induced multiple types of seizures in Gabrg2+/Q390X mice, suggesting that mutations like GABRG2(Q390X) may alter brain thermal regulation and precipitate seizures during temperature elevations.
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Affiliation(s)
- Timothy A Warner
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, United States
| | - Zhong Liu
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, United States
| | - Robert L Macdonald
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, United States; Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN 37232, United States; Vanderbilt Kennedy Center of Human Development, Vanderbilt University School of Medicine, Nashville, TN 37232, United States
| | - Jing-Qiong Kang
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, United States; Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN 37232, United States; Vanderbilt Kennedy Center of Human Development, Vanderbilt University School of Medicine, Nashville, TN 37232, United States.
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Offringa M, Newton R, Cozijnsen MA, Nevitt SJ. Prophylactic drug management for febrile seizures in children. Cochrane Database Syst Rev 2017; 2:CD003031. [PMID: 28225210 PMCID: PMC6464693 DOI: 10.1002/14651858.cd003031.pub3] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND Febrile seizures occurring in a child older than one month during an episode of fever affect 2% to 4% of children in Great Britain and the United States and recur in 30%. Rapid-acting antiepileptics and antipyretics given during subsequent fever episodes have been used to avoid the adverse effects of continuous antiepileptic drugs. OBJECTIVES To evaluate primarily the effectiveness and safety of antiepileptic and antipyretic drugs used prophylactically to treat children with febrile seizures; but also to evaluate any other drug intervention where there was a sound biological rationale for its use. SEARCH METHODS We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2016, Issue 7); MEDLINE (1966 to July 2016); Embase (1966 to July 2016); Database of Abstracts of Reviews of Effectiveness (DARE) (July 2016). We imposed no language restrictions. We also contacted researchers in the field to identify continuing or unpublished studies. SELECTION CRITERIA Trials using randomised or quasi-randomised participant allocation that compared the use of antiepileptic, antipyretic or other plausible agents with each other, placebo or no treatment. DATA COLLECTION AND ANALYSIS Two review authors (RN and MO) independently applied predefined criteria to select trials for inclusion and extracted the predefined relevant data, recording methods for randomisation, blinding and exclusions. For the 2016 update a third author (MC) checked all original inclusions, data analyses, and updated the search. Outcomes assessed were seizure recurrence at 6, 12, 18, 24, 36, and 48 months and at age 5 to 6 years in the intervention and non-intervention groups, and adverse medication effects. We assessed the presence of publication bias using funnel plots. MAIN RESULTS We included 40 articles describing 30 randomised trials with 4256 randomised participants. We analysed 13 interventions of continuous or intermittent prophylaxis and their control treatments. Methodological quality was moderate to poor in most studies. We found no significant benefit for intermittent phenobarbitone, phenytoin, valproate, pyridoxine, ibuprofen or zinc sulfate versus placebo or no treatment; nor for diclofenac versus placebo followed by ibuprofen, acetaminophen or placebo; nor for continuous phenobarbitone versus diazepam, intermittent rectal diazepam versus intermittent valproate, or oral diazepam versus clobazam.There was a significant reduction of recurrent febrile seizures with intermittent diazepam versus placebo or no treatment, with a risk ratio (RR) of 0.64 (95% confidence interval (CI) 0.48 to 0.85 at six months), RR of 0.69 (95% CI 0.56 to 0.84) at 12 months, RR 0.37 (95% CI 0.23 to 0.60) at 18 months, RR 0.73 (95% CI 0.56 to 0.95) at 24 months, RR 0.58 (95% CI 0.40 to 0.85) at 36 months, RR 0.36 (95% CI 0.15 to 0.89) at 48 months, with no benefit at 60 to 72 months. Phenobarbitone versus placebo or no treatment reduced seizures at 6, 12 and 24 months but not at 18 or 72 month follow-up (RR 0.59 (95% CI 0.42 to 0.83) at 6 months; RR 0.54 (95% CI 0.42 to 0.70) at 12 months; and RR 0.69 (95% CI 0.53 to 0.89) at 24 months). Intermittent clobazam compared to placebo at six months resulted in a RR of 0.36 (95% CI 0.20 to 0.64), an effect found against an extremely high (83.3%) recurrence rate in the controls, which is a result that needs replication.The recording of adverse effects was variable. Lower comprehension scores in phenobarbitone-treated children were found in two studies. In general, adverse effects were recorded in up to 30% of children in the phenobarbitone-treated group and in up to 36% in benzodiazepine-treated groups. We found evidence of publication bias in the meta-analyses of comparisons for phenobarbitone versus placebo (eight studies) at 12 months but not at six months (six studies); and valproate versus placebo (four studies) at 12 months, with too few studies to identify publication bias for the other comparisons.Most of the reviewed antiepileptic drug trials are of a methodological quality graded as low or very low. Methods of randomisation and allocation concealment often do not meet current standards; and treatment versus no treatment is more commonly seen than treatment versus placebo, leading to obvious risks of bias. Trials of antipyretics and zinc were of higher quality. AUTHORS' CONCLUSIONS We found reduced recurrence rates for children with febrile seizures for intermittent diazepam and continuous phenobarbitone, with adverse effects in up to 30%. Apparent benefit for clobazam treatment in one trial needs to be replicated to be judged reliable. Given the benign nature of recurrent febrile seizures, and the high prevalence of adverse effects of these drugs, parents and families should be supported with adequate contact details of medical services and information on recurrence, first aid management and, most importantly, the benign nature of the phenomenon.
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Affiliation(s)
- Martin Offringa
- Hospital for Sick ChildrenChild Health Evaluative Sciences555 University AvenueTorontoONCanadaM5G 1X8
| | - Richard Newton
- Royal Manchester Children's HospitalDepartment of Paediatric NeurologyHospital RoadPendleburyManchesterUKM27 4HA
| | - Martinus A Cozijnsen
- Erasmus MC ‐ Sophia Children's HospitalPediatric Gastroenterology's‐Gravendijkwal 230 3015 CERotterdamNetherlands3000 CB
| | - Sarah J Nevitt
- University of LiverpoolDepartment of BiostatisticsBlock F, Waterhouse Building1‐5 Brownlow HillLiverpoolUKL69 3GL
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Altered Channel Conductance States and Gating of GABA A Receptors by a Pore Mutation Linked to Dravet Syndrome. eNeuro 2017; 4:eN-NWR-0251-16. [PMID: 28197552 PMCID: PMC5301078 DOI: 10.1523/eneuro.0251-16.2017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 01/19/2017] [Accepted: 01/19/2017] [Indexed: 11/21/2022] Open
Abstract
We identified a de novo missense mutation, P302L, in the γ-aminobutyric acid type A (GABAA) receptor γ2 subunit gene GABRG2 in a patient with Dravet syndrome using targeted next-generation sequencing. The mutation was in the cytoplasmic portion of the transmembrane segment M2 of the γ2 subunit that faces the pore lumen. GABAA receptor α1 and β3 subunits were coexpressed with wild-type (wt) γ2L or mutant γ2L(P302L) subunits in HEK 293T cells and cultured mouse cortical neurons. We measured currents using whole-cell and single-channel patch clamp techniques, surface and total expression levels using surface biotinylation and Western blotting, and potential structural perturbations in mutant GABAA receptors using structural modeling. The γ2(P302L) subunit mutation produced an ∼90% reduction of whole-cell current by increasing macroscopic desensitization and reducing GABA potency, which resulted in a profound reduction of GABAA receptor-mediated miniature IPSCs (mIPSCs). The conductance of the receptor channel was reduced to 24% of control conductance by shifting the relative contribution of the conductance states from high- to low-conductance levels with only slight changes in receptor surface expression. Structural modeling of the GABAA receptor in the closed, open, and desensitized states showed that the mutation was positioned to slow activation, enhance desensitization, and shift channels to a low-conductance state by reshaping the hour-glass-like pore cavity during transitions between closed, open, and desensitized states. Our study revealed a novel γ2 subunit missense mutation (P302L) that has a novel pathogenic mechanism to cause defects in the conductance and gating of GABAA receptors, which results in hyperexcitability and contributes to the pathogenesis of the genetic epilepsy Dravet syndrome.
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Shen D, Hernandez CC, Shen W, Hu N, Poduri A, Shiedley B, Rotenberg A, Datta AN, Leiz S, Patzer S, Boor R, Ramsey K, Goldberg E, Helbig I, Ortiz-Gonzalez XR, Lemke JR, Marsh ED, Macdonald RL. De novo GABRG2 mutations associated with epileptic encephalopathies. Brain 2017; 140:49-67. [PMID: 27864268 PMCID: PMC5226060 DOI: 10.1093/brain/aww272] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 09/05/2016] [Accepted: 09/10/2016] [Indexed: 12/17/2022] Open
Abstract
Epileptic encephalopathies are a devastating group of severe childhood onset epilepsies with medication-resistant seizures and poor developmental outcomes. Many epileptic encephalopathies have a genetic aetiology and are often associated with de novo mutations in genes mediating synaptic transmission, including GABAA receptor subunit genes. Recently, we performed next generation sequencing on patients with a spectrum of epileptic encephalopathy phenotypes, and we identified five novel (A106T, I107T, P282S, R323W and F343L) and one known (R323Q) de novo GABRG2 pathogenic variants (mutations) in eight patients. To gain insight into the molecular basis for how these mutations contribute to epileptic encephalopathies, we compared the effects of the mutations on the properties of recombinant α1β2γ2L GABAA receptors transiently expressed in HEK293T cells. Using a combination of patch clamp recording, immunoblotting, confocal imaging and structural modelling, we characterized the effects of these GABRG2 mutations on GABAA receptor biogenesis and channel function. Compared with wild-type α1β2γ2L receptors, GABAA receptors containing a mutant γ2 subunit had reduced cell surface expression with altered subunit stoichiometry or decreased GABA-evoked whole-cell current amplitudes, but with different levels of reduction. While a causal role of these mutations cannot be established directly from these results, the functional analysis together with the genetic information suggests that these GABRG2 variants may be major contributors to the epileptic encephalopathy phenotypes. Our study further expands the GABRG2 phenotypic spectrum and supports growing evidence that defects in GABAergic neurotransmission participate in the pathogenesis of genetic epilepsies including epileptic encephalopathies.
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Affiliation(s)
- Dingding Shen
- 1 The Graduate Program of Neuroscience, Vanderbilt University, Nashville, TN 37232, USA
| | - Ciria C Hernandez
- 2 Department of Neurology, Vanderbilt University, Nashville, TN 37240, USA
| | - Wangzhen Shen
- 2 Department of Neurology, Vanderbilt University, Nashville, TN 37240, USA
| | - Ningning Hu
- 2 Department of Neurology, Vanderbilt University, Nashville, TN 37240, USA
| | - Annapurna Poduri
- 3 Epilepsy Genetics Program and the Department of Neurology, Boston Children's Hospital, Boston, MA 02115, USA
- 4 Harvard Medical School, Boston, MA 02115, USA
| | - Beth Shiedley
- 3 Epilepsy Genetics Program and the Department of Neurology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Alex Rotenberg
- 3 Epilepsy Genetics Program and the Department of Neurology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Alexandre N Datta
- 5 Division of Pediatric Neurology and Developmental Medicine, University of Basel Children's Hospital, Basel 4056, Switzerland
| | - Steffen Leiz
- 6 Clinic for Children and Adolescents Dritter Orden, Divison of Neuropediatrics, München, 80638 Germany
| | - Steffi Patzer
- 7 Clinic for Children and Adolescents, Halle/Saale, 06097 Germany
| | - Rainer Boor
- 8 Department of Pediatric Neurology, Kiel University, Kiel 24118 Germany; Northern German Epilepsy Centre for Children and Adolescents, Schwentinental - Raisdorf, 24223 Germany
| | - Kerri Ramsey
- 9 Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, 85004 AZ, USA
| | - Ethan Goldberg
- 10 Departments of Neurology and Paediatrics, Division of Child Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
- 11 Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Ingo Helbig
- 10 Departments of Neurology and Paediatrics, Division of Child Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
- 11 Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Xilma R Ortiz-Gonzalez
- 10 Departments of Neurology and Paediatrics, Division of Child Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
- 11 Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Johannes R Lemke
- 12 Institute of Human Genetics, University of Leipzig Hospitals and Clinics, Leipzig, 04103 Germany
| | - Eric D Marsh
- 10 Departments of Neurology and Paediatrics, Division of Child Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
- 11 Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Robert L Macdonald
- 2 Department of Neurology, Vanderbilt University, Nashville, TN 37240, USA
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Hung KL, Liang JS, Wang JS, Chen HJ, Lin LJ, Lu JF. Association of a novel GABRG2 splicing variation and a PTGS2/COX-2 single nucleotide polymorphism with Taiwanese febrile seizures. Epilepsy Res 2017; 129:1-7. [DOI: 10.1016/j.eplepsyres.2016.11.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 11/07/2016] [Accepted: 11/12/2016] [Indexed: 01/20/2023]
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Ishii A, Kang JQ, Schornak CC, Hernandez CC, Shen W, Watkins JC, Macdonald RL, Hirose S. A de novo missense mutation of GABRB2 causes early myoclonic encephalopathy. J Med Genet 2016; 54:202-211. [PMID: 27789573 PMCID: PMC5384423 DOI: 10.1136/jmedgenet-2016-104083] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Revised: 09/27/2016] [Accepted: 09/28/2016] [Indexed: 12/18/2022]
Abstract
Background Early myoclonic encephalopathy (EME), a disease with a devastating prognosis, is characterised by neonatal onset of seizures and massive myoclonus accompanied by a continuous suppression-burst EEG pattern. Three genes are associated with EMEs that have metabolic features. Here, we report a pathogenic mutation of an ion channel as a cause of EME for the first time. Methods Sequencing was performed for 214 patients with epileptic seizures using a gene panel with 109 genes that are known or suspected to cause epileptic seizures. Functional assessments were demonstrated by using electrophysiological experiments and immunostaining for mutant γ-aminobutyric acid-A (GABAA) receptor subunits in HEK293T cells. Results We discovered a de novo heterozygous missense mutation (c.859A>C [p.Thr287Pro]) in the GABRB2-encoded β2 subunit of the GABAA receptor in an infant with EME. No GABRB2 mutations were found in three other EME cases or in 166 patients with infantile spasms. GABAA receptors bearing the mutant β2 subunit were poorly trafficked to the cell membrane and prevented γ2 subunits from trafficking to the cell surface. The peak amplitudes of currents from GABAA receptors containing only mutant β2 subunits were smaller than that of those from receptors containing only wild-type β2 subunits. The decrease in peak current amplitude (96.4% reduction) associated with the mutant GABAA receptor was greater than expected, based on the degree to which cell surface expression was reduced (66% reduction). Conclusion This mutation has complex functional effects on GABAA receptors, including reduction of cell surface expression and attenuation of channel function, which would significantly perturb GABAergic inhibition in the brain.
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Affiliation(s)
- Atsushi Ishii
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan
| | - Jing-Qiong Kang
- Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Cara C Schornak
- Neuroscience Graduate Program, Vanderbilt University, Nashville, Tennessee, USA
| | - Ciria C Hernandez
- Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Wangzhen Shen
- Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Joseph C Watkins
- Department of Mathematics, University of Arizona, Tucson, Arizona, USA
| | - Robert L Macdonald
- Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Shinichi Hirose
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan
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Dixit AB, Banerjee J, Ansari A, Tripathi M, Chandra SP. Mutations in GABRG2 receptor gene are not a major factor in the pathogenesis of mesial temporal lobe epilepsy in Indian population. Ann Indian Acad Neurol 2016; 19:236-41. [PMID: 27293336 PMCID: PMC4888688 DOI: 10.4103/0972-2327.182304] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
AIM This study is focused on GABRG2 gene sequence variations in patients with mesial temporal lobe epilepsy (mTLE). The GABAAreceptor is a heteropentameric receptor and alpha-1 beta-2 gamma-2 subunits combination is most abundant and present in almost all regions of the brain. The gamma-2 subunit (GABRG2) gene mutations have been reported in different epilepsy pathologies. In the present study we have looked for GABRG2 gene sequence variations in patients with mTLE. MATERIALS AND METHODS Twenty patients (12 females and eight males, age 4.6-38 years) with MTLE were recruited for this investigation. Patients were recommended for epilepsy surgery after all clinical investigations as per the epilepsy protocol. Ethnically matched glioma or meningioma patients were considered as nonepileptic controls. During temporal lobectomy of amygdalohippocampectomy, hippocampal brain tissue samples were resected guided by intraoperative electrocorticography (ECoG) activity. All 11 exons of GABRG2 gene with their flanking intronic regions were amplified by polymerase chain reaction (PCR) and screened by DNA sequencing analysis for sequence variations. STATISTICAL ANALYSIS USED Comparison of allele frequencies between patient and control groups was determined using a c(2) test. RESULTS AND CONCLUSIONS Total five DNA sequence variations were identified, three in exonic regions (c.643A > G, rs211035), (c.T > A, rs424740), and (c.C > T, rs418210) and two in intronic regions (c.751 + 41A > G, rs211034) and (c.751 + 52G > A, rs 34281163). Allele frequencies of variants identified in this study did not differ between patients and normal controls. Thus, we conclude that GABRG2 gene may not be playing significant role in the development of epilepsy or as a susceptibility gene in patients with MTLE in Indian population.
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Affiliation(s)
- Aparna Banerjee Dixit
- Center for Excellence in Epilepsy, A joint National Brain Research Centre-All Institute of Medical Sciences Collaboration, National Brain Research Centre, Manesar, Haryana, India
| | - Jyotirmoy Banerjee
- Center for Excellence in Epilepsy, A joint National Brain Research Centre-All Institute of Medical Sciences Collaboration, National Brain Research Centre, Manesar, Haryana, India
| | - Abuzar Ansari
- Department of Neurosurgery, All Institute of Medical Sciences, New Delhi, India
| | - Manjari Tripathi
- Department of Neurology, All Institute of Medical Sciences, New Delhi, India
| | - Sarat P Chandra
- Department of Neurosurgery, All Institute of Medical Sciences, New Delhi, India
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Boillot M, Morin-Brureau M, Picard F, Weckhuysen S, Lambrecq V, Minetti C, Striano P, Zara F, Iacomino M, Ishida S, An-Gourfinkel I, Daniau M, Hardies K, Baulac M, Dulac O, Leguern E, Nabbout R, Baulac S. Novel GABRG2 mutations cause familial febrile seizures. NEUROLOGY-GENETICS 2015; 1:e35. [PMID: 27066572 PMCID: PMC4811385 DOI: 10.1212/nxg.0000000000000035] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 09/30/2015] [Indexed: 12/14/2022]
Abstract
Objective: To identify the genetic cause in a large family with febrile seizures (FS) and temporal lobe epilepsy (TLE) and subsequently search for additional mutations in a cohort of 107 families with FS, with or without epilepsy. Methods: The cohort consisted of 1 large family with FS and TLE, 64 smaller French families recruited through a national French campaign, and 43 Italian families. Molecular analyses consisted of whole-exome sequencing and mutational screening. Results: Exome sequencing revealed a p.Glu402fs*3 mutation in the γ2 subunit of the GABAA receptor gene (GABRG2) in the large family with FS and TLE. Three additional nonsense and frameshift GABRG2 mutations (p.Arg136*, p.Val462fs*33, and p.Pro59fs*12), 1 missense mutation (p.Met199Val), and 1 exonic deletion were subsequently identified in 5 families of the follow-up cohort. Conclusions: We report GABRG2 mutations in 5.6% (6/108) of families with FS, with or without associated epilepsy. This study provides evidence that GABRG2 mutations are linked to the FS phenotype, rather than epilepsy, and that loss-of-function of GABAA receptor γ2 subunit is the probable underlying pathogenic mechanism.
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Affiliation(s)
- Morgane Boillot
- Sorbonne Universités (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UPMC Univ Paris 06, UM 75, ICM; INSERM, U1127 (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), ICM; CNRS (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UMR 7225, ICM; ICM (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), Paris, France; Department of Neurology (F.P.), University Hospitals of Geneva (HUG), Switzerland; Centre de Reference Épilepsies Rares, Epilepsy Unit (S.W., M.B., V.L., I.A.-G.), and Département de Génétique et de Cytogénétique (E.L.), AP-HP Groupe Hospitalier Pitié-Salpêtrière, Paris, France; Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova (C.M., P.S.), and Laboratory of Neurogenetics, Department of Neurosciences (F.Z., M.I.), "G. Gaslini" Institute, Genova, Italy; Neurogenetics Group, VIB-Department of Molecular Genetics (K.H.), and Laboratory of Neurogenetics, Institute Born-Bunge (K.H.), University of Antwerp, Belgium; Centre de Reference Épilepsies Rares (O.D., R.N.), Department of Pediatric Neurology, Necker Enfants Malades Hospital, AP-HP, Paris; INSERM (O.D., R.N.), U1129, Necker, Paris, France; and University Paris Descartes (O.D., R.N.), Paris, France
| | - Mélanie Morin-Brureau
- Sorbonne Universités (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UPMC Univ Paris 06, UM 75, ICM; INSERM, U1127 (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), ICM; CNRS (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UMR 7225, ICM; ICM (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), Paris, France; Department of Neurology (F.P.), University Hospitals of Geneva (HUG), Switzerland; Centre de Reference Épilepsies Rares, Epilepsy Unit (S.W., M.B., V.L., I.A.-G.), and Département de Génétique et de Cytogénétique (E.L.), AP-HP Groupe Hospitalier Pitié-Salpêtrière, Paris, France; Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova (C.M., P.S.), and Laboratory of Neurogenetics, Department of Neurosciences (F.Z., M.I.), "G. Gaslini" Institute, Genova, Italy; Neurogenetics Group, VIB-Department of Molecular Genetics (K.H.), and Laboratory of Neurogenetics, Institute Born-Bunge (K.H.), University of Antwerp, Belgium; Centre de Reference Épilepsies Rares (O.D., R.N.), Department of Pediatric Neurology, Necker Enfants Malades Hospital, AP-HP, Paris; INSERM (O.D., R.N.), U1129, Necker, Paris, France; and University Paris Descartes (O.D., R.N.), Paris, France
| | - Fabienne Picard
- Sorbonne Universités (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UPMC Univ Paris 06, UM 75, ICM; INSERM, U1127 (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), ICM; CNRS (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UMR 7225, ICM; ICM (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), Paris, France; Department of Neurology (F.P.), University Hospitals of Geneva (HUG), Switzerland; Centre de Reference Épilepsies Rares, Epilepsy Unit (S.W., M.B., V.L., I.A.-G.), and Département de Génétique et de Cytogénétique (E.L.), AP-HP Groupe Hospitalier Pitié-Salpêtrière, Paris, France; Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova (C.M., P.S.), and Laboratory of Neurogenetics, Department of Neurosciences (F.Z., M.I.), "G. Gaslini" Institute, Genova, Italy; Neurogenetics Group, VIB-Department of Molecular Genetics (K.H.), and Laboratory of Neurogenetics, Institute Born-Bunge (K.H.), University of Antwerp, Belgium; Centre de Reference Épilepsies Rares (O.D., R.N.), Department of Pediatric Neurology, Necker Enfants Malades Hospital, AP-HP, Paris; INSERM (O.D., R.N.), U1129, Necker, Paris, France; and University Paris Descartes (O.D., R.N.), Paris, France
| | - Sarah Weckhuysen
- Sorbonne Universités (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UPMC Univ Paris 06, UM 75, ICM; INSERM, U1127 (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), ICM; CNRS (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UMR 7225, ICM; ICM (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), Paris, France; Department of Neurology (F.P.), University Hospitals of Geneva (HUG), Switzerland; Centre de Reference Épilepsies Rares, Epilepsy Unit (S.W., M.B., V.L., I.A.-G.), and Département de Génétique et de Cytogénétique (E.L.), AP-HP Groupe Hospitalier Pitié-Salpêtrière, Paris, France; Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova (C.M., P.S.), and Laboratory of Neurogenetics, Department of Neurosciences (F.Z., M.I.), "G. Gaslini" Institute, Genova, Italy; Neurogenetics Group, VIB-Department of Molecular Genetics (K.H.), and Laboratory of Neurogenetics, Institute Born-Bunge (K.H.), University of Antwerp, Belgium; Centre de Reference Épilepsies Rares (O.D., R.N.), Department of Pediatric Neurology, Necker Enfants Malades Hospital, AP-HP, Paris; INSERM (O.D., R.N.), U1129, Necker, Paris, France; and University Paris Descartes (O.D., R.N.), Paris, France
| | - Virginie Lambrecq
- Sorbonne Universités (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UPMC Univ Paris 06, UM 75, ICM; INSERM, U1127 (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), ICM; CNRS (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UMR 7225, ICM; ICM (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), Paris, France; Department of Neurology (F.P.), University Hospitals of Geneva (HUG), Switzerland; Centre de Reference Épilepsies Rares, Epilepsy Unit (S.W., M.B., V.L., I.A.-G.), and Département de Génétique et de Cytogénétique (E.L.), AP-HP Groupe Hospitalier Pitié-Salpêtrière, Paris, France; Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova (C.M., P.S.), and Laboratory of Neurogenetics, Department of Neurosciences (F.Z., M.I.), "G. Gaslini" Institute, Genova, Italy; Neurogenetics Group, VIB-Department of Molecular Genetics (K.H.), and Laboratory of Neurogenetics, Institute Born-Bunge (K.H.), University of Antwerp, Belgium; Centre de Reference Épilepsies Rares (O.D., R.N.), Department of Pediatric Neurology, Necker Enfants Malades Hospital, AP-HP, Paris; INSERM (O.D., R.N.), U1129, Necker, Paris, France; and University Paris Descartes (O.D., R.N.), Paris, France
| | - Carlo Minetti
- Sorbonne Universités (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UPMC Univ Paris 06, UM 75, ICM; INSERM, U1127 (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), ICM; CNRS (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UMR 7225, ICM; ICM (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), Paris, France; Department of Neurology (F.P.), University Hospitals of Geneva (HUG), Switzerland; Centre de Reference Épilepsies Rares, Epilepsy Unit (S.W., M.B., V.L., I.A.-G.), and Département de Génétique et de Cytogénétique (E.L.), AP-HP Groupe Hospitalier Pitié-Salpêtrière, Paris, France; Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova (C.M., P.S.), and Laboratory of Neurogenetics, Department of Neurosciences (F.Z., M.I.), "G. Gaslini" Institute, Genova, Italy; Neurogenetics Group, VIB-Department of Molecular Genetics (K.H.), and Laboratory of Neurogenetics, Institute Born-Bunge (K.H.), University of Antwerp, Belgium; Centre de Reference Épilepsies Rares (O.D., R.N.), Department of Pediatric Neurology, Necker Enfants Malades Hospital, AP-HP, Paris; INSERM (O.D., R.N.), U1129, Necker, Paris, France; and University Paris Descartes (O.D., R.N.), Paris, France
| | - Pasquale Striano
- Sorbonne Universités (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UPMC Univ Paris 06, UM 75, ICM; INSERM, U1127 (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), ICM; CNRS (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UMR 7225, ICM; ICM (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), Paris, France; Department of Neurology (F.P.), University Hospitals of Geneva (HUG), Switzerland; Centre de Reference Épilepsies Rares, Epilepsy Unit (S.W., M.B., V.L., I.A.-G.), and Département de Génétique et de Cytogénétique (E.L.), AP-HP Groupe Hospitalier Pitié-Salpêtrière, Paris, France; Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova (C.M., P.S.), and Laboratory of Neurogenetics, Department of Neurosciences (F.Z., M.I.), "G. Gaslini" Institute, Genova, Italy; Neurogenetics Group, VIB-Department of Molecular Genetics (K.H.), and Laboratory of Neurogenetics, Institute Born-Bunge (K.H.), University of Antwerp, Belgium; Centre de Reference Épilepsies Rares (O.D., R.N.), Department of Pediatric Neurology, Necker Enfants Malades Hospital, AP-HP, Paris; INSERM (O.D., R.N.), U1129, Necker, Paris, France; and University Paris Descartes (O.D., R.N.), Paris, France
| | - Federico Zara
- Sorbonne Universités (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UPMC Univ Paris 06, UM 75, ICM; INSERM, U1127 (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), ICM; CNRS (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UMR 7225, ICM; ICM (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), Paris, France; Department of Neurology (F.P.), University Hospitals of Geneva (HUG), Switzerland; Centre de Reference Épilepsies Rares, Epilepsy Unit (S.W., M.B., V.L., I.A.-G.), and Département de Génétique et de Cytogénétique (E.L.), AP-HP Groupe Hospitalier Pitié-Salpêtrière, Paris, France; Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova (C.M., P.S.), and Laboratory of Neurogenetics, Department of Neurosciences (F.Z., M.I.), "G. Gaslini" Institute, Genova, Italy; Neurogenetics Group, VIB-Department of Molecular Genetics (K.H.), and Laboratory of Neurogenetics, Institute Born-Bunge (K.H.), University of Antwerp, Belgium; Centre de Reference Épilepsies Rares (O.D., R.N.), Department of Pediatric Neurology, Necker Enfants Malades Hospital, AP-HP, Paris; INSERM (O.D., R.N.), U1129, Necker, Paris, France; and University Paris Descartes (O.D., R.N.), Paris, France
| | - Michele Iacomino
- Sorbonne Universités (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UPMC Univ Paris 06, UM 75, ICM; INSERM, U1127 (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), ICM; CNRS (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UMR 7225, ICM; ICM (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), Paris, France; Department of Neurology (F.P.), University Hospitals of Geneva (HUG), Switzerland; Centre de Reference Épilepsies Rares, Epilepsy Unit (S.W., M.B., V.L., I.A.-G.), and Département de Génétique et de Cytogénétique (E.L.), AP-HP Groupe Hospitalier Pitié-Salpêtrière, Paris, France; Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova (C.M., P.S.), and Laboratory of Neurogenetics, Department of Neurosciences (F.Z., M.I.), "G. Gaslini" Institute, Genova, Italy; Neurogenetics Group, VIB-Department of Molecular Genetics (K.H.), and Laboratory of Neurogenetics, Institute Born-Bunge (K.H.), University of Antwerp, Belgium; Centre de Reference Épilepsies Rares (O.D., R.N.), Department of Pediatric Neurology, Necker Enfants Malades Hospital, AP-HP, Paris; INSERM (O.D., R.N.), U1129, Necker, Paris, France; and University Paris Descartes (O.D., R.N.), Paris, France
| | - Saeko Ishida
- Sorbonne Universités (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UPMC Univ Paris 06, UM 75, ICM; INSERM, U1127 (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), ICM; CNRS (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UMR 7225, ICM; ICM (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), Paris, France; Department of Neurology (F.P.), University Hospitals of Geneva (HUG), Switzerland; Centre de Reference Épilepsies Rares, Epilepsy Unit (S.W., M.B., V.L., I.A.-G.), and Département de Génétique et de Cytogénétique (E.L.), AP-HP Groupe Hospitalier Pitié-Salpêtrière, Paris, France; Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova (C.M., P.S.), and Laboratory of Neurogenetics, Department of Neurosciences (F.Z., M.I.), "G. Gaslini" Institute, Genova, Italy; Neurogenetics Group, VIB-Department of Molecular Genetics (K.H.), and Laboratory of Neurogenetics, Institute Born-Bunge (K.H.), University of Antwerp, Belgium; Centre de Reference Épilepsies Rares (O.D., R.N.), Department of Pediatric Neurology, Necker Enfants Malades Hospital, AP-HP, Paris; INSERM (O.D., R.N.), U1129, Necker, Paris, France; and University Paris Descartes (O.D., R.N.), Paris, France
| | - Isabelle An-Gourfinkel
- Sorbonne Universités (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UPMC Univ Paris 06, UM 75, ICM; INSERM, U1127 (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), ICM; CNRS (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UMR 7225, ICM; ICM (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), Paris, France; Department of Neurology (F.P.), University Hospitals of Geneva (HUG), Switzerland; Centre de Reference Épilepsies Rares, Epilepsy Unit (S.W., M.B., V.L., I.A.-G.), and Département de Génétique et de Cytogénétique (E.L.), AP-HP Groupe Hospitalier Pitié-Salpêtrière, Paris, France; Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova (C.M., P.S.), and Laboratory of Neurogenetics, Department of Neurosciences (F.Z., M.I.), "G. Gaslini" Institute, Genova, Italy; Neurogenetics Group, VIB-Department of Molecular Genetics (K.H.), and Laboratory of Neurogenetics, Institute Born-Bunge (K.H.), University of Antwerp, Belgium; Centre de Reference Épilepsies Rares (O.D., R.N.), Department of Pediatric Neurology, Necker Enfants Malades Hospital, AP-HP, Paris; INSERM (O.D., R.N.), U1129, Necker, Paris, France; and University Paris Descartes (O.D., R.N.), Paris, France
| | - Mailys Daniau
- Sorbonne Universités (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UPMC Univ Paris 06, UM 75, ICM; INSERM, U1127 (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), ICM; CNRS (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UMR 7225, ICM; ICM (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), Paris, France; Department of Neurology (F.P.), University Hospitals of Geneva (HUG), Switzerland; Centre de Reference Épilepsies Rares, Epilepsy Unit (S.W., M.B., V.L., I.A.-G.), and Département de Génétique et de Cytogénétique (E.L.), AP-HP Groupe Hospitalier Pitié-Salpêtrière, Paris, France; Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova (C.M., P.S.), and Laboratory of Neurogenetics, Department of Neurosciences (F.Z., M.I.), "G. Gaslini" Institute, Genova, Italy; Neurogenetics Group, VIB-Department of Molecular Genetics (K.H.), and Laboratory of Neurogenetics, Institute Born-Bunge (K.H.), University of Antwerp, Belgium; Centre de Reference Épilepsies Rares (O.D., R.N.), Department of Pediatric Neurology, Necker Enfants Malades Hospital, AP-HP, Paris; INSERM (O.D., R.N.), U1129, Necker, Paris, France; and University Paris Descartes (O.D., R.N.), Paris, France
| | - Katia Hardies
- Sorbonne Universités (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UPMC Univ Paris 06, UM 75, ICM; INSERM, U1127 (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), ICM; CNRS (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UMR 7225, ICM; ICM (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), Paris, France; Department of Neurology (F.P.), University Hospitals of Geneva (HUG), Switzerland; Centre de Reference Épilepsies Rares, Epilepsy Unit (S.W., M.B., V.L., I.A.-G.), and Département de Génétique et de Cytogénétique (E.L.), AP-HP Groupe Hospitalier Pitié-Salpêtrière, Paris, France; Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova (C.M., P.S.), and Laboratory of Neurogenetics, Department of Neurosciences (F.Z., M.I.), "G. Gaslini" Institute, Genova, Italy; Neurogenetics Group, VIB-Department of Molecular Genetics (K.H.), and Laboratory of Neurogenetics, Institute Born-Bunge (K.H.), University of Antwerp, Belgium; Centre de Reference Épilepsies Rares (O.D., R.N.), Department of Pediatric Neurology, Necker Enfants Malades Hospital, AP-HP, Paris; INSERM (O.D., R.N.), U1129, Necker, Paris, France; and University Paris Descartes (O.D., R.N.), Paris, France
| | - Michel Baulac
- Sorbonne Universités (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UPMC Univ Paris 06, UM 75, ICM; INSERM, U1127 (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), ICM; CNRS (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UMR 7225, ICM; ICM (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), Paris, France; Department of Neurology (F.P.), University Hospitals of Geneva (HUG), Switzerland; Centre de Reference Épilepsies Rares, Epilepsy Unit (S.W., M.B., V.L., I.A.-G.), and Département de Génétique et de Cytogénétique (E.L.), AP-HP Groupe Hospitalier Pitié-Salpêtrière, Paris, France; Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova (C.M., P.S.), and Laboratory of Neurogenetics, Department of Neurosciences (F.Z., M.I.), "G. Gaslini" Institute, Genova, Italy; Neurogenetics Group, VIB-Department of Molecular Genetics (K.H.), and Laboratory of Neurogenetics, Institute Born-Bunge (K.H.), University of Antwerp, Belgium; Centre de Reference Épilepsies Rares (O.D., R.N.), Department of Pediatric Neurology, Necker Enfants Malades Hospital, AP-HP, Paris; INSERM (O.D., R.N.), U1129, Necker, Paris, France; and University Paris Descartes (O.D., R.N.), Paris, France
| | - Olivier Dulac
- Sorbonne Universités (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UPMC Univ Paris 06, UM 75, ICM; INSERM, U1127 (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), ICM; CNRS (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UMR 7225, ICM; ICM (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), Paris, France; Department of Neurology (F.P.), University Hospitals of Geneva (HUG), Switzerland; Centre de Reference Épilepsies Rares, Epilepsy Unit (S.W., M.B., V.L., I.A.-G.), and Département de Génétique et de Cytogénétique (E.L.), AP-HP Groupe Hospitalier Pitié-Salpêtrière, Paris, France; Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova (C.M., P.S.), and Laboratory of Neurogenetics, Department of Neurosciences (F.Z., M.I.), "G. Gaslini" Institute, Genova, Italy; Neurogenetics Group, VIB-Department of Molecular Genetics (K.H.), and Laboratory of Neurogenetics, Institute Born-Bunge (K.H.), University of Antwerp, Belgium; Centre de Reference Épilepsies Rares (O.D., R.N.), Department of Pediatric Neurology, Necker Enfants Malades Hospital, AP-HP, Paris; INSERM (O.D., R.N.), U1129, Necker, Paris, France; and University Paris Descartes (O.D., R.N.), Paris, France
| | - Eric Leguern
- Sorbonne Universités (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UPMC Univ Paris 06, UM 75, ICM; INSERM, U1127 (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), ICM; CNRS (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UMR 7225, ICM; ICM (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), Paris, France; Department of Neurology (F.P.), University Hospitals of Geneva (HUG), Switzerland; Centre de Reference Épilepsies Rares, Epilepsy Unit (S.W., M.B., V.L., I.A.-G.), and Département de Génétique et de Cytogénétique (E.L.), AP-HP Groupe Hospitalier Pitié-Salpêtrière, Paris, France; Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova (C.M., P.S.), and Laboratory of Neurogenetics, Department of Neurosciences (F.Z., M.I.), "G. Gaslini" Institute, Genova, Italy; Neurogenetics Group, VIB-Department of Molecular Genetics (K.H.), and Laboratory of Neurogenetics, Institute Born-Bunge (K.H.), University of Antwerp, Belgium; Centre de Reference Épilepsies Rares (O.D., R.N.), Department of Pediatric Neurology, Necker Enfants Malades Hospital, AP-HP, Paris; INSERM (O.D., R.N.), U1129, Necker, Paris, France; and University Paris Descartes (O.D., R.N.), Paris, France
| | - Rima Nabbout
- Sorbonne Universités (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UPMC Univ Paris 06, UM 75, ICM; INSERM, U1127 (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), ICM; CNRS (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UMR 7225, ICM; ICM (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), Paris, France; Department of Neurology (F.P.), University Hospitals of Geneva (HUG), Switzerland; Centre de Reference Épilepsies Rares, Epilepsy Unit (S.W., M.B., V.L., I.A.-G.), and Département de Génétique et de Cytogénétique (E.L.), AP-HP Groupe Hospitalier Pitié-Salpêtrière, Paris, France; Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova (C.M., P.S.), and Laboratory of Neurogenetics, Department of Neurosciences (F.Z., M.I.), "G. Gaslini" Institute, Genova, Italy; Neurogenetics Group, VIB-Department of Molecular Genetics (K.H.), and Laboratory of Neurogenetics, Institute Born-Bunge (K.H.), University of Antwerp, Belgium; Centre de Reference Épilepsies Rares (O.D., R.N.), Department of Pediatric Neurology, Necker Enfants Malades Hospital, AP-HP, Paris; INSERM (O.D., R.N.), U1129, Necker, Paris, France; and University Paris Descartes (O.D., R.N.), Paris, France
| | - Stéphanie Baulac
- Sorbonne Universités (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UPMC Univ Paris 06, UM 75, ICM; INSERM, U1127 (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), ICM; CNRS (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), UMR 7225, ICM; ICM (M.B., S.I., M.D., S.B., M.M.-B., E.L., S.W., M.B., V.L., I.A.-G.), Paris, France; Department of Neurology (F.P.), University Hospitals of Geneva (HUG), Switzerland; Centre de Reference Épilepsies Rares, Epilepsy Unit (S.W., M.B., V.L., I.A.-G.), and Département de Génétique et de Cytogénétique (E.L.), AP-HP Groupe Hospitalier Pitié-Salpêtrière, Paris, France; Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova (C.M., P.S.), and Laboratory of Neurogenetics, Department of Neurosciences (F.Z., M.I.), "G. Gaslini" Institute, Genova, Italy; Neurogenetics Group, VIB-Department of Molecular Genetics (K.H.), and Laboratory of Neurogenetics, Institute Born-Bunge (K.H.), University of Antwerp, Belgium; Centre de Reference Épilepsies Rares (O.D., R.N.), Department of Pediatric Neurology, Necker Enfants Malades Hospital, AP-HP, Paris; INSERM (O.D., R.N.), U1129, Necker, Paris, France; and University Paris Descartes (O.D., R.N.), Paris, France
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Yuan H, Low CM, Moody OA, Jenkins A, Traynelis SF. Ionotropic GABA and Glutamate Receptor Mutations and Human Neurologic Diseases. Mol Pharmacol 2015; 88:203-17. [PMID: 25904555 PMCID: PMC4468639 DOI: 10.1124/mol.115.097998] [Citation(s) in RCA: 153] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 04/22/2015] [Indexed: 01/03/2023] Open
Abstract
The advent of whole exome/genome sequencing and the technology-driven reduction in the cost of next-generation sequencing as well as the introduction of diagnostic-targeted sequencing chips have resulted in an unprecedented volume of data directly linking patient genomic variability to disorders of the brain. This information has the potential to transform our understanding of neurologic disorders by improving diagnoses, illuminating the molecular heterogeneity underlying diseases, and identifying new targets for therapeutic treatment. There is a strong history of mutations in GABA receptor genes being involved in neurologic diseases, particularly the epilepsies. In addition, a substantial number of variants and mutations have been found in GABA receptor genes in patients with autism, schizophrenia, and addiction, suggesting potential links between the GABA receptors and these conditions. A new and unexpected outcome from sequencing efforts has been the surprising number of mutations found in glutamate receptor subunits, with the GRIN2A gene encoding the GluN2A N-methyl-d-aspartate receptor subunit being most often affected. These mutations are associated with multiple neurologic conditions, for which seizure disorders comprise the largest group. The GluN2A subunit appears to be a locus for epilepsy, which holds important therapeutic implications. Virtually all α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor mutations, most of which occur within GRIA3, are from patients with intellectual disabilities, suggesting a link to this condition. Similarly, the most common phenotype for kainate receptor variants is intellectual disability. Herein, we summarize the current understanding of disease-associated mutations in ionotropic GABA and glutamate receptor families, and discuss implications regarding the identification of human mutations and treatment of neurologic diseases.
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Affiliation(s)
- Hongjie Yuan
- Departments of Pharmacology (H.Y., A.J., S.F.T.) and Anesthesiology (O.A.M., A.J.), Emory University School of Medicine, Rollins Research Center, Atlanta, Georgia; and Departments of Pharmacology and Anaesthesia, Yong Loo Lin School of Medicine, National University of Singapore Graduate School for Integrative Sciences and Engineering, and Neurobiology/Ageing Programme, National University of Singapore, Singapore (C.-M.L.)
| | - Chian-Ming Low
- Departments of Pharmacology (H.Y., A.J., S.F.T.) and Anesthesiology (O.A.M., A.J.), Emory University School of Medicine, Rollins Research Center, Atlanta, Georgia; and Departments of Pharmacology and Anaesthesia, Yong Loo Lin School of Medicine, National University of Singapore Graduate School for Integrative Sciences and Engineering, and Neurobiology/Ageing Programme, National University of Singapore, Singapore (C.-M.L.)
| | - Olivia A Moody
- Departments of Pharmacology (H.Y., A.J., S.F.T.) and Anesthesiology (O.A.M., A.J.), Emory University School of Medicine, Rollins Research Center, Atlanta, Georgia; and Departments of Pharmacology and Anaesthesia, Yong Loo Lin School of Medicine, National University of Singapore Graduate School for Integrative Sciences and Engineering, and Neurobiology/Ageing Programme, National University of Singapore, Singapore (C.-M.L.)
| | - Andrew Jenkins
- Departments of Pharmacology (H.Y., A.J., S.F.T.) and Anesthesiology (O.A.M., A.J.), Emory University School of Medicine, Rollins Research Center, Atlanta, Georgia; and Departments of Pharmacology and Anaesthesia, Yong Loo Lin School of Medicine, National University of Singapore Graduate School for Integrative Sciences and Engineering, and Neurobiology/Ageing Programme, National University of Singapore, Singapore (C.-M.L.)
| | - Stephen F Traynelis
- Departments of Pharmacology (H.Y., A.J., S.F.T.) and Anesthesiology (O.A.M., A.J.), Emory University School of Medicine, Rollins Research Center, Atlanta, Georgia; and Departments of Pharmacology and Anaesthesia, Yong Loo Lin School of Medicine, National University of Singapore Graduate School for Integrative Sciences and Engineering, and Neurobiology/Ageing Programme, National University of Singapore, Singapore (C.-M.L.)
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Reinthaler EM, Dejanovic B, Lal D, Semtner M, Merkler Y, Reinhold A, Pittrich DA, Hotzy C, Feucht M, Steinböck H, Gruber-Sedlmayr U, Ronen GM, Neophytou B, Geldner J, Haberlandt E, Muhle H, Ikram MA, van Duijn CM, Uitterlinden AG, Hofman A, Altmüller J, Kawalia A, Toliat MR, Nürnberg P, Lerche H, Nothnagel M, Thiele H, Sander T, Meier JC, Schwarz G, Neubauer BA, Zimprich F. Rare variants in γ-aminobutyric acid type A receptor genes in rolandic epilepsy and related syndromes. Ann Neurol 2015; 77:972-86. [PMID: 25726841 DOI: 10.1002/ana.24395] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 02/12/2015] [Accepted: 02/22/2015] [Indexed: 12/31/2022]
Abstract
OBJECTIVE To test whether mutations in γ-aminobutyric acid type A receptor (GABAA -R) subunit genes contribute to the etiology of rolandic epilepsy (RE) or its atypical variants (ARE). METHODS We performed exome sequencing to compare the frequency of variants in 18 GABAA -R genes in 204 European patients with RE/ARE versus 728 platform-matched controls. Identified GABRG2 variants were functionally assessed for protein stability, trafficking, postsynaptic clustering, and receptor function. RESULTS Of 18 screened GABAA -R genes, we detected an enrichment of rare variants in the GABRG2 gene in RE/ARE patients (5 of 204, 2.45%) in comparison to controls (1 of 723, 0.14%; odds ratio = 18.07, 95% confidence interval = 2.01-855.07, p = 0.0024, pcorr = 0.043). We identified a GABRG2 splice variant (c.549-3T>G) in 2 unrelated patients as well as 3 nonsynonymous variations in this gene (p.G257R, p.R323Q, p.I389V). Functional assessment showed reduced surface expression of p.G257R and decreased GABA-evoked currents for p.R323Q. The p.G257R mutation displayed diminished levels of palmitoylation, a post-translational modification crucial for trafficking of proteins to the cell membrane. Enzymatically raised palmitoylation levels restored the surface expression of the p.G257R variant γ2 subunit. INTERPRETATION The statistical association and the functional evidence suggest that mutations of the GABRG2 gene may increase the risk of RE/ARE. Restoring the impaired membrane trafficking of some GABRG2 mutations by enhancing palmitoylation might be an interesting therapeutic approach to reverse the pathogenic effect of such mutants.
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Affiliation(s)
- Eva M Reinthaler
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Borislav Dejanovic
- Institute of Biochemistry, Department of Chemistry, University of Cologne, Cologne, Germany
| | - Dennis Lal
- Department of Neuropediatrics, University Medical Center Giessen and Marburg, Giessen, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany.,Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Marcus Semtner
- RNA Editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Yvonne Merkler
- Institute of Biochemistry, Department of Chemistry, University of Cologne, Cologne, Germany
| | - Annika Reinhold
- RNA Editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | | | - Christoph Hotzy
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Martha Feucht
- Department of Pediatrics, Medical University of Vienna, Vienna, Austria
| | | | | | - Gabriel M Ronen
- Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada
| | - Birgit Neophytou
- Department of Neuropediatrics, St Anna Children's Hospital, Vienna, Austria
| | - Julia Geldner
- Department of Pediatrics, SMZ Süd - Kaiser-Franz-Josef-Hospital, Vienna, Austria
| | - Edda Haberlandt
- Department of Pediatrics, Medical University of Innsbruck, Innsbruck, Austria
| | - Hiltrud Muhle
- Department of Neuropediatrics, University Medical Center Schleswig-Holstein, Christian Albrechts University, Kiel, Germany
| | - M Arfan Ikram
- Departments of Epidemiology, Neurology, and Radiology, Erasmus Medical Center, Rotterdam, the Netherlands
| | | | - Andre G Uitterlinden
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Albert Hofman
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Janine Altmüller
- Cologne Center for Genomics, University of Cologne, Cologne, Germany.,Institute of Human Genetics, University of Cologne, Cologne, Germany
| | - Amit Kawalia
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Mohammad R Toliat
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | | | - Peter Nürnberg
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany.,Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute of Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Michael Nothnagel
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Holger Thiele
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Thomas Sander
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Jochen C Meier
- RNA Editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.,Braunschweig University of Technology, Zoological Institute, Division of Cell Physiology, Braunschweig, Germany
| | - Günter Schwarz
- Institute of Biochemistry, Department of Chemistry, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Bernd A Neubauer
- Department of Neuropediatrics, University Medical Center Giessen and Marburg, Giessen, Germany
| | - Fritz Zimprich
- Department of Neurology, Medical University of Vienna, Vienna, Austria
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Lachance-Touchette P, Choudhury M, Stoica A, Di Cristo G, Cossette P. Single-cell genetic expression of mutant GABAA receptors causing Human genetic epilepsy alters dendritic spine and GABAergic bouton formation in a mutation-specific manner. Front Cell Neurosci 2014; 8:317. [PMID: 25352779 PMCID: PMC4196543 DOI: 10.3389/fncel.2014.00317] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 09/21/2014] [Indexed: 11/13/2022] Open
Abstract
Mutations in genes encoding for GABAA receptor subunits is a well-established cause of genetic generalized epilepsy. GABA neurotransmission is implicated in several developmental processes including neurite outgrowth and synapse formation. Alteration in excitatory/inhibitory synaptic activities plays a critical role in epilepsy, thus here we investigated whether mutations in α1 subunit of GABAA receptor may affect dendritic spine and GABAergic bouton formation. In particular, we examined the effects of three mutations of the GABRA1 gene (D219N, A322D and K353delins18X) that were found in a cohort of French Canadian families with genetic generalized epilepsy. We used a novel single-cell genetic approach, by preparing cortical organotypic cultures from GABRA1flox/flox mice and simultaneously inactivating endogenous GABRA1 and transfecting mutant α1 subunits in single glutamatergic pyramidal cells and basket GABAergic interneurons by biolistic transfection. We found that GABRA1−/− GABAergic cells showed reduced innervation field, which was rescued by co-expressing α1-A322D and α1-WT but not α1-D219N. We further found that the expression of the most severe GABRA1 missense mutation (α1-A322D) induced a striking increase of spine density in pyramidal cells along with an increase in the number of mushroom-like spines. In addition, α1-A322D expression in GABAergic cells slightly increased perisomatic bouton density, whereas other mutations did not alter bouton formation. All together, these results suggest that the effects of different GABAAR mutations on GABAergic bouton and dendritic spine formation are specific to the mutation and cannot be always explained by a simple loss-of-function gene model. The use of single cell genetic manipulation in organotypic cultures may provide a better understanding of the specific and distinct neural circuit alterations caused by different GABAA receptor subunit mutations and will help define the pathophysiology of genetic generalized epilepsy syndromes.
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Affiliation(s)
- Pamela Lachance-Touchette
- Centre d'Excellence en Neuromique de l'Université de Montréal, Centre de Recherche, Centre Hospitalier de l'Université de Montréal, Université de Montréal Montréal, QC, Canada
| | - Mayukh Choudhury
- Centre Hospitalier Universitaire Sainte-Justine, Université de Montréal Montréal, QC, Canada
| | - Ana Stoica
- Centre d'Excellence en Neuromique de l'Université de Montréal, Centre de Recherche, Centre Hospitalier de l'Université de Montréal, Université de Montréal Montréal, QC, Canada
| | - Graziella Di Cristo
- Centre Hospitalier Universitaire Sainte-Justine, Université de Montréal Montréal, QC, Canada
| | - Patrick Cossette
- Centre d'Excellence en Neuromique de l'Université de Montréal, Centre de Recherche, Centre Hospitalier de l'Université de Montréal, Université de Montréal Montréal, QC, Canada
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Srivastava S, Cohen J, Pevsner J, Aradhya S, McKnight D, Butler E, Johnston M, Fatemi A. A novel variant in GABRB2 associated with intellectual disability and epilepsy. Am J Med Genet A 2014; 164A:2914-21. [PMID: 25124326 DOI: 10.1002/ajmg.a.36714] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2014] [Accepted: 07/07/2014] [Indexed: 01/26/2023]
Abstract
The γ-aminobutyric acid type A (GABAA ) receptor is one of the three main classes of receptors activated by GABA, the principal inhibitory neurotransmitter in the central nervous system. Mutations in genes encoding various subunits of this receptor (GABRA1, GABRA2, GABRA4, GABRA5, GABRA6, GABRB1, GABRB3, GABRG1, GABRG2, GABRG3, and GABRD) are implicated in a number of neurological and developmental disorders, including epilepsy and autism. To date, no human genetics studies have implicated mutations in GABRB2, encoding the β2 subunit of the GABAA receptor, with neurodevelopmental disorders. Here we present a 12-year-old girl with intellectual disability and epilepsy, who was discovered by whole exome sequencing to have a de novo heterozygous missense variant in exon 4 of GABRB2 (c.236T>C; p.M79T). This variant is likely pathogenic, based on in silico analyses, as well as the fact that it results in the non-conservative substitution of a non-polar amino acid with a polar amino acid at a position that is evolutionarily conserved across multiple species. Our findings underscore the need for further investigation into the mechanisms by which mutations in GABRB2 contribute to neurological and developmental dysfunction.
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Affiliation(s)
- Siddharth Srivastava
- Hugo W. Moser Research Institute at Kennedy Krieger Institute, Baltimore, Maryland; Departments of Neurology and Pediatrics, The Johns Hopkins Hospital, Baltimore, Maryland
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Huang X, Hernandez CC, Hu N, Macdonald RL. Three epilepsy-associated GABRG2 missense mutations at the γ+/β- interface disrupt GABAA receptor assembly and trafficking by similar mechanisms but to different extents. Neurobiol Dis 2014; 68:167-79. [PMID: 24798517 PMCID: PMC4169075 DOI: 10.1016/j.nbd.2014.04.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 04/22/2014] [Accepted: 04/25/2014] [Indexed: 11/23/2022] Open
Abstract
We compared the effects of three missense mutations in the GABAA receptor γ2 subunit on GABAA receptor assembly, trafficking and function in HEK293T cells cotransfected with α1, β2, and wildtype or mutant γ2 subunits. The mutations R82Q and P83S were identified in families with genetic epilepsy with febrile seizures plus (GEFS+), and N79S was found in a single patient with generalized tonic-clonic seizures (GTCS). Although all three mutations were located in an N-terminal loop that contributes to the γ+/β- subunit-subunit interface, we found that each mutation impaired GABAA receptor assembly to a different extent. The γ2(R82Q) and γ2(P83S) subunits had reduced α1β2γ2 receptor surface expression due to impaired assembly into pentamers, endoplasmic reticulum (ER) retention and degradation. In contrast, γ2(N79S) subunits were efficiently assembled into GABAA receptors with only minimally altered receptor trafficking, suggesting that N79S was a rare or susceptibility variant rather than an epilepsy mutation. Increased structural variability at assembly motifs was predicted by R82Q and P83S, but not N79S, substitution, suggesting that R82Q and P83S substitutions were less tolerated. Membrane proteins with missense mutations that impair folding and assembly often can be "rescued" by decreased temperatures. We coexpressed wildtype or mutant γ2 subunits with α1 and β2 subunits and found increased surface and total levels of both wildtype and mutant γ2 subunits after decreasing the incubation temperature to 30°C for 24h, suggesting that lower temperatures increased GABAA receptor stability. Thus epilepsy-associated mutations N79S, R82Q and P83S disrupted GABAA receptor assembly to different extents, an effect that could be potentially rescued by facilitating protein folding and assembly.
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Affiliation(s)
- Xuan Huang
- The Graduate Program of Neuroscience, Vanderbilt University Medical Center, Nashville, TN 37212, USA; Departments of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, USA
| | - Ciria C Hernandez
- Departments of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, USA
| | - Ningning Hu
- Departments of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, USA
| | - Robert L Macdonald
- The Graduate Program of Neuroscience, Vanderbilt University Medical Center, Nashville, TN 37212, USA; Departments of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, USA.
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Todd E, Gurba KN, Botzolakis EJ, Stanic AK, Macdonald RL. GABAA receptor biogenesis is impaired by the γ2 subunit febrile seizure-associated mutation, GABRG2(R177G). Neurobiol Dis 2014; 69:215-24. [PMID: 24874541 DOI: 10.1016/j.nbd.2014.05.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 05/08/2014] [Accepted: 05/17/2014] [Indexed: 01/17/2023] Open
Abstract
A missense mutation in the GABAA receptor γ2L subunit, R177G, was reported in a family with complex febrile seizures (FS). To gain insight into the mechanistic basis for these genetic seizures, we explored how the R177G mutation altered the properties of recombinant α1β2γ2L GABAA receptors expressed in HEK293T cells. Using a combination of electrophysiology, flow cytometry, and immunoblotting, we found that the R177G mutation decreased GABA-evoked whole-cell current amplitudes by decreasing cell surface expression of α1β2γ2L receptors. This loss of receptor surface expression resulted from endoplasmic reticulum (ER) retention of mutant γ2L(R177G) subunits, which unlike wild-type γ2L subunits, were degraded by ER-associated degradation (ERAD). Interestingly, when compared to the condition of homozygous γ2L(R177G) subunit expression, disproportionately low levels of γ2L(R177G) subunits reached the cell surface with heterozygous expression, indicating that wild-type γ2L subunits possessed a competitive advantage over mutant γ2L(R177G) subunits for receptor assembly and/or forward trafficking. Inhibiting protein synthesis with cycloheximide demonstrated that the R177G mutation primarily decreased the stability of an intracellular pool of unassembled γ2L subunits, suggesting that the mutant γ2L(R177G) subunits competed poorly with wild-type γ2L subunits due to impaired subunit folding and/or oligomerization. Molecular modeling confirmed that the R177G mutation could disrupt intrasubunit salt bridges, thereby destabilizing secondary and tertiary structure of γ2L(R177G) subunits. These findings support an emerging body of literature implicating defects in GABAA receptor biogenesis in the pathogenesis of genetic epilepsies (GEs) and FS.
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Affiliation(s)
- Emily Todd
- Program in Neuroscience, Vanderbilt University, Nashville, TN 37232, USA
| | - Katharine N Gurba
- Program in Neuroscience, Vanderbilt University, Nashville, TN 37232, USA
| | | | | | - Robert L Macdonald
- Department of Neurology, Vanderbilt University, Nashville, TN 37232, USA; Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA.
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