1
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Sajan SA, Gradisch R, Vogel FD, Coffey AJ, Salyakina D, Soler D, Jayakar P, Jayakar A, Bianconi SE, Cooper AH, Liu S, William N, Benkel-Herrenbrück I, Maiwald R, Heller C, Biskup S, Leiz S, Westphal DS, Wagner M, Clarke A, Stockner T, Ernst M, Kesari A, Krenn M. De novo variants in GABRA4 are associated with a neurological phenotype including developmental delay, behavioral abnormalities and epilepsy. Eur J Hum Genet 2024; 32:912-919. [PMID: 38565639 PMCID: PMC11291759 DOI: 10.1038/s41431-024-01600-3] [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: 11/18/2023] [Revised: 02/03/2024] [Accepted: 03/19/2024] [Indexed: 04/04/2024] Open
Abstract
Nine out of 19 genes encoding GABAA receptor subunits have been linked to monogenic syndromes characterized by seizures and developmental disorders. Previously, we reported the de novo variant p.(Thr300Ile) in GABRA4 in a patient with epilepsy and neurodevelopmental abnormalities. However, no new cases have been reported since then. Through an international collaboration, we collected molecular and phenotype data of individuals carrying de novo variants in GABRA4. Patients and their parents were investigated either by exome or genome sequencing, followed by targeted Sanger sequencing in some cases. All variants within the transmembrane domain, including the previously reported p.(Thr300Ile) variant, were characterized in silico and analyzed by molecular dynamics (MD) simulation studies. We identified three novel de novo missense variants in GABRA4 (NM_000809.4): c.797 C > T, p.(Pro266Leu), c.899 C > A, p.(Thr300Asn), and c.634 G > A, p.(Val212Ile). The p.(Thr300Asn) variant impacts the same codon as the previously reported variant p.(Thr300Ile) and likely arose post-zygotically as evidenced by sequencing oral mucosal cells. Overlapping phenotypes among affected individuals included developmental delay (4/4), epileptiform EEG abnormalities (3/4), attention deficits (3/4), seizures (2/4), autistic features (2/4) and structural brain abnormalities (2/4). MD simulations of the three variants within the transmembrane domain of the receptor indicate that sub-microsecond scale dynamics differ between wild-type and mutated subunits. Taken together, our findings further corroborate an association between GABRA4 and a neurological phenotype including variable neurodevelopmental, behavioral and epileptic abnormalities.
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Affiliation(s)
- Samin A Sajan
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Ralph Gradisch
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Florian D Vogel
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Alison J Coffey
- lllumina Clinical Services Laboratory, Illumina Inc., San Diego, CA, USA
| | - Daria Salyakina
- Personalized Medicine and Health Outcomes Research, Nicklaus Children's Hospital, Miami, FL, USA
| | - Diana Soler
- Personalized Medicine and Health Outcomes Research, Nicklaus Children's Hospital, Miami, FL, USA
| | - Parul Jayakar
- Division of Genetics and Metabolism, Nicklaus Children's Hospital, Miami, FL, USA
| | - Anuj Jayakar
- Department of Neurology, Division of Epilepsy, Nicklaus Children's Hospital, Miami, FL, USA
| | | | | | | | | | | | - Robert Maiwald
- Medizinisches Versorgungszentrum für Gerinnungsdiagnostik und Medizinische Genetik Köln, Köln, Germany
| | | | - Saskia Biskup
- Zentrum für Humangenetik, Tübingen, Germany
- Center for Genomics and Transcriptomics (CeGaT), Tübingen, Germany
| | - Steffen Leiz
- Division of Neuropediatrics, Klinikum Dritter Orden, Munich, Germany
| | - Dominik S Westphal
- Institute of Human Genetics, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
- Department of Internal Medicine I, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Matias Wagner
- Institute of Human Genetics, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Amy Clarke
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Thomas Stockner
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Margot Ernst
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Akanchha Kesari
- lllumina Clinical Services Laboratory, Illumina Inc., San Diego, CA, USA
| | - Martin Krenn
- Department of Neurology, Medical University of Vienna, Vienna, Austria.
- Comprehensive Center for Clinical Neurosciences & Mental Health, Medical University of Vienna, Vienna, Austria.
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2
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Reyes-Nava NG, Paz D, Pinales BE, Perez I, Gil CB, Gonzales AV, Grajeda BI, Estevao IL, Ellis CC, Castro VL, Quintana AM. Characterization of the zebrafish gabra1 sa43718/sa43718 germline loss of function allele confirms a function for Gabra1 in motility and nervous system development. Differentiation 2024; 138:100790. [PMID: 38908344 DOI: 10.1016/j.diff.2024.100790] [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: 06/05/2024] [Accepted: 06/13/2024] [Indexed: 06/24/2024]
Abstract
Mutation of the GABRA1 gene is associated with neurodevelopmental defects and epilepsy. GABRA1 encodes for the α1 subunit of the γ-aminobutyric acid type A receptor (GABAAR), which regulates the fast inhibitory impulses of the nervous system. Multiple model systems have been developed to understand the function of GABRA1, but these models have produced complex and, at times, incongruent data. Thus, additional model systems are required to validate and substantiate previous results. We sought to provide initial phenotypic analysis of a novel germline mutant allele. Our analysis provides a solid foundation for the future use of this allele to characterize gabra1 functionally and pharmacologically using zebrafish. We investigated the behavioral swim patterns associated with a nonsense mutation of the zebrafish gabra1 (sa43718 allele) gene. The sa43718 allele causes a decrease in gabra1 mRNA expression, which is associated with light induced hypermotility, one phenotype previously associated with seizure like behavior in zebrafish. Mutation of gabra1 was accompanied by decreased mRNA expression of gabra2, gabra3, and gabra5, indicating a reduction in the expression of additional α sub-units of the GABAAR. Although multiple sub-units were decreased, larvae continued to respond to pentylenetetrazole (PTZ), indicating that a residual GABAAR exists in the sa43718 allele. Proteomics analysis demonstrated that mutation of gabra1 is associated with abnormal expression of proteins that regulate synaptic vesicle fusion, vesicle transport, synapse development, and mitochondrial protein complexes. These data support previous studies performed in a zebrafish nonsense allele created by CRISPR/Cas9 and validate that loss of function mutations in the gabra1 gene result in seizure-like phenotypes with abnormal development of the GABA synapse. Our results add to the existing body of knowledge as to the function of GABRA1 during development and validate that zebrafish can be used to provide complete functional characterization of the gene.
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Affiliation(s)
- Nayeli G Reyes-Nava
- Department of Biological Sciences, Border Biomedical Research Center, The University of Texas at El Paso, El Paso, TX, USA
| | - David Paz
- Department of Biological Sciences, Border Biomedical Research Center, The University of Texas at El Paso, El Paso, TX, USA
| | - Briana E Pinales
- Department of Biological Sciences, Border Biomedical Research Center, The University of Texas at El Paso, El Paso, TX, USA
| | - Isaiah Perez
- Department of Biological Sciences, Border Biomedical Research Center, The University of Texas at El Paso, El Paso, TX, USA
| | - Claudia B Gil
- Department of Biological Sciences, Border Biomedical Research Center, The University of Texas at El Paso, El Paso, TX, USA
| | - Annalise V Gonzales
- Department of Biological Sciences, Border Biomedical Research Center, The University of Texas at El Paso, El Paso, TX, USA
| | - Brian I Grajeda
- Department of Biological Sciences, Border Biomedical Research Center, The University of Texas at El Paso, El Paso, TX, USA
| | - Igor L Estevao
- Department of Biological Sciences, Border Biomedical Research Center, The University of Texas at El Paso, El Paso, TX, USA
| | - Cameron C Ellis
- Department of Biological Sciences, Border Biomedical Research Center, The University of Texas at El Paso, El Paso, TX, USA
| | - Victoria L Castro
- Department of Biological Sciences, Border Biomedical Research Center, The University of Texas at El Paso, El Paso, TX, USA
| | - Anita M Quintana
- Department of Biological Sciences, Border Biomedical Research Center, The University of Texas at El Paso, El Paso, TX, USA.
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3
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Nieoczym D, Marszalek-Grabska M, Szalak R, Kundap U, Kaczor AA, Wrobel TM, Kosheva N, Komar M, Abram M, Esguerra CV, Samarut E, Pieróg M, Jakubiec M, Kaminski K, Kukula-Koch W, Gawel K. A comprehensive assessment of palmatine as anticonvulsant agent - In vivo and in silico studies. Biomed Pharmacother 2024; 172:116234. [PMID: 38325264 DOI: 10.1016/j.biopha.2024.116234] [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: 11/08/2023] [Revised: 01/22/2024] [Accepted: 01/29/2024] [Indexed: 02/09/2024] Open
Abstract
Previously, we demonstrated that palmatine (PALM) - an isoquinoline alkaloid from Berberis sibrica radix, exerted antiseizure activity in the pentylenetetrazole (PTZ)-induced seizure assay in larval zebrafish. The aim of the present study was to more precisely characterize PALM as a potential anticonvulsant drug candidate. A range of zebrafish and mouse seizure/epilepsy models were applied in the investigation. Immunostaining analysis was conducted to assess the changes in mouse brains, while in silico molecular modelling was performed to determine potential targets for PALM. Accordingly, PALM had anticonvulsant effect in ethyl 2-ketopent-4-enoate (EKP)-induced seizure assay in zebrafish larvae as well as in the 6 Hz-induced psychomotor seizure threshold and timed infusion PTZ tests in mice. The protective effect in the EKP-induced seizure assay was confirmed in the local field potential recordings. PALM did not affect seizures in the gabra1a knockout line of zebrafish larvae. In the scn1Lab-/- zebrafish line, pretreatment with PALM potentiated seizure-like behaviour of larvae. Repetitive treatment with PALM, however, did not reduce development of PTZ-induced seizure activity nor prevent the loss of parvalbumin-interneurons in the hippocampus of the PTZ kindled mice. In silico molecular modelling revealed that the noted anticonvulsant effect of PALM in EKP-induced seizure assay might result from its interactions with glutamic acid decarboxylase and/or via AMPA receptor non-competitive antagonism. Our study has demonstrated the anticonvulsant activity of PALM in some experimental models of seizures, including a model of pharmacoresistant seizures induced by EKP. These results indicate that PALM might be a suitable new drug candidate but the precise mechanism of its anticonvulsant activity has to be determined.
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Affiliation(s)
- Dorota Nieoczym
- Chair of Animal Physiology and Pharmacology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka Str. 19, 20-033 Lublin, Poland
| | - Marta Marszalek-Grabska
- Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego Str. 8b, 20-090 Lublin, Poland
| | - Radoslaw Szalak
- Department of Animal Anatomy and Histology, Faculty of Veterinary Medicine, University of Life Sciences, 12 Akademicka St., 20-950 Lublin, Poland
| | - Uday Kundap
- Research Center of the University of Montreal Hospital Center (CRCHUM), Department of Neurosciences, Université de Montréal, Montréal, QC H2X 0A9, Canada; Canada East Spine Centre, Saint John Regional Hospital, Department of Spine and Orthopaedics surgery, Horizon Health Network, Saint John, NB E2L 4L4, Canada
| | - Agnieszka A Kaczor
- Department of Synthesis and Chemical Technology of Pharmaceutical Substances with Computer Modeling Laboratory, Faculty of Pharmacy, Medical University of Lublin, 4A Chodżki St., PL-20093 Lublin, Poland; School of Pharmacy, University of Eastern Finland, Yliopistonranta 1, P.O. Box 1627, FI-70211 Kuopio, Finland
| | - Tomasz M Wrobel
- Department of Synthesis and Chemical Technology of Pharmaceutical Substances with Computer Modeling Laboratory, Faculty of Pharmacy, Medical University of Lublin, 4A Chodżki St., PL-20093 Lublin, Poland
| | - Nataliia Kosheva
- Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego Str. 8b, 20-090 Lublin, Poland
| | - Malgorzata Komar
- Department of Animal Anatomy and Histology, Faculty of Veterinary Medicine, University of Life Sciences, 12 Akademicka St., 20-950 Lublin, Poland
| | - Michal Abram
- Department of Medicinal Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688 Cracow, Poland
| | - Camila V Esguerra
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway, University of Oslo, Gaustadalleen 21, Forskningsparken, 0349 Oslo, Norway
| | - Eric Samarut
- Research Center of the University of Montreal Hospital Center (CRCHUM), Department of Neurosciences, Université de Montréal, Montréal, QC H2X 0A9, Canada; Neurosciences Department, University of Montreal, Montreal, QC, Canada
| | - Mateusz Pieróg
- Chair of Animal Physiology and Pharmacology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka Str. 19, 20-033 Lublin, Poland
| | - Marcin Jakubiec
- Department of Medicinal Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688 Cracow, Poland
| | - Krzysztof Kaminski
- Department of Medicinal Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688 Cracow, Poland
| | - Wirginia Kukula-Koch
- Department of Pharmacognosy with Medicinal Plants Garden, Medical University of Lublin, Chodzki Str. 1, 20-093 Lublin, Poland
| | - Kinga Gawel
- Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego Str. 8b, 20-090 Lublin, Poland.
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Snyder HE, Jain P, RamachandranNair R, Jones KC, Whitney R. Genetic Advancements in Infantile Epileptic Spasms Syndrome and Opportunities for Precision Medicine. Genes (Basel) 2024; 15:266. [PMID: 38540325 PMCID: PMC10970414 DOI: 10.3390/genes15030266] [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: 01/19/2024] [Revised: 02/13/2024] [Accepted: 02/20/2024] [Indexed: 06/15/2024] Open
Abstract
Infantile epileptic spasms syndrome (IESS) is a devastating developmental epileptic encephalopathy (DEE) consisting of epileptic spasms, as well as one or both of developmental regression or stagnation and hypsarrhythmia on EEG. A myriad of aetiologies are associated with the development of IESS; broadly, 60% of cases are thought to be structural, metabolic or infectious in nature, with the remainder genetic or of unknown cause. Epilepsy genetics is a growing field, and over 28 copy number variants and 70 single gene pathogenic variants related to IESS have been discovered to date. While not exhaustive, some of the most commonly reported genetic aetiologies include trisomy 21 and pathogenic variants in genes such as TSC1, TSC2, CDKL5, ARX, KCNQ2, STXBP1 and SCN2A. Understanding the genetic mechanisms of IESS may provide the opportunity to better discern IESS pathophysiology and improve treatments for this condition. This narrative review presents an overview of our current understanding of IESS genetics, with an emphasis on animal models of IESS pathogenesis, the spectrum of genetic aetiologies of IESS (i.e., chromosomal disorders, single-gene disorders, trinucleotide repeat disorders and mitochondrial disorders), as well as available genetic testing methods and their respective diagnostic yields. Future opportunities as they relate to precision medicine and epilepsy genetics in the treatment of IESS are also explored.
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Affiliation(s)
- Hannah E. Snyder
- Division of Neurology, Department of Paediatrics, McMaster University, Hamilton, ON L8N 3Z5, Canada (R.R.)
| | - Puneet Jain
- Division of Neurology, Department of Paediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON M5G 1E8, Canada
| | - Rajesh RamachandranNair
- Division of Neurology, Department of Paediatrics, McMaster University, Hamilton, ON L8N 3Z5, Canada (R.R.)
| | - Kevin C. Jones
- Division of Neurology, Department of Paediatrics, McMaster University, Hamilton, ON L8N 3Z5, Canada (R.R.)
| | - Robyn Whitney
- Division of Neurology, Department of Paediatrics, McMaster University, Hamilton, ON L8N 3Z5, Canada (R.R.)
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5
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Ng ACH, Choudhary A, Barrett KT, Gavrilovici C, Scantlebury MH. Mechanisms of infantile epileptic spasms syndrome: What have we learned from animal models? Epilepsia 2024; 65:266-280. [PMID: 38036453 DOI: 10.1111/epi.17841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 11/27/2023] [Accepted: 11/28/2023] [Indexed: 12/02/2023]
Abstract
The devastating developmental and epileptic encephalopathy of infantile epileptic spasms syndrome (IESS) has numerous causes, including, but not limited to, brain injury, metabolic, and genetic conditions. Given the stereotyped electrophysiologic, age-dependent, and clinical findings, there likely exists one or more final common pathways in the development of IESS. The identity of this final common pathway is unknown, but it may represent a novel therapeutic target for infantile spasms. Previous research on IESS has focused largely on identifying the neuroanatomic substrate using specialized neuroimaging techniques and cerebrospinal fluid analysis in human patients. Over the past three decades, several animal models of IESS were created with an aim to interrogate the underlying pathogenesis of IESS, to identify novel therapeutic targets, and to test various treatments. Each of these models have been successful at recapitulating multiple aspects of the human IESS condition. These animal models have implicated several different molecular pathways in the development of infantile spasms. In this review we outline the progress that has been made thus far using these animal models and discuss future directions to help researchers identify novel treatments for drug-resistant IESS.
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Affiliation(s)
- Andy Cheuk-Him Ng
- Department of Pediatrics, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Anamika Choudhary
- Department of Pediatrics, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Karlene T Barrett
- Department of Pediatrics, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Cezar Gavrilovici
- Department of Pediatrics, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Morris H Scantlebury
- Department of Pediatrics, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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Zhang S, Wang Y, Liu M, Du Z, Lu Y, Sun P, Han J. Identification of novel and de novo GABRB1 mutation in Chinese patient with developmental and epileptic encephalopathy 45. Intractable Rare Dis Res 2023; 12:234-240. [PMID: 38024579 PMCID: PMC10680165 DOI: 10.5582/irdr.2023.01092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 11/02/2023] [Accepted: 11/04/2023] [Indexed: 12/01/2023] Open
Abstract
Developmental and epileptic encephalopathy 45 (DEE45) is an autosomal dominant disease caused by variation in the gamma-aminobutyric acid type A receptor subunit beta 1 (GABRB1) gene. Affected individuals have severely impaired intellectual development, hypotonia, and other persistent neurological deficits. However, DEE45 is rare; only four infants with DEE45 have been reported worldwide and no case has been reported in China. Confirming a diagnosis of DEE45 is of great significance for guiding further treatment, assessing patient prognosis, and genetic counseling. The clinical characteristics of DEE45 and the medical history of DEE45 patients requires supplementation and clarification. Here, we present the clinical and genetic findings of a 7-year-old girl with DEE45 carrying a novel de novo GABRB1 mutation (c.858_859delinsTT, p.286_287delinsIleSer) identified by whole exome sequencing (WES). The mutation is phylogenetic conserved in the second helix of the β1-subunit's transmembrane region. Western blot and RT-qPCR both indicated significant increase in the expression levels of GABRB1 mutant when compared with wild. The proband has epileptic encephalopathy and experienced refractory epilepsy onset at age 2 months and showed developmental delay at age 8 months. Electroencephalography (EEG) displayed hypsarrhythmia. Magnetic resonance imaging (MRI) showed no significant abnormalities in the internal structure of the patient's brain, which is displayed in two previously reported cases. The patient's symptoms of hypotonia, ataxia, profound mental retardation, and dysmetria became evident with development. In summary, we report the genetic and clinical characteristics of the first Chinese patient with DEE45 and explores the relationship between mutation and clinical symptoms.
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Affiliation(s)
- Shanshan Zhang
- Key Laboratory for Biotech-Drugs of National Health Commission, Key Laboratory for Rare & Uncommon Diseases of Shandong Province, Biomedical Sciences College & Shandong Medicinal Biotechnology Centre, Shandong First Medical University & Shandong Academy of Medical Sciences, Ji'nan, Shandong, China
| | - Yu Wang
- Prenatal Diagnostic Center of Obstetrics and Gynecology Department, Qilu Hospital of Shandong University, Ji'nan, Shandong, China
| | - Meilin Liu
- Key Laboratory for Biotech-Drugs of National Health Commission, Key Laboratory for Rare & Uncommon Diseases of Shandong Province, Biomedical Sciences College & Shandong Medicinal Biotechnology Centre, Shandong First Medical University & Shandong Academy of Medical Sciences, Ji'nan, Shandong, China
| | - Zhaoli Du
- Yinfeng Gene Technology Company Limited, Ji'nan, Shandong, China
| | - Yanqin Lu
- Key Laboratory for Biotech-Drugs of National Health Commission, Key Laboratory for Rare & Uncommon Diseases of Shandong Province, Biomedical Sciences College & Shandong Medicinal Biotechnology Centre, Shandong First Medical University & Shandong Academy of Medical Sciences, Ji'nan, Shandong, China
| | - Ping Sun
- Prenatal Diagnostic Center of Obstetrics and Gynecology Department, Qilu Hospital of Shandong University, Ji'nan, Shandong, China
| | - Jinxiang Han
- Key Laboratory for Biotech-Drugs of National Health Commission, Key Laboratory for Rare & Uncommon Diseases of Shandong Province, Biomedical Sciences College & Shandong Medicinal Biotechnology Centre, Shandong First Medical University & Shandong Academy of Medical Sciences, Ji'nan, Shandong, China
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7
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Paz D, Reyes-Nava NG, Pinales BE, Perez I, Gil CB, Gonzales AV, Grajeda B, Estevao IL, Ellis CC, Castro VL, Quintana AM. Characterization of the zebrafish gabra1sa43718/sa43718 germline loss of function allele confirms a function for Gabra1 in motility and nervous system development. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.27.525860. [PMID: 36747751 PMCID: PMC9900897 DOI: 10.1101/2023.01.27.525860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Mutation of the GABRA1 gene is associated with neurodevelopmental defects and epilepsy. GABRA1 encodes for the α1 subunit of the gamma-aminobutyric acid type A receptor (GABAAR), which regulates the fast inhibitory impulses of the nervous system. Multiple model systems have previously been developed to understand the function of GABRA1 during development, but these models have produced complex and at times incongruent data. Thus, additional model systems are required to validate and substantiate previously published results. We investigated the behavioral swim patterns associated with a nonsense mutation of the zebrafish gabra1 (sa43718 allele) gene. The sa43718 allele causes a decrease in gabra1 mRNA expression, which is associated with light induced hypermotility, one phenotype associated with seizure like behavior in zebrafish. Mutation of gabra1 was accompanied by decreased mRNA expression of gabra2, gabra3, and gabra5, indicating a reduction in the expression of additional alpha sub-units of the GABAAR. Although multiple sub-units were decreased in total expression, larvae continued to respond to pentylenetetrazole (PTZ) indicating that a residual GABAAR exists in the sa43718 allele. Proteomics analysis demonstrated that nonsense mutation of gabra1 is associated with abnormal expression of proteins that regulate proton transport, ion homeostasis, vesicle transport, and mitochondrial protein complexes. These data support previous studies performed in a zebrafish nonsense allele created by CRISPR/Cas9 and validate that loss of function mutations in the gabra1 gene result in seizure like phenotypes with abnormal function of inhibitory synapses.
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Affiliation(s)
- David Paz
- Department of Biological Sciences, Border Biomedical Research Center, The University of Texas at El Paso, El Paso, Texas, United States of America
| | - Nayeli G Reyes-Nava
- Department of Biological Sciences, Border Biomedical Research Center, The University of Texas at El Paso, El Paso, Texas, United States of America
| | - Briana E Pinales
- Department of Biological Sciences, Border Biomedical Research Center, The University of Texas at El Paso, El Paso, Texas, United States of America
| | - Isaiah Perez
- Department of Biological Sciences, Border Biomedical Research Center, The University of Texas at El Paso, El Paso, Texas, United States of America
| | - Claudia B Gil
- Department of Biological Sciences, Border Biomedical Research Center, The University of Texas at El Paso, El Paso, Texas, United States of America
| | - Annalise V Gonzales
- Department of Biological Sciences, Border Biomedical Research Center, The University of Texas at El Paso, El Paso, Texas, United States of America
| | - Brian Grajeda
- Department of Biological Sciences, Border Biomedical Research Center, The University of Texas at El Paso, El Paso, Texas, United States of America
| | - Igor L Estevao
- Department of Biological Sciences, Border Biomedical Research Center, The University of Texas at El Paso, El Paso, Texas, United States of America
| | - Cameron C Ellis
- Department of Biological Sciences, Border Biomedical Research Center, The University of Texas at El Paso, El Paso, Texas, United States of America
| | - Victoria L Castro
- Department of Biological Sciences, Border Biomedical Research Center, The University of Texas at El Paso, El Paso, Texas, United States of America
| | - Anita M Quintana
- Department of Biological Sciences, Border Biomedical Research Center, The University of Texas at El Paso, El Paso, Texas, United States of America
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8
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Arslan A. Pathogenic variants of human GABRA1 gene associated with epilepsy: A computational approach. Heliyon 2023; 9:e20218. [PMID: 37809401 PMCID: PMC10559982 DOI: 10.1016/j.heliyon.2023.e20218] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 08/17/2023] [Accepted: 09/13/2023] [Indexed: 10/10/2023] Open
Abstract
Critical for brain development, neurodevelopmental and network disorders, the GABRA1 gene encodes for the α1 subunit, an abundantly and developmentally expressed subunit of heteropentameric gamma-aminobutyric acid A receptors (GABAARs) mediating primary inhibition in the brain. Mutations of the GABAAR subunit genes including GABRA1 gene are associated with epilepsy, a group of syndromes, characterized by unprovoked seizures and diagnosed by integrative approach, that involves genetic testing. Despite the diagnostic use of genetic testing, a large fraction of the GABAAR subunit gene variants including the variants of GABRA1 gene is not known in terms of their molecular consequence, a challenge for precision and personalized medicine. Addressing this, one hundred thirty-seven GABRA1 gene variants of unknown clinical significance have been extracted from the ClinVar database and computationally analyzed for pathogenicity. Eight variants (L49H, P59L, W97R, D99G, G152S, V270G, T294R, P305L) are predicted as pathogenic and mapped to the α1 subunit's extracellular domain (ECD), transmembrane domains (TMDs) and extracellular linker. This is followed by the integration with relevant data for cellular pathology and severity of the epilepsy syndromes retrieved from the literature. Our results suggest that the pathogenic variants in the ECD of GABRA1 (L49H, P59L, W97R, D99G, G152S) will probably manifest decreased surface expression and reduced current with mild epilepsy phenotypes while V270G, T294R in the TMDs and P305L in the linker between the second and the third TMDs will likely cause reduced cell current with severe epilepsy phenotypes. The results presented in this study provides insights for clinical genetics and wet lab experimentation.
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Affiliation(s)
- Ayla Arslan
- Department of Molecular Biology and Genetics, Faculty of Engineering and Natural Sciences, Üsküdar University, Istanbul, Turkey
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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: 3] [Impact Index Per Article: 3.0] [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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Musto E, Liao VWY, Johannesen KM, Fenger CD, Lederer D, Kothur K, Fisk K, Bennetts B, Vrielynck P, Delaby D, Ceulemans B, Weckhuysen S, Sparber P, Bouman A, Ardern-Holmes S, Troedson C, Battaglia DI, Goel H, Feyma T, Bakhtiari S, Tjoa L, Boxill M, Demina N, Shchagina O, Dadali E, Kruer M, Cantalupo G, Contaldo I, Polster T, Isidor B, Bova SM, Fazeli W, Wouters L, Miranda MJ, Darra F, Pede E, Le Duc D, Jamra RA, Küry S, Proietti J, McSweeney N, Brokamp E, Andrews PI, Gouray Garcia M, Chebib M, Møller RS, Ahring PK, Gardella E. GABRA1-Related Disorders: From Genetic to Functional Pathways. Ann Neurol 2023; 95:27-41. [PMID: 37606373 DOI: 10.1002/ana.26774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 08/18/2023] [Accepted: 08/18/2023] [Indexed: 08/23/2023]
Abstract
OBJECTIVE Variants in GABRA1 have been associated with a broad epilepsy spectrum, ranging from genetic generalized epilepsies to developmental and epileptic encephalopathies. However, our understanding of what determines the phenotype severity and best treatment options remains inadequate. We therefore aimed to analyze the electroclinical features and the functional effects of GABRA1 variants to establish genotype-phenotype correlations. METHODS Genetic and electroclinical data of 27 individuals (22 unrelated and 2 families) harboring 20 different GABRA1 variants were collected and accompanied by functional analysis of 19 variants. RESULTS Individuals in this cohort could be assigned into different clinical subgroups based on the functional effect of their variant and its structural position within the GABRA1 subunit. A homogenous phenotype with mild cognitive impairment and infantile onset epilepsy (focal seizures, fever sensitivity, and electroencephalographic posterior epileptiform discharges) was described for variants in the extracellular domain and the small transmembrane loops. These variants displayed loss-of-function (LoF) effects, and the patients generally had a favorable outcome. A more severe phenotype was associated with variants in the pore-forming transmembrane helices. These variants displayed either gain-of-function (GoF) or LoF effects. GoF variants were associated with severe early onset neurodevelopmental disorders, including early infantile developmental and epileptic encephalopathy. INTERPRETATION Our data expand the genetic and phenotypic spectrum of GABRA1 epilepsies and permit delineation of specific subphenotypes for LoF and GoF variants, through the heterogeneity of phenotypes and variants. Generally, variants in the transmembrane helices cause more severe phenotypes, in particular GoF variants. These findings establish the basis for a better understanding of the pathomechanism and a precision medicine approach in GABRA1-related disorders. Further studies in larger populations are needed to provide a conclusive genotype-phenotype correlation. ANN NEUROL 2023.
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Affiliation(s)
- Elisa Musto
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center, Dianalund, Denmark
- Pediatric Neurology, Department of Woman and Child Health and Public Health, Child Health Area, Catholic University UCSC, Rome, Italy
- Epilepsy and Movement Disorder Neurology, Ospedale Pediatrico Bambino Gesù IRCCS, Rome, Italy
| | - 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
| | - Katrine M Johannesen
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center, Dianalund, Denmark
- Department of Genetics, University Hospital of Copenhagen, Copenhagen, Denmark
| | - Christina D Fenger
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center, Dianalund, Denmark
- Amplexa Genetics, Odense, Denmark
| | - Damien Lederer
- Center for Human Genetics, Institut de Pathologie et de Génétique, Gosselies, Belgium
| | - Kavitha Kothur
- Kids Neuroscience Centre, Children's Hospital at Westmead, University of Sydney, Sydney, New South Wales, Australia
| | - Katrina Fisk
- Sydney Genome Diagnostics, Western Sydney Genetics Program, Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Bruce Bennetts
- Sydney Genome Diagnostics, Western Sydney Genetics Program, Children's Hospital at Westmead, Sydney, New South Wales, Australia
- Specialty of Genomic Medicine, Children's Hospital at Westmead Clinical School, Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
| | - Pascal Vrielynck
- Reference Center for Refractory Epilepsy, Catholic University of Louvain, William Lennox Neurological Hospital, Ottignies, Belgium
| | - Delphine Delaby
- Reference Center for Refractory Epilepsy, Catholic University of Louvain, William Lennox Neurological Hospital, Ottignies, Belgium
| | - Berten Ceulemans
- Department of Pediatric Neurology, Antwerp University Hospital, University of Antwerp, Antwerp, Belgium
| | - Sarah Weckhuysen
- Applied & Translational Neurogenomics Group, VIB-Department of Molecular Genetics, University of Antwerp, Antwerp, Belgium
- Department of Neurology, Antwerp University Hospital, Antwerp, Belgium
- Translational Neurosciences, Faculty of Medicine and Health Science, University of Antwerp, Antwerp, Belgium
| | - Peter Sparber
- Research Center for Medical Genetics Moskvorechie 1, Moscow, Russia
| | - Arjan Bouman
- Department of Clinical Genetics, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Simone Ardern-Holmes
- Kids Neuroscience Centre, Children's Hospital at Westmead, University of Sydney, Sydney, New South Wales, Australia
- T. Y. Nelson Department of Neurology and Neurosurgery, Children's Hospital at Westmead, Westmead, New South Wales, Australia
| | - Christopher Troedson
- T. Y. Nelson Department of Neurology and Neurosurgery, Children's Hospital at Westmead, Westmead, New South Wales, Australia
| | - Domenica I Battaglia
- Pediatric Neurology, Department of Woman and Child Health and Public Health, Child Health Area, Catholic University UCSC, Rome, Italy
| | - Himanshu Goel
- Hunter Genetics, Newcastle, New South Wales, Australia
| | - Timothy Feyma
- Gillette Children's Specialty Healthcare, Saint Paul, MN, USA
| | - Somayeh Bakhtiari
- Pediatric Movement Disorders Program, Division of Pediatric Neurology, Barrow Neurological Institute, Phoenix Children's Hospital, Phoenix, AZ, USA
- Departments of Child Health, Neurology, and Cellular & Molecular Medicine and Program in Genetics, University of Arizona College of Medicine, Phoenix, AZ, USA
| | - Linda Tjoa
- Townsville University Hospital, Douglas, Queensland, Australia
| | - Martin Boxill
- Department of Pediatrics, Viborg Regional Hospital, Viborg, Denmark
| | - Nina Demina
- Research Center for Medical Genetics Moskvorechie 1, Moscow, Russia
| | - Olga Shchagina
- Research Center for Medical Genetics Moskvorechie 1, Moscow, Russia
| | - Elena Dadali
- Research Center for Medical Genetics Moskvorechie 1, Moscow, Russia
| | - Michael Kruer
- Pediatric Movement Disorders Program, Division of Pediatric Neurology, Barrow Neurological Institute, Phoenix Children's Hospital, Phoenix, AZ, USA
- Departments of Child Health, Neurology, and Cellular & Molecular Medicine and Program in Genetics, University of Arizona College of Medicine, Phoenix, AZ, USA
| | - Gaetano Cantalupo
- Child Neuropsychiatry Section, Department of Surgical Sciences, Dentistry, Gynecology and Paediatrics, University of Verona, Verona, Italy
- UOC Neuropsichiatria Infantile, Dipartimento Materno-Infantile, Azienda Ospedaliero-Universitaria Integrata (full member of the ERN EpiCare), Verona, Italy
- Center for Research on Epilepsies in Pediatric age (CREP), Verona, Italy
| | - Ilaria Contaldo
- Pediatric Neurology, Department of Woman and Child Health and Public Health, Child Health Area, Catholic University UCSC, Rome, Italy
| | - Tilman Polster
- Department of Epileptology (Krankenhaus Mara), Bielefeld University Medical School, Bielefeld, Germany
| | | | - Stefania M Bova
- Pediatric Neurology Unit, V. Buzzi Children's Hospital, Milan, Italy
| | - Walid Fazeli
- Department of Neuropediatrics, Children's Hospital, University of Bonn, Bonn, Germany
| | - Leen Wouters
- Department of Pediatrics, Ziekenhuis Oost-Limburg, Genk, Belgium
| | - Maria J Miranda
- Department of Pediatrics, Pediatric Neurology, Herlev University Hospital, Copenhagen University, Herlev, Denmark
| | - Francesca Darra
- Child Neuropsychiatry Section, Department of Surgical Sciences, Dentistry, Gynecology and Paediatrics, University of Verona, Verona, Italy
- UOC Neuropsichiatria Infantile, Dipartimento Materno-Infantile, Azienda Ospedaliero-Universitaria Integrata (full member of the ERN EpiCare), Verona, Italy
- Center for Research on Epilepsies in Pediatric age (CREP), Verona, Italy
| | - Elisa Pede
- Pediatric Neurology, Department of Woman and Child Health and Public Health, Child Health Area, Catholic University UCSC, Rome, Italy
| | - Diana Le Duc
- Department of Human Genetics, University of Leipzig Faculty of Medicine, Leipzig, Germany
| | - Rami Abou Jamra
- Department of Human Genetics, University of Leipzig Faculty of Medicine, Leipzig, Germany
| | - Sébastien Küry
- Service de Génétique Médicale, CHU Nantes, Nantes, France
- l'Institut du Thorax, INSERM, CNRS, Université de Nantes, Nantes, France
| | - Jacopo Proietti
- Child Neuropsychiatry Section, Department of Surgical Sciences, Dentistry, Gynecology and Paediatrics, University of Verona, Verona, Italy
- Irish Centre for Fetal and Neonatal Translational Research, Child Neuropsychiatry, Cork, Ireland
| | - Niamh McSweeney
- Department of Paediatrics, Cork University Hospital, Cork, Ireland
| | - Elly Brokamp
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Peter Ian Andrews
- Department of Neurology, Sydney Children's Hospital, Randwick, New South Wales, Australia
| | | | - Mary Chebib
- Brain and Mind Centre, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center, Dianalund, Denmark
- Department of Regional Health Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
| | - 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
| | - Elena Gardella
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center, Dianalund, Denmark
- Department of Regional Health Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
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Gjerulfsen CE, Mieszczanek TS, Johannesen KM, Liao VWY, Chebib M, Nørby HAJ, Gardella E, Rubboli G, Ahring P, Møller RS. Vinpocetine improved neuropsychiatric and epileptic outcomes in a patient with a GABRA1 loss-of-function variant. Ann Clin Transl Neurol 2023; 10:1493-1498. [PMID: 37434477 PMCID: PMC10424645 DOI: 10.1002/acn3.51838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 03/09/2023] [Accepted: 06/12/2023] [Indexed: 07/13/2023] Open
Abstract
Vinpocetine is a synthetic derivative of the alkaloid vincamine and has been used as a dietary supplement for decades. Following a positive report of the use of vinpocetine in a patient with a loss-of-function GABRB3 variant, we here describe another patient with a loss-of-function GABRA1 variant (p.(Arg112Gln)) who benefited from vinpocetine treatment. This patient was diagnosed with autism spectrum disorder, psychiatric complications, and therapy-resistant focal epilepsy. Upon add-on treatment with 40 mg vinpocetine daily for 16 months, the patient experienced an overall improved quality of life as well as seizure freedom. Our findings corroborate that vinpocetine can attenuate epilepsy-associated behavioral issues in patients with loss-of-function GABAA receptor gene variants.
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Affiliation(s)
- Cathrine E. Gjerulfsen
- Department of Epilepsy Genetics and Personalized MedicineDanish Epilepsy CentreDianalundDenmark
| | | | - Katrine M. Johannesen
- Department of Epilepsy Genetics and Personalized MedicineDanish Epilepsy CentreDianalundDenmark
- Department of GeneticsUniversity Hospital of Copenhagen, RigshospitaletCopenhagenDenmark
| | - Vivian W. Y. Liao
- Brain and Mind Centre, Sydney Pharmacy School, Faculty of Medicine and HealthThe University of SydneySydneyNew South WalesAustralia
| | - Mary Chebib
- Brain and Mind Centre, Sydney Pharmacy School, Faculty of Medicine and HealthThe University of SydneySydneyNew South WalesAustralia
| | | | - Elena Gardella
- Department of Epilepsy Genetics and Personalized MedicineDanish Epilepsy CentreDianalundDenmark
- Department of Regional Health Research, Faculty of Health SciencesUniversity of Southern DenmarkOdenseDenmark
| | - Guido Rubboli
- Department of Epilepsy Genetics and Personalized MedicineDanish Epilepsy CentreDianalundDenmark
- Institute of Clinical MedicineUniversity of CopenhagenCopenhagenDenmark
| | - Philip Ahring
- Brain and Mind Centre, Sydney Pharmacy School, Faculty of Medicine and HealthThe University of SydneySydneyNew South WalesAustralia
| | - Rikke S. Møller
- Department of Epilepsy Genetics and Personalized MedicineDanish Epilepsy CentreDianalundDenmark
- Department of Regional Health Research, Faculty of Health SciencesUniversity of Southern DenmarkOdenseDenmark
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Wang YJ, Seibert H, Ahn LY, Schaffer AE, Mu TW. Pharmacological chaperones restore proteostasis of epilepsy-associated GABA A receptor variants. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.18.537383. [PMID: 37131660 PMCID: PMC10153171 DOI: 10.1101/2023.04.18.537383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Recent advances in genetic diagnosis identified variants in genes encoding GABAA receptors as causative for genetic epilepsy. Here, we selected eight disease-associated variants in the α 1 subunit of GABAA receptors causing mild to severe clinical phenotypes and showed that they are loss of function, mainly by reducing the folding and surface trafficking of the α 1 protein. Furthermore, we sought client protein-specific pharmacological chaperones to restore the function of pathogenic receptors. Applications of positive allosteric modulators, including Hispidulin and TP003, increase the functional surface expression of the α 1 variants. Mechanism of action study demonstrated that they enhance the folding and assembly and reduce the degradation of GABAA variants without activating the unfolded protein response in HEK293T cells and human iPSC-derived neurons. Since these compounds cross the blood-brain barrier, such a pharmacological chaperoning strategy holds great promise to treat genetic epilepsy in a GABAA receptor-specific manner.
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Affiliation(s)
- Ya-Juan Wang
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, USA
| | - Hailey Seibert
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, USA
| | - Lucie Y. Ahn
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Ashleigh E. Schaffer
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Ting-Wei Mu
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, USA
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13
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Wang X, Rao X, Zhang J, Gan J. Genetic mechanisms in generalized epilepsies. ACTA EPILEPTOLOGICA 2023. [DOI: 10.1186/s42494-023-00118-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023] Open
Abstract
AbstractThe genetic generalized epilepsies (GGEs) have been proved to generate from genetic impact by twin studies and family studies. The genetic mechanisms of generalized epilepsies are always updating over time. Although the genetics of GGE is complex, there are always new susceptibility genes coming up as well as copy number variations which can lead to important breakthroughs in exploring the problem. At the same time, the development of ClinGen fades out some of the candidate genes. This means we have to figure out what accounts for a reliable gene for GGE, in another word, which gene has sufficient evidence for GGE. This will improve our understanding of the genetic mechanisms of GGE. In this review, important up-to-date genetic mechanisms of GGE were discussed.
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Altered GABA A Receptor Expression in the Primary Somatosensory Cortex of a Mouse Model of Genetic Absence Epilepsy. Int J Mol Sci 2022; 23:ijms232415685. [PMID: 36555327 PMCID: PMC9778655 DOI: 10.3390/ijms232415685] [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: 11/09/2022] [Revised: 11/26/2022] [Accepted: 12/07/2022] [Indexed: 12/14/2022] Open
Abstract
Absence seizures are hyperexcitations within the cortico-thalamocortical (CTC) network, however the underlying causative mechanisms at the cellular and molecular level are still being elucidated and appear to be multifactorial. Dysfunctional feed-forward inhibition (FFI) is implicated as one cause of absence seizures. Previously, we reported altered excitation onto parvalbumin-positive (PV+) interneurons in the CTC network of the stargazer mouse model of absence epilepsy. In addition, downstream changes in GABAergic neurotransmission have also been identified in this model. Our current study assessed whether dysfunctional FFI affects GABAA receptor (GABAAR) subunit expression in the stargazer primary somatosensory cortex (SoCx). Global tissue expression of GABAAR subunits α1, α3, α4, α5, β2, β3, γ2 and δ were assessed using Western blotting (WB), while biochemically isolated subcellular fractions were assessed for the α and δ subunits. We found significant reductions in tissue and synaptic expression of GABAAR α1, 18% and 12.2%, respectively. However, immunogold-cytochemistry electron microscopy (ICC-EM), conducted to assess GABAAR α1 specifically at synapses between PV+ interneurons and their targets, showed no significant difference. These data demonstrate a loss of phasic GABAAR α1, indicating altered GABAergic inhibition which, coupled with dysfunctional FFI, could be one mechanism contributing to the generation or maintenance of absence seizures.
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15
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Rodent Models of Audiogenic Epilepsy: Genetic Aspects, Advantages, Current Problems and Perspectives. Biomedicines 2022; 10:biomedicines10112934. [PMID: 36428502 PMCID: PMC9687921 DOI: 10.3390/biomedicines10112934] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/10/2022] [Accepted: 11/11/2022] [Indexed: 11/18/2022] Open
Abstract
Animal models of epilepsy are of great importance in epileptology. They are used to study the mechanisms of epileptogenesis, and search for new genes and regulatory pathways involved in the development of epilepsy as well as screening new antiepileptic drugs. Today, many methods of modeling epilepsy in animals are used, including electroconvulsive, pharmacological in intact animals, and genetic, with the predisposition for spontaneous or refractory epileptic seizures. Due to the simplicity of manipulation and universality, genetic models of audiogenic epilepsy in rodents stand out among this diversity. We tried to combine data on the genetics of audiogenic epilepsy in rodents, the relevance of various models of audiogenic epilepsy to certain epileptic syndromes in humans, and the advantages of using of rodent strains predisposed to audiogenic epilepsy in current epileptology.
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16
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Maillard P, Baer S, Schaefer É, Desnous B, Villeneuve N, Lépine A, Fabre A, Lacoste C, El Chehadeh S, Piton A, Porter LF, Perriard C, Wardé MA, Spitz M, Laugel V, Lesca G, Putoux A, Ville D, Mignot C, Héron D, Nabbout R, Barcia G, Rio M, Roubertie A, Meyer P, Paquis‐Flucklinger V, Patat O, Lefranc J, Gerard M, de Bellescize J, Villard L, De Saint Martin A, Milh M. Molecular and clinical descriptions of patients with GABA A receptor gene variants (GABRA1, GABRB2, GABRB3, GABRG2): A cohort study, review of literature, and genotype-phenotype correlation. Epilepsia 2022; 63:2519-2533. [PMID: 35718920 PMCID: PMC9804453 DOI: 10.1111/epi.17336] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 06/16/2022] [Accepted: 06/16/2022] [Indexed: 01/05/2023]
Abstract
OBJECTIVE γ-Aminobutyric acid (GABA)A -receptor subunit variants have recently been associated with neurodevelopmental disorders and/or epilepsy. The phenotype linked with each gene is becoming better known. Because of the common molecular structure and physiological role of these phenotypes, it seemed interesting to describe a putative phenotype associated with GABAA -receptor-related disorders as a whole and seek possible genotype-phenotype correlations. METHODS We collected clinical, electrophysiological, therapeutic, and molecular data from patients with GABAA -receptor subunit variants (GABRA1, GABRB2, GABRB3, and GABRG2) through a national French collaboration using the EPIGENE network and compared these data to the one already described in the literature. RESULTS We gathered the reported patients in three epileptic phenotypes: 15 patients with fever-related epilepsy (40%), 11 with early developmental epileptic encephalopathy (30%), 10 with generalized epilepsy spectrum (27%), and 1 patient without seizures (3%). We did not find a specific phenotype for any gene, but we showed that the location of variants on the transmembrane (TM) segment was associated with a more severe phenotype, irrespective of the GABAA -receptor subunit gene, whereas N-terminal variants seemed to be related to milder phenotypes. SIGNIFICANCE GABAA -receptor subunit variants are associated with highly variable phenotypes despite their molecular and physiological proximity. None of the genes described here was associated with a specific phenotype. On the other hand, it appears that the location of the variant on the protein may be a marker of severity. Variant location may have important weight in the development of targeted therapeutics.
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Affiliation(s)
- Pierre‐Yves Maillard
- Department of Medical GeneticsIGMA, Hôpitaux Universitaires de StrasbourgStrasbourgFrance,Present address:
Institut Jérome LejeuneParisFrance
| | - Sarah Baer
- Department of NeuropediatricsERN EpiCare, Hôpitaux Universitaires de StrasbourgStrasbourgFrance,Institute for Genetics and Molecular and Cellular Biology (IGBMC), University of Strasbourg, CNRS UMR7104, INSERM U1258IllkirchFrance
| | - Élise Schaefer
- Department of Medical GeneticsIGMA, Hôpitaux Universitaires de StrasbourgStrasbourgFrance
| | - Béatrice Desnous
- Department of Pediatric NeurologyAP‐HM, La Timone Children's HospitalMarseilleFrance
| | - Nathalie Villeneuve
- Department of Pediatric NeurologyAP‐HM, La Timone Children's HospitalMarseilleFrance
| | - Anne Lépine
- Department of Pediatric NeurologyAP‐HM, La Timone Children's HospitalMarseilleFrance
| | - Alexandre Fabre
- Pediatric Multidisciplinary UnitAP‐HM, Timone EnfantMarseilleFrance,Aix‐Marseille University, INSERM, GMGFMarseilleFrance
| | - Caroline Lacoste
- Department of Medical GeneticsLa Timone Children's HospitalMarseilleFrance
| | - Salima El Chehadeh
- Department of Medical GeneticsIGMA, Hôpitaux Universitaires de StrasbourgStrasbourgFrance,Institute for Genetics and Molecular and Cellular Biology (IGBMC), University of Strasbourg, CNRS UMR7104, INSERM U1258IllkirchFrance
| | - Amélie Piton
- Institute for Genetics and Molecular and Cellular Biology (IGBMC), University of Strasbourg, CNRS UMR7104, INSERM U1258IllkirchFrance,Laboratory of Genetic DiagnosisInstitut de Génétique Médicale d'Alsace, Hôpitaux Universitaires de StrasbourgStrasbourgFrance
| | - Louise Frances Porter
- Department of Medical GeneticsInstitut de Génétique Médicale d'Alsace, Centre de Référence pour les Affections Rares en Génétique Ophtalmologique (CARGO)StrasbourgFrance
| | - Caroline Perriard
- Department of NeuropediatricsERN EpiCare, Hôpitaux Universitaires de StrasbourgStrasbourgFrance
| | - Marie‐Thérèse Abi Wardé
- Department of NeuropediatricsERN EpiCare, Hôpitaux Universitaires de StrasbourgStrasbourgFrance
| | - Marie‐Aude Spitz
- Department of NeuropediatricsERN EpiCare, Hôpitaux Universitaires de StrasbourgStrasbourgFrance
| | - Vincent Laugel
- Department of NeuropediatricsERN EpiCare, Hôpitaux Universitaires de StrasbourgStrasbourgFrance
| | - Gaëtan Lesca
- Department of GeneticsHospices Civils de LyonBronFrance
| | - Audrey Putoux
- Department of GeneticsHospices Civils de LyonBronFrance
| | - Dorothée Ville
- Pediatric Neurology Department and Reference Center of Rare EpilepsiesMother Child Women's Hospital, Lyon University HospitalLyonFrance
| | - Cyril Mignot
- Department of GeneticsGroupe Hospitalier Pitié‐Salpêtrière and Hôpital Armand Trousseau, APHP‐Sorbonne UniversitéParisFrance,Centre de Référence Déficiences Intellectuelles de Causes RaresParisFrance
| | - Delphine Héron
- Department of GeneticsGroupe Hospitalier Pitié‐Salpêtrière and Hôpital Armand Trousseau, APHP‐Sorbonne UniversitéParisFrance,Centre de Référence Déficiences Intellectuelles de Causes RaresParisFrance
| | - Rima Nabbout
- Department of Pediatric NeurologyReference Centre for Rare Epilepsies, Necker Enfants Malades University Hospital, APHP, Université de ParisParisFrance
| | - Giulia Barcia
- Department of Medical GeneticsNecker‐Enfants Malades Hospital, Université de ParisParisFrance
| | - Marlène Rio
- Department of Medical GeneticsNecker‐Enfants Malades Hospital, Université de ParisParisFrance
| | - Agathe Roubertie
- Pediatric Neurology DepartmentINM, INSERM, CHU Montpellier, University of MontpellierMontpellierFrance
| | - Pierre Meyer
- Pediatric Neurology DepartmentINM, INSERM, CHU Montpellier, University of MontpellierMontpellierFrance
| | | | - Olivier Patat
- Department of Medical GeneticsCHU Toulouse PurpanToulouseFrance
| | | | - Marion Gerard
- Department of Medical GeneticsCentre Hospitalier Universitaire de CaenCaenFrance
| | | | - Julietta de Bellescize
- Paediatric Clinical Epileptology and Functional Neurology DepartmentReference Center of Rare Epilepsies, Member of the ERN EpiCARE, University Hospitals of Lyon (HCL)LyonFrance
| | - Laurent Villard
- Pediatric Multidisciplinary UnitAP‐HM, Timone EnfantMarseilleFrance,Faculté de Médecine TimoneAix Marseille Univ, INSERM, MMG, U1251, ERN EpicareMarseilleFrance
| | - Anne De Saint Martin
- Department of NeuropediatricsERN EpiCare, Hôpitaux Universitaires de StrasbourgStrasbourgFrance,Institute for Genetics and Molecular and Cellular Biology (IGBMC), University of Strasbourg, CNRS UMR7104, INSERM U1258IllkirchFrance
| | - Mathieu Milh
- Department of Pediatric NeurologyAP‐HM, La Timone Children's HospitalMarseilleFrance,Faculté de Médecine TimoneAix Marseille Univ, INSERM, MMG, U1251, ERN EpicareMarseilleFrance
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Chakraborty S, Parayil R, Mishra S, Nongthomba U, Clement JP. Epilepsy Characteristics in Neurodevelopmental Disorders: Research from Patient Cohorts and Animal Models Focusing on Autism Spectrum Disorder. Int J Mol Sci 2022; 23:ijms231810807. [PMID: 36142719 PMCID: PMC9501968 DOI: 10.3390/ijms231810807] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 08/31/2022] [Accepted: 09/05/2022] [Indexed: 11/24/2022] Open
Abstract
Epilepsy, a heterogeneous group of brain-related diseases, has continued to significantly burden society and families. Epilepsy comorbid with neurodevelopmental disorders (NDDs) is believed to occur due to multifaceted pathophysiological mechanisms involving disruptions in the excitation and inhibition (E/I) balance impeding widespread functional neuronal circuitry. Although the field has received much attention from the scientific community recently, the research has not yet translated into actionable therapeutics to completely cure epilepsy, particularly those comorbid with NDDs. In this review, we sought to elucidate the basic causes underlying epilepsy as well as those contributing to the association of epilepsy with NDDs. Comprehensive emphasis is put on some key neurodevelopmental genes implicated in epilepsy, such as MeCP2, SYNGAP1, FMR1, SHANK1-3 and TSC1, along with a few others, and the main electrophysiological and behavioral deficits are highlighted. For these genes, the progress made in developing appropriate and valid rodent models to accelerate basic research is also detailed. Further, we discuss the recent development in the therapeutic management of epilepsy and provide a briefing on the challenges and caveats in identifying and testing species-specific epilepsy models.
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Affiliation(s)
- Sukanya Chakraborty
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru 560064, India
| | - Rrejusha Parayil
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru 560064, India
| | - Shefali Mishra
- Molecular Reproduction, Development and Genetics (MRDG), Indian Institute of Science, Bengaluru 560012, India
| | - Upendra Nongthomba
- Molecular Reproduction, Development and Genetics (MRDG), Indian Institute of Science, Bengaluru 560012, India
| | - James P. Clement
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru 560064, India
- Correspondence: ; Tel.: +91-08-2208-2613
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18
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Whittsette AL, Wang YJ, Mu TW. The endoplasmic reticulum membrane complex promotes proteostasis of GABA A receptors. iScience 2022; 25:104754. [PMID: 35938049 PMCID: PMC9352529 DOI: 10.1016/j.isci.2022.104754] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 06/30/2022] [Accepted: 07/07/2022] [Indexed: 11/29/2022] Open
Abstract
The endoplasmic reticulum membrane complex (EMC) plays a critical role in the biogenesis of tail-anchored proteins and a subset of multi-pass membrane proteins in the endoplasmic reticulum (ER). However, because of nearly exclusive expression of neurotransmitter-gated ion channels in the central nervous system (CNS), the role of the EMC in their biogenesis is not well understood. In this study, we demonstrated that the EMC positively regulates the surface trafficking and thus function of endogenous γ-aminobutyric acid type A (GABAA) receptors, the primary inhibitory ion channels in the mammalian brain. Moreover, among ten EMC subunits, EMC3 and EMC6 have the most prominent effect, and overexpression of EMC3 or EMC6 is sufficient to restore the function of epilepsy-associated GABAA receptor variants. In addition, EMC3 and EMC6 demonstrate endogenous interactions with major neuroreceptors, which depends on their transmembrane domains, suggesting a general role of the EMC in the biogenesis of neuroreceptors.
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Affiliation(s)
- Angela L. Whittsette
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Ya-Juan Wang
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Ting-Wei Mu
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106, USA
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19
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Zhang L, Liu X. Clinical phenotype and genotype of children with GABAA receptor α1 subunit gene-related epilepsy. Front Neurol 2022; 13:941054. [PMID: 35937053 PMCID: PMC9350551 DOI: 10.3389/fneur.2022.941054] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 06/27/2022] [Indexed: 12/03/2022] Open
Abstract
Objective This study aimed to summarize the clinical phenotype and genotype of children with epilepsy caused by GABRA1 gene variants. Methods Eight epilepsy patients, who were admitted to Qilu Hospital of Shandong University from 2015 to 2021, were enrolled in the study. GABRA1 gene variants were detected by whole-exome sequencing. Epilepsy clinical manifestations, electroencephalography, neuroimaging characteristics and treatment methods were retrospectively analyzed. Results Among the eight patients, four were males and four were females. Epilepsy onset age was between 3 and 8 months of age. Two patients had a family history of epilepsy. Six cases were de novo variants, and two were hereditary variants. Two children carried the same pathogenic variants, and five carried novel pathogenic variants that had not been reported internationally. The types of seizures were diverse, including focal seizures in five cases, generalized tonic-clonic seizures in five cases, and spasms in two cases. Electroencephalography of seven cases showed abnormal background rhythms, and six cases showed abnormal discharge during the interictal period. No obvious abnormalities were found on magnetic resonance imaging in five cases. All eight children had different degrees of developmental retardation. Conclusion De novo pathogenic variants in GABRA1 are more common than inherited pathogenic variants, and most epilepsy symptoms begin in the first year of life, manifesting with a variety of seizure types and developmental delays. Conventional treatment usually involves one or more drugs; although drug treatment can control seizures in some cases, cognitive and developmental deficits often exist. The five newly discovered pathogenic variants enrich the GABRA1 gene pathogenic variant spectrum.
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20
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Ding J, Wang L, Jin Z, Qiang Y, Li W, Wang Y, Zhu C, Jiang S, Xiao L, Hao X, Hu X, Li X, Wang F, Sun T. Do All Roads Lead to Rome? Genes Causing Dravet Syndrome and Dravet Syndrome-Like Phenotypes. Front Neurol 2022; 13:832380. [PMID: 35359639 PMCID: PMC8961694 DOI: 10.3389/fneur.2022.832380] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 01/26/2022] [Indexed: 11/16/2022] Open
Abstract
Background Dravet syndrome (DS) is a severe epileptic encephalopathy mainly caused by haploinsufficiency of the gene SCN1A, which encodes the voltage-gated sodium channel NaV1. 1 in the brain. While SCN1A mutations are known to be the primary cause of DS, other genes that may cause DS are poorly understood. Several genes with pathogenic mutations result in DS or DS-like phenotypes, which may require different drug treatment approaches. Therefore, it is urgent for clinicians, especially epilepsy specialists to fully understand these genes involved in DS in addition to SCN1A. Particularly for healthcare providers, a deep understanding of these pathogenic genes is useful in properly selecting and adjusting drugs in a more effective and timely manner. Objective The purpose of this study was to identify genes other than SCN1A that may also cause DS or DS-like phenotypes. Methods A comprehensive search of relevant Dravet syndrome and severe myoclonic epilepsy in infancy was performed in PubMed, until December 1, 2021. Two independent authors performed the screening for potentially eligible studies. Disagreements were decided by a third, more professional researcher or by all three. The results reported by each study were narratively summarized. Results A PubMed search yielded 5,064 items, and other sources search 12 records. A total of 29 studies published between 2009 and 2021 met the inclusion criteria. Regarding the included articles, seven studies on PCDH19, three on SCN2A, two on SCN8A, five on SCN1B, two on GABRA1, three on GABRB3, three on GABRG2, and three on STXBP1 were included. Only one study was recorded for CHD2, CPLX1, HCN1 and KCNA2, respectively. It is worth noting that a few articles reported on more than one epilepsy gene. Conclusion DS is not only identified in variants of SCN1A, but other genes such as PCDH19, SCN2A, SCN8A, SCN1B, GABRA1, GABRB3, GABRG2, KCNA2, CHD2, CPLX1, HCN1A, STXBP1 can also be involved in DS or DS-like phenotypes. As genetic testing becomes more widely available, more genes associated with DS and DS-like phenotypes may be identified and gene-based diagnosis of subtypes of phenotypes in this spectrum may improve the management of these diseases in the future.
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Affiliation(s)
- Jiangwei Ding
- Ningxia Key Laboratory of Cerebrocranial Disease, The Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
- Department of Neurosurgery, General Hospital of Ningxia Medical University, Yinchuan, China
| | - Lei Wang
- Ningxia Key Laboratory of Cerebrocranial Disease, The Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
- Department of Neurosurgery, The First Affiliated Hospital of Xinxiang Medical University, Weihui, China
| | - Zhe Jin
- Ningxia Key Laboratory of Cerebrocranial Disease, The Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Yuanyuan Qiang
- Ningxia Key Laboratory of Cerebrocranial Disease, The Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
| | - Wenchao Li
- Ningxia Key Laboratory of Cerebrocranial Disease, The Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
- Department of Neurosurgery, The First Affiliated Hospital of Xinxiang Medical University, Weihui, China
| | - Yangyang Wang
- Ningxia Key Laboratory of Cerebrocranial Disease, The Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
- Department of Neurosurgery, The First Affiliated Hospital of Xinxiang Medical University, Weihui, China
| | - Changliang Zhu
- Ningxia Key Laboratory of Cerebrocranial Disease, The Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
- Department of Neurosurgery, General Hospital of Ningxia Medical University, Yinchuan, China
| | - Shucai Jiang
- Ningxia Key Laboratory of Cerebrocranial Disease, The Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
- Department of Neurosurgery, General Hospital of Ningxia Medical University, Yinchuan, China
| | - Lifei Xiao
- Ningxia Key Laboratory of Cerebrocranial Disease, The Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
- Department of Neurosurgery, General Hospital of Ningxia Medical University, Yinchuan, China
| | - Xiaoyan Hao
- Department of Neurology, First Affiliated Hospital of Zhengzhou Universiy, Zhengzhou, China
| | - Xulei Hu
- Ningxia Key Laboratory of Cerebrocranial Disease, The Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
- Department of Neurosurgery, General Hospital of Ningxia Medical University, Yinchuan, China
| | - Xinxiao Li
- Department of Neurosurgery, The Fifth Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- Xinxiao Li
| | - Feng Wang
- Ningxia Key Laboratory of Cerebrocranial Disease, The Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
- Department of Neurosurgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Feng Wang
| | - Tao Sun
- Ningxia Key Laboratory of Cerebrocranial Disease, The Incubation Base of National Key Laboratory, Ningxia Medical University, Yinchuan, China
- Department of Neurosurgery, General Hospital of Ningxia Medical University, Yinchuan, China
- *Correspondence: Tao Sun
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21
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Distinct Functional Alterations and Therapeutic Options of Two Pathological De Novo Variants of the T292 Residue of GABRA1 Identified in Children with Epileptic Encephalopathy and Neurodevelopmental Disorders. Int J Mol Sci 2022; 23:ijms23052723. [PMID: 35269865 PMCID: PMC8911174 DOI: 10.3390/ijms23052723] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/25/2022] [Accepted: 02/27/2022] [Indexed: 11/17/2022] Open
Abstract
Mutations of GABAAR have reportedly led to epileptic encephalopathy and neurodevelopmental disorders. We have identified a novel de novo T292S missense variant of GABRA1 from a pediatric patient with grievous global developmental delay but without obvious epileptic activity. This mutation coincidentally occurs at the same residue as that of a previously reported GABRA1 variant T292I identified from a pediatric patient with severe epilepsy. The distinct phenotypes of these two patients prompted us to compare the impacts of the two mutants on the receptor function and to search for suitable therapeutics. In this study, we used biochemical techniques and patch-clamp recordings in HEK293 cells overexpressing either wild-type or mutated rat recombinant GABAARs. We found that the α1T292S variant significantly increased GABA-evoked whole-cell currents, shifting the dose-response curve to the left without altering the maximal response. In contrast, the α1T292I variant significantly reduced GABA-evoked currents, shifting the dose-response curve to the right with a severely diminished maximum response. Single-channel recordings further revealed that the α1T292S variant increased, while the α1T292I variant decreased the GABAAR single-channel open time and open probability. Importantly, we found that the T292S mutation-induced increase in GABAAR function could be fully normalized by the negative GABAAR modulator thiocolchicoside, whereas the T292I mutation-induced impairment of GABAAR function was largely rescued with a combination of the GABAAR positive modulators diazepam and verapamil. Our study demonstrated that α1T292 is a critical residue for controlling GABAAR channel gating, and mutations at this residue may produce opposite impacts on the function of the receptors. Thus, the present work highlights the importance of functionally characterizing each individual GABAAR mutation for ensuring precision medicine.
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22
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Olivotto S, Freddi A, Lavatelli R, Basso E, Leidi A, Castellotti B, Spaccini L, Bova SM, Veggiotti P. Successful use of perampanel in GABRA1-related myoclonic epilepsy with photosensitivity. Epilepsy Behav Rep 2022; 19:100544. [PMID: 35520951 PMCID: PMC9062212 DOI: 10.1016/j.ebr.2022.100544] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 04/13/2022] [Accepted: 04/16/2022] [Indexed: 11/22/2022] Open
Abstract
Generalized epilepsies with variants in GABRA1 may be a treatment challenge when myoclonus remains drug-resistant. Photosensitivity may be particularly disabling and is without feature-specific treatments. We describe an adolescent with GABRA1 mutation and photosensitivity who improved with PER.
Pathogenic variants in gamma-aminobutyric acid type A receptor subunit alpha1 (GABRA1) is a protein coding gene that has been associated with a broad phenotypic spectrum of epilepsies. These have ranged from mild generalized forms to early-onset severe epileptic encephalopathies. Both in mild and in severe forms, tonic-clonic and myoclonic seizures with generalized spike and wave discharges and photoparoxysmal responses are common clinical manifestations. We present the case of a 14-year-old girl referred to our clinic with uncontrolled epilepsy. She was found to carry a heterozygous variant (c.335G > A) in GABRA1, already described in the literature and classified as “pathogenic” according to ACMG guidelines. The patient showed severe drug resistance with seizures often triggered by photic stimulation. The introduction of perampanel therapy led to overall reduction of the focal and generalized myoclonic seizures and complete clinical control of the light-triggered seizures. To our knowledge this is the first report of perampanel efficacy in photosensitive epilepsy, and in particular in the presence of a GABRA1 variant. New evidence is needed to confirm our findings in this case.
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Affiliation(s)
- Sara Olivotto
- Vittore Buzzi Children's Hospital, Pediatric Neurology Unit, Milan, Italy
| | | | | | | | | | - Barbara Castellotti
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico ‘Carlo Besta’, Milan, Italy
| | - Luigina Spaccini
- Clinical Genetics Service, Vittore Buzzi Children's Hospital, Milan, Italy
| | | | - Pierangelo Veggiotti
- Vittore Buzzi Children's Hospital, Pediatric Neurology Unit, Milan, Italy
- Department of Biomedical and Clinical Sciences, L. Sacco, University of Milan, Milan, Italy
- Corresponding author at: Vittore Buzzi Children's Hospital, Pediatric Neurology Unit, Milan, Italy.
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23
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Dzinovic I, Škorvánek M, Necpál J, Boesch S, Švantnerová J, Wagner M, Havránková P, Pavelekova P, Haň V, Janzarik WG, Berweck S, Diebold I, Kuster A, Jech R, Winkelmann J, Zech M. Dystonia as a prominent presenting feature in developmental and epileptic encephalopathies: A case series. Parkinsonism Relat Disord 2021; 90:73-78. [PMID: 34399161 DOI: 10.1016/j.parkreldis.2021.08.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 08/03/2021] [Accepted: 08/06/2021] [Indexed: 01/04/2023]
Abstract
INTRODUCTION Although there has been increasing recognition of the occurrence of non-epileptic involuntary movements in developmental and epileptic encephalopathies (DEEs), the spectrum of dystonic presentations associated with these conditions remains poorly described. We sought to expand the catalogue of dystonia-predominant phenotypes in monogenic DEEs, building on the recently introduced concept of an epilepsy-movement disorder spectrum. METHODS Cases were identified from a whole-exome-sequenced cohort of 45 pediatric index patients with complex dystonia (67% sequenced as parent-child trios). Review of molecular findings in DEE-associated genes was performed. For five individuals with identified DEE-causing variants, detailed information about presenting phenotypic features and the natural history of disease was obtained. RESULTS De-novo pathogenic and likely pathogenic missense variants in GABRA1, GABBR2, GNAO1, and FOXG1 gave rise to infantile-onset persistent and paroxysmal dystonic manifestations, beginning in the limb or truncal musculature and progressing gradually to a generalized state. Coexisting, less prominent movement-disorder symptoms were observed and included myoclonic, ballistic, and stereotypic abnormal movements as well as choreoathetosis. Dystonia dominated over epileptic neurodevelopmental comorbidities in all four subjects and represented the primary indication for molecular genetic analysis. We also report the unusual case of an adult female patient with dystonia, tremor, and mild learning disability who was found to harbor a pathogenic frameshift variant in MECP2. CONCLUSIONS Dystonia can be a leading clinical manifestation in different DEEs. A monogenic basis of disease should be considered on the association of dystonia and developmental delay-epilepsy presentations, justifying a molecular screening for variants in DEE-associated genes.
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Affiliation(s)
- Ivana Dzinovic
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
| | - Matej Škorvánek
- Department of Neurology, P.J. Safarik University, Kosice, Slovak Republic; Department of Neurology, University Hospital of L. Pasteur, Kosice, Slovak Republic
| | - Ján Necpál
- Department of Neurology, Zvolen Hospital, Slovakia
| | - Sylvia Boesch
- Department of Neurology, Medical University Innsbruck, Innsbruck, Austria
| | - Jana Švantnerová
- Second Department of Neurology, Faculty of Medicine, Comenius University, University Hospital Bratislava, Bratislava, Slovakia
| | - Matias Wagner
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany; Technical University of Munich, Munich, Germany; School of Medicine, Institute of Human Genetics
| | - Petra Havránková
- Department of Neurology, Charles University, 1st Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - Petra Pavelekova
- Department of Neurology, P.J. Safarik University, Kosice, Slovak Republic; Department of Neurology, University Hospital of L. Pasteur, Kosice, Slovak Republic
| | - Vladimír Haň
- Department of Neurology, P.J. Safarik University, Kosice, Slovak Republic; Department of Neurology, University Hospital of L. Pasteur, Kosice, Slovak Republic
| | - Wibke G Janzarik
- Department of Neuropediatrics and Muscle Disorders, University Medical Center, Faculty of Medicine, University of Freiburg, Germany
| | - Steffen Berweck
- Ludwig Maximilian University of Munich, Munich, Germany; Hospital for Neuropediatrics and Neurological Rehabilitation, Centre of Epilepsy for Children and Adolescents, Schoen Klinik Vogtareuth, Vogtareuth, Germany
| | - Isabel Diebold
- MGZ - Medical Genetics Center Munich, Munich, Germany; Department of Pediatrics, Technical University of Munich School of Medicine, Munich, Germany
| | - Alice Kuster
- Inborn Errors of Metabolism, Pediatric Intensive Care Unit, University Hospital of Nantes, Nantes, France
| | - Robert Jech
- Department of Neurology, Charles University, 1st Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - Juliane Winkelmann
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany; Technical University of Munich, Munich, Germany; School of Medicine, Institute of Human Genetics; Lehrstuhl für Neurogenetik, Technische Universität München, Munich, Germany; Munich Cluster for Systems Neurology, SyNergy, Munich, Germany
| | - Michael Zech
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany; Technical University of Munich, Munich, Germany; School of Medicine, Institute of Human Genetics.
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Spagnoli C, Fusco C, Pisani F. Rett Syndrome Spectrum in Monogenic Developmental-Epileptic Encephalopathies and Epilepsies: A Review. Genes (Basel) 2021; 12:genes12081157. [PMID: 34440332 PMCID: PMC8394997 DOI: 10.3390/genes12081157] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 07/21/2021] [Accepted: 07/23/2021] [Indexed: 01/22/2023] Open
Abstract
INTRODUCTION Progress in the clinical application of next-generation-sequencing-based techniques has resulted in a dramatic increase in the recognized genetic heterogeneity of the Rett syndrome spectrum (RSS). Our awareness of the considerable overlap with pediatric-onset epilepsies and epileptic/developmental encephalopathies (EE/DE) genes is also growing, and the presence of variable clinical features inside a general frame of commonalities has drawn renewed attention into deep phenotyping. METHODS We decided to review the medical literature on atypical Rett syndrome and "Rett-like" phenotypes, with special emphasis on described cases with pediatric-onset epilepsies and/or EE-DE, evaluating Neul's criteria for Rett syndrome and associated movement disorders and notable stereotypies. RESULTS "Rett-like" features were described in syndromic and non-syndromic monogenic epilepsy- and DE/EE-related genes, in "intellectual disability plus epilepsy"-related genes and in neurodegenerative disorders. Additionally, prominent stereotypies can be observed in monogenic complex neurodevelopmental disorders featuring epilepsy with or without autistic features outside of the RSS. CONCLUSIONS Patients share a complex neurodevelopmental and neurological phenotype (developmental delay, movement disorder) with impaired gait, abnormal tone and hand stereotypies. However, the presence and characteristics of regression and loss of language and functional hand use can differ. Finally, the frequency of additional supportive criteria and their distribution also vary widely.
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Affiliation(s)
- Carlotta Spagnoli
- Child Neurology Unit, AUSL-IRCCS di Reggio Emilia, 42123 Reggio Emilia, Italy;
- Correspondence:
| | - Carlo Fusco
- Child Neurology Unit, AUSL-IRCCS di Reggio Emilia, 42123 Reggio Emilia, Italy;
| | - Francesco Pisani
- Child Neuropsychiatry Unit, University-Hospital of Parma, 43123 Parma, Italy;
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25
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Current Pharmacologic Strategies for Treatment of Intractable Epilepsy in Children. Int Neurourol J 2021; 25:S8-18. [PMID: 34053206 PMCID: PMC8171244 DOI: 10.5213/inj.2142166.083] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Accepted: 05/02/2021] [Indexed: 11/26/2022] Open
Abstract
Epileptic encephalopathy (EE) is a devastating pediatric disease that features medically resistant seizures, which can contribute to global developmental delays. Despite technological advancements in genetics, the neurobiological mechanisms of EEs are not fully understood, leaving few therapeutic options for affected patients. In this review, we introduce the most common EEs in pediatrics (i.e., Ohtahara syndrome, Dravet syndrome, and Lennox-Gastaut syndrome) and their molecular mechanisms that cause excitation/inhibition imbalances. We then discuss some of the essential molecules that are frequently dysregulated in EEs. Specifically, we explore voltage-gated ion channels, synaptic transmission-related proteins, and ligand-gated ion channels in association with the pathophysiology of Ohtahara syndrome, Dravet syndrome, and Lennox-Gastaut syndrome. Finally, we review currently available antiepileptic drugs used to treat seizures in patients with EEs. Since these patients often fail to achieve seizure relief even with the combination therapy, further extensive research efforts to explore the involved molecular mechanisms will be required to develop new drugs for patients with intractable epilepsy.
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Xue J, Song Z, Yi Z, Yang C, Li F, Liu K, Zhang Y. Hemiconvulsion-hemiplegia-epilepsy syndrome with 5q33.3q34 microdeletion: Causal or chance association. Int J Dev Neurosci 2021; 81:539-543. [PMID: 33866597 DOI: 10.1002/jdn.10114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 04/10/2021] [Accepted: 04/12/2021] [Indexed: 11/10/2022] Open
Abstract
Hemiconvulsion-hemiplegia-epilepsy (HHE) syndrome is a rare syndrome characterized by childhood onset partial motor convulsions, hemiplegia, and epilepsy in sequence. We presented a girl with global developmental delay with history and brain MRI consistent with the diagnosis of HHE syndrome. The cytogenetic microarray (CMA) showed 9.1 Mb deletion in 5q33.3q34 region. Along with HHE syndrome, the patient also had global developmental delay. Clinical phenotype of this microdeletion region has not been described in association with HHE syndrome in the literature. We compared the patient's phenotype with other patients in previously published papers of a common region of deletion spanning 157501989-164166203. GABRA1, GABRB2, GABRG2, CYFIP2, and THG1 are the important genes in the present deleted region, which may be responsible for the fever sensitivity and global developmental delay. This is the first case of HHE syndrome in which CMA showed a microdeletion of 5q33.3q34 region. This case report links HHE syndrome and global developmental delay to microdeletion of 5q33.3q34, which has never been reported in literature. The cause of HHE syndrome remains unexplained in present case and HHE may be a causal or chance co-occurrence.
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Affiliation(s)
- Jiao Xue
- Department of Pediatric Neurology, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Zhenfeng Song
- Department of Pediatric Neurology, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Zhi Yi
- Department of Pediatric Neurology, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Chengqing Yang
- Department of Pediatric Neurology, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Fei Li
- Department of Pediatric Neurology, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Kaixuan Liu
- Department of Pediatric Neurology, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Ying Zhang
- Department of Pediatric Neurology, the Affiliated Hospital of Qingdao University, Qingdao, China
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Genetic Neonatal-Onset Epilepsies and Developmental/Epileptic Encephalopathies with Movement Disorders: A Systematic Review. Int J Mol Sci 2021; 22:ijms22084202. [PMID: 33919646 PMCID: PMC8072943 DOI: 10.3390/ijms22084202] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 04/09/2021] [Accepted: 04/14/2021] [Indexed: 02/06/2023] Open
Abstract
Despite expanding next generation sequencing technologies and increasing clinical interest into complex neurologic phenotypes associating epilepsies and developmental/epileptic encephalopathies (DE/EE) with movement disorders (MD), these monogenic conditions have been less extensively investigated in the neonatal period compared to infancy. We reviewed the medical literature in the study period 2000–2020 to report on monogenic conditions characterized by neonatal onset epilepsy and/or DE/EE and development of an MD, and described their electroclinical, genetic and neuroimaging spectra. In accordance with a PRISMA statement, we created a data collection sheet and a protocol specifying inclusion and exclusion criteria. A total of 28 different genes (from 49 papers) leading to neonatal-onset DE/EE with multiple seizure types, mainly featuring tonic and myoclonic, but also focal motor seizures and a hyperkinetic MD in 89% of conditions, with neonatal onset in 22%, were identified. Neonatal seizure semiology, or MD age of onset, were not always available. The rate of hypokinetic MD was low, and was described from the neonatal period only, with WW domain containing oxidoreductase (WWOX) pathogenic variants. The outcome is characterized by high rates of associated neurodevelopmental disorders and microcephaly. Brain MRI findings are either normal or nonspecific in most conditions, but serial imaging can be necessary in order to detect progressive abnormalities. We found high genetic heterogeneity and low numbers of described patients. Neurological phenotypes are complex, reflecting the involvement of genes necessary for early brain development. Future studies should focus on accurate neonatal epileptic phenotyping, and detailed description of semiology and time-course, of the associated MD, especially for the rarest conditions.
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Brafa Musicoro V, Sortino V, Pecora G, Tosto M, Lo Bianco M, Soma R, Romano C, Falsaperla R, Praticò AD. Gamma-Aminobutyric Acid Type A Receptor Genes and Their Related Epilepsies. JOURNAL OF PEDIATRIC NEUROLOGY 2021. [DOI: 10.1055/s-0041-1727269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
AbstractGamma-aminobutyric acid type A (GABA-A) receptor subunit gene mutations, which include GABRA1, GABRB3, GABRD, and GABRG2, are often involved in several genetic epilepsy syndromes and other neuropsychiatric diseases like autism spectrum disorder, schizophrenia, and anxiety. GABA-A are ligand-gated ionic channels, and are involved firstly in the fast inhibitory synaptic transmission of the central nervous system. The GABA receptors include the ionotropic GABA-A and GABA-C receptors and the metabotropic GABA-B receptors. According to the site in which mutations occur, they cause disorders in channel opening, “lock-and-pull” receptor system functioning, and capable of causing a specific epilepsy phenotype. The aim of this article is to summarize the most recent literature findings, considering genetic mutations, clinical features, genotype/phenotype correlation, and therapy about neurodevelopment diseases correlated to GABA receptors dysfunction, in particular epilepsy. According to our findings, we conclude that further mutation analysis could permit genotype–phenotype correlation and give more information about the best efficient treatment, even if—at present—more clinical and genetic studies are necessary.
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Affiliation(s)
- Viviana Brafa Musicoro
- Pediatric Postgraduate Residency Program, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
| | - Vincenzo Sortino
- Pediatric Postgraduate Residency Program, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
| | - Giulia Pecora
- Pediatric Postgraduate Residency Program, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
| | - Monica Tosto
- Pediatric Postgraduate Residency Program, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
| | - Manuela Lo Bianco
- Pediatric Postgraduate Residency Program, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
| | - Rachele Soma
- Unit of Rare Diseases of the Nervous System in Childhood, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
| | | | - Raffaele Falsaperla
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco”, Catania, Italy
- Unit of Neonatal Intensive Care and Neonatology, University Hospital “Policlinico Rodolico-San Marco”, Catania, Italy
| | - Andrea D. Praticò
- Unit of Rare Diseases of the Nervous System in Childhood, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
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Hernandez CC, Tian X, Hu N, Shen W, Catron MA, Yang Y, Chen J, Jiang Y, Zhang Y, Macdonald RL. Dravet syndrome-associated mutations in GABRA1, GABRB2 and GABRG2 define the genetic landscape of defects of GABA A receptors. Brain Commun 2021; 3:fcab033. [PMID: 34095830 PMCID: PMC8176149 DOI: 10.1093/braincomms/fcab033] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 01/07/2021] [Accepted: 01/14/2021] [Indexed: 12/29/2022] Open
Abstract
Dravet syndrome is a rare, catastrophic epileptic encephalopathy that begins in the first year of life, usually with febrile or afebrile hemiclonic or generalized tonic-clonic seizures followed by status epilepticus. De novo variants in genes that mediate synaptic transmission such as SCN1A and PCDH19 are often associated with Dravet syndrome. Recently, GABAA receptor subunit genes (GABRs) encoding α1 (GABRA1), β3 (GABRB3) and γ2 (GABRG2), but not β2 (GABRB2) or β1 (GABRB1), subunits are frequently associated with Dravet syndrome or Dravet syndrome-like phenotype. We performed next generation sequencing on 870 patients with Dravet syndrome and identified nine variants in three different GABRs. Interestingly, the variants were all in genes encoding the most common GABAA receptor, the α1β2γ2 receptor. Mutations in GABRA1 (c.644T>C, p. L215P; c.640C>T, p. R214C; c.859G>A; V287I; c.641G>A, p. R214H) and GABRG2 (c.269C>G, p. T90R; c.1025C>T, p. P342L) presented as de novo cases, while in GABRB2 two variants were de novo (c.992T>C, p. F331S; c.542A>T, p. Y181F) and one was autosomal dominant and inherited from the maternal side (c.990_992del, p.330_331del). We characterized the effects of these GABR variants on GABAA receptor biogenesis and channel function. We found that defects in receptor gating were the common deficiency of GABRA1 and GABRB2 Dravet syndrome variants, while mainly trafficking defects were found with the GABRG2 (c.269C>G, p. T90R) variant. It seems that variants in α1 and β2 subunits are less tolerated than in γ2 subunits, since variant α1 and β2 subunits express well but were functionally deficient. This suggests that all of these GABR variants are all targeting GABR genes that encode the assembled α1β2γ2 receptor, and regardless of which of the three subunits are mutated, variants in genes coding for α1, β2 and γ2 receptor subunits make them candidate causative genes in the pathogenesis of Dravet syndrome.
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Affiliation(s)
- Ciria C Hernandez
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48198, USA
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37240, USA
| | - XiaoJuan Tian
- Department of Pediatrics and Pediatric Epilepsy Center, Peking University First Hospital, Beijing 100034, China
- Department of Neurology, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing 100045, China
| | - Ningning Hu
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37240, USA
| | - Wangzhen Shen
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37240, USA
| | - Mackenzie A Catron
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37240, USA
- Neuroscience Graduate Program, Vanderbilt University, Nashville, TN 37240, USA
| | - Ying Yang
- Department of Pediatrics and Pediatric Epilepsy Center, Peking University First Hospital, Beijing 100034, China
| | - Jiaoyang Chen
- Department of Pediatrics and Pediatric Epilepsy Center, Peking University First Hospital, Beijing 100034, China
| | - Yuwu Jiang
- Department of Pediatrics and Pediatric Epilepsy Center, Peking University First Hospital, Beijing 100034, China
- Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing 100069, China
| | - Yuehua Zhang
- Department of Pediatrics and Pediatric Epilepsy Center, Peking University First Hospital, Beijing 100034, China
| | - Robert L Macdonald
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37240, USA
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El Achkar CM, Harrer M, Smith L, Kelly M, Iqbal S, Maljevic S, Niturad CE, Vissers LELM, Poduri A, Yang E, Lal D, Lerche H, Møller RS, Olson HE. Characterization of the GABRB2-Associated Neurodevelopmental Disorders. Ann Neurol 2020; 89:573-586. [PMID: 33325057 DOI: 10.1002/ana.25985] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 11/30/2020] [Accepted: 12/01/2020] [Indexed: 11/09/2022]
Abstract
OBJECTIVE We aimed to characterize the phenotypic spectrum and functional consequences associated with variants in the gene GABRB2, coding for the γ-aminobutyric acid type A (GABAA ) receptor subunit β2. METHODS We recruited and systematically evaluated 25 individuals with variants in GABRB2, 17 of whom are newly described and 8 previously reported with additional clinical data. Functional analysis was performed using a Xenopus laevis oocyte model system. RESULTS Our cohort of 25 individuals from 22 families with variants in GABRB2 demonstrated a range of epilepsy phenotypes from genetic generalized epilepsy to developmental and epileptic encephalopathy. Fifty-eight percent of individuals had pharmacoresistant epilepsy; response to medications targeting the GABAergic pathway was inconsistent. Developmental disability (present in 84%) ranged from mild intellectual disability to severe global disability; movement disorders (present in 44%) included choreoathetosis, dystonia, and ataxia. Disease-associated variants cluster in the extracellular N-terminus and transmembrane domains 1-3, with more severe phenotypes seen in association with variants in transmembrane domains 1 and 2 and the allosteric binding site between transmembrane domains 2 and 3. Functional analysis of 4 variants in transmembrane domains 1 or 2 (p.Ile246Thr, p.Pro252Leu, p.Ile288Ser, p.Val282Ala) revealed strongly reduced amplitudes of GABA-evoked anionic currents. INTERPRETATION GABRB2-related epilepsy ranges broadly in severity from genetic generalized epilepsy to developmental and epileptic encephalopathies. Developmental disability and movement disorder are key features. The phenotypic spectrum is comparable to other GABAA receptor-encoding genes. Phenotypic severity varies by protein domain. Experimental evidence supports loss of GABAergic inhibition as the mechanism underlying GABRB2-associated neurodevelopmental disorders. ANN NEUROL 2021;89:573-586.
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Affiliation(s)
- Christelle M El Achkar
- Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, MA.,Department of Neurology, Harvard Medical School, Boston, MA
| | - Merle Harrer
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Lacey Smith
- Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, MA
| | - McKenna Kelly
- Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, MA.,Dartmouth Geisel School of Medicine, Hanover, NH
| | - Sumaiya Iqbal
- Center for Development of Therapeutics and Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA
| | - Snezana Maljevic
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia
| | - Cristina E Niturad
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Lisenka E L M Vissers
- Department of Human Genetics, Donders Institute for Brain, Cognition, and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Annapurna Poduri
- Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, MA.,Department of Neurology, Harvard Medical School, Boston, MA
| | - Edward Yang
- Department of Radiology, Boston Children's Hospital, Boston, MA
| | - Dennis Lal
- Cleveland Clinic Genomic Medicine Institute and Neurological Institute, Cleveland, OH
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Treatment, Danish Epilepsy Center Filadelfia, Dianalund, Denmark.,Department of Regional Health Research, University of Southern Denmark, Odense, Denmark
| | - Heather E Olson
- Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, MA.,Department of Neurology, Harvard Medical School, Boston, MA
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Markus F, Angelini C, Trimouille A, Rudolf G, Lesca G, Goizet C, Lasseaux E, Arveiler B, van Slegtenhorst M, Brooks AS, Abou Jamra R, Korenke G, Neidhardt J, Owczarek‐Lipska M. Rare variants in the GABA A receptor subunit ε identified in patients with a wide spectrum of epileptic phenotypes. Mol Genet Genomic Med 2020; 8:e1388. [PMID: 32588540 PMCID: PMC7507344 DOI: 10.1002/mgg3.1388] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 05/29/2020] [Accepted: 05/31/2020] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Epilepsy belongs to a group of chronic and highly heterogeneous brain disorders. Many types of epilepsy and epileptic syndromes are caused by genetic factors. The neural amino acid y-aminobutyric acid (GABA) is a major inhibitory neurotransmitter in the mammalian central nervous system. It regulates activity of channel pores by binding to transmembrane GABA-receptors (GABRs). The GABRs are heteropentamers assembled from different receptor subunits (α1-6, β1-3, γ1-3, δ, ε, θ, π, and ρ1-3). Several epileptic disorders are caused by mutations in genes encoding single GABRs. METHODS We applied trio- and single-whole exome sequencing to search for genetic sequence variants associated with a wide range of epileptic phenotypes accompanied by intellectual disability and/or global developmental delay in the investigated patients. RESULTS We identified four hemizygous sequence variants in the GABAA receptor subunit ε gene (GABRE), including one nonsense (NM_004961.3: c.399C>A, p.Tyr133*), two missense variants (NM_004961.3: c.664G>A, p.Glu222Lys; NM_004961.3: c.1045G>A, p.Val349Ile), and one variant affecting the translation initiation codon (NM_004961.3: c.1A>G, p.Met1?) in four unrelated families. CONCLUSION Our clinical and molecular genetic findings suggest that GABRE is a likely candidate gene for epilepsy. Nevertheless, functional studies are necessary to better understand pathogenicity of the GABRE-mutations and their associations with epileptic phenotypes.
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Affiliation(s)
- Fenja Markus
- Junior Research GroupGenetics of Childhood Brain MalformationsFaculty VI‐School of Medicine and Health SciencesUniversity of OldenburgOldenburgGermany
- Human GeneticsFaculty VI‐School of Medicine and Health SciencesUniversity of OldenburgOldenburgGermany
| | - Chloé Angelini
- Service de Génétique médicaleCHU de BordeauxBordeauxFrance
| | | | - Gabrielle Rudolf
- CNRS U7104INSERM U1258Institut de Génétique et de Biologie Moléculaire et CellulaireIllkirchFrance
- Service de NeurologieCentre de Références des Maladies Neurogénétique RaresHôpitaux Universitaires de StrasbourgStrasbourgFrance
| | - Gaetan Lesca
- Genetics departmentLyon University Hospital and University of LyonLyonFrance
| | - Cyril Goizet
- Service de Génétique médicaleCHU de BordeauxBordeauxFrance
- CNRS U7104INSERM U1258Institut de Génétique et de Biologie Moléculaire et CellulaireIllkirchFrance
| | | | | | | | - Alice S. Brooks
- Department of Clinical GeneticsErasmus MC University Medical CenterRotterdamThe Netherlands
| | - Rami Abou Jamra
- Institute of Human GeneticsUniversity Medical Center LeipzigLeipzigGermany
| | | | - John Neidhardt
- Human GeneticsFaculty VI‐School of Medicine and Health SciencesUniversity of OldenburgOldenburgGermany
- Research Center Neurosensory ScienceUniversity of OldenburgOldenburgGermany
| | - Marta Owczarek‐Lipska
- Junior Research GroupGenetics of Childhood Brain MalformationsFaculty VI‐School of Medicine and Health SciencesUniversity of OldenburgOldenburgGermany
- Human GeneticsFaculty VI‐School of Medicine and Health SciencesUniversity of OldenburgOldenburgGermany
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Velíšek L, Velíšková J. Modeling epileptic spasms during infancy: Are we heading for the treatment yet? Pharmacol Ther 2020; 212:107578. [PMID: 32417271 PMCID: PMC7299814 DOI: 10.1016/j.pharmthera.2020.107578] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 05/07/2020] [Indexed: 12/22/2022]
Abstract
Infantile spasms (IS or epileptic spasms during infancy) were first described by Dr. William James West (aka West syndrome) in his own son in 1841. While rare by definition (occurring in 1 per 3200-3400 live births), IS represent a major social and treatment burden. The etiology of IS varies - there are many (>200) different known pathologies resulting in IS and still in about one third of cases there is no obvious reason. With the advancement of genetic analysis, role of certain genes (such as ARX or CDKL5 and others) in IS appears to be important. Current treatment strategies with incomplete efficacy and serious potential adverse effects include adrenocorticotropin (ACTH), corticosteroids (prednisone, prednisolone) and vigabatrin, more recently also a combination of hormones and vigabatrin. Second line treatments include pyridoxine (vitamin B6) and ketogenic diet. Additional treatment approaches use rapamycin, cannabidiol, valproic acid and other anti-seizure medications. Efficacy of these second line medications is variable but usually inferior to hormonal treatments and vigabatrin. Thus, new and effective models of this devastating condition are required for the search of additional treatment options as well as for better understanding the mechanisms of IS. Currently, eight models of IS are reviewed along with the ideas and mechanisms behind these models, drugs tested using the models and their efficacy and usefulness. Etiological variety of IS is somewhat reflected in the variety of the models. However, it seems that for finding precise personalized approaches, this variety is necessary as there is no "one-size-fits-all" approach possible for both IS in particular and epilepsy in general.
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Affiliation(s)
- Libor Velíšek
- Departments of Cell Biology & Anatomy, New York Medical College, Valhalla, NY, USA; Departments of Pediatrics, New York Medical College, Valhalla, NY, USA; Departments of Neurology, New York Medical College, Valhalla, NY, USA.
| | - Jana Velíšková
- Departments of Cell Biology & Anatomy, New York Medical College, Valhalla, NY, USA; Departments of Neurology, New York Medical College, Valhalla, NY, USA; Departments of Obstetrics & Gynecology, New York Medical College, Valhalla, NY, USA
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Sanchis-Juan A, Hasenahuer MA, Baker JA, McTague A, Barwick K, Kurian MA, Duarte ST, Carss KJ, Thornton J, Raymond FL. Structural analysis of pathogenic missense mutations in GABRA2 and identification of a novel de novo variant in the desensitization gate. Mol Genet Genomic Med 2020; 8:e1106. [PMID: 32347641 PMCID: PMC7336760 DOI: 10.1002/mgg3.1106] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 11/29/2019] [Accepted: 12/10/2019] [Indexed: 12/19/2022] Open
Abstract
Background Cys‐loop receptors control neuronal excitability in the brain and their dysfunction results in numerous neurological disorders. Recently, six missense variants in GABRA2, a member of this family, have been associated with early infantile epileptic encephalopathy (EIEE). We identified a novel de novo missense variant in GABRA2 in a patient with EIEE and performed protein structural analysis of the seven variants. Methods The novel variant was identified by trio whole‐genome sequencing. We performed protein structural analysis of the seven variants, and compared them to previously reported pathogenic mutations at equivalent positions in other Cys‐loop receptors. Additionally, we studied the distribution of disease‐associated variants in the transmembrane helices of these proteins. Results The seven variants are in the transmembrane domain, either close to the desensitization gate, the activation gate, or in inter‐subunit interfaces. Six of them have pathogenic mutations at equivalent positions in other Cys‐loop receptors, emphasizing the importance of these residues. Also, pathogenic mutations are more common in the pore‐lining helix, consistent with this region being highly constrained for variation in control populations. Conclusion Our study reports a novel pathogenic variant in GABRA2, characterizes the regions where pathogenic mutations are in the transmembrane helices, and underscores the value of considering sequence, evolutionary, and structural information as a strategy for variant interpretation of novel missense mutations.
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Affiliation(s)
- Alba Sanchis-Juan
- Department of Haematology, University of Cambridge, NHS Blood and Transplant Centre, Cambridge, UK.,NIHR BioResource, Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, UK
| | - Marcia A Hasenahuer
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK.,Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - James A Baker
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Amy McTague
- Developmental Neurosciences, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Katy Barwick
- Developmental Neurosciences, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Manju A Kurian
- Developmental Neurosciences, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Sofia T Duarte
- Hospital Dona Estefânia, Centro Hospitalar de Lisboa Central, Lisbon, Portugal
| | | | - Keren J Carss
- Department of Haematology, University of Cambridge, NHS Blood and Transplant Centre, Cambridge, UK.,NIHR BioResource, Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, UK
| | - Janet Thornton
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - F Lucy Raymond
- NIHR BioResource, Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, UK.,Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
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Reyes-Nava NG, Yu HC, Coughlin CR, Shaikh TH, Quintana AM. Abnormal expression of GABA A receptor subunits and hypomotility upon loss of gabra1 in zebrafish. Biol Open 2020; 9:bio051367. [PMID: 32205311 PMCID: PMC7197724 DOI: 10.1242/bio.051367] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 03/16/2020] [Indexed: 12/31/2022] Open
Abstract
We used whole-exome sequencing (WES) to determine the genetic etiology of a patient with a multi-system disorder characterized by a seizure phenotype. WES identified a heterozygous de novo missense mutation in the GABRA1 gene (c.875C>T). GABRA1 encodes the alpha subunit of the gamma-aminobutyric acid receptor A (GABAAR). The GABAAR is a ligand gated ion channel that mediates the fast inhibitory signals of the nervous system, and mutations in the subunits that compose the GABAAR have been previously associated with human disease. To understand the mechanisms by which GABRA1 regulates brain development, we developed a zebrafish model of gabra1 deficiency. gabra1 expression is restricted to the nervous system and behavioral analysis of morpholino injected larvae suggests that the knockdown of gabra1 results in hypoactivity and defects in the expression of other subunits of the GABAAR. Expression of the human GABRA1 protein in morphants partially restored the hypomotility phenotype. In contrast, the expression of the c.875C>T variant did not restore these behavioral deficits. Collectively, these results represent a functional approach to understand the mechanisms by which loss-of-function alleles cause disease.
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Affiliation(s)
- Nayeli G Reyes-Nava
- Department of Biological Sciences, Border Biomedical Research Center, University of Texas El Paso, El Paso, TX 79968, USA
| | - Hung-Chun Yu
- Department of Pediatrics, Section of Genetics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Curtis R Coughlin
- Department of Pediatrics, Section of Genetics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Tamim H Shaikh
- Department of Pediatrics, Section of Genetics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Anita M Quintana
- Department of Biological Sciences, Border Biomedical Research Center, University of Texas El Paso, El Paso, TX 79968, USA
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Lee S, Kim SH, Kim B, Lee ST, Choi JR, Kim HD, Lee JS, Kang HC. Genetic diagnosis and clinical characteristics by etiological classification in early-onset epileptic encephalopathy with burst suppression pattern. Epilepsy Res 2020; 163:106323. [PMID: 32247221 DOI: 10.1016/j.eplepsyres.2020.106323] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 03/01/2020] [Accepted: 03/20/2020] [Indexed: 01/17/2023]
Abstract
BACKGROUND Early-onset epileptic encephalopathies with burst suppression (EOEE-BS) are a group of neonatal epileptic syndromes characterized by intractable epilepsy and severe psychomotor delay with structural and metabolic factors accounting for major etiologies. However, recent advances in gene sequencing have identified that genetic factors might also play a significant role in the development of EOEE-BS. Herein, we used various genetic tests to identify pathogenic genetic variants in EOEE-BS irrespective of structural malformations and analyzed the clinical features associated with each different etiology. METHODS A total of 48 patients with EOEE-BS were included. Except for patients with severe hypoxic damage, patients with structural malformations were included in our patient cohort. Clinical features of the patients were reviewed, and etiological diagnoses were made based on several genetic tests, metabolic studies, and radiological findings. RESULT A genetic diagnosis was made in 31 (64.6 %) patients, with the most commonly diagnosed gene being STXBP1 (n = 13, 27.1 %), followed by KCNQ2 (n = 5, 10.4 %), SCN2A (n = 5, 10.4 %), DEPDC5 (n = 3, 6.3 %), CASK (n = 1, 2.1 %), CDKL5 (n = 1, 2.1 %), GNAO1 (n = 1, 2.1 %), SLC6A8 (n = 1, 2.1 %), and LIS1 deletion (n = 1, 2.1 %). Other than the classification of epilepsy syndrome, no clinical features were associated with the genetically diagnosed group. Among eight patients with structural malformations, genetic diagnosis was achieved in five (62.5 %), and those patients had pathogenic mutations in DEPDC5 and CASK or LIS1 deletion, indicating the significance of gene sequencing irrespective of structural abnormalities. Treatment responses to a variety of medications and the ketogenic diet differed by etiology, and surgical resection proved to be effective in patients with cortical dysplasia. CONCLUSION Genetic etiologies are an important factor in EOEE-BS irrespective of structural malformations and the treatment options may differ by etiology.
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Affiliation(s)
- Sangbo Lee
- Division of Pediatric Neurology, Epilepsy Research Institute, Severance Children's Hospital, Department of Pediatrics, Yonsei University College of Medicine, Yonsei-ro 50-1, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Se Hee Kim
- Division of Pediatric Neurology, Epilepsy Research Institute, Severance Children's Hospital, Department of Pediatrics, Yonsei University College of Medicine, Yonsei-ro 50-1, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Borahm Kim
- Department of Laboratory Medicine, Severance Hospital, Yonsei University College of Medicine, Yonsei-ro 50-1, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Seung-Tae Lee
- Department of Laboratory Medicine, Severance Hospital, Yonsei University College of Medicine, Yonsei-ro 50-1, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Jong Rak Choi
- Department of Laboratory Medicine, Severance Hospital, Yonsei University College of Medicine, Yonsei-ro 50-1, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Heung Dong Kim
- Division of Pediatric Neurology, Epilepsy Research Institute, Severance Children's Hospital, Department of Pediatrics, Yonsei University College of Medicine, Yonsei-ro 50-1, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Joon Soo Lee
- Division of Pediatric Neurology, Epilepsy Research Institute, Severance Children's Hospital, Department of Pediatrics, Yonsei University College of Medicine, Yonsei-ro 50-1, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Hoon-Chul Kang
- Division of Pediatric Neurology, Epilepsy Research Institute, Severance Children's Hospital, Department of Pediatrics, Yonsei University College of Medicine, Yonsei-ro 50-1, Seodaemun-gu, Seoul, 03722, Republic of Korea.
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Papandreou A, Danti FR, Spaull R, Leuzzi V, Mctague A, Kurian MA. The expanding spectrum of movement disorders in genetic epilepsies. Dev Med Child Neurol 2020; 62:178-191. [PMID: 31784983 DOI: 10.1111/dmcn.14407] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/01/2019] [Indexed: 12/27/2022]
Abstract
An ever-increasing number of neurogenetic conditions presenting with both epilepsy and atypical movements are now recognized. These disorders within the 'genetic epilepsy-dyskinesia' spectrum are clinically and genetically heterogeneous. Increased clinical awareness is therefore necessary for a rational diagnostic approach. Furthermore, careful interpretation of genetic results is key to establishing the correct diagnosis and initiating disease-specific management strategies in a timely fashion. In this review we describe the spectrum of movement disorders associated with genetically determined epilepsies. We also propose diagnostic strategies and putative pathogenic mechanisms causing these complex syndromes associated with both seizures and atypical motor control. WHAT THIS PAPER ADDS: Implicated genes encode proteins with very diverse functions. Pathophysiological mechanisms by which epilepsy and movement disorder phenotypes manifest are often not clear. Early diagnosis of treatable disorders is essential and next generation sequencing may be required.
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Affiliation(s)
- Apostolos Papandreou
- Molecular Neurosciences, Developmental Neurosciences Programme, UCL Great Ormond Street Institute of Child Health, London, UK
- Department of Neurology, Great Ormond Street Hospital, London, UK
| | - Federica Rachele Danti
- Molecular Neurosciences, Developmental Neurosciences Programme, UCL Great Ormond Street Institute of Child Health, London, UK
- Department of Human Neuroscience, Unit of Child Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy
| | - Robert Spaull
- Department of Paediatric Neurology, Bristol Royal Hospital for Children, Bristol, UK
- Bristol Medical School, University of Bristol, Bristol, UK
| | - Vincenzo Leuzzi
- Department of Human Neuroscience, Unit of Child Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy
| | - Amy Mctague
- Molecular Neurosciences, Developmental Neurosciences Programme, UCL Great Ormond Street Institute of Child Health, London, UK
- Department of Neurology, Great Ormond Street Hospital, London, UK
| | - Manju A Kurian
- Molecular Neurosciences, Developmental Neurosciences Programme, UCL Great Ormond Street Institute of Child Health, London, UK
- Department of Neurology, Great Ormond Street Hospital, London, UK
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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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Gataullina S, Bienvenu T, Nabbout R, Huberfeld G, Dulac O. Gene mutations in paediatric epilepsies cause NMDA-pathy, and phasic and tonic GABA-pathy. Dev Med Child Neurol 2019; 61:891-898. [PMID: 30680721 DOI: 10.1111/dmcn.14152] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/20/2018] [Indexed: 12/28/2022]
Abstract
The aim of this study was to disentangle mechanisms of epileptogenesis in monogenic epilepsies in children. We reviewed paediatric monogenic epilepsies excluding brain malformation or an inborn error of metabolism, but including the gene function whether there is loss-of-function or gain-of-function, age at gene expression when available, and associated epilepsy syndrome. Genes for which at least five patients with similar epilepsy phenotype had been reported were selected. Three mechanisms are shared by most monogenic epilepsies: (1) excess of N-methyl-d-aspartate (NMDA) transmission activation (NMDA-pathies); (2) abnormal gamma-aminobutyric acid (GABA) transmission with reduced inhibition (phasic GABA-pathies); and (3) tonic activation of extrasynaptic GABAA receptors by extracellular GABA (tonic GABA-pathies). NMDA-pathies comprise early epileptic encephalopathy with suppression-burst, neonatal/infantile benign seizures, West and Lennox-Gastaut syndromes, and encephalopathy with continuous spike waves in slow sleep, thus brief seizures with major interictal spiking. Phasic GABA-pathies comprise mostly generalized epilepsy with febrile seizures plus and Dravet syndrome, thus long-lasting seizures with mild interictal spiking. Tonic GABA-pathies cause epilepsy with myoclonic-atonic seizures and Angelman syndrome, thus major high-amplitude slow-wave activity. This pathophysiological approach to monogenic epilepsies provides diagnostic clues and helps to guide treatment strategy. WHAT THIS PAPER ADDS: In paediatric monogenic epilepsies, electroclinical patterns point to three main mechanisms: NMDA-pathies, and phasic and tonic GABA-pathies. Antiepileptic treatment choice could be guided by each of these mechanisms.
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Affiliation(s)
- Svetlana Gataullina
- Service d' Explorations Fonctionnelles multidisciplinaires Hôpital Antoine Béclère, AP-HP, Clamart, France.,Inserm U1129, Infantile Epilepsies and Brain Plasticity, CEA Gif/Yvette, Pôle de Recherche et d'Enseignement Supérieur Sorbonne Paris Cité, Paris Descartes University, Paris, France.,Service de Pédiatrie, Centre Hospitalier Intercommunal, Montreuil, France
| | - Thierry Bienvenu
- Biochemistry and Molecular Genetics Laboratory, Hôpital Cochin, Paris Centre University Group, Paris, France.,Institut Cochin, Inserm U1016, Paris Descartes University, Paris, France
| | - Rima Nabbout
- Centre de Reference Épilepsies Rares, Necker-Enfants Malades Hospital, Paris, France
| | - Gilles Huberfeld
- Inserm U1129, Infantile Epilepsies and Brain Plasticity, CEA Gif/Yvette, Pôle de Recherche et d'Enseignement Supérieur Sorbonne Paris Cité, Paris Descartes University, Paris, France.,Clinical Neurophysiology Department, Pitié-Salpêtrière Hospital, Sorbone University, AP-HP, Paris, France.,Neuroglial Interactions in Cerebral Pathophysiology, Center for Interdisciplinary Research in Biology, Collège de France, CNR UMR 7421, Inserm U1050, Labex MemolifePSL Research University, Paris, France
| | - Olivier Dulac
- Inserm U1129, Infantile Epilepsies and Brain Plasticity, CEA Gif/Yvette, Pôle de Recherche et d'Enseignement Supérieur Sorbonne Paris Cité, Paris Descartes University, Paris, France.,AdPueriVitam, Antony, France
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Hernandez CC, XiangWei W, Hu N, Shen D, Shen W, Lagrange AH, Zhang Y, Dai L, Ding C, Sun Z, Hu J, Zhu H, Jiang Y, Macdonald RL. Altered inhibitory synapses in de novo GABRA5 and GABRA1 mutations associated with early onset epileptic encephalopathies. Brain 2019; 142:1938-1954. [PMID: 31056671 PMCID: PMC6598634 DOI: 10.1093/brain/awz123] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 02/20/2019] [Accepted: 03/07/2019] [Indexed: 12/22/2022] Open
Abstract
We performed next generation sequencing on 1696 patients with epilepsy and intellectual disability using a gene panel with 480 epilepsy-related genes including all GABAA receptor subunit genes (GABRs), and we identified six de novo GABR mutations, two novel GABRA5 mutations (c.880G>T, p.V294F and c.1238C>T, p.S413F), two novel GABRA1 mutations (c.778C>T, p.P260S and c.887T>C, p.L296S/c.944G>T, p.W315L) and two known GABRA1 mutations (c.335G>A, p.R112Q and c.343A>G, p.N115D) in six patients with intractable early onset epileptic encephalopathy. The α5(V294F and S413F) and α1(P260S and L296S/W315L) subunit residue substitutions were all in transmembrane domains, while the α1(R112Q and N115R) subunit residue substitutions were in the N-terminal GABA binding domain. Using multidisciplinary approaches, we compared effects of mutant GABAA receptor α5 and α1 subunits on the properties of recombinant α5β3γ2 and α1β3γ2 GABAA receptors in both neuronal and non-neuronal cells and characterized their effects on receptor clustering, biogenesis and channel function. GABAA receptors containing mutant α5 and α1 subunits all had reduced cell surface and total cell expression with altered endoplasmic reticulum processing, impaired synaptic clustering, reduced GABAA receptor function and decreased GABA binding potency. Our study identified GABRA5 as a causative gene for early onset epileptic encephalopathy and expands the mutant GABRA1 phenotypic spectrum, supporting growing evidence that defects in GABAergic neurotransmission contribute to early onset epileptic encephalopathy phenotypes.
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Affiliation(s)
- Ciria C Hernandez
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Wenshu XiangWei
- Department of Pediatrics and Pediatric Epilepsy Center, Peking University First Hospital, Beijing, China
- Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing, China
| | - Ningning Hu
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Dingding Shen
- The Graduate Program of Neuroscience, Vanderbilt University, Nashville, TN, USA
- Department of Neurology, Rui Jin Hospital, Shanghai Jiao Tong University, School of Medicine. Shanghai, China
| | - Wangzhen Shen
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Andre H Lagrange
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Pharmacology and Molecular Physiology and Biophysics, Vanderbilt University, and the Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN, USA
| | - Yujia Zhang
- Department of Neurology, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing, China
| | - Lifang Dai
- Department of Neurology, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing, China
| | - Changhong Ding
- Department of Neurology, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing, China
| | - Zhaohui Sun
- Epilepsy center of Yuquan Hospital, Tsinghua University, Beijing, China
| | - Jiasheng Hu
- Department of Neurology, Wuhan Children’s Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hongmin Zhu
- Department of Neurology, Wuhan Children’s Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yuwu Jiang
- Department of Pediatrics and Pediatric Epilepsy Center, Peking University First Hospital, Beijing, China
- Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing, China
| | - Robert L Macdonald
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
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40
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Zorio DAR, Monsma S, Sanes DH, Golding NL, Rubel EW, Wang Y. De novo sequencing and initial annotation of the Mongolian gerbil (Meriones unguiculatus) genome. Genomics 2019; 111:441-449. [PMID: 29526484 PMCID: PMC6129228 DOI: 10.1016/j.ygeno.2018.03.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 02/26/2018] [Accepted: 03/01/2018] [Indexed: 12/28/2022]
Abstract
The Mongolian gerbil (Meriones unguiculatus) is a member of the rodent family that displays several features not found in mice or rats, including sensory specializations and social patterns more similar to those in humans. These features have made gerbils a valuable animal for research studies of auditory and visual processing, brain development, learning and memory, and neurological disorders. Here, we report the whole gerbil annotated genome sequence, and identify important similarities and differences to the human and mouse genomes. We further analyze the chromosomal structure of eight genes with high relevance for controlling neural signaling and demonstrate a high degree of homology between these genes in mouse and gerbil. This homology increases the likelihood that individual genes can be rapidly identified in gerbil and used for genetic manipulations. The availability of the gerbil genome provides a foundation for advancing our knowledge towards understanding evolution, behavior and neural function in mammals. ACCESSION NUMBER: The Whole Genome Shotgun sequence data from this project has been deposited at DDBJ/ENA/GenBank under the accession NHTI00000000. The version described in this paper is version NHTI01000000. The fragment reads, and mate pair reads have been deposited in the Sequence Read Archive under BioSample accession SAMN06897401.
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Affiliation(s)
- Diego A R Zorio
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL, USA.
| | | | - Dan H Sanes
- Center for Neural Science, New York University, New York, NY, USA
| | - Nace L Golding
- University of Texas at Austin, Department of Neuroscience, Center for Learning and Memory, Austin, TX, USA
| | - Edwin W Rubel
- Virginia Merrill Bloedel Hearing Research Center, Department of Otolaryngology-Head and Neck Surgery, University of Washington, Seattle, WA, USA
| | - Yuan Wang
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL, USA; Program in Neuroscience, Florida State University, Tallahassee, FL, USA.
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42
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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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Absalom NL, Ahring PK, Liao VW, Balle T, Jiang T, Anderson LL, Arnold JC, McGregor IS, Bowen MT, Chebib M. Functional genomics of epilepsy-associated mutations in the GABA A receptor subunits reveal that one mutation impairs function and two are catastrophic. J Biol Chem 2019; 294:6157-6171. [PMID: 30728247 DOI: 10.1074/jbc.ra118.005697] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 01/30/2019] [Indexed: 12/29/2022] Open
Abstract
A number of epilepsy-causing mutations have recently been identified in the genes of the α1, β3, and γ2 subunits comprising the γ-aminobutyric acid type A (GABAA) receptor. These mutations are typically dominant, and in certain cases, such as the α1 and β3 subunits, they may lead to a mix of receptors at the cell surface that contain no mutant subunits, a single mutated subunit, or two mutated subunits. To determine the effects of mutations in a single subunit or in two subunits on receptor activation, we created a concatenated protein assembly that links all five subunits of the α1β3γ2 receptor and expresses them in the correct orientation. We created nine separate receptor variants with a single-mutant subunit and four receptors containing two subunits of the γ2R323Q, β3D120N, β3T157M, β3Y302C, and β3S254F epilepsy-causing mutations. We found that the singly mutated γ2R323Q subunit impairs GABA activation of the receptor by reducing GABA potency. A single β3D120N, β3T157M, or β3Y302C mutation also substantially impaired receptor activation, and two copies of these mutants within a receptor were catastrophic. Of note, an effect of the β3S254F mutation on GABA potency depended on the location of this mutant subunit within the receptor, possibly because of the membrane environment surrounding the transmembrane region of the receptor. Our results highlight that precise functional genomic analyses of GABAA receptor mutations using concatenated constructs can identify receptors with an intermediate phenotype that contribute to epileptic phenotypes and that are potential drug targets for precision medicine approaches.
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Affiliation(s)
- Nathan L Absalom
- From the Brain and Mind Centre, University of Sydney, 94 Mallett Street, Camperdown, New South Wales 2050, Australia; School of Pharmacy, University of Sydney, Camperdown, New South Wales 2006, Australia
| | - Philip K Ahring
- From the Brain and Mind Centre, University of Sydney, 94 Mallett Street, Camperdown, New South Wales 2050, Australia; School of Pharmacy, University of Sydney, Camperdown, New South Wales 2006, Australia
| | - Vivian W Liao
- From the Brain and Mind Centre, University of Sydney, 94 Mallett Street, Camperdown, New South Wales 2050, Australia; School of Pharmacy, University of Sydney, Camperdown, New South Wales 2006, Australia
| | - Thomas Balle
- From the Brain and Mind Centre, University of Sydney, 94 Mallett Street, Camperdown, New South Wales 2050, Australia; School of Pharmacy, University of Sydney, Camperdown, New South Wales 2006, Australia
| | - Tian Jiang
- From the Brain and Mind Centre, University of Sydney, 94 Mallett Street, Camperdown, New South Wales 2050, Australia; School of Pharmacy, University of Sydney, Camperdown, New South Wales 2006, Australia
| | - Lyndsey L Anderson
- From the Brain and Mind Centre, University of Sydney, 94 Mallett Street, Camperdown, New South Wales 2050, Australia; Discipline of Pharmacology, Faculty of Medicine and Health, University of Sydney, Camperdown, New South Wales 2006, Australia; Lambert Initiative for Cannabinoid Therapeutics, University of Sydney, 94 Mallett Street, Camperdown, New South Wales 2050, Australia
| | - Jonathon C Arnold
- From the Brain and Mind Centre, University of Sydney, 94 Mallett Street, Camperdown, New South Wales 2050, Australia; Discipline of Pharmacology, Faculty of Medicine and Health, University of Sydney, Camperdown, New South Wales 2006, Australia; Lambert Initiative for Cannabinoid Therapeutics, University of Sydney, 94 Mallett Street, Camperdown, New South Wales 2050, Australia
| | - Iain S McGregor
- From the Brain and Mind Centre, University of Sydney, 94 Mallett Street, Camperdown, New South Wales 2050, Australia; Lambert Initiative for Cannabinoid Therapeutics, University of Sydney, 94 Mallett Street, Camperdown, New South Wales 2050, Australia; the School of Psychology, Faculty of Science, University of Sydney, Camperdown, New South Wales 2006, Australia
| | - Michael T Bowen
- From the Brain and Mind Centre, University of Sydney, 94 Mallett Street, Camperdown, New South Wales 2050, Australia; Lambert Initiative for Cannabinoid Therapeutics, University of Sydney, 94 Mallett Street, Camperdown, New South Wales 2050, Australia; the School of Psychology, Faculty of Science, University of Sydney, Camperdown, New South Wales 2006, Australia
| | - Mary Chebib
- From the Brain and Mind Centre, University of Sydney, 94 Mallett Street, Camperdown, New South Wales 2050, Australia; School of Pharmacy, University of Sydney, Camperdown, New South Wales 2006, Australia.
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Abstract
Idiopathic generalized epilepsies (IGE) are characterized by normal background EEG activity and generalized interictal spike-and-wave discharges in the absence of any evidence of brain lesion. Absence epilepsies are the prototypes of IGEs. In childhood and juvenile absence epilepsies, by definition, all patients manifest absence seizures associated with an EEG pattern of generalized spike-wave (GSW) discharges. In juvenile myoclonic epilepsy, myoclonic jerks, usually affecting shoulders and arms bilaterally and appearing upon awakening, are the most characteristic clinical feature. Myoclonic jerks are accompanied on the EEG by generalized spike/polyspike-and-wave (GSW, GPWS) complexes at 3.5-6Hz. Idiopathic generalized epilepsy with generalized tonic-clonic seizures only is a broad and nonspecific category including all patients with generalized tonic-clonic seizures and an interictal EEG pattern of GSW discharges. Despite the strong heritability and the recent advances in genetic technology, the genetic basis of IGEs remains largely elusive and only in a small minority of patients with classic IGE phenotypes is a monogenic cause identified. Early myoclonic encephalopathy (EME), early infantile encephalopathy with suppression bursts, West syndrome, and Lennox-Gastaut syndrome, once classified among the generalized epilepsies, are now considered to be epileptic encephalopathies. Among them, only Lennox-Gastaut syndrome is characterized by prominent generalized clinical and EEG features.
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Affiliation(s)
- Renzo Guerrini
- Neuroscience Department, Children's Hospital A. Meyer-University of Florence, Florence, Italy.
| | - Carla Marini
- Neuroscience Department, Children's Hospital A. Meyer-University of Florence, Florence, Italy
| | - Carmen Barba
- Neuroscience Department, Children's Hospital A. Meyer-University of Florence, Florence, Italy
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Fu YL, Han DY, Wang YJ, Di XJ, Yu HB, Mu TW. Remodeling the endoplasmic reticulum proteostasis network restores proteostasis of pathogenic GABAA receptors. PLoS One 2018; 13:e0207948. [PMID: 30481215 PMCID: PMC6258528 DOI: 10.1371/journal.pone.0207948] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 11/08/2018] [Indexed: 01/12/2023] Open
Abstract
Biogenesis of membrane proteins is controlled by the protein homeostasis (proteostasis) network. We have been focusing on protein quality control of γ-aminobutyric acid type A (GABAA) receptors, the major inhibitory neurotransmitter-gated ion channels in mammalian central nervous system. Proteostasis deficiency in GABAA receptors causes loss of their surface expression and thus function on the plasma membrane, leading to epilepsy and other neurological diseases. One well-characterized example is the A322D mutation in the α1 subunit that causes its extensive misfolding and expedited degradation in the endoplasmic reticulum (ER), resulting in autosomal dominant juvenile myoclonic epilepsy. We aimed to correct misfolding of the α1(A322D) subunits in the ER as an approach to restore their functional surface expression. Here, we showed that application of BIX, a specific, potent ER resident HSP70 family protein BiP activator, significantly increases the surface expression of the mutant receptors in human HEK293T cells and neuronal SH-SY5Y cells. BIX attenuates the degradation of α1(A322D) and enhances their forward trafficking and function. Furthermore, because BiP is one major target of the two unfolded protein response (UPR) pathways: ATF6 and IRE1, we continued to demonstrate that modest activations of the ATF6 pathway and IRE1 pathway genetically enhance the plasma membrane trafficking of the α1(A322D) protein in HEK293T cells. Our results underlie the potential of regulating the ER proteostasis network to correct loss-of-function protein conformational diseases.
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Affiliation(s)
- Yan-Lin Fu
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
| | - Dong-Yun Han
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
| | - Ya-Juan Wang
- Center for Proteomics and Bioinformatics and Department of Epidemiology and Biostatistics, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
| | - Xiao-Jing Di
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
| | - Hai-Bo Yu
- School of Chemistry and Molecular Bioscience & Molecular Horizons, University of Wollongong, Wollongong, Australia
| | - Ting-Wei Mu
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
- * E-mail:
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Structural basis of neurosteroid anesthetic action on GABA A receptors. Nat Commun 2018; 9:3972. [PMID: 30266951 PMCID: PMC6162318 DOI: 10.1038/s41467-018-06361-4] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 08/28/2018] [Indexed: 12/05/2022] Open
Abstract
Type A γ-aminobutyric acid receptors (GABAARs) are inhibitory pentameric ligand-gated ion channels in the brain. Many anesthetics and neurosteroids act through binding to the GABAAR transmembrane domain (TMD), but the structural basis of their actions is not well understood and no resting-state GABAAR structure has been determined. Here, we report crystal structures of apo and the neurosteroid anesthetic alphaxalone-bound desensitized chimeric α1GABAAR (ELIC-α1GABAAR). The chimera retains the functional and pharmacological properties of GABAARs, including potentiation, activation and desensitization by alphaxalone. The apo-state structure reveals an unconventional activation gate at the intracellular end of the pore. The desensitized structure illustrates molecular determinants for alphaxalone binding to an inter-subunit TMD site. These structures suggest a plausible signaling pathway from alphaxalone binding at the bottom of the TMD to the channel gate in the pore-lining TM2 through the TM1–TM2 linker. The study provides a framework to discover new GABAAR modulators with therapeutic potential. The anesthetic alphaxalone binds γ-aminobutyric acid type A receptors (GABAARs) that play an important role in regulating sensory processes. Here the authors present the structures of a α1GABAAR chimera in the resting state and in an alphaxalone-bound desensitized state, which might facilitate the development of new GABAAR modulators.
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Butler KM, Moody OA, Schuler E, Coryell J, Alexander JJ, Jenkins A, Escayg A. De novo variants in GABRA2 and GABRA5 alter receptor function and contribute to early-onset epilepsy. Brain 2018; 141:2392-2405. [PMID: 29961870 PMCID: PMC6061692 DOI: 10.1093/brain/awy171] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 04/02/2018] [Accepted: 05/04/2018] [Indexed: 01/19/2023] Open
Abstract
GABAA receptors are ligand-gated anion channels that are important regulators of neuronal inhibition. Mutations in several genes encoding receptor subunits have been identified in patients with various types of epilepsy, ranging from mild febrile seizures to severe epileptic encephalopathy. Using whole-genome sequencing, we identified a novel de novo missense variant in GABRA5 (c.880G > C, p.V294L) in a patient with severe early-onset epilepsy and developmental delay. Targeted resequencing of 279 additional epilepsy patients identified 19 rare variants from nine GABAA receptor genes, including a novel de novo missense variant in GABRA2 (c.875C > A, p.T292K) and a recurrent missense variant in GABRB3 (c.902C > T, p.P301L). Patients with the GABRA2 and GABRB3 variants also presented with severe epilepsy and developmental delay. We evaluated the effects of the GABRA5, GABRA2 and GABRB3 missense variants on receptor function using whole-cell patch-clamp recordings from human embryonic kidney 293T cells expressing appropriate α, β and γ subunits. The GABRA5 p.V294L variant produced receptors that were 10-times more sensitive to GABA but had reduced maximal GABA-evoked current due to increased receptor desensitization. The GABRA2 p.T292K variant reduced channel expression and produced mutant channels that were tonically open, even in the absence of GABA. Receptors containing the GABRB3 p.P301L variant were less sensitive to GABA and produced less GABA-evoked current. These results provide the first functional evidence that de novo variants in the GABRA5 and GABRA2 genes contribute to early-onset epilepsy and developmental delay, and demonstrate that epilepsy can result from reduced neuronal inhibition via a wide range of alterations in GABAA receptor function.
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Affiliation(s)
- Kameryn M Butler
- Department of Human Genetics, Emory University, Atlanta, Georgia, 30322, USA
- Genetics and Molecular Biology Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, Georgia, 30322, USA
| | - Olivia A Moody
- Departments of Anesthesiology and Pharmacology, Emory University, Atlanta, Georgia, 30322, USA
- Neuroscience Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, Georgia, 30322, USA
| | - Elisabeth Schuler
- Department for Pediatric Metabolic Medicine and Neurology, University Children’s Hospital, Heidelberg, 69120, Germany
| | - Jason Coryell
- Departments of Pediatrics and Neurology, School of Medicine, Oregon Health & Sciences University, Portland, Oregon, 97239, USA
| | - John J Alexander
- Department of Human Genetics, Emory University, Atlanta, Georgia, 30322, USA
- EGL Genetics, Tucker, Georgia, 30084, USA
| | - Andrew Jenkins
- Departments of Anesthesiology and Pharmacology, Emory University, Atlanta, Georgia, 30322, USA
| | - Andrew Escayg
- Department of Human Genetics, Emory University, Atlanta, Georgia, 30322, USA
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Abstract
Neonatal epilepsy genetics is a rapidly expanding field with recent technological advances in genomics leading to an expanding list of genetic disorders associated with neonatal-onset epilepsy. The genetic causes of neonatal epilepsy can be grouped into the following categories: (i) malformations of cortical development, (ii) genetic-metabolic, (iii) genetic-vascular, (iv) genetic-syndromic, and (v) genetic-cellular. Clinically, epilepsy in the neonate shows phenotypic overlap with pathogenic variants in unrelated genes causing similar clinical presentation (locus heterogeneity) and variants in the same gene leading to a wide clinical spectrum ranging from benign familial neonatal seizures to more severe epileptic encephalopathies (variable expressivity). We suggest a diagnostic approach to obtaining a genetic diagnosis with emphasis on clinical features such as electro-clinical phenotype and magnetic resonance imaging findings. Rapid identification of genetic disorders with targeted treatments should be a clinical priority. Achieving a genetic diagnosis can be challenging in a rapidly changing genetic landscape, but is increasingly possible.
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Orenstein N, Goldberg-Stern H, Straussberg R, Bazak L, Weisz Hubshman M, Kropach N, Gilad O, Scheuerman O, Dory Y, Kraus D, Tzur S, Magal N, Kilim Y, Shkalim Zemer V, Basel-Salmon L. A de novo GABRA2 missense mutation in severe early-onset epileptic encephalopathy with a choreiform movement disorder. Eur J Paediatr Neurol 2018; 22:516-524. [PMID: 29422393 DOI: 10.1016/j.ejpn.2017.12.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Revised: 12/16/2017] [Accepted: 12/22/2017] [Indexed: 01/13/2023]
Abstract
BACKGROUND Early-onset epileptic encephalopathy (EOEE) is a severe convulsive disorder with a poor developmental prognosis. Although it has been associated with mutations in a number of genes, the fact that there is a large proportion of patients who remain undiagnosed suggests that there are many more still-unknown genetic causes of EOEE. Achieving a genetic diagnosis is important for understanding the biological basis of the disease, with its implications for treatment and family planning. METHODS Whole-exome sequencing was performed in a family of Ashkenazi Jewish origin in which a male infant was diagnosed with EOEE. There was no family history of a similar neurologic disease. The patient had extreme hypotonia, neonatal hypothermia, choreiform movements, and vision impairment in addition to the convulsive disorder. RESULTS A de novo heterozygous missense mutation, c.1003A > C, p.Asn335His, was identified in a conserved domain of GABRA2. GABRA2 encodes the α2 subunit of the GABAA receptor. CONCLUSIONS In the context of previous reports of an association of de novo mutations in genes encoding different subunits of the GABAA receptor (GABRB1, GABRA1, GABRG2, GABRB3) with autosomal dominant epileptic disorders, we conclude that a de novo mutation in GABRA2 is likely to cause autosomal dominant EOEE accompanied by a movement disorder and vision impairment.
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Affiliation(s)
- Naama Orenstein
- Pediatric Genetics Clinic, Schneider Children's Medical Center of Israel, Petach Tikva 4920235, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel.
| | - Hadassa Goldberg-Stern
- Pediatric Genetics Clinic, Schneider Children's Medical Center of Israel, Petach Tikva 4920235, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel; Pediatric Epilepsy Unit, Neurological Institute, Schneider Children's Medical Center of Israel, Petach Tikva 4920235, Israel.
| | - Rachel Straussberg
- Pediatric Genetics Clinic, Schneider Children's Medical Center of Israel, Petach Tikva 4920235, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel; Neurogenetic Service, Neurological Institute, Schneider Children's Medical Center of Israel, Petach Tikva 4920235, Israel.
| | - Lily Bazak
- Raphael Recanati Genetics Institute, Rabin Medical Center- Beilinson Hospital, Petach Tikva 4941492, Israel; Mina and Everard Goodman Faculty of Life Science, Bar Ilan University, Ramat Gan 5290002, Israel; Felsenstein Medical Research Center, Rabin Medical Center, Petach Tikva 4941492, Israel.
| | - Monika Weisz Hubshman
- Pediatric Genetics Clinic, Schneider Children's Medical Center of Israel, Petach Tikva 4920235, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel; Raphael Recanati Genetics Institute, Rabin Medical Center- Beilinson Hospital, Petach Tikva 4941492, Israel; Felsenstein Medical Research Center, Rabin Medical Center, Petach Tikva 4941492, Israel.
| | - Nesia Kropach
- Pediatric Genetics Clinic, Schneider Children's Medical Center of Israel, Petach Tikva 4920235, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel.
| | - Oded Gilad
- Pediatric Genetics Clinic, Schneider Children's Medical Center of Israel, Petach Tikva 4920235, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel.
| | - Oded Scheuerman
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel; Department of Pediatrics B, Schneider Children's Medical Center of Israel, Petach Tikva 4920235, Israel.
| | - Yahav Dory
- Pediatric Genetics Clinic, Schneider Children's Medical Center of Israel, Petach Tikva 4920235, Israel.
| | - Dror Kraus
- Pediatric Genetics Clinic, Schneider Children's Medical Center of Israel, Petach Tikva 4920235, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel; Pediatric Epilepsy Unit, Neurological Institute, Schneider Children's Medical Center of Israel, Petach Tikva 4920235, Israel.
| | - Shay Tzur
- Mina and Everard Goodman Faculty of Life Science, Bar Ilan University, Ramat Gan 5290002, Israel; Laboratory of Molecular Medicine, Rambam Health Care Campus, Haifa 3109601, Israel; Genomic Research Department, Emedgene Technologies, Tel Aviv, Israel.
| | - Nurit Magal
- Raphael Recanati Genetics Institute, Rabin Medical Center- Beilinson Hospital, Petach Tikva 4941492, Israel; Felsenstein Medical Research Center, Rabin Medical Center, Petach Tikva 4941492, Israel.
| | - Yael Kilim
- Raphael Recanati Genetics Institute, Rabin Medical Center- Beilinson Hospital, Petach Tikva 4941492, Israel; Felsenstein Medical Research Center, Rabin Medical Center, Petach Tikva 4941492, Israel.
| | - Vered Shkalim Zemer
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel; Department of Hematology-Oncology, Schneider Children's Medical Center of Israel, Petach Tikva 4920235, Israel.
| | - Lina Basel-Salmon
- Pediatric Genetics Clinic, Schneider Children's Medical Center of Israel, Petach Tikva 4920235, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel; Raphael Recanati Genetics Institute, Rabin Medical Center- Beilinson Hospital, Petach Tikva 4941492, Israel; Felsenstein Medical Research Center, Rabin Medical Center, Petach Tikva 4941492, Israel.
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Rosch R, Baldeweg T, Moeller F, Baier G. Network dynamics in the healthy and epileptic developing brain. Netw Neurosci 2018; 2:41-59. [PMID: 29911676 PMCID: PMC5989999 DOI: 10.1162/netn_a_00026] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 09/09/2017] [Indexed: 12/29/2022] Open
Abstract
Electroencephalography (EEG) allows recording of cortical activity at high temporal resolution. EEG recordings can be summarized along different dimensions using network-level quantitative measures, such as channel-to-channel correlation, or band power distributions across channels. These reveal network patterns that unfold over a range of different timescales and can be tracked dynamically. Here we describe the dynamics of network state transitions in EEG recordings of spontaneous brain activity in normally developing infants and infants with severe early infantile epileptic encephalopathies (n = 8, age: 1–8 months). We describe differences in measures of EEG dynamics derived from band power, and correlation-based summaries of network-wide brain activity. We further show that EEGs from different patient groups and controls may be distinguishable on a small set of the novel quantitative measures introduced here, which describe dynamic network state switching. Quantitative measures related to the sharpness of switching from one correlation pattern to another show the largest differences between groups. These findings reveal that the early epileptic encephalopathies are associated with characteristic dynamic features at the network level. Quantitative network-based analyses like the one presented here may in the future inform the clinical use of quantitative EEG for diagnosis.
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Affiliation(s)
- Richard Rosch
- Wellcome Trust Centre for Neuroimaging, University College London, United Kingdom.,Developmental Neurosciences Programme, UCL Great Ormond Street Institute of Child Health, University College London, United Kingdom
| | - Torsten Baldeweg
- Developmental Neurosciences Programme, UCL Great Ormond Street Institute of Child Health, University College London, United Kingdom
| | - Friederike Moeller
- Department of Clinical Neurophysiology, Great Ormond Street Hospital, London, United Kingdom
| | - Gerold Baier
- Cell and Developmental Biology, University College London, United Kingdom
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