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Wei X, Campagna JJ, Jagodzinska B, Wi D, Cohn W, Lee JT, Zhu C, Huang CS, Molnár L, Houser CR, John V, Mody I. A therapeutic small molecule enhances γ-oscillations and improves cognition/memory in Alzheimer's disease model mice. Proc Natl Acad Sci U S A 2024; 121:e2400420121. [PMID: 39106304 PMCID: PMC11331084 DOI: 10.1073/pnas.2400420121] [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: 01/08/2024] [Accepted: 07/08/2024] [Indexed: 08/09/2024] Open
Abstract
Brain rhythms provide the timing for recruitment of brain activity required for linking together neuronal ensembles engaged in specific tasks. The γ-oscillations (30 to 120 Hz) orchestrate neuronal circuits underlying cognitive processes and working memory. These oscillations are reduced in numerous neurological and psychiatric disorders, including early cognitive decline in Alzheimer's disease (AD). Here, we report on a potent brain-permeable small molecule, DDL-920 that increases γ-oscillations and improves cognition/memory in a mouse model of AD, thus showing promise as a class of therapeutics for AD. We employed anatomical, in vitro and in vivo electrophysiological, and behavioral methods to examine the effects of our lead therapeutic candidate small molecule. As a novel in central nervous system pharmacotherapy, our lead molecule acts as a potent, efficacious, and selective negative allosteric modulator of the γ-aminobutyric acid type A receptors most likely assembled from α1β2δ subunits. These receptors, identified through anatomical and pharmacological means, underlie the tonic inhibition of parvalbumin (PV) expressing interneurons (PV+INs) critically involved in the generation of γ-oscillations. When orally administered twice daily for 2 wk, DDL-920 restored the cognitive/memory impairments of 3- to 4-mo-old AD model mice as measured by their performance in the Barnes maze. Our approach is unique as it is meant to enhance cognitive performance and working memory in a state-dependent manner by engaging and amplifying the brain's endogenous γ-oscillations through enhancing the function of PV+INs.
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Affiliation(s)
- Xiaofei Wei
- Department of Neurology, The David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA90095
- Department of Neurosurgery, The David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA90095
| | - Jesus J. Campagna
- Department of Neurology, Drug Development Laboratory, Mary S. Easton Center for Alzheimer’s Disease Research and Care, The David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA90095
| | - Barbara Jagodzinska
- Department of Neurology, Drug Development Laboratory, Mary S. Easton Center for Alzheimer’s Disease Research and Care, The David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA90095
| | - Dongwook Wi
- Department of Neurology, Drug Development Laboratory, Mary S. Easton Center for Alzheimer’s Disease Research and Care, The David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA90095
| | - Whitaker Cohn
- Department of Neurology, Drug Development Laboratory, Mary S. Easton Center for Alzheimer’s Disease Research and Care, The David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA90095
| | - Jessica T. Lee
- Department of Neurology, Drug Development Laboratory, Mary S. Easton Center for Alzheimer’s Disease Research and Care, The David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA90095
| | - Chunni Zhu
- Department of Neurology, Drug Development Laboratory, Mary S. Easton Center for Alzheimer’s Disease Research and Care, The David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA90095
| | - Christine S. Huang
- Department of Neurobiology, The David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA90095
| | - László Molnár
- Department of Electrical Engineering, Sapientia Hungarian University of Transylvania, Târgu Mureş540485, Romania
| | - Carolyn R. Houser
- Department of Neurobiology, The David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA90095
| | - Varghese John
- Department of Neurology, Drug Development Laboratory, Mary S. Easton Center for Alzheimer’s Disease Research and Care, The David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA90095
| | - Istvan Mody
- Department of Neurology, The David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA90095
- Department of Physiology, The David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA90095
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Mohammadi NA, Ahring PK, Yu Liao VW, Chua HC, Ortiz de la Rosa S, Johannesen KM, Michaeli-Yossef Y, Vincent-Devulder A, Meridda C, Bruel AL, Rossi A, Patel C, Klepper J, Bonanni P, Minghetti S, Trivisano M, Specchio N, Amor D, Auvin S, Baer S, Meyer P, Milh M, Salpietro V, Maroofian R, Lemke JR, Weckhuysen S, Christophersen P, Rubboli G, Chebib M, Jensen AA, Absalom NL, Møller RS. Distinct neurodevelopmental and epileptic phenotypes associated with gain- and loss-of-function GABRB2 variants. EBioMedicine 2024; 106:105236. [PMID: 38996765 PMCID: PMC11296288 DOI: 10.1016/j.ebiom.2024.105236] [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: 01/05/2024] [Revised: 06/23/2024] [Accepted: 06/26/2024] [Indexed: 07/14/2024] Open
Abstract
BACKGROUND Variants in GABRB2, encoding the β2 subunit of the γ-aminobutyric acid type A (GABAA) receptor, can result in a diverse range of conditions, ranging from febrile seizures to severe developmental and epileptic encephalopathies. However, the mechanisms underlying the risk of developing milder vs more severe forms of disorder remain unclear. In this study, we conducted a comprehensive genotype-phenotype correlation analysis in a cohort of individuals with GABRB2 variants. METHODS Genetic and electroclinical data of 42 individuals harbouring 26 different GABRB2 variants were collected and accompanied by electrophysiological analysis of the effects of the variants on receptor function. FINDINGS Electrophysiological assessments of α1β2γ2 receptors revealed that 25/26 variants caused dysfunction to core receptor properties such as GABA sensitivity. Of these, 17 resulted in gain-of-function (GOF) while eight yielded loss-of-function traits (LOF). Genotype-phenotype correlation analysis revealed that individuals harbouring GOF variants suffered from severe developmental delay/intellectual disability (DD/ID, 74%), movement disorders such as dystonia or dyskinesia (59%), microcephaly (50%) and high risk of early mortality (26%). Conversely, LOF variants were associated with milder disease manifestations. Individuals with these variants typically exhibited fever-triggered seizures (92%), milder degrees of DD/ID (85%), and maintained ambulatory function (85%). Notably, severe movement disorders or microcephaly were not reported in individuals with loss-of-function variants. INTERPRETATION The data reveals that genetic variants in GABRB2 can lead to both gain and loss-of-function, and this divergence is correlated with distinct disease manifestations. Utilising this information, we constructed a diagnostic flowchart that aids in predicting the pathogenicity of recently identified variants by considering clinical phenotypes. FUNDING This work was funded by the Australian National Health & Medical Research Council, the Novo Nordisk Foundation and The Lundbeck Foundation.
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Affiliation(s)
- Nazanin Azarinejad Mohammadi
- Department of Epilepsy Genetics and Personalized Treatment, Danish Epilepsy Centre, Filadelfia (Member of the ERN EpiCARE), Dianalund, Denmark; Department of Regional Health Research, University of Southern Denmark, Odense, Denmark
| | - Philip Kiær Ahring
- School of Medical Sciences, Faculty of Medicine and Health, Brain and Mind Centre, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Vivian Wan Yu Liao
- School of Medical Sciences, Faculty of Medicine and Health, Brain and Mind Centre, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Han Chow Chua
- Sydney Pharmacy School, Faculty of Medicine and Health, Charles Perkins Centre, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Sebastián Ortiz de la Rosa
- Department of Epilepsy Genetics and Personalized Treatment, Danish Epilepsy Centre, Filadelfia (Member of the ERN EpiCARE), Dianalund, Denmark; Department of Regional Health Research, University of Southern Denmark, Odense, Denmark
| | - Katrine Marie Johannesen
- Department of Epilepsy Genetics and Personalized Treatment, Danish Epilepsy Centre, Filadelfia (Member of the ERN EpiCARE), Dianalund, Denmark; Department of Genetics, University Hospital of Copenhagen, Rigshospitalet, Copenhagen, Denmark
| | - Yael Michaeli-Yossef
- Pediatric Neurology Unit and Metabolic Neurogenetic Clinic, Wolfson Medical Center, Holon, Israel
| | | | | | | | - Alessandra Rossi
- Department of Epilepsy Genetics and Personalized Treatment, Danish Epilepsy Centre, Filadelfia (Member of the ERN EpiCARE), Dianalund, Denmark; Pediatric Clinic, IRCCS San Matteo Hospital Foundation, University of Pavia, Pavia, Italy
| | - Chirag Patel
- Genetic Health Queensland, Royal Brisbane & Women's Hospital, Brisbane, QLD 4029, Australia
| | - Joerg Klepper
- Children's Hospital Aschaffenburg-Alzenau, Aschaffenburg, Germany
| | - Paolo Bonanni
- IRCCS E. Medea Scientific Institute, Epilepsy Unit, Conegliano, Treviso, Italy
| | - Sara Minghetti
- IRCCS E. Medea Scientific Institute, Clinical Neurophysiology Unit, Bosisio Parini, LC, Italy
| | - Marina Trivisano
- Neurology, Epilepsy and Movement Disorders, Bambino Gesù Children's Hospital, IRCCS, Full Member of European Reference Network EpiCARE, Rome, Italy
| | - Nicola Specchio
- Neurology, Epilepsy and Movement Disorders, Bambino Gesù Children's Hospital, IRCCS, Full Member of European Reference Network EpiCARE, Rome, Italy
| | - David Amor
- Murdoch Children's Research Institute, Melbourne, Australia
| | - Stéphane Auvin
- Université de Paris, Child Neurology & Epilepsy, Paris, France; Robert-Debré Hospital, Center for Rare Epilepsies - Pediatric Neurology, Paris, France
| | - Sarah Baer
- Department of Paediatric Neurology, French Reference Center of Rare Epilepsies CREER, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Pierre Meyer
- Paediatric Neurology Department, Phymedexp, Montpellier University, Inserm, CNRS, University Hospital Montpellier, Montpellier, France
| | - Mathieu Milh
- Department of Pediatric Neurology, AP-HM, La Timone Children's Hospital, Marseille, France; Faculté de Médecine Timone, Aix Marseille Univ, INSERM, MMG, U1251, ERN EpiCARE, Marseille, France
| | - Vincenzo Salpietro
- Department of Neurosciences Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DiNOGMI), University of Genoa, Genoa, Italy; Pediatric Neurology and Muscular Diseases Unit, IRCCS Giannina Gaslini Institute, Genoa, Italy
| | - Reza Maroofian
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, London, UK
| | - Johannes R Lemke
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany; Center for Rare Diseases, University of Leipzig Medical Center, Leipzig, Germany
| | - Sarah Weckhuysen
- Applied & Translational Neurogenomics Group, VIB Center for Molecular Neurology, VIB, Antwerp, Belgium; Department of Neurology, Antwerp University Hospital, Antwerp, Belgium; Translational Neurosciences, Faculty of Medicine and Health Science, University of Antwerp, Antwerp, Belgium
| | | | - Guido Rubboli
- Department of Epilepsy Genetics and Personalized Treatment, Danish Epilepsy Centre, Filadelfia (Member of the ERN EpiCARE), Dianalund, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mary Chebib
- School of Medical Sciences, Faculty of Medicine and Health, Brain and Mind Centre, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Anders A Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nathan L Absalom
- School of Medical Sciences, Faculty of Medicine and Health, Brain and Mind Centre, The University of Sydney, Sydney, New South Wales 2006, Australia; School of Science, Western Sydney University, Sydney, Australia.
| | - Rikke Steensbjerre Møller
- Department of Epilepsy Genetics and Personalized Treatment, Danish Epilepsy Centre, Filadelfia (Member of the ERN EpiCARE), Dianalund, Denmark; Department of Regional Health Research, University of Southern Denmark, Odense, Denmark.
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O'Connor EC, Kambara K, Bertrand D. Advancements in the use of xenopus oocytes for modelling neurological disease for novel drug discovery. Expert Opin Drug Discov 2024; 19:173-187. [PMID: 37850233 DOI: 10.1080/17460441.2023.2270902] [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: 05/31/2023] [Accepted: 10/11/2023] [Indexed: 10/19/2023]
Abstract
INTRODUCTION Introduced about 50 years ago, the model of Xenopus oocytes for the expression of recombinant proteins has gained a broad spectrum of applications. The authors herein review the benefits brought from using this model system, with a focus on modeling neurological disease mechanisms and application to drug discovery. AREAS COVERED Using multiple examples spanning from ligand gated ion channels to transporters, this review presents, in the light of the latest publications, the benefits offered from using Xenopus oocytes. Studies range from the characterization of gene mutations to the discovery of novel treatments for disorders of the central nervous system (CNS). EXPERT OPINION Development of new drugs targeting CNS disorders has been marked by failures in the translation from preclinical to clinical studies. As progress in genetics and molecular biology highlights large functional differences arising from a single to a few amino acid exchanges, the need for drug screening and functional testing against human proteins is increasing. The use of Xenopus oocytes to enable precise modeling and characterization of clinically relevant genetic variants constitutes a powerful model system that can be used to inform various aspects of CNS drug discovery and development.
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Affiliation(s)
- Eoin C O'Connor
- Roche Pharma Research and Early Development, Neuroscience & Rare Diseases, Roche Innovation Center Basel, Basel, Switzerland
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4
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Wei X, Campagna JJ, Jagodzinska B, Wi D, Cohn W, Lee J, Zhu C, Huang CS, Molnár L, Houser CR, John V, Mody I. A therapeutic small molecule lead enhances γ-oscillations and improves cognition/memory in Alzheimer's disease model mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.04.569994. [PMID: 38106006 PMCID: PMC10723366 DOI: 10.1101/2023.12.04.569994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Brain rhythms provide the timing and concurrence of brain activity required for linking together neuronal ensembles engaged in specific tasks. In particular, the γ-oscillations (30-120 Hz) orchestrate neuronal circuits underlying cognitive processes and working memory. These oscillations are reduced in numerous neurological and psychiatric disorders, including early cognitive decline in Alzheimer's disease (AD). Here we report on a potent brain permeable small molecule, DDL-920 that increases γ-oscillations and improves cognition/memory in a mouse model of AD, thus showing promise as a new class of therapeutics for AD. As a first in CNS pharmacotherapy, our lead candidate acts as a potent, efficacious, and selective negative allosteric modulator (NAM) of the γ-aminobutyric acid type A receptors (GABA A Rs) assembled from α1β2δ subunits. We identified these receptors through anatomical and pharmacological means to mediate the tonic inhibition of parvalbumin (PV) expressing interneurons (PV+INs) critically involved in the generation of γ-oscillations. Our approach is unique as it is meant to enhance cognitive performance and working memory in a state-dependent manner by engaging and amplifying the brain's endogenous γ-oscillations through enhancing the function of PV+INs.
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5
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Absalom NL, Lin SXN, Liao VWY, Chua HC, Møller RS, Chebib M, Ahring PK. GABA A receptors in epilepsy: Elucidating phenotypic divergence through functional analysis of genetic variants. J Neurochem 2023. [PMID: 37621067 DOI: 10.1111/jnc.15932] [Citation(s) in RCA: 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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6
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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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Ahring PK, Liao VWY, Lin S, Absalom NL, Chebib M, Møller RS. The de novo GABRA4 p.Thr300Ile variant found in a patient with early-onset intractable epilepsy and neurodevelopmental abnormalities displays gain-of-function traits. Epilepsia 2022; 63:2439-2441. [PMID: 35781801 DOI: 10.1111/epi.17358] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 06/28/2022] [Accepted: 06/28/2022] [Indexed: 11/29/2022]
Affiliation(s)
- Philip K Ahring
- Brain and Mind Centre, Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Vivian W Y Liao
- Brain and Mind Centre, Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Susan Lin
- Brain and Mind Centre, Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Nathan L Absalom
- School of Science, University of Western Sydney, Sydney, New South Wales, Australia
| | - Mary Chebib
- 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 Treatment, Member of the ERN EpiCARE, The Danish Epilepsy Centre, Dianalund, Denmark.,Department of Regional Health Research, University of Southern Denmark, Odense, Denmark
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Ahring PK, Liao VWY, Gardella E, Johannesen KM, Krey I, Selmer KK, Stadheim BF, Davis H, Peinhardt C, Koko M, Coorg RK, Syrbe S, Bertsche A, Santiago-Sim T, Diemer T, Fenger CD, Platzer K, Eichler EE, Lerche H, Lemke JR, Chebib M, Møller RS. Gain-of-function variants in GABRD reveal a novel pathway for neurodevelopmental disorders and epilepsy. Brain 2021; 145:1299-1309. [PMID: 34633442 DOI: 10.1093/brain/awab391] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 09/15/2021] [Accepted: 09/20/2021] [Indexed: 11/14/2022] Open
Abstract
A potential link between GABRD encoding the δ subunit of extrasynaptic GABAA receptors and neurodevelopmental disorders has largely been disregarded due to conflicting conclusions from early studies. However, we identified seven heterozygous missense GABRD variants in 10 patients with neurodevelopmental disorders and generalized epilepsy. One variant occurred in two sibs of healthy parents with presumed somatic mosaicism, another segregated with the disease in three affected family members, and the remaining five occurred de novo in sporadic patients. Electrophysiological measurements were used to determine the functional consequence of the seven missense δ subunit variants in receptor combinations of α1β3δ and α4β2δ GABAA receptors. This was accompanied by analysis of electro-clinical phenotypes of the affected individuals. We determined that five of the seven variants caused altered function of the resulting α1β3δ and α4β2δ GABAA receptors. Surprisingly, four of the five variants led to gain-of-function effects whereas one led to a loss-of-function effect. The stark differences between the gain-of-function and loss-of function effects were mirrored by the clinical phenotypes. Six patients with gain-of-function variants shared common phenotypes: neurodevelopmental disorders with generalized epilepsy, behavioral issues, and various degrees of intellectual disability. Six patients with gain-of-function variants shared common phenotypes: neurodevelopmental disorders with behavioral issues, various degrees of intellectual disability, generalized epilepsy with atypical absences and generalized myoclonic and/or bilateral tonic-clonic seizures. The EEG showed qualitative analogies among the different gain-of-function variant carriers consisting of focal slowing in the occipital regions often preceding irregular generalized epileptiform discharges, with frontal predominance. In contrast, the one patient carrying a loss-of-function variant had normal intelligence, no seizure history but has a diagnosis of autism spectrum disorder and suffering from elevated internalizing psychiatric symptoms. We hypothesize that increase in tonic GABA-evoked current levels mediated by δ-containing extrasynaptic GABAA receptors lead to abnormal neurotransmission, which represent a novel mechanism for severe neurodevelopmental disorders. In support of this, the electro-clinical findings for the gain-of-function GABRD variants resemble the phenotypic spectrum reported in patients with missense SLC6A1 (GABA uptake transporter) variants. This also indicates that the phenomenon of extrasynaptic receptor over-activity is observed in a broader range of patients with neurodevelopmental disorders, since SLC6A1 loss-of-function variants also lead to overactive extrasynaptic δ-containing GABAA receptors. These findings have implications when selecting potential treatment options, since a substantial portion of available anti-seizure medication act by enhancing GABAergic function either directly or indirectly, which could exacerbate symptoms in patients with gain-of-function GABRD variants.
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Affiliation(s)
- Philip K Ahring
- Brain and Mind Centre, School of Pharmacy, Faculty of Medicine and Health, The University of Sydney; Sydney, New South Wales, Australia
| | - Vivian W Y Liao
- Brain and Mind Centre, School of Pharmacy, Faculty of Medicine and Health, The University of Sydney; Sydney, New South Wales, Australia
| | - Elena Gardella
- Department of Epilepsy Genetics and Personalized Treatment, The Danish Epilepsy Centre; Dianalund, Denmark.,Department of Regional Health Research, University of Southern Denmark; Odense, Denmark
| | - Katrine M Johannesen
- Department of Epilepsy Genetics and Personalized Treatment, The Danish Epilepsy Centre; Dianalund, Denmark.,Department of Regional Health Research, University of Southern Denmark; Odense, Denmark
| | - Ilona Krey
- Institute of Human Genetics, University of Leipzig Medical Center; Leipzig, Germany
| | - Kaja K Selmer
- National Centre for Rare Epilepsy-Related Disorders, Oslo University Hospital; Oslo, Norway.,Department of Medical Genetics, Oslo University Hospital; Oslo, Norway
| | - Barbro F Stadheim
- Department of Medical Genetics, Oslo University Hospital; Oslo, Norway
| | - Hannah Davis
- Division of Medical Genetics, Department of Human Genetics, Emory University School of Medicine; Atlanta, GA, USA
| | - Charlotte Peinhardt
- Division of Medical Genetics, Department of Human Genetics, Emory University School of Medicine; Atlanta, GA, USA
| | - Mahmoud Koko
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen; Tübingen, Germany
| | - Rohini K Coorg
- Department of Pediatrics and Neurology, Neurophysiology and Epilepsy, Baylor College of Medicine; Houston, Texas, USA
| | - Steffen Syrbe
- Division of Paediatric Epileptology, Centre for Paediatric and Adolescent Medicine, University Hospital Heidelberg; Heidelberg, Germany
| | - Astrid Bertsche
- University Hospital for Children and Adolescents, Neuropaediatrics; Rostock, Germany.,University Hospital for Children and Adolescents, Center for Pediatric Research; Leipzig, Germany
| | | | - Tue Diemer
- Department of Clinical Genetics, Aalborg University Hospital; Aalborg, Denmark
| | - Christina D Fenger
- Department of Epilepsy Genetics and Personalized Treatment, The Danish Epilepsy Centre; Dianalund, Denmark.,Department of Regional Health Research, University of Southern Denmark; Odense, Denmark
| | - Konrad Platzer
- Institute of Human Genetics, University of Leipzig Medical Center; Leipzig, Germany
| | - Evan E Eichler
- Department of Genome Sciences, University of Washington School of Medicine; Seattle, WA, USA.,Howard Hughes Medical Institute, University of Washington; Seattle, WA 98195, USA
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen; Tübingen, Germany
| | - Johannes R Lemke
- Institute of Human Genetics, University of Leipzig Medical Center; Leipzig, Germany
| | - Mary Chebib
- Brain and Mind Centre, School of Pharmacy, Faculty of Medicine and Health, The University of Sydney; Sydney, New South Wales, Australia
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Treatment, The Danish Epilepsy Centre; Dianalund, Denmark.,Department of Regional Health Research, University of Southern Denmark; Odense, Denmark
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