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Fenton TA, Haouchine OY, Hallam EL, Smith EM, Jackson KC, Rahbarian D, Canales C, Adhikari A, Nord AS, Ben-Shalom R, Silverman JL. Hyperexcitability and translational phenotypes in a preclinical mouse model of SYNGAP1-Related Intellectual Disability. RESEARCH SQUARE 2024:rs.3.rs-4067746. [PMID: 38562838 PMCID: PMC10984035 DOI: 10.21203/rs.3.rs-4067746/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Disruption of SYNGAP1 directly causes a genetically identifiable neurodevelopmental disorder (NDD) called SYNGAP1-related intellectual disability (SRID). Without functional SynGAP1 protein, individuals are developmentally delayed and have prominent features of intellectual disability, motor impairments, and epilepsy. Over the past two decades, there have been numerous discoveries indicting the critical role of Syngap1. Several rodent models with a loss of Syngap1 have been engineered identifying precise roles in neuronal structure and function, as well as key biochemical pathways key for synapse integrity. Homozygous loss of SYNGAP1/Syngap1 is lethal. Heterozygous mutations of Syngap1 result in a broad range of behavioral phenotypes. Our in vivo functional data, using the original mouse model from the Huganir laboratory, corroborated behaviors including robust hyperactivity and deficits in learning and memory in young adults. Furthermore, we described impairments in the domain of sleep, characterized using neurophysiological data collected with wireless, telemetric electroencephalography (EEG). Syngap1+/- mice exhibited elevated spiking events and spike trains, in addition to elevated power, most notably in the delta power frequency. For the first time, we illustrated primary neurons from Syngap1+/- mice displayed increased network firing activity, greater bursts, and shorter inter-burst intervals between peaks by employing high density microelectrode arrays (HD-MEA). Our work bridges in-vitro electrophysiological neuronal activity and function with in vivo neurophysiological brain activity and function. These data elucidate quantitative, translational biomarkers in vivo and in vitro that can be utilized for the development and efficacy assessment of targeted treatments for SRID.
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Affiliation(s)
- Timothy A Fenton
- MIND Institute, University of California Davis School of Medicine, Sacramento, CA 95817
- Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA 95817
| | - Olivia Y Haouchine
- MIND Institute, University of California Davis School of Medicine, Sacramento, CA 95817
- Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA 95817
| | - Elizabeth L Hallam
- MIND Institute, University of California Davis School of Medicine, Sacramento, CA 95817
- Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA 95817
| | - Emily M Smith
- UC Davis Center for Neuroscience; Department of Psychiatry and Behavioral Sciences & Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, CA 95616
| | - Kiya C. Jackson
- UC Davis Center for Neuroscience; Department of Psychiatry and Behavioral Sciences & Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, CA 95616
| | - Darlene Rahbarian
- UC Davis Center for Neuroscience; Department of Psychiatry and Behavioral Sciences & Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, CA 95616
| | - Cesar Canales
- Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA 95817
- UC Davis Center for Neuroscience; Department of Psychiatry and Behavioral Sciences & Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, CA 95616
| | - Anna Adhikari
- MIND Institute, University of California Davis School of Medicine, Sacramento, CA 95817
- Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA 95817
| | - Alexander S. Nord
- MIND Institute, University of California Davis School of Medicine, Sacramento, CA 95817
- Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA 95817
- UC Davis Center for Neuroscience; Department of Psychiatry and Behavioral Sciences & Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, CA 95616
| | - Roy Ben-Shalom
- MIND Institute, University of California Davis School of Medicine, Sacramento, CA 95817
- Department of Neurology, University of California Davis School of Medicine, Sacramento, CA 95817
| | - Jill L Silverman
- MIND Institute, University of California Davis School of Medicine, Sacramento, CA 95817
- Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA 95817
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2
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Marotta N, Boland MJ, Prosser BL. Accelerating therapeutic development and clinical trial readiness for STXBP1 and SYNGAP1 disorders. Curr Probl Pediatr Adolesc Health Care 2024:101576. [PMID: 38472035 DOI: 10.1016/j.cppeds.2024.101576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/14/2024]
Abstract
Gene-targeted therapies for genetic neurodevelopmental disorders (NDDs) are becoming a reality. The Center for Epilepsy and Neurodevelopmental Disorders (ENDD) is currently focused on the development of therapeutics for STXBP1 and SYNGAP1 disorders. Here we review the known clinical features of these disorders, highlight the biological role of STXBP1 and SYNGAP1, and discuss our current understanding of pathogenic mechanisms and therapeutic development. Finally, we provide our perspective as scientists and parents of children with NDDs, and comment on the current challenges for both clinical and basic science endeavors.
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Affiliation(s)
- Nicolas Marotta
- Department of Biochemistry and Molecular Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA; Center for Epilepsy and Neurodevelopmental Disorders (ENDD), University of Pennsylvania Perelman School of Medicine and Children's Hospital of Philadelphia, Philadelphia, PA, USA; Department of Physiology, Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Michael J Boland
- Center for Epilepsy and Neurodevelopmental Disorders (ENDD), University of Pennsylvania Perelman School of Medicine and Children's Hospital of Philadelphia, Philadelphia, PA, USA.
| | - Benjamin L Prosser
- Center for Epilepsy and Neurodevelopmental Disorders (ENDD), University of Pennsylvania Perelman School of Medicine and Children's Hospital of Philadelphia, Philadelphia, PA, USA; Department of Physiology, Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.
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3
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Vieira BS, Airoldi MJ, Chalfun D, Bonfim RGAS, Teplicky R, Rosenbaum P, Mancini MC, Brandão MB. "From All, To All": Implementing a collaborative online conference to reflect on the daily living of individuals with cerebral palsy. Child Care Health Dev 2024; 50:e13254. [PMID: 38517156 DOI: 10.1111/cch.13254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 10/26/2023] [Accepted: 02/25/2024] [Indexed: 03/23/2024]
Abstract
BACKGROUND Translating knowledge to improve paediatric rehabilitation has become a research area of interest. This study describes the development and evaluation of an online conference that brought together perspectives of individuals with cerebral palsy (CP), families, health care professionals, and researchers to discuss the daily living of individuals with CP. METHODS We anchored the development and implementation of the online conference in the action cycle of the Knowledge to Action Framework. To develop the meeting, we included representatives from each stakeholder group in the programme committee. The conference programme was designed having the lifespan perspective of individuals with CP, from birth to adulthood, as its central core, with themes related to daily living (e.g., self-care, mobility, and continuing education). Participants' satisfaction with the conference was assessed using an anonymized online survey sent to all participants. RESULTS The conference had 1656 attendees, of whom 675 answered the online satisfaction survey. Most participants rated the structure of the conference (i.e., quality of the technical support, audio and video, and online platform) and discussed topics (i.e., relevance, content, discussion, speakers, and available time) positively. CONCLUSION Collaborative conferences that include stakeholders throughout the planning and implementation are a viable, effective knowledge translation strategy that allows for sharing experiences and disseminating knowledge among families and individuals with CP, health care professionals, and researchers.
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Affiliation(s)
| | - Marina J Airoldi
- Instituto Nossa Casa, Campinas, Brazil
- Graduate Program in Rehabilitation Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | | | | | - Rachel Teplicky
- CanChild Centre for Childhood Disability, McMaster University, Hamilton, Ontario, Canada
| | - Peter Rosenbaum
- CanChild Centre for Childhood Disability, McMaster University, Hamilton, Ontario, Canada
| | - Marisa C Mancini
- Graduate Program in Rehabilitation Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Marina B Brandão
- Graduate Program in Rehabilitation Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
- Department of Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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Fitzgerald PJ. Neural hyperexcitability in Angelman syndrome: Genetic factors and pharmacologic treatment approaches. Epilepsy Res 2024; 200:107286. [PMID: 38217951 DOI: 10.1016/j.eplepsyres.2024.107286] [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: 09/10/2023] [Revised: 12/18/2023] [Accepted: 01/02/2024] [Indexed: 01/15/2024]
Abstract
Angelman syndrome (AS) is a rare neurodevelopmental disorder that is typically caused by deletion or a loss-of-function mutation of the maternal copy of the ubiquitin ligase E3A (UBE3A) gene. The disorder is characterized by severe intellectual disability, deficits in speech, motor abnormalities, altered electroencephalography (EEG) activity, spontaneous epileptic seizures, sleep disturbances, and a happy demeanor with frequent laughter. Regarding electrophysiologic abnormalities in particular, enhanced delta oscillatory power and an elevated excitatory/inhibitory (E/I) ratio have been documented in AS, with E/I ratio especially studied in rodent models. These electrophysiologic characteristics appear to relate with the greatly elevated rates of epilepsy in individuals with AS, and associated hypersynchronous neural activity. Here we briefly review findings on EEG, E/I ratio, and epileptic seizures in AS, including data from rodent models of the disorder. We summarize pharmacologic approaches that have been used to treat behavioral aspects of AS, including neuropsychiatric phenomena and sleep disturbances, as well as seizures in the context of the disorder. Antidepressants such as SSRIs and atypical antipsychotics are among the medications that have been used behaviorally, whereas anticonvulsant drugs such as valproic acid and lamotrigine have frequently been used to control seizures in AS. We end by suggesting novel uses for some existing pharmacologic agents in AS, including noradrenergic transmission reducing drugs (alpha2 agonists, beta blockers, alpha1 antagonists) and cholinesterase inhibitors, where these various classes of drugs may have the ability to ameliorate both behavioral disturbances and seizures.
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Affiliation(s)
- Paul J Fitzgerald
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, USA.
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Jimenez-Gomez A, Nguyen MX, Gill JS. Understanding the role of AMPA receptors in autism: insights from circuit and synapse dysfunction. Front Psychiatry 2024; 15:1304300. [PMID: 38352654 PMCID: PMC10861716 DOI: 10.3389/fpsyt.2024.1304300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 01/08/2024] [Indexed: 02/16/2024] Open
Abstract
Autism spectrum disorders represent a diverse etiological spectrum that converge on a syndrome characterized by discrepant deficits in developmental domains often highlighted by concerns in socialization, sensory integration, and autonomic functioning. Importantly, the incidence and prevalence of autism spectrum disorders have seen sharp increases since the syndrome was first described in the 1940s. The wide etiological spectrum and rising number of individuals being diagnosed with the condition lend urgency to capturing a more nuanced understanding of the pathogenic mechanisms underlying the autism spectrum disorders. The current review seeks to understand how the disruption of AMPA receptor (AMPAr)-mediated neurotransmission in the cerebro-cerebellar circuit, particularly in genetic autism related to SHANK3 or SYNGAP1 protein dysfunction function and autism associated with in utero exposure to the anti-seizure medications valproic acid and topiramate, may contribute to the disease presentation. Initially, a discussion contextualizing AMPAr signaling in the cerebro-cerebellar circuitry and microstructural circuit considerations is offered. Subsequently, a detailed review of the literature implicating mutations or deletions of SHANK3 and SYNGAP1 in disrupted AMPAr signaling reveals how bidirectional pathogenic modulation of this key circuit may contribute to autism. Finally, how pharmacological exposure may interact with this pathway, via increased risk of autism diagnosis with valproic acid and topiramate exposure and potential treatment of autism using AMPAr modulator perampanel, is discussed. Through the lens of the review, we will offer speculation on how neuromodulation may be used as a rational adjunct to therapy. Together, the present review seeks to synthesize the disparate considerations of circuit understanding, genetic etiology, and pharmacological modulation to understand the mechanistic interaction of this important and complex disorder.
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Affiliation(s)
- Andres Jimenez-Gomez
- Neurodevelopmental Disabilities Program, Department of Neurology, Joe DiMaggio Children’s Hospital, Hollywood, FL, United States
| | - Megan X. Nguyen
- Department of Pediatrics, Division of Neurology & Developmental Neurosciences, Baylor College of Medicine, Houston, TX, United States
- Jan & Dan Duncan Neurologic Research Institute, Texas Children’s Hospital, Houston, TX, United States
| | - Jason S. Gill
- Department of Pediatrics, Division of Neurology & Developmental Neurosciences, Baylor College of Medicine, Houston, TX, United States
- Jan & Dan Duncan Neurologic Research Institute, Texas Children’s Hospital, Houston, TX, United States
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Rosti G, Boeri S, Divizia MT, Pisciotta L, Mancardi MM, Lerone M, Cerminara M, Servetti M, Spirito G, Vozzi D, Fontana M, Gustincich S, Nobili L, Zara F, Puliti A. Novel SYNGAP1 Variant in an Adult Individual Affected by Intellectual Disability and Epilepsy: A Cold Case Solved through Whole-Exome Sequencing. Mol Syndromol 2023; 14:433-438. [PMID: 37915395 PMCID: PMC10617251 DOI: 10.1159/000529408] [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: 09/15/2022] [Accepted: 01/27/2023] [Indexed: 11/03/2023] Open
Abstract
Introduction Nowadays, whole-exome sequencing (WES) analysis is an essential part in the diagnostic pathway of individuals with complex phenotypes when routine exams, such as array-CGH and gene panels, have proved inconclusive. However, data on the diagnostic rate of WES analysis in adult individuals, negative to first-tier tests, are lacking. This is because initiatives with the aim of diagnosing rare diseases focus mainly on pediatric unsolved cases. Case Presentation We hereby present a 45-year-old woman with severe intellectual disability, previous psychomotor developmental delay, behavioral disorders, stereotypies, nonconvulsive epilepsy, and dysmorphisms. The proband first came to our attention when she was 4 years old (in 1982); since then, she has undergone several clinical and instrumental assessments, without reaching a genetic diagnosis. At last, through WES analysis, a novel de novo variant in SYNGAP1 was found. The clinical characteristics associated with SYNGAP1 are similar to those presented by the proband. Conclusion The variant is predicted to be deleterious and is most probably the cause of the proband's phenotype. The perseverance of the clinicians and the family allowed us to reach a diagnosis in a woman with a more than 30-year history of clinical evaluations, instrumental assessments, and genetic tests. This diagnosis was of significant relevance in genetic counseling for family members and the proband herself.
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Affiliation(s)
- Giulia Rosti
- Dipartimento di Neuroscienze, Riabilitazione, Oftalmologia, Genetica e Scienze Materno-Infantili (DINOGMI), Università di Genova, Genoa, Italy
- Medical Genetics Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Silvia Boeri
- Dipartimento di Neuroscienze, Riabilitazione, Oftalmologia, Genetica e Scienze Materno-Infantili (DINOGMI), Università di Genova, Genoa, Italy
- Child Neuropsychiatry Unit, ERN EpiCARE Centre, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | | | - Livia Pisciotta
- Child Neuropsychiatry Unit, ASST Fatebenefratelli Sacco, Milan, Italy
| | | | - Margherita Lerone
- Medical Genetics Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Maria Cerminara
- Dipartimento di Neuroscienze, Riabilitazione, Oftalmologia, Genetica e Scienze Materno-Infantili (DINOGMI), Università di Genova, Genoa, Italy
- Medical Genetics Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Martina Servetti
- Dipartimento di Neuroscienze, Riabilitazione, Oftalmologia, Genetica e Scienze Materno-Infantili (DINOGMI), Università di Genova, Genoa, Italy
| | - Giovanni Spirito
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia (IIT), Genoa, Italy
| | - Diego Vozzi
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia (IIT), Genoa, Italy
| | - Marco Fontana
- Medical Genetics Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Stefano Gustincich
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia (IIT), Genoa, Italy
| | - Lino Nobili
- Dipartimento di Neuroscienze, Riabilitazione, Oftalmologia, Genetica e Scienze Materno-Infantili (DINOGMI), Università di Genova, Genoa, Italy
- Child Neuropsychiatry Unit, ERN EpiCARE Centre, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Federico Zara
- Dipartimento di Neuroscienze, Riabilitazione, Oftalmologia, Genetica e Scienze Materno-Infantili (DINOGMI), Università di Genova, Genoa, Italy
- Medical Genetics Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Aldamaria Puliti
- Dipartimento di Neuroscienze, Riabilitazione, Oftalmologia, Genetica e Scienze Materno-Infantili (DINOGMI), Università di Genova, Genoa, Italy
- Medical Genetics Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy
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Sumathipala SH, Khan S, Kozol RA, Araki Y, Syed S, Huganir RL, Dallman JE. Context-dependent hyperactivity in syngap1a and syngap1b zebrafish autism models. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.20.557316. [PMID: 37786701 PMCID: PMC10541574 DOI: 10.1101/2023.09.20.557316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
Background and Aims SYNGAP1 disorder is a prevalent genetic form of Autism Spectrum Disorder and Intellectual Disability (ASD/ID) and is caused by de novo or inherited mutations in one copy of the SYNGAP1 gene. In addition to ASD/ID, SYNGAP1 disorder is associated with comorbid symptoms including treatment-resistant-epilepsy, sleep disturbances, and gastrointestinal distress. Mechanistic links between these diverse symptoms and SYNGAP1 variants remain obscure, therefore, our goal was to generate a zebrafish model in which this range of symptoms can be studied. Methods We used CRISPR/Cas9 to introduce frameshift mutations in the syngap1a and syngap1b zebrafish duplicates (syngap1ab) and validated these stable models for Syngap1 loss-of-function. Because SYNGAP1 is extensively spliced, we mapped splice variants to the two zebrafish syngap1a and b genes and identified mammalian-like isoforms. We then quantified locomotory behaviors in zebrafish syngap1ab larvae under three conditions that normally evoke different arousal states in wild type larvae: aversive, high-arousal acoustic, medium-arousal dark, and low-arousal light stimuli. Results We show that CRISPR/Cas9 indels in zebrafish syngap1a and syngap1b produced loss-of-function alleles at RNA and protein levels. Our analyses of zebrafish Syngap1 isoforms showed that, as in mammals, zebrafish Syngap1 N- and C-termini are extensively spliced. We identified a zebrafish syngap1 α1-like variant that maps exclusively to the syngap1b gene. Quantifying locomotor behaviors showed that syngap1ab larvae are hyperactive compared to wild type but to differing degrees depending on the stimulus. Hyperactivity was most pronounced in low arousal settings, with overall movement increasing with the number of mutant syngap1 alleles. Conclusions Our data support mutations in zebrafish syngap1ab as causal for hyperactivity associated with elevated arousal that is especially pronounced in low-arousal environments.
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Affiliation(s)
- Sureni H. Sumathipala
- Department of Biology, University of Miami, Coral Gables, FL USA
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - Suha Khan
- Department of Biology, University of Miami, Coral Gables, FL USA
| | - Robert A. Kozol
- Department of Biology, University of Miami, Coral Gables, FL USA
- Jupiter Life Science Initiative, Florida Atlantic University, Jupiter FL, USA
| | - Yoichi Araki
- Department of Neuroscience and Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Sheyum Syed
- Department of Physics, University of Miami, Coral Gables, FL USA
| | - Richard L. Huganir
- Department of Neuroscience and Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Julia E. Dallman
- Department of Biology, University of Miami, Coral Gables, FL USA
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8
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Silverman JL, Fenton T, Haouchine O, Hallam E, Smith E, Jackson K, Rahbarian D, Canales C, Adhikari A, Nord A, Ben-Shalom R. Hyperexcitability and translational phenotypes in a preclinical model of SYNGAP1 mutations. RESEARCH SQUARE 2023:rs.3.rs-3246655. [PMID: 37790402 PMCID: PMC10543290 DOI: 10.21203/rs.3.rs-3246655/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
SYNGAP1 is a critical gene for neuronal development, synaptic structure, and function. Although rare, the disruption of SYNGAP1 directly causes a genetically identifiable neurodevelopmental disorder (NDD) called SYNGAP1 -related intellectual disability. Without functional SynGAP1 protein, patients present with intellectual disability, motor impairments, and epilepsy. Previous work using mouse models with a variety of germline and conditional mutations has helped delineate SynGAP1's critical roles in neuronal structure and function, as well as key biochemical signaling pathways essential to synapse integrity. Homozygous loss of SYNGAP1 is embryonically lethal. Heterozygous mutations of SynGAP1 result in a broad range of phenotypes including increased locomotor activity, impaired working spatial memory, impaired cued fear memory, and increased stereotypic behavior. Our in vivo functional data, using the original germline mutation mouse line from the Huganir laboratory, corroborated robust hyperactivity and learning and memory deficits. Here, we describe impairments in the translational biomarker domain of sleep, characterized using neurophysiological data collected with wireless telemetric electroencephalography (EEG). We discovered Syngap1+/- mice exhibited elevated spike trains in both number and duration, in addition to elevated power, most notably in the delta power band. Primary neurons from Syngap1+/- mice displayed increased network firing activity, greater spikes per burst, and shorter inter-burst intervals between peaks using high density micro-electrode arrays (HD-MEA). This work is translational, innovative, and highly significant as it outlines functional impairments in Syngap1 mutant mice. Simultaneously, the work utilized untethered, wireless neurophysiology that can discover potential biomarkers of Syngap1 RI-D, for clinical trials, as it has done with other NDDs. Our work is substantial forward progress toward translational work for SynGAP1R-ID as it bridges in-vitro electrophysiological neuronal activity and function with in vivo neurophysiological brain activity and function. These data elucidate multiple quantitative, translational biomarkers in vivo and in vitro for the development of treatments for SYNGAP1-related intellectual disability.
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Affiliation(s)
- Jill L Silverman
- MIND Institute and Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine
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9
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Davidson EA, Holingue C, Jimenez-Gomez A, Dallman JE, Moshiree B. Gastrointestinal Dysfunction in Genetically Defined Neurodevelopmental Disorders. Semin Neurol 2023; 43:645-660. [PMID: 37586397 PMCID: PMC10895389 DOI: 10.1055/s-0043-1771460] [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] [Indexed: 08/18/2023]
Abstract
Gastrointestinal symptoms are common in most forms of neurodevelopment disorders (NDDs) such as in autism spectrum disorders (ASD). The current patient-reported outcome measures with validated questionnaires used in the general population of children without NDDS cannot be used in the autistic individuals. We explore here the multifactorial pathophysiology of ASD and the role of genetics and the environment in this disease spectrum and focus instead on possible diagnostics that could provide future objective insight into the connection of the gut-brain-microbiome in this disease entity. We provide our own data from both humans and a zebrafish model of ASD called Phelan-McDermid Syndrome. We hope that this review highlights the gaps in our current knowledge on many of these profound NDDs and that it provides a future framework upon which clinicians and researchers can build and network with other interested multidisciplinary specialties.
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Affiliation(s)
| | - Calliope Holingue
- Center for Autism and Related Disorders, Kennedy Krieger Institute, Baltimore, Maryland
- Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Andres Jimenez-Gomez
- Neuroscience Center, Joe DiMaggio Children’s Hospital, Hollywood, Florida
- Department of Child Neurology, Florida Atlantic University Stiles - Nicholson Brain Institute, Jupiter, Florida
| | - Julia E. Dallman
- Department of Biology, University of Miami, Coral Gables, Miami, Florida
| | - Baharak Moshiree
- Atrium Health, Wake Forest Medical University, Charlotte, North Carolina
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10
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Fenton TA, Haouchine OY, Hallam EL, Smith EM, Jackson KC, Rahbarian D, Canales C, Adhikari A, Nord AS, Ben-Shalom R, Silverman JL. Hyperexcitability and translational phenotypes in a preclinical model of SYNGAP1 mutations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.24.550093. [PMID: 37546838 PMCID: PMC10402099 DOI: 10.1101/2023.07.24.550093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
SYNGAP1 is a critical gene for neuronal development, synaptic structure, and function. Although rare, the disruption of SYNGAP1 directly causes a genetically identifiable neurodevelopmental disorder (NDD) called SYNGAP1-related intellectual disability. Without functional SynGAP1 protein, patients present with intellectual disability, motor impairments, and epilepsy. Previous work using mouse models with a variety of germline and conditional mutations has helped delineate SynGAP1's critical roles in neuronal structure and function, as well as key biochemical signaling pathways essential to synapse integrity. Homozygous loss of SYNGAP1 is embryonically lethal. Heterozygous mutations of SynGAP1 result in a broad range of phenotypes including increased locomotor activity, impaired working spatial memory, impaired cued fear memory, and increased stereotypic behavior. Our in vivo functional data, using the original germline mutation mouse line from the Huganir laboratory, corroborated robust hyperactivity and learning and memory deficits. Here, we describe impairments in the translational biomarker domain of sleep, characterized using neurophysiological data collected with wireless telemetric electroencephalography (EEG). We discovered Syngap1 +/- mice exhibited elevated spike trains in both number and duration, in addition to elevated power, most notably in the delta power band. Primary neurons from Syngap1 +/- mice displayed increased network firing activity, greater spikes per burst, and shorter inter-burst intervals between peaks using high density micro-electrode arrays (HD-MEA). This work is translational, innovative, and highly significant as it outlines functional impairments in Syngap1 mutant mice. Simultaneously, the work utilized untethered, wireless neurophysiology that can discover potential biomarkers of Syngap1R-ID, for clinical trials, as it has done with other NDDs. Our work is substantial forward progress toward translational work for SynGAP1R-ID as it bridges in-vitro electrophysiological neuronal activity and function with in vivo neurophysiological brain activity and function. These data elucidate multiple quantitative, translational biomarkers in vivo and in vitro for the development of treatments for SYNGAP1-related intellectual disability.
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11
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Zeng X, Chen Y, Yu X, Che Y, Chen H, Yi Z, Qin J, Zhong J. Novel variants of SYNGAP1 associated epileptic encephalopathy: two cases report and literature review. ACTA EPILEPTOLOGICA 2023. [DOI: 10.1186/s42494-022-00114-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023] Open
Abstract
Abstract
Background
SYNGAP1 is a significant genetic risk factor for global developmental delay, autism spectrum disorder, and epileptic encephalopathy. De novo loss-of-function variants in this gene cause a neurodevelopmental disorder, for example, early-onset and drug-refractory seizures. We report two children with global developmental delay and epileptic encephalopathy, which are caused by SYNGAP1 gene novel mutations, and drug treatment is effective.
Case presentation
We report a boy and a girl presented with global developmental delay when they were young babies; as they grew up, cognitive impairment and social-communication disorder became more and more prominent; unfortunately, the patients developed into various seizure types, including eyelid myoclonia, myoclonic and absences when the boy was 1 year 8 mouths old and the girl was 3 years old. The two patients were found two previously unknown mutations by high throughput sequencing [c.3271_ c.3272insT; (p.L1091L fs*62), c.2515A > T (p.K839*)] in exon 15 of the SYNGAP in the proband. Sanger sequencing confirmed the heterozygous nature, and neither of their parents carried the same mutation. The girl treated with valproic acid and prednisone became seizure-free, and valproic acid and levetiracetam combined with clonazepam were influential in the other.
Conclusions
The global developmental delay and epileptic encephalopathy of the children were probably due to the pathogenic mutation of the SYNGAP1 gene, and prednisone and clonazepam may be effective in achieving seizure-free.
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Muacevic A, Adler JR, Lacasse BM, Beggs J, Lou J, Motta FC, Nemzer LR, Worth R, Cravens GD. A Literature Review of Similarities Between and Among Patients With Autism Spectrum Disorder and Epilepsy. Cureus 2023; 15:e33946. [PMID: 36819340 PMCID: PMC9937677 DOI: 10.7759/cureus.33946] [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: 08/11/2022] [Accepted: 01/18/2023] [Indexed: 01/20/2023] Open
Abstract
Autism spectrum disorder (ASD) has been shown to be associated with various other conditions, and most commonly, ASD has been demonstrated to be linked to epilepsy. ASD and epilepsy have been observed to exhibit high rates of comorbidity, even when compared to the co-occurrence of other disorders with similar pathologies. At present, nearly one-half of the individuals diagnosed with ASD also have been diagnosed with comorbid epilepsy. Research suggests that both conditions likely share similarities in their underlying disease pathophysiology, possibly associated with disturbances in the central nervous system (CNS), and may be linked to an imbalance between excitation and inhibition in the brain. Meanwhile, it remains unclear whether one condition is the consequence of the other, as the pathologies of both disorders are commonly linked to many different underlying signal transduction mechanisms. In this review, we aim to investigate the co-occurrence of ASD and epilepsy, with the intent of gaining insights into the similarities in pathophysiology that both conditions present with. Elucidating the underlying disease pathophysiology as a result of both disorders could lead to a better understanding of the underlying mechanism of disease activity that drives co-occurrence, as well as provide insight into the underlying mechanisms of each condition individually.
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13
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Wang Y, Lv Y, Li Z, Gao M, Yang X, Li Y, Shi J, Gao Z, Liu Y, Gai Z. Phenotype and genotype analyses of Chinese patients with autosomal dominant mental retardation type 5 caused by SYNGAP1 gene mutations. Front Genet 2022; 13:957915. [PMID: 36583017 PMCID: PMC9792850 DOI: 10.3389/fgene.2022.957915] [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: 06/17/2022] [Accepted: 11/09/2022] [Indexed: 12/15/2022] Open
Abstract
Background: Autosomal dominant mental retardation type 5 (MRD5), a rare neurodevelopmental disorder (NDD) characterized by intellectual disability (ID), developmental delay (DD), and epilepsy predominantly, is caused by a heterozygous mutation in the SYNGAP1 gene. SYNGAP1 mutations have been rarely reported in the Chinese population. Here, we present an investigation of SYNGAP1 mutations in a clinical cohort with ID and DD in Shandong, a northern province in China, to further explore the genotype and phenotype correlations. Methods: A retrospective study was conducted on 10 children with SYNGAP1 mutations presenting ID, DD, and epilepsy who were diagnosed between January 2014 and May 2022. Clinical data and genetic tests were collected. Treatment and regular follow-ups were carried out to pay close attention to the prognosis of the patients. Results: We described 10 unrelated affected individuals with SYNGAP1 mutations, displaying ID, DD, epilepsy, or seizures. All mutations of SYNGAP1 in the 10 patients were de novo, except patient 3 whose father was unavailable, including five nonsense mutations, two frameshift mutations, two splicing mutations, and one codon deletion. Among these mutations, five were novel and the other five were previously reported. Significantly, all patients with epilepsy were sensitive to anti-seizure drugs, especially sodium valproate. Furthermore, rehabilitation training seemed to exert a more improved effect on motor development than language development for the patients. Conclusion The 10 patients carrying SYNGAP1 mutations were diagnosed as MRD5. Five novel genetic mutations were found, which expanded the mutational spectrum of the SYNGAP1 gene. The identification of these mutations in this study helps explore the relationship between genotypes and phenotypes and contributes to genetic counseling and therapeutic intervention for patients with MRD5.
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Affiliation(s)
- Yanxin Wang
- Department of Pediatrics, Children’s Hospital Affiliated to Shandong University, Ji’nan, China
| | - Yuqiang Lv
- Pediatric Research Institute, Children’s Hospital Affiliated to Shandong University, Ji’nan, China,Shandong Provincial Clinical Research Center for Children’s Health and Disease, Ji’nan, China
| | - Zilong Li
- Pediatric Research Institute, Children’s Hospital Affiliated to Shandong University, Ji’nan, China,Shandong Provincial Clinical Research Center for Children’s Health and Disease, Ji’nan, China
| | - Min Gao
- Pediatric Research Institute, Children’s Hospital Affiliated to Shandong University, Ji’nan, China,Shandong Provincial Clinical Research Center for Children’s Health and Disease, Ji’nan, China
| | - Xiaomeng Yang
- Pediatric Research Institute, Children’s Hospital Affiliated to Shandong University, Ji’nan, China,Shandong Provincial Clinical Research Center for Children’s Health and Disease, Ji’nan, China
| | - Yue Li
- Pediatric Research Institute, Children’s Hospital Affiliated to Shandong University, Ji’nan, China,Shandong Provincial Clinical Research Center for Children’s Health and Disease, Ji’nan, China
| | - Jianguo Shi
- Shandong Provincial Clinical Research Center for Children’s Health and Disease, Ji’nan, China,Epilepsy Center, Children’s Hospital Affiliated to Shandong University, Ji’nan, China
| | - Zaifen Gao
- Shandong Provincial Clinical Research Center for Children’s Health and Disease, Ji’nan, China,Epilepsy Center, Children’s Hospital Affiliated to Shandong University, Ji’nan, China
| | - Yi Liu
- Pediatric Research Institute, Children’s Hospital Affiliated to Shandong University, Ji’nan, China,Shandong Provincial Clinical Research Center for Children’s Health and Disease, Ji’nan, China,*Correspondence: Yi Liu, ; Zhongtao Gai,
| | - Zhongtao Gai
- Pediatric Research Institute, Children’s Hospital Affiliated to Shandong University, Ji’nan, China,Shandong Provincial Clinical Research Center for Children’s Health and Disease, Ji’nan, China,Epilepsy Center, Children’s Hospital Affiliated to Shandong University, Ji’nan, China,*Correspondence: Yi Liu, ; Zhongtao Gai,
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Lyu S, Xing H, Liu Y, Girdhar P, Yokoi F, Li Y. Further Studies on the Role of BTBD9 in the Cerebellum, Sleep-like Behaviors and the Restless Legs Syndrome. Neuroscience 2022; 505:78-90. [PMID: 36244636 PMCID: PMC10367443 DOI: 10.1016/j.neuroscience.2022.10.008] [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: 08/05/2022] [Revised: 09/15/2022] [Accepted: 10/09/2022] [Indexed: 11/26/2022]
Abstract
Genetic analyses have linked BTBD9 to restless legs syndrome (RLS) and sleep regulation. Btbd9 knockout mice show RLS-like motor restlessness. Previously, we found hyperactivity of cerebellar Purkinje cells (PCs) in Btbd9 knockout mice, which may contribute to the motor restlessness observed. However, underlying mechanisms for PC hyperactivity in Btbd9 knockout mice are unknown. Here, we used dissociated PC recording, brain slice recording and western blot to address this question. Our dissociated recording shows that knockout PCs had increased TEA-sensitive, Ca2+-dependent K+ currents. Applying antagonist to large conductance Ca2+-activated K+ (BK) channels further isolated the increased current as BK current. Consistently, we found increased amplitude of afterhyperpolarization and elevated BK protein levels in the knockout mice. Dissociated recording also shows a decrease in TEA-insensitive, Ca2+-dependent K+ currents. The result is consistent with reduced amplitude of tail currents, mainly composed of small conductance Ca2+-activated K+ (SK) currents, in slice recording. Our results suggest that BK and SK channels may be responsible for the hyperactivity of knockout PCs. Recently, BTBD9 protein was shown to associate with SYNGAP1 protein. We found a decreased cerebellar level of SYNGAP1 in Btbd9 knockout mice. However, Syngap1 heterozygous knockout mice showed nocturnal, instead of diurnal, motor restlessness. Our results suggest that SYNGAP1 deficiency may not contribute directly to the RLS-like motor restlessness observed in Btbd9 knockout mice. Finally, we found that PC-specific Btbd9 knockout mice exhibited deficits in motor coordination and balance similar to Btbd9 knockout mice, suggesting that the motor effect of BTBD9 in PCs is cell-autonomous.
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Affiliation(s)
- Shangru Lyu
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Hong Xing
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Yuning Liu
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Pallavi Girdhar
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Fumiaki Yokoi
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Yuqing Li
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA.
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15
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Wright D, Kenny A, Eley S, McKechanie AG, Stanfield AC. Clinical and behavioural features of SYNGAP1-related intellectual disability: a parent and caregiver description. J Neurodev Disord 2022; 14:34. [PMID: 35655128 PMCID: PMC9164368 DOI: 10.1186/s11689-022-09437-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 04/05/2022] [Indexed: 11/26/2022] Open
Abstract
Background SYNGAP1-related intellectual disability (ID) is a recently described neurodevelopmental disorder that is caused by pathogenic variation in the SYNGAP1 gene. To date, the behavioural characteristics of this disorder have mainly been highlighted via the prevalence of existing diagnoses in case series. We set out to detail the behavioural features of this disorder by undertaking interviews with those who have a child with SYNGAP1-related ID to allow them to describe their child’s behaviour. Methods We conducted 27 semi-structured interviews with parents and caregivers which covered basic information (e.g., age, gender), family history, perinatal history, past medical history, developmental history, epilepsy, behavioural history, and a general description of their child’s behaviour. Results Using a mixed quantitative and qualitative approach, the responses from the parents indicated that those with SYNGAP1-related ID showed high rates of autism spectrum disorder (52%), difficulties with fine and gross motor skills, delays in language development, and a high prevalence of epilepsy (70%). A qualitative analysis highlighted their general behaviour affected the themes of daily living skills, distress-related behaviours, emotional regulation, difficulties with change, a lack of danger awareness, and sensory differences. Sensory features described involved auditory, visual, tactile, gustatory, and proprioceptive themes. Conclusions Our findings and behavioural descriptions provide important insights as well as implications for the diagnosis and care of those with SYNGAP1-related ID. Supplementary Information The online version contains supplementary material available at 10.1186/s11689-022-09437-x.
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Affiliation(s)
- Damien Wright
- Patrick Wild Centre, Division of Psychiatry, Kennedy Tower, Royal Edinburgh Hospital, University of Edinburgh, Edinburgh, EH10 5HF, Scotland.
| | - Aisling Kenny
- Patrick Wild Centre, Division of Psychiatry, Kennedy Tower, Royal Edinburgh Hospital, University of Edinburgh, Edinburgh, EH10 5HF, Scotland
| | - Sarah Eley
- Patrick Wild Centre, Division of Psychiatry, Kennedy Tower, Royal Edinburgh Hospital, University of Edinburgh, Edinburgh, EH10 5HF, Scotland
| | - Andrew G McKechanie
- Patrick Wild Centre, Division of Psychiatry, Kennedy Tower, Royal Edinburgh Hospital, University of Edinburgh, Edinburgh, EH10 5HF, Scotland
| | - Andrew C Stanfield
- Patrick Wild Centre, Division of Psychiatry, Kennedy Tower, Royal Edinburgh Hospital, University of Edinburgh, Edinburgh, EH10 5HF, Scotland
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Kilinc M, Arora V, Creson TK, Rojas C, Le AA, Lauterborn J, Wilkinson B, Hartel N, Graham N, Reich A, Gou G, Araki Y, Bayés À, Coba M, Lynch G, Miller CA, Rumbaugh G. Endogenous Syngap1 alpha splice forms promote cognitive function and seizure protection. eLife 2022; 11:e75707. [PMID: 35394425 PMCID: PMC9064290 DOI: 10.7554/elife.75707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 04/08/2022] [Indexed: 11/13/2022] Open
Abstract
Loss-of-function variants in SYNGAP1 cause a developmental encephalopathy defined by cognitive impairment, autistic features, and epilepsy. SYNGAP1 splicing leads to expression of distinct functional protein isoforms. Splicing imparts multiple cellular functions of SynGAP proteins through coding of distinct C-terminal motifs. However, it remains unknown how these different splice sequences function in vivo to regulate neuronal function and behavior. Reduced expression of SynGAP-α1/2 C-terminal splice variants in mice caused severe phenotypes, including reduced survival, impaired learning, and reduced seizure latency. In contrast, upregulation of α1/2 expression improved learning and increased seizure latency. Mice expressing α1-specific mutations, which disrupted SynGAP cellular functions without altering protein expression, promoted seizure, disrupted synapse plasticity, and impaired learning. These findings demonstrate that endogenous SynGAP isoforms with α1/2 spliced sequences promote cognitive function and impart seizure protection. Regulation of SynGAP-αexpression or function may be a viable therapeutic strategy to broadly improve cognitive function and mitigate seizure.
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Affiliation(s)
- Murat Kilinc
- Graduate School of Chemical and Biological Sciences, The Scripps Research InstituteJupiterUnited States
- Departments of Neuroscience and Molecular Medicine, The Scripps Research InstituteJupiterUnited States
| | - Vineet Arora
- Departments of Neuroscience and Molecular Medicine, The Scripps Research InstituteJupiterUnited States
| | - Thomas K Creson
- Departments of Neuroscience and Molecular Medicine, The Scripps Research InstituteJupiterUnited States
| | - Camilo Rojas
- Departments of Neuroscience and Molecular Medicine, The Scripps Research InstituteJupiterUnited States
| | - Aliza A Le
- Department of Anatomy and Neurobiology, The University of CaliforniaIrvineUnited States
| | - Julie Lauterborn
- Department of Anatomy and Neurobiology, The University of CaliforniaIrvineUnited States
| | - Brent Wilkinson
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern CaliforniaLos AngelesUnited States
| | - Nicolas Hartel
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern CaliforniaLos AngelesUnited States
| | - Nicholas Graham
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern CaliforniaLos AngelesUnited States
| | - Adrian Reich
- Bioinformatics and Statistics Core, The Scripps Research InstituteJupiterUnited States
| | - Gemma Gou
- Molecular Physiology of the Synapse Laboratory, Institut d'Investigació Biomèdica Sant PauBarcelonaSpain
- Universitat Autònoma de BarcelonaBellaterraSpain
| | - Yoichi Araki
- Department of Neuroscience, Johns Hopkins School of MedicineBaltimoreUnited States
| | - Àlex Bayés
- Molecular Physiology of the Synapse Laboratory, Institut d'Investigació Biomèdica Sant PauBarcelonaSpain
| | - Marcelo Coba
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern CaliforniaLos AngelesUnited States
| | - Gary Lynch
- Department of Anatomy and Neurobiology, The University of CaliforniaIrvineUnited States
| | - Courtney A Miller
- Graduate School of Chemical and Biological Sciences, The Scripps Research InstituteJupiterUnited States
- Departments of Neuroscience and Molecular Medicine, The Scripps Research InstituteJupiterUnited States
| | - Gavin Rumbaugh
- Graduate School of Chemical and Biological Sciences, The Scripps Research InstituteJupiterUnited States
- Departments of Neuroscience and Molecular Medicine, The Scripps Research InstituteJupiterUnited States
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17
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Sensory Processing Phenotypes in Phelan-McDermid Syndrome and SYNGAP1-Related Intellectual Disability. Brain Sci 2022; 12:brainsci12020137. [PMID: 35203901 PMCID: PMC8869824 DOI: 10.3390/brainsci12020137] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/11/2022] [Accepted: 01/14/2022] [Indexed: 02/06/2023] Open
Abstract
Sensory processing differences are an established feature of both syndromic and non-syndromic Autism Spectrum Disorders (ASDs). Significant work has been carried out to characterize and classify specific sensory profiles in non-syndromic autism. However, it is not known if syndromic autism disorders, such as Phelan-McDermid Syndrome (PMD) or SYNGAP1-related Intellectual Disability (SYNGAP1-ID), have unique sensory phenotypes. Understanding the sensory features of these disorders is important for providing appropriate care and for understanding their underlying mechanisms. Our objective in this work was to determine the sensory processing abnormalities present in two syndromic ASDs: Phelan-McDermid Syndrome and SYNGAP1-related Intellectual Disability. Using a standardized instrument, the Short Sensory Profile-2, we characterized sensory features in 41 patients with PMD and 24 patients with SYNGAP1-ID, and sub-scores were then calculated for seeking, avoiding, sensitivity and registration, as well as overall sensory and behavior scores. We found both patient groups exhibited atypical sensory features, including high scores in the areas of avoiding and seeking. Thus, we discovered significant sensory processing abnormalities are common in these syndromic ASDs. Measurements of sensory processing could serve as useful clinical endpoints for trials of novel therapeutics for these populations.
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18
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Montero-Bullón JF, González-Velasco Ó, Isidoro-García M, Lacal J. Integrated in silico MS-based phosphoproteomics and network enrichment analysis of RASopathy proteins. Orphanet J Rare Dis 2021; 16:303. [PMID: 34229750 PMCID: PMC8258961 DOI: 10.1186/s13023-021-01934-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 06/27/2021] [Indexed: 11/30/2022] Open
Abstract
Background RASopathies are a group of syndromes showing clinical overlap caused by mutations in genes affecting the RAS-MAPK pathway. Consequent disruption on cellular signaling leads and is driven by phosphoproteome remodeling. However, we still lack a comprehensive picture of the different key players and altered downstream effectors. Methods An in silico interactome of RASopathy proteins was generated using pathway enrichment analysis/STRING tool, including identification of main hub proteins. We also integrated phosphoproteomic and immunoblotting studies using previous published information on RASopathy proteins and their neighbors in the context of RASopathy syndromes. Data from Phosphosite database (www.phosphosite.org) was collected in order to obtain the potential phosphosites subjected to regulation in the 27 causative RASopathy proteins. We compiled a dataset of dysregulated phosphosites in RASopathies, searched for commonalities between syndromes in harmonized data, and analyzed the role of phosphorylation in the syndromes by the identification of key players between the causative RASopathy proteins and the associated interactome. Results In this study, we provide a curated data set of 27 causative RASopathy genes, identify up to 511 protein–protein associations using pathway enrichment analysis/STRING tool, and identify 12 nodes as main hub proteins. We found that a large group of proteins contain tyrosine residues and their biological processes include but are not limited to the nervous system. Harmonizing published RASopathy phosphoproteomic and immunoblotting studies we identified a total of 147 phosphosites with increased phosphorylation, whereas 47 have reduced phosphorylation. The PKB signaling pathway is the most represented among the dysregulated phosphoproteins within the RASopathy proteins and their neighbors, followed by phosphoproteins implicated in the regulation of cell proliferation and the MAPK pathway. Conclusions This work illustrates the complex network underlying the RASopathies and the potential of phosphoproteomics for dissecting the molecular mechanisms in these syndromes. A combined study of associated genes, their interactome and phosphorylation events in RASopathies, elucidates key players and mechanisms to direct future research, diagnosis and therapeutic windows. Supplementary Information The online version contains supplementary material available at 10.1186/s13023-021-01934-x.
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Affiliation(s)
- Javier-Fernando Montero-Bullón
- Metabolic Engineering Group, Department of Microbiology and Genetics, Faculty of Biology, University of Salamanca, 37007, Salamanca, Spain
| | - Óscar González-Velasco
- Bioinformatics and Functional Genomics Group, IBMCC Cancer Research Center, Campus Miguel de Unamuno, 37007, Salamanca, Spain
| | - María Isidoro-García
- Institute for Biomedical Research of Salamanca (IBSAL), 37007, Salamanca, Spain.,Network for Cooperative Research in Health-RETICS ARADyAL, 37007, Salamanca, Spain.,Department of Clinical Biochemistry, University Hospital of Salamanca, 37007, Salamanca, Spain.,Department of Medicine, University of Salamanca, 37007, Salamanca, Spain
| | - Jesus Lacal
- Institute for Biomedical Research of Salamanca (IBSAL), 37007, Salamanca, Spain. .,Molecular Genetics of Human Diseases Group, Department of Microbiology and Genetics, Faculty of Biology, University of Salamanca, 37007, Salamanca, Spain.
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Brock DC, Demarest S, Benke TA. Clinical Trial Design for Disease-Modifying Therapies for Genetic Epilepsies. Neurotherapeutics 2021; 18:1445-1457. [PMID: 34595733 PMCID: PMC8609073 DOI: 10.1007/s13311-021-01123-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2021] [Indexed: 02/04/2023] Open
Abstract
Although trials with anti-seizure medications (ASMs) have not shown clear anti-epileptogenic or disease-modifying activity in humans to date, rapid advancements in genomic technology and emerging gene-mediated and gene replacement options offer hope for the successful development of disease-modifying therapies (DMTs) for genetic epilepsies. In fact, more than 26 potential DMTs are in various stages of preclinical and/or clinical development for genetic syndromes associated with epilepsy. The scope of disease-modification includes but is not limited to effects on the underlying pathophysiology, the condition's natural history, epilepsy severity, developmental achievement, function, behavior, sleep, and quality of life. While conventional regulatory clinical trials for epilepsy therapeutics have historically focused on seizure reduction, similarly designed trials may prove ill-equipped to identify these broader disease-modifying benefits. As we look forward to this pipeline of DMTs, focused consideration should be given to the challenges they pose to conventional clinical trial designs for epilepsy therapeutics. Just as DMTs promise to fundamentally alter how we approach the care of patients with genetic epilepsy syndromes, DMTs likewise challenge how we traditionally construct and measure the success of clinical trials. In the following, we briefly review the historical and preclinical frameworks for DMT development for genetic epilepsies and explore the many novel challenges posed for such trials, including the choice of suitable outcome measures, trial structure, timing and duration of treatment, feasible follow-up period, varying safety profile, and ethical concerns.
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Affiliation(s)
- Dylan C Brock
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, 80045, USA.
- Children's Hospital Colorado, Aurora, CO, 80045, USA.
| | - Scott Demarest
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, 80045, USA
- Children's Hospital Colorado, Aurora, CO, 80045, USA
| | - Tim A Benke
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, 80045, USA
- Departments of Neurology, Pharmacology, and Otolaryngology, University of Colorado School of Medicine, CO, 80045, Aurora, USA
- Children's Hospital Colorado, Aurora, CO, 80045, USA
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20
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Côté V, Knoth IS, Agbogba K, Vannasing P, Côté L, Major P, Michaud JL, Barlaam F, Lippé S. Differential auditory brain response abnormalities in two intellectual disability conditions: SYNGAP1 mutations and Down syndrome. Clin Neurophysiol 2021; 132:1802-1812. [PMID: 34130248 DOI: 10.1016/j.clinph.2021.03.054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 03/06/2021] [Accepted: 03/31/2021] [Indexed: 10/21/2022]
Abstract
OBJECTIVE Altered sensory processing is common in intellectual disability (ID). Here, we study electroencephalographic responses to auditory stimulation in human subjects presenting a rare condition (mutations in SYNGAP1) which causes ID, epilepsy and autism. METHODS Auditory evoked potentials, time-frequency and inter-trial coherence analyses were used to compare subjects with SYNGAP1 mutations with Down syndrome (DS) and neurotypical (NT) participants (N = 61 ranging from three to 19 years of age). RESULTS Altered synchronization in the brain responses to sound were found in both ID groups. The SYNGAP1 mutations group showed less phase-locking in early time windows and lower frequency bands compared to NT, and in later time windows compared to NT and DS. Time-frequency analysis showed more power in beta-gamma in the SYNGAP1 group compared to NT participants. CONCLUSIONS This study indicated reduced synchronization as well as more high frequencies power in SYNGAP1 mutations, while maintained synchronization was found in the DS group. These results might reflect dysfunctional sensory information processing caused by excitation/inhibition imbalance, or an imperfect compensatory mechanism in SYNGAP1 mutations individuals. SIGNIFICANCE Our study is the first to reveal brain response abnormalities in auditory sensory processing in SYNGAP1 mutations individuals, that are distinct from DS, another ID condition.
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Affiliation(s)
- Valérie Côté
- Department of Psychology, University of Montreal, Montreal, Québec, Canada; CHU Sainte-Justine Research Center, Montreal, Quebec, Canada
| | - Inga S Knoth
- CHU Sainte-Justine Research Center, Montreal, Quebec, Canada
| | | | | | - Lucie Côté
- CHU Sainte-Justine Research Center, Montreal, Quebec, Canada
| | - Philippe Major
- CHU Sainte-Justine Research Center, Montreal, Quebec, Canada; Department of Pediatrics and Neurosciences, University of Montreal, Montreal, Quebec, Canada
| | - Jacques L Michaud
- CHU Sainte-Justine Research Center, Montreal, Quebec, Canada; Department of Pediatrics and Neurosciences, University of Montreal, Montreal, Quebec, Canada
| | - Fanny Barlaam
- CHU Sainte-Justine Research Center, Montreal, Quebec, Canada
| | - Sarah Lippé
- Department of Psychology, University of Montreal, Montreal, Québec, Canada; CHU Sainte-Justine Research Center, Montreal, Quebec, Canada.
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21
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Garozzo MT, Caruso D, La Mendola FMC, Di Nora A, Romano K, Leonardi R, Falsaperla R, Zanghì A, Praticò AD. SYNGAP1 and Its Related Epileptic Syndromes. JOURNAL OF PEDIATRIC NEUROLOGY 2021. [DOI: 10.1055/s-0041-1727144] [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
AbstractSynaptic Ras GTPase-activating protein 1 (SYNGAP1) is abundantly expressed in the postsynaptic space in brain tissue and has a crucial role in the regulation of the excitatory/inhibitory balance and in brain development. It is estimated that SYNGAP1 loss of function variants have an incidence of 1 to 4/10,000 individuals, mostly occurring de novo, even if few cases of vertical transmission of mosaic mutations have been reported. Loss-of-function mutations within this gene have been related with an epileptic encephalopathy characterized by eyelid myoclonia with absences (EMA) and myoclonic-atonic seizures (MAE) with early onset, commonly resistant to antiepileptic drugs (AED). Epilepsy is often associated with other clinical features, including truncal and/or facial hypotonia and/or ataxia with a wide-based and unsteady gate. Other clinical signs are intellectual disability, developmental delay, and behavioral and speech impairment, in a context of a normal neuroimaging study. In selected cases, dysmorphic features, skeletal abnormalities, and eye involvement are also described. The diagnosis of the disorder is usually established by multigene panel and, in unsolved cases, by exome sequencing. Management of the affected individuals involves different specialists and is mainly symptomatic. No clinical trials about the efficacy of AED in SYNGAP1 encephalopathy have been performed yet and Lamotrigine and valproate are commonly prescribed. In more than half of cases, however, epilepsy is refractory to AED.
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Affiliation(s)
- Maria Teresa Garozzo
- Unit of Pediatric and Pediatric Emergency, Hospital “Cannizzaro,” Catania, Italy
| | - Daniela Caruso
- Pediatrics Postgraduate Residency Program, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
| | | | - Alessandra Di Nora
- Pediatrics Postgraduate Residency Program, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
| | | | - Roberta Leonardi
- 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
| | - Antonio Zanghì
- Department of Medical and Surgical Sciences and Advanced Technology “G.F. Ingrassia,” University of Catania, Catania, Italy
| | - Andrea D. Praticò
- Unit of Rare Diseases of the Nervous System in Childhood, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
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22
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Zhang H, Yang L, Duan J, Zeng Q, Chen L, Fang Y, Hu J, Cao D, Liao J. Phenotypes in Children With SYNGAP1 Encephalopathy in China. Front Neurosci 2021; 15:761473. [PMID: 34924933 PMCID: PMC8678593 DOI: 10.3389/fnins.2021.761473] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 10/22/2021] [Indexed: 02/05/2023] Open
Abstract
Objective: We aimed to explore the associated clinical phenotype and the natural history of patients with SYNGAP1 gene variations during early childhood and to identify their genotype-phenotype correlations. Methods: This study used a cohort of 13 patients with epilepsy and developmental disorder due to SYNGAP1 mutations, namely, 7 patients from Shenzhen Children's Hospital between September 2014 and January 2020 and 6 patients from previously published studies. Their clinical data were studied. Results: A total of 13 children with SYNGAP1 gene variants (eight boys and five girls) were identified. The age of disease onset was in infancy. Mutations were located between exons 8 and 15; most were frameshift or truncated mutations. Four mutation sites (c.924G > A, c.1532-2_1532del, c.1747_1755dup, and c.1735_1738del) had not been reported before. All patients had global developmental delay within the first year of life, and intellectual impairment became gradually apparent. Some of them developed behavioral problems. The developmental delay occurred before the onset of seizures. All seven patients in our cohort presented with epilepsy; myoclonic seizures, absence seizures, and epileptic spasms were the most common seizure types. Abnormal electroencephalograms were identified from five patients before the onset of their seizures. All patients suffered from drug-resistance seizures. However, comorbidities such as behavioral problems were less frequently observed. Conclusion: The most common age of disease onset in SYNGAP1 gene mutations is in infancy, while neurodevelopmental delay and epilepsy are the major phenotypes. They have a higher percentage of drug-resistant epilepsy and epileptic spasms than those in previous reports. We should give attention to the patients with abnormal EEGs without seizures and think about the suitable time of the anti-seizure medications for them. We have not found the genotype-phenotype correlation. Trial registration: Chinese Clinical Trial Registry, Registration number: ChiCTR2100049289 (https://www.chictr.org.cn/listbycreater.aspx).
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Affiliation(s)
- Huiting Zhang
- Shenzhen Children’s Hospital, China Medical University, Shenzhen, China
| | - Liu Yang
- Guangdong Women and Children Hospital, Guangzhou, China
| | - Jing Duan
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Qi Zeng
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Li Chen
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Yu Fang
- Shenzhen Children’s Hospital, China Medical University, Shenzhen, China
| | - Junjie Hu
- Shenzhen Children’s Hospital, Shantou University, Shenzhen, China
| | - Dezhi Cao
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Jianxiang Liao
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
- *Correspondence: Jianxiang Liao,
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23
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Kuchenbuch M, D'Onofrio G, Chemaly N, Barcia G, Teng T, Nabbout R. Add-on cannabidiol significantly decreases seizures in 3 patients with SYNGAP1 developmental and epileptic encephalopathy. Epilepsia Open 2020; 5:496-500. [PMID: 32913957 PMCID: PMC7469777 DOI: 10.1002/epi4.12411] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 05/03/2020] [Accepted: 05/28/2020] [Indexed: 01/11/2023] Open
Abstract
Mutations in SYNGAP1 are associated with developmental delay, epilepsy, and autism spectrum disorder (ASD). Epilepsy is often drug-resistant in this syndrome with frequent drop attacks. In a prospective study of add-on cannabidiol (CBD), we identified three patients with SYNGAP1 mutations: two boys and one girl. Seizure onset was at 3.5, 8, and 18 months (M), respectively, with numerous atypical absences per day associated with eyelid myoclonia (2/3 patients), upper limb myoclonic jerks (2/3 patients), and drop attacks (all patients). Seizures were resistant to at least 5 antiepileptic drugs (AEDs). After CBD introduction, two patients were responders since M2 and achieve a seizure reduction of 90% and 80%, respectively, at M9 with disappearance of drop attacks. EEGs showed an improvement regarding background activity and interictal anomalies. The last patient showed a late response at M7 of treatment with an 80% decrease in seizure frequency. Caregiver in all three evaluated as much improved the status of their children. Treatment was well-tolerated in all, and no major adverse events (AEs) were reported. CBD showed efficacy in patients with drug-resistant epilepsy due to SYNGAP1 mutations. Other patients with rare genetic developmental and epileptic encephalopathies with drug-resistant epilepsies might benefit from CBD.
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Affiliation(s)
- Mathieu Kuchenbuch
- Department of Pediatric NeurologyReference Centre for Rare EpilepsiesHôpital Necker‐Enfants MaladesParisFrance
- Laboratory of Translational Research for Neurological DisordersINSERMUMR 1163Imagine InstituteParisFrance
- Université Paris Descartes ‐Université de ParisParisFrance
| | - Gianluca D'Onofrio
- Department of Pediatric NeurologyReference Centre for Rare EpilepsiesHôpital Necker‐Enfants MaladesParisFrance
| | - Nicole Chemaly
- Department of Pediatric NeurologyReference Centre for Rare EpilepsiesHôpital Necker‐Enfants MaladesParisFrance
- Laboratory of Translational Research for Neurological DisordersINSERMUMR 1163Imagine InstituteParisFrance
| | - Giulia Barcia
- Laboratory of Translational Research for Neurological DisordersINSERMUMR 1163Imagine InstituteParisFrance
- Department of geneticHôpital Necker‐Enfants MaladesParisFrance
| | - Théo Teng
- Department of Pediatric NeurologyReference Centre for Rare EpilepsiesHôpital Necker‐Enfants MaladesParisFrance
| | - Rima Nabbout
- Department of Pediatric NeurologyReference Centre for Rare EpilepsiesHôpital Necker‐Enfants MaladesParisFrance
- Laboratory of Translational Research for Neurological DisordersINSERMUMR 1163Imagine InstituteParisFrance
- Université Paris Descartes ‐Université de ParisParisFrance
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24
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Twenty Years of SynGAP Research: From Synapses to Cognition. J Neurosci 2020; 40:1596-1605. [PMID: 32075947 DOI: 10.1523/jneurosci.0420-19.2020] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 01/03/2020] [Accepted: 01/07/2020] [Indexed: 12/11/2022] Open
Abstract
SynGAP is a potent regulator of biochemical signaling in neurons and plays critical roles in neuronal function. It was first identified in 1998, and has since been extensively characterized as a mediator of synaptic plasticity. Because of its involvement in synaptic plasticity, SynGAP has emerged as a critical protein for normal cognitive function. In recent years, mutations in the SYNGAP1 gene have been shown to cause intellectual disability in humans and have been linked to other neurodevelopmental disorders, such as autism spectrum disorders and schizophrenia. While the structure and biochemical function of SynGAP have been well characterized, a unified understanding of the various roles of SynGAP at the synapse and its contributions to neuronal function remains to be achieved. In this review, we summarize and discuss the current understanding of the multifactorial role of SynGAP in regulating neuronal function gathered over the last two decades.
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25
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Creson TK, Rojas C, Hwaun E, Vaissiere T, Kilinc M, Jimenez-Gomez A, Holder JL, Tang J, Colgin LL, Miller CA, Rumbaugh G. Re-expression of SynGAP protein in adulthood improves translatable measures of brain function and behavior. eLife 2019; 8:46752. [PMID: 31025938 PMCID: PMC6504227 DOI: 10.7554/elife.46752] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 04/15/2019] [Indexed: 12/13/2022] Open
Abstract
It remains unclear to what extent neurodevelopmental disorder (NDD) risk genes retain functions into adulthood and how they may influence disease phenotypes. SYNGAP1 haploinsufficiency causes a severe NDD defined by autistic traits, cognitive impairment, and epilepsy. To determine if this gene retains therapeutically-relevant biological functions into adulthood, we performed a gene restoration technique in a mouse model for SYNGAP1 haploinsufficiency. Adult restoration of SynGAP protein improved behavioral and electrophysiological measures of memory and seizure. This included the elimination of interictal events that worsened during sleep. These events may be a biomarker for generalized cortical dysfunction in SYNGAP1 disorders because they also worsened during sleep in the human patient population. We conclude that SynGAP protein retains biological functions throughout adulthood and that non-developmental functions may contribute to disease phenotypes. Thus, treatments that target debilitating aspects of severe NDDs, such as medically-refractory seizures and cognitive impairment, may be effective in adult patients.
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Affiliation(s)
- Thomas K Creson
- Department of Neuroscience, The Scripps Research Institute, Jupiter, United States.,Department of Molecular Medicine, The Scripps Research Institute, Jupiter, United States
| | - Camilo Rojas
- Department of Neuroscience, The Scripps Research Institute, Jupiter, United States.,Department of Molecular Medicine, The Scripps Research Institute, Jupiter, United States
| | - Ernie Hwaun
- Department of Neuroscience, Institute for Neuroscience, Center for Learning and Memory, University of Texas at Austin, Austin, United States
| | - Thomas Vaissiere
- Department of Neuroscience, The Scripps Research Institute, Jupiter, United States.,Department of Molecular Medicine, The Scripps Research Institute, Jupiter, United States
| | - Murat Kilinc
- Department of Neuroscience, The Scripps Research Institute, Jupiter, United States.,Department of Molecular Medicine, The Scripps Research Institute, Jupiter, United States
| | - Andres Jimenez-Gomez
- Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, United States.,Department of Pediatrics, Baylor College of Medicine, Houston, United States
| | - Jimmy Lloyd Holder
- Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, United States.,Department of Pediatrics, Baylor College of Medicine, Houston, United States
| | - Jianrong Tang
- Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, United States.,Department of Pediatrics, Baylor College of Medicine, Houston, United States
| | - Laura L Colgin
- Department of Neuroscience, Institute for Neuroscience, Center for Learning and Memory, University of Texas at Austin, Austin, United States
| | - Courtney A Miller
- Department of Neuroscience, The Scripps Research Institute, Jupiter, United States.,Department of Molecular Medicine, The Scripps Research Institute, Jupiter, United States
| | - Gavin Rumbaugh
- Department of Neuroscience, The Scripps Research Institute, Jupiter, United States.,Department of Molecular Medicine, The Scripps Research Institute, Jupiter, United States
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26
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Dual diagnosis causing severe phenotype in a patient with Angelman syndrome. Clin Dysmorphol 2019; 28:160-163. [PMID: 30998607 DOI: 10.1097/mcd.0000000000000280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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27
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Brimble E, Lee-Messer C, Nagy PL, Propst J, Ruzhnikov MRZ. Clinical Transcriptome Sequencing Confirms Activation of a Cryptic Splice Site in Suspected SYNGAP1-Related Disorder. Mol Syndromol 2019; 9:295-299. [PMID: 30800045 DOI: 10.1159/000492706] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2018] [Indexed: 11/19/2022] Open
Abstract
SYNGAP1 encodes a brain-specific Ras GTPase activating protein (GAP) that regulates synaptic strength in glutamatergic neurons. Pathogenic variants in this gene are associated with a neurodevelopmental disorder characterized by intellectual and developmental disabilities, generalized epilepsy, hypotonia, and autism spectrum disorders. We describe a young male with suspected SYNGAP1-related disorder given clinical overlap and identification of an intronic variant of uncertain significance; clinical transcriptome analysis demonstrated activation of a cryptic acceptor splice site resulting in frameshift and introduction of a stop codon. This report highlights the utility of functional studies newly available to clinical practice in confirming a suspected genetic diagnosis, which can directly impact medical management and preclude the need for additional diagnostic testing.
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Affiliation(s)
- Elise Brimble
- Department of Neurology and Neurological Sciences, Stanford, CA
| | | | | | - Jennifer Propst
- Division of Clinical Genetics, Virginia Commonwealth University Health System, Richmond, VA, USA
| | - Maura R Z Ruzhnikov
- Department of Neurology and Neurological Sciences, Stanford, CA.,Division of Medical Genetics, Department of Pediatrics, Stanford Medicine, Stanford, CA
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28
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Kilinc M, Creson T, Rojas C, Aceti M, Ellegood J, Vaissiere T, Lerch JP, Rumbaugh G. Species-conserved SYNGAP1 phenotypes associated with neurodevelopmental disorders. Mol Cell Neurosci 2018; 91:140-150. [PMID: 29580901 DOI: 10.1016/j.mcn.2018.03.008] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 03/16/2018] [Accepted: 03/17/2018] [Indexed: 01/22/2023] Open
Abstract
SYNGAP1 loss-of-function variants are causally associated with intellectual disability, severe epilepsy, autism spectrum disorder and schizophrenia. While there are hundreds of genetic risk factors for neurodevelopmental disorders (NDDs), this gene is somewhat unique because of the frequency and penetrance of loss-of-function variants found in patients combined with the range of brain disorders associated with SYNGAP1 pathogenicity. These clinical findings indicate that SYNGAP1 regulates fundamental neurodevelopmental processes that are necessary for brain development. Here, we describe four phenotypic domains that are controlled by Syngap1 expression across vertebrate species. Two domains, the maturation of cognitive functions and maintenance of excitatory-inhibitory balance, are defined exclusively through a review of the current literature. Two additional domains are defined by integrating the current literature with new data indicating that SYNGAP1/Syngap1 regulates innate survival behaviors and brain structure. These four phenotypic domains are commonly disrupted in NDDs, suggesting that a deeper understanding of developmental Syngap1 functions will be generalizable to other NDDs of known or unknown etiology. Therefore, we discuss the known molecular and cellular functions of Syngap1 and consider how these functions may contribute to the emergence of disease-relevant phenotypes. Finally, we identify major unexplored areas of Syngap1 neurobiology and discuss how a deeper understanding of this gene may uncover general principles of NDD pathobiology.
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Affiliation(s)
- Murat Kilinc
- Graduate School of Chemical and Biological Sciences, The Scripps Research Institute, Jupiter, FL, United States
| | - Thomas Creson
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL, United States
| | - Camilo Rojas
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL, United States
| | - Massimiliano Aceti
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL, United States
| | - Jacob Ellegood
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, ONT, Canada
| | - Thomas Vaissiere
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL, United States
| | - Jason P Lerch
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, ONT, Canada; Medical Biophysics, University of Toronto, Toronto, ONT, Canada
| | - Gavin Rumbaugh
- Graduate School of Chemical and Biological Sciences, The Scripps Research Institute, Jupiter, FL, United States; Department of Neuroscience, The Scripps Research Institute, Jupiter, FL, United States.
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