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Khoja S, Chen LY. Conditional deletion of neurexin-2 impaired behavioral flexibility to alterations in action-outcome contingency. Sci Rep 2024; 14:10187. [PMID: 38702381 PMCID: PMC11068883 DOI: 10.1038/s41598-024-60760-w] [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: 01/17/2024] [Accepted: 04/26/2024] [Indexed: 05/06/2024] Open
Abstract
Neurexins (Nrxns) are critical for synapse organization and their mutations have been documented in autism spectrum disorder, schizophrenia, and epilepsy. We recently reported that conditional deletion of Nrxn2, under the control of Emx1Cre promoter, predominately expressed in the neocortex and hippocampus (Emx1-Nrxn2 cKO mice) induced stereotyped patterns of behavior in mice, suggesting behavioral inflexibility. In this study, we investigated the effects of Nrxn2 deletion through two different conditional approaches targeting presynaptic cortical neurons projecting to dorsomedial striatum on the flexibility between goal-directed and habitual actions in response to devaluation of action-outcome (A-O) contingencies in an instrumental learning paradigm or upon reversal of A-O contingencies in a water T-maze paradigm. Nrxn2 deletion through both the conditional approaches induced an inability of mice to discriminate between goal-directed and habitual action strategies in their response to devaluation of A-O contingency. Emx1-Nrxn2 cKO mice exhibited reversal learning deficits, indicating their inability to adopt new action strategies. Overall, our studies showed that Nrxn2 deletion through two distinct conditional deletion approaches impaired flexibility in response to alterations in A-O contingencies. These investigations can lay the foundation for identification of novel genetic factors underlying behavioral inflexibility.
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Affiliation(s)
- Sheraz Khoja
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA, 92697, USA
| | - Lulu Y Chen
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA, 92697, USA.
- Center for Neurobiology of Learning and Memory, Herklotz Research Facility, University of California, Irvine, CA, 92697, USA.
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Feichtinger RG, Preisel M, Brugger K, Wortmann SB, Mayr JA. Case Report-An Inherited Loss-of-Function NRXN3 Variant Potentially Causes a Neurodevelopmental Disorder with Autism Consistent with Previously Described 14q24.3-31.1 Deletions. Genes (Basel) 2023; 14:1217. [PMID: 37372397 DOI: 10.3390/genes14061217] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 05/26/2023] [Accepted: 05/31/2023] [Indexed: 06/29/2023] Open
Abstract
BACKGROUND Heterozygous, large-scale deletions at 14q24.3-31.1 affecting the neurexin-3 gene have been associated with neurodevelopmental disorders such as autism. Both "de novo" occurrences and inheritance from a healthy parent suggest incomplete penetrance and expressivity, especially in autism spectrum disorder. NRXN3 encodes neurexin-3, a neuronal cell surface protein involved in cell recognition and adhesion, as well as mediating intracellular signaling. NRXN3 is expressed in two distinct isoforms (alpha and beta) generated by alternative promoters and splicing. MM/Results: Using exome sequencing, we identified a monoallelic frameshift variant c.159_160del (p.Gln54AlafsTer50) in the NRXN3 beta isoform (NM_001272020.2) in a 5-year-old girl with developmental delay, autism spectrum disorder, and behavioral issues. This variant was inherited from her mother, who did not have any medical complaints. DISCUSSION This is the first detailed report of a loss-of-function variant in NRXN3 causing an identical phenotype, as reported for heterozygous large-scale deletions in the same genomic region, thereby confirming NRXN3 as a novel gene for neurodevelopmental disorders with autism.
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Affiliation(s)
- René G Feichtinger
- University Children's Hospital, Salzburger Landeskliniken (SALK) und Paracelsus Medical University (PMU), 5020 Salzburg, Austria
| | - Martin Preisel
- University Children's Hospital, Salzburger Landeskliniken (SALK) und Paracelsus Medical University (PMU), 5020 Salzburg, Austria
| | - Karin Brugger
- University Children's Hospital, Salzburger Landeskliniken (SALK) und Paracelsus Medical University (PMU), 5020 Salzburg, Austria
| | - Saskia B Wortmann
- University Children's Hospital, Salzburger Landeskliniken (SALK) und Paracelsus Medical University (PMU), 5020 Salzburg, Austria
- Amalia Children's Hospital, Radboudumc, 6525 HB Nijmegen, The Netherlands
| | - Johannes A Mayr
- University Children's Hospital, Salzburger Landeskliniken (SALK) und Paracelsus Medical University (PMU), 5020 Salzburg, Austria
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Brownstein CA, Douard E, Haynes RL, Koh HY, Haghighi A, Keywan C, Martin B, Alexandrescu S, Haas EA, Vargas SO, Wojcik MH, Jacquemont S, Poduri AH, Goldstein RD, Holm IA. Copy Number Variation and Structural Genomic Findings in 116 Cases of Sudden Unexplained Death between 1 and 28 Months of Age. ADVANCED GENETICS (HOBOKEN, N.J.) 2023; 4:2200012. [PMID: 36910592 PMCID: PMC10000288 DOI: 10.1002/ggn2.202200012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 08/31/2022] [Indexed: 11/09/2022]
Abstract
In sudden unexplained death in pediatrics (SUDP) the cause of death is unknown despite an autopsy and investigation. The role of copy number variations (CNVs) in SUDP has not been well-studied. Chromosomal microarray (CMA) data are generated for 116 SUDP cases with age at death between 1 and 28 months. CNVs are classified using the American College of Medical Genetics and Genomics guidelines and CNVs in our cohort are compared to an autism spectrum disorder (ASD) cohort, and to a control cohort. Pathogenic CNVs are identified in 5 of 116 cases (4.3%). Variants of uncertain significance (VUS) favoring pathogenic CNVs are identified in 9 cases (7.8%). Several CNVs are associated with neurodevelopmental phenotypes including seizures, ASD, developmental delay, and schizophrenia. The structural variant 47,XXY is identified in two cases (2/69 boys, 2.9%) not previously diagnosed with Klinefelter syndrome. Pathogenicity scores for deletions are significantly elevated in the SUDP cohort versus controls (p = 0.007) and are not significantly different from the ASD cohort. The finding of pathogenic or VUS favoring pathogenic CNVs, or structural variants, in 12.1% of cases, combined with the observation of higher pathogenicity scores for deletions in SUDP versus controls, suggests that CMA should be included in the genetic evaluation of SUDP.
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The emergence of genotypic divergence and future precision medicine applications. HANDBOOK OF CLINICAL NEUROLOGY 2023; 192:87-99. [PMID: 36796950 DOI: 10.1016/b978-0-323-85538-9.00013-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Genotypic divergence is a term adapted from population genetics and intimately linked to evolution. We use divergence here to emphasize the differences that set individuals apart in any cohort. The history of genetics is filled with descriptions of genotypic differences, but causal inference of interindividual biological variation has been scarce. We suggest that the practice of precision medicine requires a divergent approach, an approach dependent on the causal interpretation of previous convergent (and preliminary) knowledge in the field. This knowledge has relied on convergent descriptive syndromology (lumping), which has overemphasized a reductionistic gene determinism on the quest of seeking associations without causal understanding. Regulatory variants with small effect and somatic mutations are some of the modifying factors that lead to incomplete penetrance and intrafamilial variable expressivity often observed in apparently monogenic clinical disorders. A truly divergent approach to precision medicine requires splitting, that is, the consideration of different layers of genetic phenomena that interact causally in a nonlinear fashion. This chapter reviews convergences and divergences in genetics and genomics, aiming to discuss what can be causally understood to approximate the as-yet utopian lands of Precision Medicine for patients with neurodegenerative disorders.
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Haviland I, Daniels CI, Greene CA, Drew J, Love-Nichols JA, Swanson LC, Smith L, Nie DA, Benke T, Sheidley BR, Zhang B, Poduri A, Olson HE. Genetic Diagnosis Impacts Medical Management for Pediatric Epilepsies. Pediatr Neurol 2023; 138:71-80. [PMID: 36403551 PMCID: PMC10099530 DOI: 10.1016/j.pediatrneurol.2022.10.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 10/05/2022] [Accepted: 10/19/2022] [Indexed: 11/18/2022]
Abstract
BACKGROUND Evidence of the impact of genetic diagnosis on medical management in individuals with previously unexplained epilepsy is lacking in the literature. Our goal was to determine the impact of genetic diagnosis on medical management in a cohort of individuals with early-onset epilepsy. METHODS We performed detailed phenotyping of individuals with epilepsy who underwent clinical genetic testing with an epilepsy panel and/or exome sequencing at Boston Children's Hospital between 2012 and 2019. We assessed the impact of genetic diagnosis on medical management. RESULTS We identified a genetic etiology in 152 of 602 (25%) individuals with infantile- or childhood-onset epilepsy who underwent next-generation sequencing. Diagnosis impacted medical management in at least one category for 72% of patients (110 of 152) and in more than one category in 34%. Treatment was impacted in 45% of individuals, including 36% with impact on antiseizure medication choice, 7% on use of disease-specific vitamin or metabolic treatments, 3% on pathway-driven off-label use of medications, and 10% on discussion of gene-specific clinical trials. Care coordination was impacted in 48% of individuals. Counseling on a change in prognosis was reported in 28% of individuals, and 1% of individuals had a correction of diagnosis. Impact was documented in 13 of 13 individuals with neurotypical development and in 55% of those with epilepsy onset after age two years. CONCLUSION We demonstrated meaningful impact of genetic diagnosis on medical care and prognosis in over 70% of individuals, including those with neurotypical development and age of epilepsy onset after age two years.
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Affiliation(s)
- Isabel Haviland
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Carolyn I Daniels
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Caitlin A Greene
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Jacqueline Drew
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts; Boston University Clinical Investigation Master's Program, Boston, Massachusetts
| | - Jamie A Love-Nichols
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts; Department of Genetics, Seattle Children's Hospital, Seattle, Washington
| | - Lindsay C Swanson
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Lacey Smith
- Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Duyu A Nie
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts; Departments of Pediatrics, Neurology and Neurosurgery, Warren Alpert Medical School of Brown University, Providence, Rhode Island; Division of Pediatric Neurology and the Children's Neurodevelopment Center (CNDC), Hasbro Children's Hospital, Providence, Rhode Island
| | - Timothy Benke
- Departments of Pediatrics, Neurology, Pharmacology, and Otolaryngology, Children's Hospital Colorado, University of Colorado School of Medicine, Aurora, Colorado
| | - Beth R Sheidley
- Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Bo Zhang
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts; Biostatistics and Research Design Center, Institutional Centers for Clinical and Translational Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Annapurna Poduri
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts; Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Heather E Olson
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts; Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts.
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Khoja S, Haile MT, Chen LY. Advances in neurexin studies and the emerging role of neurexin-2 in autism spectrum disorder. Front Mol Neurosci 2023; 16:1125087. [PMID: 36923655 PMCID: PMC10009110 DOI: 10.3389/fnmol.2023.1125087] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 02/08/2023] [Indexed: 03/02/2023] Open
Abstract
Over the past 3 decades, the prevalence of autism spectrum disorder (ASD) has increased globally from 20 to 28 million cases making ASD the fastest-growing developmental disability in the world. Neurexins are a family of presynaptic cell adhesion molecules that have been increasingly implicated in ASD, as evidenced by genetic mutations in the clinical population. Neurexins function as context-dependent specifiers of synapse properties and critical modulators in maintaining the balance between excitatory and inhibitory transmission (E/I balance). Disrupted E/I balance has long been established as a hallmark of ASD making neurexins excellent starting points for understanding the etiology of ASD. Herein we review neurexin mutations that have been discovered in ASD patients. Further, we discuss distinct synaptic mechanisms underlying the aberrant neurotransmission and behavioral deficits observed in different neurexin mouse models, with focus on recent discoveries from the previously overlooked neurexin-2 gene (Nrxn2 in mice and NRXN2 in humans). Hence, the aim of this review is to provide a summary of new synaptic insights into the molecular underpinnings of ASD.
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Affiliation(s)
- Sheraz Khoja
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, Irvine, CA, United States
| | - Mulatwa T Haile
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, Irvine, CA, United States
| | - Lulu Y Chen
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, Irvine, CA, United States
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Janz P, Bainier M, Marashli S, Schoenenberger P, Valencia M, Redondo RL. Neurexin1α knockout rats display oscillatory abnormalities and sensory processing deficits back-translating key endophenotypes of psychiatric disorders. Transl Psychiatry 2022; 12:455. [PMID: 36307390 PMCID: PMC9616904 DOI: 10.1038/s41398-022-02224-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 10/14/2022] [Accepted: 10/18/2022] [Indexed: 11/09/2022] Open
Abstract
Neurexins are presynaptic transmembrane proteins crucial for synapse development and organization. Deletion and missense mutations in all three Neurexin genes have been identified in psychiatric disorders, with mutations in the NRXN1 gene most strongly linked to schizophrenia (SZ) and autism spectrum disorder (ASD). While the consequences of NRXN1 deletion have been extensively studied on the synaptic and behavioral levels, circuit endophenotypes that translate to the human condition have not been characterized yet. Therefore, we investigated the electrophysiology of cortico-striatal-thalamic circuits in Nrxn1α-/- rats and wildtype littermates focusing on a set of translational readouts, including spontaneous oscillatory activity, auditory-evoked oscillations and potentials, as well as mismatch negativity-like (MMN) responses and responses to social stimuli. On the behavioral level Nrxn1α-/- rats showed locomotor hyperactivity. In vivo freely moving electrophysiology revealed pronounced increases of spontaneous oscillatory power within the gamma band in all studied brain areas and elevation of gamma coherence in cortico-striatal and thalamocortical circuits of Nrxn1α-/- rats. In contrast, auditory-evoked oscillations driven by chirp-modulated tones showed reduced power in cortical areas confined to slower oscillations. Finally, Nrxn1α-/- rats exhibited altered auditory evoked-potentials and profound deficits in MMN-like responses, explained by reduced prediction error. Despite deficits for auditory stimuli, responses to social stimuli appeared intact. A central hypothesis for psychiatric and neurodevelopmental disorders is that a disbalance of excitation-to-inhibition is underlying oscillatory and sensory deficits. In a first attempt to explore the impact of inhibitory circuit modulation, we assessed the effects of enhancing tonic inhibition via δ-containing GABAA receptors (using Gaboxadol) on endophenotypes possibly associated with network hyperexcitability. Pharmacological experiments applying Gaboxadol showed genotype-specific differences, but failed to normalize oscillatory or sensory processing abnormalities. In conclusion, our study revealed endophenotypes in Nrxn1α-/- rats that could be used as translational biomarkers for drug development in psychiatric disorders.
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Affiliation(s)
- Philipp Janz
- Roche Pharma Research and Early Development, Neuroscience and Rare Diseases Discovery & Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070, Basel, Switzerland.
| | - Marie Bainier
- grid.417570.00000 0004 0374 1269Roche Pharma Research and Early Development, Neuroscience and Rare Diseases Discovery & Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Samuel Marashli
- grid.417570.00000 0004 0374 1269Roche Pharma Research and Early Development, Neuroscience and Rare Diseases Discovery & Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Philipp Schoenenberger
- grid.417570.00000 0004 0374 1269Roche Pharma Research and Early Development, Neuroscience and Rare Diseases Discovery & Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Miguel Valencia
- grid.5924.a0000000419370271Universidad de Navarra, CIMA, Program of Neuroscience, 31080 Pamplona, Spain ,grid.508840.10000 0004 7662 6114IdiSNA, Navarra Institute for Health Research, 31080 Pamplona, Spain ,grid.5924.a0000000419370271Institute of Data Science and Artificial Intelligence, Universidad de Navarra, 31080 Pamplona, Spain
| | - Roger L. Redondo
- grid.417570.00000 0004 0374 1269Roche Pharma Research and Early Development, Neuroscience and Rare Diseases Discovery & Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070 Basel, Switzerland
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Ma C, Zhang Y. NRXN2 Possesses a Tumor Suppressor Potential via Inhibiting the Growth of Thyroid Cancer Cells. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2021; 2021:7993622. [PMID: 34777568 PMCID: PMC8580640 DOI: 10.1155/2021/7993622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 10/09/2021] [Indexed: 11/23/2022]
Abstract
Thyroid cancer (THCA) is a common endocrine malignant tumor, and its global incidence of THCA has increased significantly. Neurexin 2 (NRXN2) is involved in the progression of some diseases. Nevertheless, it is still elusive towards the clinical implication and function of NRXN2 in THCA. As The Cancer Genome Atlas (TCGA) data demonstrated, we conducted a study to explore the links between NRXN2 expression and clinical features. Additionally, our data exhibited that, compared to normal thyroid tissues, NRXN2 showed low expression in THCA tissues. 20 important genes associated with NRXN2 were screened and identified. KEGG analysis data displayed that NRXN2 exhibited a link to the neuronal system, insulin secretion modulation, energy metabolism integration, muscle contraction, cardiac conduction, and neural adhesion molecule 1 (NCAM1) interactions. Our results in depth affirmed that NRXN2 was decreased in the tissues and cell lines of THCA patients. Functionally, we proved that overexpressing NRXN2 resulted in an inhibition of THCA cell proliferation, migration, and invasion in vitro. Collectively, our study demonstrated that, for the first time, NRXN2 behaved as an inhibitor of neoplasm and a promising biomarker in THCA.
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Affiliation(s)
- Cui Ma
- Department of Endocrinology, Liangzhu Hospital, Moganshan Road, Hangzhou, Zhejiang, China 311113
| | - Youyou Zhang
- Department of Endocrinology, First People's Hospital of Taizhou Affiliated Wenzhou Medical University, Hengjie Road, Taizhou, China 318020
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John A, Ng-Cordell E, Hanna N, Brkic D, Baker K. The neurodevelopmental spectrum of synaptic vesicle cycling disorders. J Neurochem 2021; 157:208-228. [PMID: 32738165 DOI: 10.1111/jnc.15135] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 12/11/2022]
Abstract
In this review, we describe and discuss neurodevelopmental phenotypes arising from rare, high penetrance genomic variants which directly influence synaptic vesicle cycling (SVC disorders). Pathogenic variants in each SVC disorder gene lead to disturbance of at least one SVC subprocess, namely vesicle trafficking (e.g. KIF1A and GDI1), clustering (e.g. TRIO, NRXN1 and SYN1), docking and priming (e.g. STXBP1), fusion (e.g. SYT1 and PRRT2) or re-uptake (e.g. DNM1, AP1S2 and TBC1D24). We observe that SVC disorders share a common set of neurological symptoms (movement disorders, epilepsies), cognitive impairments (developmental delay, intellectual disabilities, cerebral visual impairment) and mental health difficulties (autism, ADHD, psychiatric symptoms). On the other hand, there is notable phenotypic variation between and within disorders, which may reflect selective disruption to SVC subprocesses, spatiotemporal and cell-specific gene expression profiles, mutation-specific effects, or modifying factors. Understanding the common cellular and systems mechanisms underlying neurodevelopmental phenotypes in SVC disorders, and the factors responsible for variation in clinical presentations and outcomes, may translate to personalized clinical management and improved quality of life for patients and families.
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Affiliation(s)
- Abinayah John
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Elise Ng-Cordell
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Nancy Hanna
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Diandra Brkic
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Kate Baker
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
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Tromp A, Mowry B, Giacomotto J. Neurexins in autism and schizophrenia-a review of patient mutations, mouse models and potential future directions. Mol Psychiatry 2021; 26:747-760. [PMID: 33191396 DOI: 10.1038/s41380-020-00944-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 10/15/2020] [Accepted: 10/26/2020] [Indexed: 01/29/2023]
Abstract
Mutations in the family of neurexins (NRXN1, NRXN2 and NRXN3) have been repeatedly identified in patients with autism spectrum disorder (ASD) and schizophrenia (SCZ). However, it remains unclear how these DNA variants affect neurexin functions and thereby predispose to these neurodevelopmental disorders. Understanding both the wild-type and pathologic roles of these genes in the brain could help unveil biological mechanisms underlying mental disorders. In this regard, numerous studies have focused on generating relevant loss-of-function (LOF) mammalian models. Although this has increased our knowledge about their normal functions, the potential pathologic role(s) of these human variants remains elusive. Indeed, after reviewing the literature, it seems apparent that a traditional LOF-genetic approach based on complete LOF might not be sufficient to unveil the role of these human mutations. First, these genes present a very complex transcriptome and total-LOF of all isoforms may not be the cause of toxicity in patients, particularly given evidence that causative variants act through haploinsufficiency. Moreover, human DNA variants may not all lead to LOF but potentially to intricate transcriptome changes that could also include the generation of aberrant isoforms acting as a gain-of-function (GOF). Furthermore, their transcriptomic complexity most likely renders them prone to genetic compensation when one tries to manipulate them using traditional site-directed mutagenesis approaches, and this could act differently from model to model leading to heterogeneous and conflicting phenotypes. This review compiles the relevant literature on variants identified in human studies and on the mouse models currently deployed, and offers suggestions for future research.
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Affiliation(s)
- Alisha Tromp
- Queensland Brain Institute, University of Queensland, St Lucia, QLD, Australia
| | - Bryan Mowry
- Queensland Brain Institute, University of Queensland, St Lucia, QLD, Australia.
- Queensland Centre for Mental Health Research, Brisbane, QLD, Australia.
| | - Jean Giacomotto
- Queensland Brain Institute, University of Queensland, St Lucia, QLD, Australia.
- Queensland Centre for Mental Health Research, Brisbane, QLD, Australia.
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11
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Abstract
The function of neuronal circuits relies on the properties of individual neuronal cells and their synapses. We propose that a substantial degree of synapse formation and function is instructed by molecular codes resulting from transcriptional programmes. Recent studies on the Neurexin protein family and its ligands provide fundamental insight into how synapses are assembled and remodelled, how synaptic properties are specified and how single gene mutations associated with neurodevelopmental and psychiatric disorders might modify the operation of neuronal circuits and behaviour. In this Review, we first summarize insights into Neurexin function obtained from various model organisms. We then discuss the mechanisms and logic of the cell type-specific regulation of Neurexin isoforms, in particular at the level of alternative mRNA splicing. Finally, we propose a conceptual framework for how combinations of synaptic protein isoforms act as 'senders' and 'readers' to instruct synapse formation and the acquisition of cell type-specific and synapse-specific functional properties.
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12
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Rochtus A, Olson HE, Smith L, Keith LG, El Achkar C, Taylor A, Mahida S, Park M, Kelly M, Shain C, Rockowitz S, Sheidley BR, Poduri A. Genetic diagnoses in epilepsy: The impact of dynamic exome analysis in a pediatric cohort. Epilepsia 2020; 61:249-258. [PMID: 31957018 PMCID: PMC7404709 DOI: 10.1111/epi.16427] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 12/18/2019] [Accepted: 12/20/2019] [Indexed: 01/02/2023]
Abstract
OBJECTIVE We evaluated the yield of systematic analysis and/or reanalysis of whole exome sequencing (WES) data from a cohort of well-phenotyped pediatric patients with epilepsy and suspected but previously undetermined genetic etiology. METHODS We identified and phenotyped 125 participants with pediatric epilepsy. Etiology was unexplained at the time of enrollment despite clinical testing, which included chromosomal microarray (57 patients), epilepsy gene panel (n = 48), both (n = 28), or WES (n = 8). Clinical epilepsy diagnoses included developmental and epileptic encephalopathy (DEE), febrile infection-related epilepsy syndrome, Rasmussen encephalitis, and other focal and generalized epilepsies. We analyzed WES data and compared the yield in participants with and without prior clinical genetic testing. RESULTS Overall, we identified pathogenic or likely pathogenic variants in 40% (50/125) of our study participants. Nine patients with DEE had genetic variants in recently published genes that had not been recognized as epilepsy-related at the time of clinical testing (FGF12, GABBR1, GABBR2, ITPA, KAT6A, PTPN23, RHOBTB2, SATB2), and eight patients had genetic variants in candidate epilepsy genes (CAMTA1, FAT3, GABRA6, HUWE1, PTCHD1). Ninety participants had concomitant or subsequent clinical genetic testing, which was ultimately explanatory for 26% (23/90). Of the 67 participants whose molecular diagnoses were "unsolved" through clinical genetic testing, we identified pathogenic or likely pathogenic variants in 17 (25%). SIGNIFICANCE Our data argue for early consideration of WES with iterative reanalysis for patients with epilepsy, particularly those with DEE or epilepsy with intellectual disability. Rigorous analysis of WES data of well-phenotyped patients with epilepsy leads to a broader understanding of gene-specific phenotypic spectra as well as candidate disease gene identification. We illustrate the dynamic nature of genetic diagnosis over time, with analysis and in some cases reanalysis of exome data leading to the identification of disease-associated variants among participants with previously nondiagnostic results from a variety of clinical testing strategies.
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Affiliation(s)
- Anne Rochtus
- Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
- Department of Pediatrics, University of Leuven, Leuven, Belgium
| | - Heather E. Olson
- Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
- Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Lacey Smith
- Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
| | - Louisa G. Keith
- Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
| | - Christelle El Achkar
- Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
- Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Alan Taylor
- Department of Genomics, Al Jalila Children’s Specialty Hospital, Dubai, UAE
| | - Sonal Mahida
- Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
| | - Meredith Park
- Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
| | - McKenna Kelly
- Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
| | - Catherine Shain
- Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
| | - Shira Rockowitz
- Information Services Department, Boston Children’s Hospital, Boston, MA, USA
| | - Beth Rosen Sheidley
- Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
| | - Annapurna Poduri
- Epilepsy Genetics Program, Department of Neurology, Boston Children’s Hospital, Boston, MA, USA
- Department of Neurology, Harvard Medical School, Boston, MA, USA
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13
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In silico analysis of the functional and structural consequences of SNPs in human ARX gene associated with EIEE1. INFORMATICS IN MEDICINE UNLOCKED 2020. [DOI: 10.1016/j.imu.2020.100447] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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14
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Moreno-Salinas AL, Avila-Zozaya M, Ugalde-Silva P, Hernández-Guzmán DA, Missirlis F, Boucard AA. Latrophilins: A Neuro-Centric View of an Evolutionary Conserved Adhesion G Protein-Coupled Receptor Subfamily. Front Neurosci 2019; 13:700. [PMID: 31354411 PMCID: PMC6629964 DOI: 10.3389/fnins.2019.00700] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 06/20/2019] [Indexed: 12/21/2022] Open
Abstract
The adhesion G protein-coupled receptors latrophilins have been in the limelight for more than 20 years since their discovery as calcium-independent receptors for α-latrotoxin, a spider venom toxin with potent activity directed at neurotransmitter release from a variety of synapse types. Latrophilins are highly expressed in the nervous system. Although a substantial amount of studies has been conducted to describe the role of latrophilins in the toxin-mediated action, the recent identification of endogenous ligands for these receptors helped confirm their function as mediators of adhesion events. Here we hypothesize a role for latrophilins in inter-neuronal contacts and the formation of neuronal networks and we review the most recent information on their role in neurons. We explore molecular, cellular and behavioral aspects related to latrophilin adhesion function in mice, zebrafish, Drosophila melanogaster and Caenorhabditis elegans, in physiological and pathophysiological conditions, including autism spectrum, bipolar, attention deficit and hyperactivity and substance use disorders.
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Affiliation(s)
- Ana L. Moreno-Salinas
- Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City, Mexico
| | - Monserrat Avila-Zozaya
- Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City, Mexico
| | - Paul Ugalde-Silva
- Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City, Mexico
| | - David A. Hernández-Guzmán
- Department of Physiology, Biophysics and Neurosciences, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City, Mexico
| | - Fanis Missirlis
- Department of Physiology, Biophysics and Neurosciences, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City, Mexico
| | - Antony A. Boucard
- Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City, Mexico
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15
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Castronovo P, Baccarin M, Ricciardello A, Picinelli C, Tomaiuolo P, Cucinotta F, Frittoli M, Lintas C, Sacco R, Persico AM. Phenotypic spectrum of NRXN1 mono- and bi-allelic deficiency: A systematic review. Clin Genet 2019; 97:125-137. [PMID: 30873608 DOI: 10.1111/cge.13537] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 03/01/2019] [Accepted: 03/10/2019] [Indexed: 01/13/2023]
Abstract
Neurexins are presynaptic cell adhesion molecules critically involved in synaptogenesis and vesicular neurotransmitter release. They are encoded by three genes (NRXN1-3), each yielding a longer alpha (α) and a shorter beta (β) transcript. Deletions spanning the promoter and the initial exons of the NRXN1 gene, located in chromosome 2p16.3, are associated with a variety of neurodevelopmental, psychiatric, neurological and neuropsychological phenotypes. We have performed a systematic review to define (a) the clinical phenotypes most associated with mono-allelic exonic NRXN1 deletions, and (b) the phenotypic features of NRXN1 bi-allelic deficiency due to compound heterozygous deletions/mutations. Clinically, three major conclusions can be drawn: (a) incomplete penetrance and pleiotropy do not allow reliable predictions of clinical outcome following prenatal detection of mono-allelic exonic NRXN1 deletions. Newborn carriers should undergo periodic neuro-behavioral observations for the timely detection of warning signs and the prescription of early behavioral intervention; (b) the presence of additional independent genetic risk factors should always be sought, as they may influence prognosis; (c) children with exonic NRXN1 deletions displaying early-onset, severe psychomotor delay in the context of a Pitt-Hopkins-like syndrome 2 phenotype, should undergo DNA sequencing of the spared NRXN1 allele in search for mutations or very small insertions/deletions.
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Affiliation(s)
- Paola Castronovo
- Laboratory for Pervasive Developmental Disorders, Mafalda Luce Center, Milan, Italy
| | - Marco Baccarin
- Laboratory for Pervasive Developmental Disorders, Mafalda Luce Center, Milan, Italy
| | - Arianna Ricciardello
- Interdepartmental Program "Autism 0-90", "Gaetano Martino" University Hospital, University of Messina, Messina, Italy
| | - Chiara Picinelli
- Laboratory for Pervasive Developmental Disorders, Mafalda Luce Center, Milan, Italy
| | - Pasquale Tomaiuolo
- Laboratory for Pervasive Developmental Disorders, Mafalda Luce Center, Milan, Italy
| | - Francesca Cucinotta
- Interdepartmental Program "Autism 0-90", "Gaetano Martino" University Hospital, University of Messina, Messina, Italy
| | - Myriam Frittoli
- Laboratory for Pervasive Developmental Disorders, Mafalda Luce Center, Milan, Italy
| | - Carla Lintas
- Service for Neurodevelopmental Disorders & Laboratory of Molecular Psychiatry and Neurogenetics, University "Campus Bio-Medico", Rome, Italy
| | - Roberto Sacco
- Service for Neurodevelopmental Disorders & Laboratory of Molecular Psychiatry and Neurogenetics, University "Campus Bio-Medico", Rome, Italy
| | - Antonio M Persico
- Interdepartmental Program "Autism 0-90", "Gaetano Martino" University Hospital, University of Messina, Messina, Italy
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