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Xiong GJ, Sheng ZH. Presynaptic perspective: Axonal transport defects in neurodevelopmental disorders. J Cell Biol 2024; 223:e202401145. [PMID: 38568173 PMCID: PMC10988239 DOI: 10.1083/jcb.202401145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 03/20/2024] [Accepted: 03/21/2024] [Indexed: 04/05/2024] Open
Abstract
Disruption of synapse assembly and maturation leads to a broad spectrum of neurodevelopmental disorders. Presynaptic proteins are largely synthesized in the soma, where they are packaged into precursor vesicles and transported into distal axons to ensure precise assembly and maintenance of presynapses. Due to their morphological features, neurons face challenges in the delivery of presynaptic cargos to nascent boutons. Thus, targeted axonal transport is vital to build functional synapses. A growing number of mutations in genes encoding the transport machinery have been linked to neurodevelopmental disorders. Emerging lines of evidence have started to uncover presynaptic mechanisms underlying axonal transport defects, thus broadening the view of neurodevelopmental disorders beyond postsynaptic mechanisms. In this review, we discuss presynaptic perspectives of neurodevelopmental disorders by focusing on impaired axonal transport and disturbed assembly and maintenance of presynapses. We also discuss potential strategies for restoring axonal transport as an early therapeutic intervention.
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Affiliation(s)
- Gui-Jing Xiong
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Zu-Hang Sheng
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
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2
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Zhang Y, Zhao L, Sun Y. Using single-sample networks to identify the contrasting patterns of gene interactions and reveal the radiation dose-dependent effects in multiple tissues of spaceflight mice. NPJ Microgravity 2024; 10:45. [PMID: 38575629 PMCID: PMC10995210 DOI: 10.1038/s41526-024-00383-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 03/08/2024] [Indexed: 04/06/2024] Open
Abstract
Transcriptome profiles are sensitive to space stressors and serve as valuable indicators of the biological effects during spaceflight. Herein, we transformed the expression profiles into gene interaction patterns by single-sample networks (SSNs) and performed the integrated analysis on the 301 spaceflight and 290 ground control samples, which were obtained from the GeneLab platform. Specifically, an individual SSN was established for each sample. Based on the topological structures of 591 SSNs, the differentially interacted genes (DIGs) were identified between spaceflights and ground controls. The results showed that spaceflight disrupted the gene interaction patterns in mice and resulted in significant enrichment of biological processes such as protein/amino acid metabolism and nucleic acid (DNA/RNA) metabolism (P-value < 0.05). We observed that the mice exposed to radiation doses within the three intervals (4.66-7.14, 7.592-8.295, 8.49-22.099 mGy) exhibited similar gene interaction patterns. Low and medium doses resulted in changes to the circadian rhythm, while the damaging effects on genetic material became more pronounced in higher doses. The gene interaction patterns in response to space stressors varied among different tissues, with the spleen, lung, and skin being the most responsive to space radiation (P-value < 0.01). The changes observed in gene networks during spaceflight conditions might contribute to the development of various diseases, such as mental disorders, depression, and metabolic disorders, among others. Additionally, organisms activated specific gene networks in response to virus reactivation. We identified several hub genes that were associated with circadian rhythms, suggesting that spaceflight could lead to substantial circadian rhythm dysregulation.
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Affiliation(s)
- Yan Zhang
- Institute of Environmental Systems Biology, College of Environmental Science and Engineering, Dalian Maritime University, 116026, Dalian, Liaoning, China
| | - Lei Zhao
- Institute of Environmental Systems Biology, College of Environmental Science and Engineering, Dalian Maritime University, 116026, Dalian, Liaoning, China.
| | - Yeqing Sun
- Institute of Environmental Systems Biology, College of Environmental Science and Engineering, Dalian Maritime University, 116026, Dalian, Liaoning, China.
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Tantry MSA, Santhakumar K. Insights on the Role of α- and β-Tubulin Isotypes in Early Brain Development. Mol Neurobiol 2023; 60:3803-3823. [PMID: 36943622 DOI: 10.1007/s12035-023-03302-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 03/05/2023] [Indexed: 03/23/2023]
Abstract
Tubulins are the highly conserved subunit of microtubules which involve in various fundamental functions including brain development. Microtubules help in neuronal proliferation, migration, differentiation, cargo transport along the axons, synapse formation, and many more. Tubulin gene family consisting of multiple isotypes, their differential expression and varied post translational modifications create a whole new level of complexity and diversity in accomplishing manifold neuronal functions. The studies on the relation between tubulin genes and brain development opened a new avenue to understand the role of each tubulin isotype in neurodevelopment. Mutations in tubulin genes are reported to cause brain development defects especially cortical malformations, referred as tubulinopathies. There is an increased need to understand the molecular correlation between various tubulin mutations and the associated brain pathology. Recently, mutations in tubulin isotypes (TUBA1A, TUBB, TUBB1, TUBB2A, TUBB2B, TUBB3, and TUBG1) have been linked to cause various neurodevelopmental defects like lissencephaly, microcephaly, cortical dysplasia, polymicrogyria, schizencephaly, subcortical band heterotopia, periventricular heterotopia, corpus callosum agenesis, and cerebellar hypoplasia. This review summarizes on the microtubule dynamics, their role in neurodevelopment, tubulin isotypes, post translational modifications, and the role of tubulin mutations in causing specific neurodevelopmental defects. A comprehensive list containing all the reported tubulin pathogenic variants associated with brain developmental defects has been prepared to give a bird's eye view on the broad range of tubulin functions.
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Affiliation(s)
- M S Ananthakrishna Tantry
- Department of Genetic Engineering, SRM Institute of Science and Technology, Kattankulathur, 603203, India
| | - Kirankumar Santhakumar
- Department of Genetic Engineering, SRM Institute of Science and Technology, Kattankulathur, 603203, India.
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4
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Ragoussis V, Pagnamenta AT, Haines RL, Giacopuzzi E, McClatchey MA, Sampson JR, Suri M, Gardham A, Cobben JM, Osio D, Fry AE, Taylor JC. Using data from the 100,000 Genomes Project to resolve conflicting interpretations of a recurrent TUBB2A mutation. J Med Genet 2022; 59:366-369. [PMID: 33547136 PMCID: PMC8961759 DOI: 10.1136/jmedgenet-2020-107528] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 12/23/2020] [Accepted: 01/10/2021] [Indexed: 01/03/2023]
Affiliation(s)
- Vassilis Ragoussis
- Wellcome Centre for Human Genetics, Oxford University, Oxford, Oxfordshire, UK
- NIHR Biomedical Research Centre, Oxford, UK
| | - Alistair T Pagnamenta
- Wellcome Centre for Human Genetics, Oxford University, Oxford, Oxfordshire, UK
- NIHR Biomedical Research Centre, Oxford, UK
| | - Rebecca L Haines
- East Midlands Regional Molecular Genetics Service, Nottingham University Hospitals NHS Trust, Nottingham, UK
| | - Edoardo Giacopuzzi
- Wellcome Centre for Human Genetics, Oxford University, Oxford, Oxfordshire, UK
- NIHR Biomedical Research Centre, Oxford, UK
| | - Martin A McClatchey
- Institute of Medical Genetics, University Hospital of Wales, Cardiff, UK
- Division of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff, UK
| | - Julian R Sampson
- Institute of Medical Genetics, University Hospital of Wales, Cardiff, UK
- Division of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff, UK
| | - Mohnish Suri
- Nottingham Clinical Genetics Service, Nottingham University Hospitals NHS Trust, Nottingham, UK
| | - Alice Gardham
- North West Thames Regional Genetics Service, Northwick Park Hospital, Harrow, London, UK
| | - Jan-Maarten Cobben
- North West Thames Regional Genetics Service, Northwick Park Hospital, Harrow, London, UK
- Department of Pediatrics, Amsterdam University Medical Centres, Duivendrecht, Noord-Holland, Netherlands
| | - Deborah Osio
- West Midlands Regional Clinical Genetics Service and Birmingham Health Partners, Birmingham Women's and Children's Hospitals NHS Foundation Trust, Birmingham, UK
| | - Andrew E Fry
- Institute of Medical Genetics, University Hospital of Wales, Cardiff, UK
- Division of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff, UK
| | - Jenny C Taylor
- Wellcome Centre for Human Genetics, Oxford University, Oxford, Oxfordshire, UK
- NIHR Biomedical Research Centre, Oxford, UK
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5
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Park K, Hoff KJ, Wethekam L, Stence N, Saenz M, Moore JK. Kinetically Stabilizing Mutations in Beta Tubulins Create Isotype-Specific Brain Malformations. Front Cell Dev Biol 2021; 9:765992. [PMID: 34869359 PMCID: PMC8637541 DOI: 10.3389/fcell.2021.765992] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 10/29/2021] [Indexed: 11/13/2022] Open
Abstract
Mutations in the family of genes encoding the tubulin subunits of microtubules are associated with a spectrum of human brain malformations known as tubulinopathies. How these mutations impact tubulin activity to give rise to distinct developmental consequences is poorly understood. Here we report two patients exhibiting brain malformations characteristic of tubulinopathies and heterozygous T178M missense mutations in different β-tubulin genes, TUBB2A or TUBB3. RNAseq analysis indicates that both TUBB2A and TUBB3 are expressed in the brain during development, but only TUBB2A maintains high expression in neurons into adulthood. The T178 residue is highly conserved in β-tubulins and located in the exchangeable GTP-binding pocket of β-tubulin. To determine the impact of T178M on β-tubulin function we created an analogous mutation in the β-tubulin of budding yeast and show that the substitution acts dominantly to produce kinetically stabilized microtubules that assemble and disassemble slowly, with fewer transitions between these states. In vitro experiments with purified mutant tubulin demonstrate that T178M decreases the intrinsic assembly activity of β-tubulin and forms microtubules that rarely transition to disassembly. We provide evidence that the T178M substitution disrupts GTPase-dependent conformational changes in tubulin, providing a mechanistic explanation for kinetic stabilization. Our findings demonstrate the importance of tubulin’s GTPase activity during brain development, and indicate that tubulin isotypes play different, important roles during brain development.
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Affiliation(s)
- Kristen Park
- Department of Pediatrics and Neurology, Children's Hospital Colorado, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Katelyn J Hoff
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Linnea Wethekam
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Nicholas Stence
- Section of Pediatric Radiology, Department of Radiology, Children's Hospital Colorado, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Margarita Saenz
- Section of Genetics, Department of Pediatrics, Children's Hospital Colorado, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Jeffrey K Moore
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
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6
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The Names of Things: The 2018 Bernard Sachs Lecture. Pediatr Neurol 2021; 122:41-49. [PMID: 34330614 DOI: 10.1016/j.pediatrneurol.2021.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 05/05/2021] [Indexed: 11/22/2022]
Abstract
In 2018, I was honored to receive the Bernard Sachs Award for a lifetime of work expanding knowledge of diverse neurodevelopmental disorders. Summarizing work over more than 30 years is difficult but is an opportunity to chronicle the dramatic changes in the medical and scientific world that have transformed the field of Child Neurology over this time, as reflected in my own work. Here I have chosen to highlight five broad themes of my research beginning with my interest in descriptive terms that drive wider understanding and my choice for the title of this review. From there I will go on to contrast the state of knowledge as I entered the field with the state of knowledge today for four human brain malformations-lissencephaly, megalencephaly, cerebellar malformations, and polymicrogyria. For all, the changes have been dramatic.
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7
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Schmidt L, Wain KE, Hajek C, Estrada-Veras JI, Guillen Sacoto MJ, Wentzensen IM, Malhotra A, Clause A, Perry D, Moreno-De-Luca A, Bell M. Expanding the Phenotype of TUBB2A-Related Tubulinopathy: Three Cases of a Novel, Heterozygous TUBB2A Pathogenic Variant p.Gly98Arg. Mol Syndromol 2020; 12:33-40. [PMID: 33776625 DOI: 10.1159/000512160] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Accepted: 10/08/2020] [Indexed: 01/22/2023] Open
Abstract
Tubulinopathies are a group of conditions caused by variants in 6 tubulin genes that present with a spectrum of brain malformations. One of these conditions is TUBB2A-related tubulinopathy. Currently, there are 9 reported individuals with pathogenic variants within the TUBB2A gene, with common manifestations including, but not limited to, global developmental delay, seizures, cortical dysplasia, and dysmorphic corpus callosum. We report 3 patients identified by exome and genome sequencing to have a novel, pathogenic, missense variant in TUBB2A (p.Gly98Arg). They presented similarly with intellectual disability, hypotonia, and global developmental delay and varied with respect to the type of cortical brain malformation, seizure history, diagnosis of autism spectrum disorder, and other features. This case series expands the natural history of TUBB2A-related tubulinopathy while describing the presentation of a novel, pathogenic, missense variant in 3 patients.
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Affiliation(s)
- Lindsey Schmidt
- Sanford Health, Augustana-Sanford Genetic Counseling Program, Sioux Falls, South Dakota, USA
| | - Karen E Wain
- Geisinger Autism & Developmental Medicine Institute, Lewisburg, Pennsylvania, USA
| | | | - Juvianee I Estrada-Veras
- Henry M Jackson Foundation for the Advancement of Military Medicine and Walter Reed National Military Medical Center, Bethesda, Maryland, USA
| | | | | | - Alka Malhotra
- Illumina Clinical Services Laboratory, San Diego, California, USA
| | - Amanda Clause
- Illumina Clinical Services Laboratory, San Diego, California, USA
| | - Denise Perry
- Illumina Clinical Services Laboratory, San Diego, California, USA
| | - Andres Moreno-De-Luca
- Department of Radiology, Geisinger Autism & Developmental Medicine Institute, Genomic Medicine Institute, Lewisburg, Pennsylvania, USA
| | - Megan Bell
- Sanford Health, Sioux Falls, South Dakota, USA
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Brock S, Vanderhasselt T, Vermaning S, Keymolen K, Régal L, Romaniello R, Wieczorek D, Storm TM, Schaeferhoff K, Hehr U, Kuechler A, Krägeloh-Mann I, Haack TB, Kasteleijn E, Schot R, Mancini GMS, Webster R, Mohammad S, Leventer RJ, Mirzaa G, Dobyns WB, Bahi-Buisson N, Meuwissen M, Jansen AC, Stouffs K. Defining the phenotypical spectrum associated with variants in TUBB2A. J Med Genet 2020; 58:33-40. [PMID: 32571897 PMCID: PMC7803914 DOI: 10.1136/jmedgenet-2019-106740] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 02/05/2020] [Accepted: 03/05/2020] [Indexed: 01/18/2023]
Abstract
BACKGROUND Variants in genes belonging to the tubulin superfamily account for a heterogeneous spectrum of brain malformations referred to as tubulinopathies. Variants in TUBB2A have been reported in 10 patients with a broad spectrum of brain imaging features, ranging from a normal cortex to polymicrogyria, while one patient has been reported with progressive atrophy of the cerebellar vermis. METHODS In order to further refine the phenotypical spectrum associated with TUBB2A, clinical and imaging features of 12 patients with pathogenic TUBB2A variants, recruited via the international network of the authors, were reviewed. RESULTS We report 12 patients with eight novel and one recurrent variants spread throughout the TUBB2A gene but encoding for amino acids clustering at the protein surface. Eleven patients (91.7%) developed seizures in early life. All patients suffered from intellectual disability, and 11 patients had severe motor developmental delay, with 4 patients (36.4 %) being non-ambulatory. The cerebral cortex was normal in five individuals and showed dysgyria of variable severity in seven patients. Associated brain malformations were less frequent in TUBB2A patients compared with other tubulinopathies. None of the patients had progressive cerebellar atrophy. CONCLUSION The imaging phenotype associated with pathogenic variants in TUBB2A is highly variable, ranging from a normal cortex to extensive dysgyria with associated brain malformations. For recurrent variants, no clear genotype-phenotype correlations could be established, suggesting the role of additional modifiers.
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Affiliation(s)
- Stefanie Brock
- Department of Pathology, Universitair Ziekenhuis Brussel, Brussels, Belgium .,Neurogenetics Research Group, Reproduction Genetics and Regenerative Medicine Research Cluster, Vrije Universiteit Brussel, Brussels, Belgium
| | - Tim Vanderhasselt
- Department of Radiology, Universitair Ziekenhuis Brussel, Brussels, Belgium
| | - Sietske Vermaning
- Belgium Center for Reproduction and Genetics, Universitair Ziekenhuis Brussel, Brussels, Belgium
| | - Kathelijn Keymolen
- Belgium Center for Reproduction and Genetics, Universitair Ziekenhuis Brussel, Brussels, Belgium
| | - Luc Régal
- Pediatric Neurology Unit, Department of Pediatrics, Universitair Ziekenhuis, Brussels, Belgium
| | - Romina Romaniello
- Neuropsychiatry and Neurorehabilitation Unit, Scientific Institute, IRCCS Eugenio Medea, Lecco, Italy
| | - Dagmar Wieczorek
- Institut fuer Humangenetik, Universitaetsklininikum Essen, Essen, Germany.,Institute of Human Genetics, Heinrich Heine University Düsseldorf, Dusseldorf, Nordrhein-Westfalen, Germany
| | - Tim Matthias Storm
- Institut für Humangenetik, Technische Universität München, Munchen, Bayern, Germany
| | - Karin Schaeferhoff
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Baden-Württemberg, Germany
| | - Ute Hehr
- Zentrum für Humangenetik Regensburg, Universitätsklinikum Regensburg, Regensburg, Bayern, Germany
| | - Alma Kuechler
- Institut fuer Humangenetik, Universitaetsklininikum Essen, Essen, Germany
| | - Ingeborg Krägeloh-Mann
- Department of Pediatric Neurology and Developmental Medicine, University Children's Hospital Tübingen, University of Tübingen, Tübingen, Germany
| | - Tobias B Haack
- Institute of Medical Genetics and Applied Genomics, Eberhard-Karls-Universitat Tubingen Medizinische Fakultat, Tübingen, Baden-Württemberg, Germany
| | - Esmee Kasteleijn
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, Zuid-Holland, The Netherlands
| | - Rachel Schot
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, Zuid-Holland, The Netherlands
| | - Grazia Maria Simonetta Mancini
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, Zuid-Holland, The Netherlands.,ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus Medical Center, Rotterdam, Zuid-Holland, The Netherlands
| | - Richard Webster
- Department of Neurology, Children's Hospital at Westmead, Westmead, New South Wales, Australia
| | - Shekeeb Mohammad
- Department of Neurology, Children's Hospital at Westmead, Westmead, New South Wales, Australia
| | - Richard J Leventer
- Department of Neurology, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia
| | - Ghayda Mirzaa
- Division of Genetic Medicine, Department of Pediatrics, Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - William B Dobyns
- Division of Genetic Medicine, Department of Pediatrics, Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Nadia Bahi-Buisson
- Embryology and Genetics of Congenital Malformations, INSERM, Paris, Île-de-France, France
| | - Marije Meuwissen
- Center of Human Genetics, Universiteit Antwerpen, Antwerpen, Belgium
| | - Anna C Jansen
- Neurogenetics Research Group, Reproduction Genetics and Regenerative Medicine Research Cluster, Vrije Universiteit Brussel, Brussels, Belgium.,Pediatric Neurology Unit, Universitair Ziekenhuis Brussel, Brussels, Belgium
| | - Katrien Stouffs
- Neurogenetics Research Group, Reproduction Genetics and Regenerative Medicine Research Cluster, Vrije Universiteit Brussel, Brussels, Belgium.,Center for Medical Genetics, Universitair Ziekenhuis Brussel, Brussels, Belgium, Brussels, Belgium
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9
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De novo mutations of TUBB2A cause infantile-onset epilepsy and developmental delay. J Hum Genet 2020; 65:601-608. [PMID: 32203252 DOI: 10.1038/s10038-020-0739-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 02/06/2020] [Accepted: 02/27/2020] [Indexed: 01/20/2023]
Abstract
We analyzed our two new cases of infantile-onset epilepsy with developmental delay with de novo variant in TUBB2A and review the related literatures. Our two probands were both girls with infantile-onset epilepsy and global developmental delay. Case 1 had a novel de novo heterozygous missense variant: c.728C>T [p.Pro243Leu] (NM_001069.2). Her brain magnetic resonance imaging (MRI) showed nonspecific white matter myelination delay and slightly enlarged anterior horn of lateral ventricle. Her epilepsy had been controlled by TPM monotherapy. Case 2 had a reported de novo variant c.743C>T [p.Ala248Val] (NM_001069.2). Her brain MRI showed bilateral microgyria and corpus callosum dysplasia. A total of seven TUBB2A mutations cases had been published previously in five papers, therefore, until now, there were nine patients with TUBB2A mutations. All patients had developmental delay, among them seven cases also with infantile-onset epilepsy, one case with abnormal EEG but without clinical seizures. There are six cases that have different degree of cortical dysplasia, one case with cerebellar vermis atrophy and brainstem sacsinopathy, the rest two cases have no obvious brain structural abnormalities. There was one case with variant c.1249G>A (p.D417N) that had atypical clinical presentation, including prominent progressive spastic ataxia, sensory motor axonal neuropathy, and bilateral optic macular dystrophy, but relatively mild intellectual disability, his MRI showed cerebellar atrophy, thinning of the corpus callosum and pons sacsinopathy, but no cortical malformation. The p.A248V mutation was the most common mutation occurred in three patients (3/9). The clinical phenotypes of these three patients were similar, all of them had global developmental delay with no language and corpus callosum dysplasia, two cases with epilepsy and the other one only have EEG epileptic discharges without clinical seizure, two cases with cortical dysplasia and the other one without obvious brain malformation. In brief, global developmental delay was the most common phenotype of TUBB2A mutation-related disease, most cases also had infantile-onset epilepsy and cortical dysplasia and corpus callosum dysplasia. The region between seventh and eighth alpha-helix of TUBB2A may be a "hot spot" mutation domain.
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10
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Bittermann E, Abdelhamed Z, Liegel RP, Menke C, Timms A, Beier DR, Stottmann RW. Differential requirements of tubulin genes in mammalian forebrain development. PLoS Genet 2019; 15:e1008243. [PMID: 31386652 PMCID: PMC6697361 DOI: 10.1371/journal.pgen.1008243] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 08/16/2019] [Accepted: 06/12/2019] [Indexed: 11/24/2022] Open
Abstract
Tubulin genes encode a series of homologous proteins used to construct microtubules which are essential for multiple cellular processes. Neural development is particularly reliant on functional microtubule structures. Tubulin genes comprise a large family of genes with very high sequence similarity between multiple family members. Human genetics has demonstrated that a large spectrum of cortical malformations are associated with de novo heterozygous mutations in tubulin genes. However, the absolute requirement for many of these genes in development and disease has not been previously tested in genetic loss of function models. Here we directly test the requirement for Tuba1a, Tubb2a and Tubb2b in the mouse by deleting each gene individually using CRISPR-Cas9 genome editing. We show that loss of Tubb2a or Tubb2b does not impair survival but does lead to relatively mild cortical malformation phenotypes. In contrast, loss of Tuba1a is perinatal lethal and leads to significant forebrain dysmorphology. We also present a novel mouse ENU allele of Tuba1a with phenotypes similar to the null allele. This demonstrates the requirements for each of the tubulin genes and levels of functional redundancy are quite different throughout the gene family. The ability of the mouse to survive in the absence of some tubulin genes known to cause disease in humans suggests future intervention strategies for these devastating tubulinopathy diseases.
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Affiliation(s)
- Elizabeth Bittermann
- Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Zakia Abdelhamed
- Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
- Department of Anatomy and Embryology, Faculty of Medicine (Girl’s Section), Al-Azhar University, Cairo, Egypt
| | - Ryan P. Liegel
- Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Chelsea Menke
- Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Andrew Timms
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, Washington, United States of America
| | - David R. Beier
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, Washington, United States of America
- Department of Pediatrics, University of Washington Medical School, Seattle, Washington, United States of America
| | - Rolf W. Stottmann
- Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
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11
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Yuskaitis CJ, Ruzhnikov MR, Howell KB, Allen IE, Kapur K, Dlugos DJ, Scheffer IE, Poduri A, Sherr EH. Infantile Spasms of Unknown Cause: Predictors of Outcome and Genotype-Phenotype Correlation. Pediatr Neurol 2018; 87:48-56. [PMID: 30174244 PMCID: PMC8188823 DOI: 10.1016/j.pediatrneurol.2018.04.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 04/28/2018] [Indexed: 12/14/2022]
Abstract
BACKGROUND No large-scale studies have specifically evaluated the outcomes of infantile spasms (IS) of unknown cause, previously known as cryptogenic or idiopathic. The Epilepsy Phenome/Genome Project aimed to characterize IS of unknown cause by phenotype and genotype analysis. METHODS We undertook a retrospective multicenter observational cohort of 133 individuals within the Epilepsy Phenome/Genome Project database met criteria for IS of unknown cause with at least six months of follow-up data. Clinical medical records, imaging, and electroencephalography were examined. RESULTS Normal development occurred in only 15% of IS of unknown cause. The majority (85%) had clinically documented developmental delay (15% mild, 20% moderate, and 50% severe) at last assessment (median 2.7 years; interquartile interval 1.71-6.25 years). Predictors of positive developmental outcomes included no delay prior to IS (P < 0.001), older age of IS onset (median six months old), and resolution of IS after initial treatment (P < 0.001). Additional seizures after IS occurred in 67%, with predictors being seizures prior to IS (P = 0.018), earlier age of IS onset (median five months old), and refractory IS (P = 0.008). On a research basis, whole exome sequencing identified 15% with de novo variants in known epilepsy genes. Individuals with a genetic finding were more likely to have poor developmental outcomes (P = 0.035). CONCLUSIONS The current study highlights the predominately unfavorable developmental outcomes and that subsequent seizures are common in children with IS of unknown cause. Ongoing genetic evaluation of IS of seemingly unknown cause is likely to yield a diagnosis and provide valuable prognostic information.
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Affiliation(s)
- Christopher J. Yuskaitis
- Department of Neurology and Division of Epilepsy, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - Maura R.Z. Ruzhnikov
- Division of Medical Genetics and Department of Pediatrics, Stanford University, Stanford, California
| | - Katherine B. Howell
- Department of Neurology, Royal Children’s Hospital, Parkville, Victoria, Australia
| | - I. Elaine Allen
- Department of Epidemiology and Biostatistics/UCSF, University of California San Francisco, San Francisco, California
| | - Kush Kapur
- Department of Neurology and Division of Epilepsy, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - Dennis J. Dlugos
- The Children’s Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ingrid E. Scheffer
- Epilepsy Research Centre, Austin Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Annapurna Poduri
- Department of Neurology and Division of Epilepsy, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - Elliott H. Sherr
- Departments of Neurology and Pediatrics, University of California San Francisco, San Francisco, California,Corresponding author.
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12
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Tubulin genes and malformations of cortical development. Eur J Med Genet 2018; 61:744-754. [PMID: 30016746 DOI: 10.1016/j.ejmg.2018.07.012] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 06/03/2018] [Accepted: 07/12/2018] [Indexed: 01/18/2023]
Abstract
A large number of genes encoding for tubulin proteins are expressed in the developing brain. Each is subject to specific spatial and temporal expression patterns. However, most are highly expressed in post-mitotic neurons during stages of neuronal migration and differentiation. The major tubulin subclasses (alpha- and beta-tubulin) share high sequence and structural homology. These globular proteins form heterodimers and subsequently co-assemble into microtubules. Microtubules are dynamic, cytoskeletal polymers which play key roles in cellular processes crucial for cortical development, including neuronal proliferation, migration and cortical laminar organisation. Mutations in seven genes encoding alpha-tubulin (TUBA1A), beta-tubulin (TUBB2A, TUBB2B, TUBB3, TUBB4A, TUBB) and gamma-tubulin (TUBG1) isoforms have been associated with a wide and overlapping range of brain malformations or "Tubulinopathies". The majority of cortical phenotypes include lissencephaly, polymicrogyria, microlissencephaly and simplified gyration. Well-known hallmarks of the tubulinopathies include dysmorphism of the basal ganglia (fusion of the caudate nucleus and putamen with absence of the anterior limb of the internal capsule), midline commissural structures hypoplasia and/or agenesis (anterior commissure, corpus callosum and fornix), hypoplasia of the oculomotor and optic nerves, cerebellar hypoplasia or dysplasia and dysmorphism of the hind-brain structures. The cortical and extra-cortical brain phenotypes observed are largely dependent on the specific tubulin gene affected. In the present review, all the published data on tubulin family gene mutations and the associated cortical phenotypes are summarized. In addition, the most typical neuroimaging patterns of malformations of cortical development associated with tubulin gene mutations detected on the basis of our own experience are described.
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13
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Genetics and mechanisms leading to human cortical malformations. Semin Cell Dev Biol 2018; 76:33-75. [DOI: 10.1016/j.semcdb.2017.09.031] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 09/21/2017] [Accepted: 09/21/2017] [Indexed: 02/06/2023]
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14
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Sferra A, Fattori F, Rizza T, Flex E, Bellacchio E, Bruselles A, Petrini S, Cecchetti S, Teson M, Restaldi F, Ciolfi A, Santorelli FM, Zanni G, Barresi S, Castiglioni C, Tartaglia M, Bertini E. Defective kinesin binding of TUBB2A causes progressive spastic ataxia syndrome resembling sacsinopathy. Hum Mol Genet 2018; 27:1892-1904. [DOI: 10.1093/hmg/ddy096] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 03/12/2018] [Indexed: 12/28/2022] Open
Affiliation(s)
- Antonella Sferra
- Unit of Neuromuscular and Neurodegenerative Disorders, Department Neurosciences, Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy
| | - Fabiana Fattori
- Unit of Neuromuscular and Neurodegenerative Disorders, Department Neurosciences, Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy
| | - Teresa Rizza
- Unit of Neuromuscular and Neurodegenerative Disorders, Department Neurosciences, Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy
| | - Elsabetta Flex
- Department of Oncology and Molecular Medicine, Istituto Superiore di Sanità, 00161 Rome, Italy
| | - Emanuele Bellacchio
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy
| | - Alessandro Bruselles
- Department of Oncology and Molecular Medicine, Istituto Superiore di Sanità, 00161 Rome, Italy
| | - Stefania Petrini
- Confocal Microscopy Core Facility, Research Laboratories, Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy
| | - Serena Cecchetti
- Confocal Microscopy Unit, Core Facilities, Istituto Superiore di Sanità, 00161 Rome, Italy
| | - Massimo Teson
- Laboratory of Molecular and Cell Biology, Istituto Dermopatico Dell’Immacolata IDI-IRCCS, 00167 Rome, Italy
| | - Fabrizia Restaldi
- Unit of Medical Genetics, Department of Laboratories, Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy
| | - Andrea Ciolfi
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy
| | - Filippo M Santorelli
- IRCCS Stella Maris, Molecular Medicine and Neuromuscular Disorders, 56128 Pisa, Italy
| | - Ginevra Zanni
- Unit of Neuromuscular and Neurodegenerative Disorders, Department Neurosciences, Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy
| | - Sabina Barresi
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy
| | - Claudia Castiglioni
- Neurology Unit, Department of Pediatrics, Clínica Las Condes, 7550000 Santiago, Chile
| | - Marco Tartaglia
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy
| | - Enrico Bertini
- Unit of Neuromuscular and Neurodegenerative Disorders, Department Neurosciences, Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy
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15
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Ejaz R, Lionel AC, Blaser S, Walker S, Scherer SW, Babul-Hirji R, Marshall CR, Stavropoulos DJ, Chitayat D. De novo pathogenic variant in TUBB2A presenting with arthrogryposis multiplex congenita, brain abnormalities, and severe developmental delay. Am J Med Genet A 2017; 173:2725-2730. [PMID: 28840640 DOI: 10.1002/ajmg.a.38352] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 05/21/2017] [Accepted: 06/15/2017] [Indexed: 12/29/2022]
Abstract
Disorders of brain formation can occur from pathogenic variants in various alpha and beta tubulin genes. Heterozygous pathogenic variants in the beta tubulin isotype A gene, TUBB2A, have been recently implicated in brain malformations, seizures, and developmental delay. Limited information is known regarding the phenotypic spectrum associated with pathogenic variants in this gene given the rarity of the condition. We report the sixth individual with a de novo heterozygous TUBB2A pathogenic variant, who presented with a severe neurological phenotype along with unique features of arthrogryposis multiplex congenita, optic nerve hypoplasia, dysmorphic facial features, and vocal cord paralysis, thereby expanding the gene-related phenotype.
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Affiliation(s)
- Resham Ejaz
- Division of Clinical and Metabolic Genetics, Department of Paediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Anath C Lionel
- The Centre for Applied Genomics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Susan Blaser
- Division of Neuroradiology, Department of Diagnostic Imaging, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Susan Walker
- The Centre for Applied Genomics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Stephen W Scherer
- The Centre for Applied Genomics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.,McLaughlin Centre and Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Riyana Babul-Hirji
- Division of Clinical and Metabolic Genetics, Department of Paediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Christian R Marshall
- The Centre for Applied Genomics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.,Genome Diagnostics, Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Dimitri J Stavropoulos
- Genome Diagnostics, Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - David Chitayat
- Division of Clinical and Metabolic Genetics, Department of Paediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.,The Prenatal Diagnosis and Medical Genetics Program, Department of Obstetrics and Gynecology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
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