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Kooshavar D, Amor DJ, Boggs K, Baker N, Barnett C, de Silva MG, Edwards S, Fahey MC, Marum JE, Snell P, Bozaoglu K, Pope K, Mohammad SS, Riney K, Sachdev R, Scheffer IE, Schenscher S, Silberstein J, Smith N, Tom M, Ware TL, Lockhart PJ, Leventer RJ. Diagnostic utility of exome sequencing followed by research reanalysis in human brain malformations. Brain Commun 2024; 6:fcae056. [PMID: 38444904 PMCID: PMC10914449 DOI: 10.1093/braincomms/fcae056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 12/13/2023] [Accepted: 02/27/2024] [Indexed: 03/07/2024] Open
Abstract
This study aimed to determine the diagnostic yield of singleton exome sequencing and subsequent research-based trio exome analysis in children with a spectrum of brain malformations seen commonly in clinical practice. We recruited children ≤ 18 years old with a brain malformation diagnosed by magnetic resonance imaging and consistent with an established list of known genetic causes. Patients were ascertained nationally from eight tertiary paediatric centres as part of the Australian Genomics Brain Malformation Flagship. Chromosome microarray was required for all children, and those with pathogenic copy number changes were excluded. Cytomegalovirus polymerase chain reaction on neonatal blood spots was performed on all children with polymicrogyria with positive patients excluded. Singleton exome sequencing was performed through a diagnostic laboratory and analysed using a clinical exome sequencing pipeline. Undiagnosed patients were followed up in a research setting, including reanalysis of the singleton exome data and subsequent trio exome sequencing. A total of 102 children were recruited. Ten malformation subtypes were identified with the commonest being polymicrogyria (36%), pontocerebellar hypoplasia (14%), periventricular nodular heterotopia (11%), tubulinopathy (10%), lissencephaly (10%) and cortical dysplasia (9%). The overall diagnostic yield for the clinical singleton exome sequencing was 36%, which increased to 43% after research follow-up. The main source of increased diagnostic yield was the reanalysis of the singleton exome data to include newly discovered gene-disease associations. One additional diagnosis was made by trio exome sequencing. The highest phenotype-based diagnostic yields were for cobblestone malformation, tubulinopathy and lissencephaly and the lowest for cortical dysplasia and polymicrogyria. Pathogenic variants were identified in 32 genes, with variants in 6/32 genes occurring in more than one patient. The most frequent genetic diagnosis was pathogenic variants in TUBA1A. This study shows that over 40% of patients with common brain malformations have a genetic aetiology identified by exome sequencing. Periodic reanalysis of exome data to include newly identified genes was of greater value in increasing diagnostic yield than the expansion to trio exome. This study highlights the genetic and phenotypic heterogeneity of brain malformations, the importance of a multidisciplinary approach to diagnosis and the large number of patients that remain without a genetic diagnosis despite clinical exome sequencing and research reanalysis.
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Affiliation(s)
- Daniz Kooshavar
- Murdoch Children’s Research Institute, Parkville, VIC 3052, Australia
- Department of Paediatrics, The University of Melbourne, Parkville, VIC 3052, Australia
| | - David J Amor
- Murdoch Children’s Research Institute, Parkville, VIC 3052, Australia
- Department of Paediatrics, The University of Melbourne, Parkville, VIC 3052, Australia
| | - Kirsten Boggs
- Centre for Clinical Genetics, Sydney Children’s Hospital, Randwick, NSW 2031, Australia
- Department of Clinical Genetics, The Children’s Hospital Westmead, Westmead, NSW 2145, Australia
- Australian Genomics, Parkville, VIC 3052, Australia
| | - Naomi Baker
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Parkville, VIC 3052, Australia
| | - Christopher Barnett
- SA Clinical Genetics Service, Women's and Children's Hospital, North Adelaide, SA 5006, Australia
| | - Michelle G de Silva
- Murdoch Children’s Research Institute, Parkville, VIC 3052, Australia
- Australian Genomics, Parkville, VIC 3052, Australia
| | - Samantha Edwards
- Harry Perkins Institute of Medical Research, University of Western Australia, Nedlands, WA 6009, Australia
| | - Michael C Fahey
- Department of Paediatrics, Monash University, Clayton, VIC 3168, Australia
| | | | - Penny Snell
- Murdoch Children’s Research Institute, Parkville, VIC 3052, Australia
| | - Kiymet Bozaoglu
- Murdoch Children’s Research Institute, Parkville, VIC 3052, Australia
- Department of Paediatrics, The University of Melbourne, Parkville, VIC 3052, Australia
| | - Kate Pope
- Murdoch Children’s Research Institute, Parkville, VIC 3052, Australia
| | - Shekeeb S Mohammad
- Department of Neurology, Westmead Hospital, Westmead, NSW 2145, Australia
| | - Kate Riney
- Neurosciences Unit, Queensland Children’s Hospital, South Brisbane, QLD 4101, Australia
- Faculty of Medicine, University of Queensland, St Lucia, QLD 4072, Australia
| | - Rani Sachdev
- Centre for Clinical Genetics, Sydney Children’s Hospital, Randwick, NSW 2031, Australia
| | - Ingrid E Scheffer
- Murdoch Children’s Research Institute, Parkville, VIC 3052, Australia
- Department of Paediatrics, The University of Melbourne, Parkville, VIC 3052, Australia
- Department of Medicine, Epilepsy Research Centre, University of Melbourne, Austin Health and Florey Institute, Heidelberg, VIC 3084, Australia
- Department of Neurology, The Royal Children's Hospital, Parkville, VIC 3052, Australia
| | - Sarah Schenscher
- Paediatric and Reproductive Genetics Unit, Women’s and Children’s Hospital, Adelaide, SA 5006Australia
| | - John Silberstein
- Department of Neurology, Princess Margaret Hospital, Nedlands, WA 6009, Australia
| | - Nicholas Smith
- Department of Neurology and Clinical Neurophysiology, Women’s and Children’s Hospital, North Adelaide, SA 5006, Australia
| | - Melanie Tom
- Genetic Health Queensland, Royal Brisbane and Women’s Hospital, Herston, QLD 4029Australia
| | - Tyson L Ware
- Department of Paediatrics, Royal Hobart Hospital, Hobart, TAS 7000, Australia
| | - Paul J Lockhart
- Murdoch Children’s Research Institute, Parkville, VIC 3052, Australia
- Department of Paediatrics, The University of Melbourne, Parkville, VIC 3052, Australia
| | - Richard J Leventer
- Murdoch Children’s Research Institute, Parkville, VIC 3052, Australia
- Department of Paediatrics, The University of Melbourne, Parkville, VIC 3052, Australia
- Department of Neurology, The Royal Children's Hospital, Parkville, VIC 3052, Australia
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2
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Abbaali I, Truong D, Day SD, Mushayeed F, Ganesh B, Haro-Ramirez N, Isles J, Nag H, Pham C, Shah P, Tomar I, Manel-Romero C, Morrissette NS. The tubulin database: Linking mutations, modifications, ligands and local interactions. PLoS One 2023; 18:e0295279. [PMID: 38064432 PMCID: PMC10707541 DOI: 10.1371/journal.pone.0295279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 11/20/2023] [Indexed: 12/18/2023] Open
Abstract
Microtubules are polymeric filaments, constructed of α-β tubulin heterodimers that underlie critical subcellular structures in eukaryotic organisms. Four homologous proteins (γ-, δ-, ε- and ζ-tubulin) additionally contribute to specialized microtubule functions. Although there is an immense volume of publicly available data pertaining to tubulins, it is difficult to assimilate all potentially relevant information across diverse organisms, isotypes, and categories of data. We previously assembled an extensive web-based catalogue of published missense mutations to tubulins with >1,500 entries that each document a specific substitution to a discrete tubulin, the species where the mutation was described and the associated phenotype with hyperlinks to the amino acid sequence and citation(s) for research. This report describes a significant update and expansion of our online resource (TubulinDB.bio.uci.edu) to nearly 18,000 entries. It now encompasses a cross-referenced catalog of post-translational modifications (PTMs) to tubulin drawn from public datasets, primary literature, and predictive algorithms. In addition, tubulin protein structures were used to define local interactions with bound ligands (GTP, GDP and diverse microtubule-targeting agents) and amino acids at the intradimer interface, within the microtubule lattice and with associated proteins. To effectively cross-reference these datasets, we established a universal tubulin numbering system to map entries into a common framework that accommodates specific insertions and deletions to tubulins. Indexing and cross-referencing permitted us to discern previously unappreciated patterns. We describe previously unlinked observations of loss of PTM sites in the context of cancer cells and tubulinopathies. Similarly, we expanded the set of clinical substitutions that may compromise MAP or microtubule-motor interactions by collecting tubulin missense mutations that alter amino acids at the interface with dynein and doublecortin. By expanding the database as a curated resource, we hope to relate model organism data to clinical findings of pathogenic tubulin variants. Ultimately, we aim to aid researchers in hypothesis generation and design of studies to dissect tubulin function.
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Affiliation(s)
- Izra Abbaali
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Danny Truong
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Shania Deon Day
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Faliha Mushayeed
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Bhargavi Ganesh
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Nancy Haro-Ramirez
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Juliet Isles
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Hindol Nag
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Catherine Pham
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Priya Shah
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Ishaan Tomar
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Carolina Manel-Romero
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Naomi S. Morrissette
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
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Costa FV, Zabegalov KN, Kolesnikova TO, de Abreu MS, Kotova MM, Petersen EV, Kalueff AV. Experimental models of human cortical malformations: from mammals to 'acortical' zebrafish. Neurosci Biobehav Rev 2023; 155:105429. [PMID: 37863278 DOI: 10.1016/j.neubiorev.2023.105429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 10/05/2023] [Accepted: 10/16/2023] [Indexed: 10/22/2023]
Abstract
Human neocortex controls and integrates cognition, emotions, perception and complex behaviors. Aberrant cortical development can be triggered by multiple genetic and environmental factors, causing cortical malformations. Animal models, especially rodents, are a valuable tool to probe molecular and physiological mechanisms of cortical malformations. Complementing rodent studies, the zebrafish (Danio rerio) is an important model organism in biomedicine. Although the zebrafish (like other fishes) lacks neocortex, here we argue that this species can still be used to model various aspects and brain phenomena related to human cortical malformations. We also discuss novel perspectives in this field, covering both advantages and limitations of using mammalian and zebrafish models in cortical malformation research. Summarizing mounting evidence, we also highlight the importance of translationally-relevant insights into the pathogenesis of cortical malformations from animal models, and discuss future strategies of research in the field.
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Affiliation(s)
- Fabiano V Costa
- World-class Research Center "Center for Personalized Medicine", Almazov National Medical Research Center, Ministry of Healthcare of Russian Federation, St. Petersburg, Russia; Neurobiology Program, Sirius University of Science and Technology, Sirius Federal Territory, Russia
| | - Konstantin N Zabegalov
- Neurobiology Program, Sirius University of Science and Technology, Sirius Federal Territory, Russia
| | - Tatiana O Kolesnikova
- World-class Research Center "Center for Personalized Medicine", Almazov National Medical Research Center, Ministry of Healthcare of Russian Federation, St. Petersburg, Russia; Neurobiology Program, Sirius University of Science and Technology, Sirius Federal Territory, Russia
| | | | - Maria M Kotova
- World-class Research Center "Center for Personalized Medicine", Almazov National Medical Research Center, Ministry of Healthcare of Russian Federation, St. Petersburg, Russia; Neurobiology Program, Sirius University of Science and Technology, Sirius Federal Territory, Russia
| | | | - Allan V Kalueff
- World-class Research Center "Center for Personalized Medicine", Almazov National Medical Research Center, Ministry of Healthcare of Russian Federation, St. Petersburg, Russia; Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg, Russia; Institute of Experimental Medicine, Almazov National Medical Research Centre, Ministry of Healthcare of Russian Federation, St. Petersburg, Russia; Laboratory of Preclinical Bioscreening, Granov Russian Research Center of Radiology and Surgical Technologies, Ministry of Healthcare of Russian Federation, Pesochny, Russia; Ural Federal University, Yekaterinburg, Russia; Neurobiology Program, Sirius University of Science and Technology, Sirius Federal Territory, Russia.
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Ben Jdila M, Kammoun F, Abdelmaksoud-Dammak R, Triki C, Fakhfakh F. Mutation in the β-tubulin gene TUBB4A results in epileptic encephalopathy associated with hypomyelinated leucodystrophy: Unexpected findings reveal genetic mosaicism. Int J Dev Neurosci 2023; 83:532-545. [PMID: 37529938 DOI: 10.1002/jdn.10284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 05/10/2023] [Accepted: 06/15/2023] [Indexed: 08/03/2023] Open
Abstract
INTRODUCTION Epileptic encephalopathies (EEs) are a group of heterogeneous epileptic syndromes characterized by early-onset refractory seizures, specific EEG abnormalities, developmental delay or regression and intellectual disability. The genetic spectrum of EE is very wide with mutations in a number of genes having various functions, such as those encoding AMPA ionotropic and glutamate receptors as well as voltage-gated ion channels. However, the list of EE-responsible genes could certainly be enlarged by next-generation sequencing. PATIENTS AND METHODS The present study reports a clinical investigation and a molecular analysis by the whole exome sequencing (WES) and pyrosequencing of a patient's family affected by epileptic spasms and severe psychomotor delay. RESULTS Clinical and radiological investigations revealed that the patient presented clinical features of severe and drug-resistant EE-type infantile epileptic spasm syndrome that evolved to Lennox Gastaut syndrome with radiological findings of hypomyelinated leukodystrophy. The results of WES revealed the presence of a novel heterozygous c.466C>T mutation in exon 4 of the TUBB4A gene in the patient. This transition led to the replacement of arginine by cysteine at position 156 (p.R156C) of the conserved helix 4 among the N-terminal domain of the TUBB4A protein. Bioinformatic tools predicted its deleterious effects on the structural arrangement and stability of the protein. The presence of the mutation in the asymptomatic father suggested the hypothesis of somatic mosaicism that was tested by pyrosequencing of DNA from two tissues of the patient and her father. The obtained results showed a lower rate of mutated alleles in the asymptomatic father compared with the affected daughter in both lymphocytes and buccal mucosa cells, confirming the occurrence of paternal mosaicism. The phenotypic features of the patient were also compared with those of previously described patients presenting TUBB4A mutations. CONCLUSIONS Our study is the first to report a disease-causing variant in the TUBB4A gene in a patient with EE associated with hypomyelinated leucodystrophy. In addition, we expanded the phenotypic spectrum associated with the TUBB4A gene.
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Affiliation(s)
- Marwa Ben Jdila
- Research Laboratory 'NeuroPédiatrie' (LR19ES15), Sfax Medical School, Sfax University, Sfax, Tunisia
- Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, Sfax University, Sfax, Tunisia
| | - Fatma Kammoun
- Research Laboratory 'NeuroPédiatrie' (LR19ES15), Sfax Medical School, Sfax University, Sfax, Tunisia
- Child Neurology Department, Hedi Chaker University Hospital of Sfax, Sfax, Tunisia
| | - Rania Abdelmaksoud-Dammak
- Center of Biotechnology of Sfax, Laboratory of Eucaryotes Molecular Biotechnology, University of Sfax, Sfax, Tunisia
| | - Chahnez Triki
- Research Laboratory 'NeuroPédiatrie' (LR19ES15), Sfax Medical School, Sfax University, Sfax, Tunisia
- Child Neurology Department, Hedi Chaker University Hospital of Sfax, Sfax, Tunisia
| | - Faiza Fakhfakh
- Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, Sfax University, Sfax, Tunisia
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Pavone P, Striano P, Cacciaguerra G, Marino SD, Parano E, Pappalardo XG, Falsaperla R, Ruggieri M. Case report: Structural brain abnormalities in TUBA1A-tubulinopathies: a narrative review. Front Pediatr 2023; 11:1210272. [PMID: 37744437 PMCID: PMC10515619 DOI: 10.3389/fped.2023.1210272] [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: 04/22/2023] [Accepted: 08/15/2023] [Indexed: 09/26/2023] Open
Abstract
Introduction Tubulin genes have been related to severe neurological complications and the term "tubulinopathy" now refers to a heterogeneous group of disorders involving an extensive family of tubulin genes with TUBA1A being the most common. A review was carried out on the complex and severe brain abnormalities associated with this genetic anomaly. Methods A literature review of the cases of TUBA1A-tubulopathy was performed to investigate the molecular findings linked with cerebral anomalies and to describe the clinical and neuroradiological features related to this genetic disorder. Results Clinical manifestations of TUBA1A-tubulinopathy patients are heterogeneous and severe ranging from craniofacial dysmorphism, notable developmental delay, and intellectual delay to early-onset seizures, neuroradiologically associated with complex abnormalities. TUBA1A-tubulinopathy may display various and complex cortical and subcortical malformations. Discussion A range of clinical manifestations related to different cerebral structures involved may be observed in patients with TUBA1A-tubulinopathy. Genotype-phenotype correlations are discussed here. Individuals with cortical and subcortical anomalies should be screened also for pathogenic variants in TUBA1A.
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Affiliation(s)
- Piero Pavone
- Section of Pediatrics and Child Neuropsychiatry, Department of Child and Experimental Medicine, University of Catania, Catania, Italy
- National Council of Research, Institute for Biomedical Research and Innovation (IRIB), Unit of Catania, Catania, Italy
| | - Pasquale Striano
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genova, Italy
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto “G. Gaslini”, Genova, Italy
| | - Giovanni Cacciaguerra
- Section of Pediatrics and Child Neuropsychiatry, Department of Child and Experimental Medicine, University of Catania, Catania, Italy
| | - Simona Domenica Marino
- Pediatrics and Pediatric Emergency Department, University Hospital, A.U.O “Policlinico-Vittorio Emanuele”, Catania, Italy
| | - Enrico Parano
- National Council of Research, Institute for Biomedical Research and Innovation (IRIB), Unit of Catania, Catania, Italy
| | - Xena Giada Pappalardo
- National Council of Research, Institute for Biomedical Research and Innovation (IRIB), Unit of Catania, Catania, Italy
| | - Raffaele Falsaperla
- Pediatrics and Pediatric Emergency Department, University Hospital, A.U.O “Policlinico-Vittorio Emanuele”, Catania, Italy
| | - Martino Ruggieri
- Section of Pediatrics and Child Neuropsychiatry, Department of Child and Experimental Medicine, University of Catania, Catania, Italy
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Zocchi R, Bellacchio E, Piccione M, Scardigli R, D’Oria V, Petrini S, Baranano K, Bertini E, Sferra A. Novel loss of function mutation in TUBA1A gene compromises tubulin stability and proteostasis causing spastic paraplegia and ataxia. Front Cell Neurosci 2023; 17:1162363. [PMID: 37435044 PMCID: PMC10332271 DOI: 10.3389/fncel.2023.1162363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 06/01/2023] [Indexed: 07/13/2023] Open
Abstract
Microtubules are dynamic cytoskeletal structures involved in several cellular functions, such as intracellular trafficking, cell division and motility. More than other cell types, neurons rely on the proper functioning of microtubules to conduct their activities and achieve complex morphologies. Pathogenic variants in genes encoding for α and β-tubulins, the structural subunits of microtubules, give rise to a wide class of neurological disorders collectively known as "tubulinopathies" and mainly involving a wide and overlapping range of brain malformations resulting from defective neuronal proliferation, migration, differentiation and axon guidance. Although tubulin mutations have been classically linked to neurodevelopmental defects, growing evidence demonstrates that perturbations of tubulin functions and activities may also drive neurodegeneration. In this study, we causally link the previously unreported missense mutation p.I384N in TUBA1A, one of the neuron-specific α-tubulin isotype I, to a neurodegenerative disorder characterized by progressive spastic paraplegia and ataxia. We demonstrate that, in contrast to the p.R402H substitution, which is one of the most recurrent TUBA1A pathogenic variants associated to lissencephaly, the present mutation impairs TUBA1A stability, reducing the abundance of TUBA1A available in the cell and preventing its incorporation into microtubules. We also show that the isoleucine at position 384 is an amino acid residue, which is critical for α-tubulin stability, since the introduction of the p.I384N substitution in three different tubulin paralogs reduces their protein level and assembly into microtubules, increasing their propensity to aggregation. Moreover, we demonstrate that the inhibition of the proteasome degradative systems increases the protein levels of TUBA1A mutant, promoting the formation of tubulin aggregates that, as their size increases, coalesce into inclusions that precipitate within the insoluble cellular fraction. Overall, our data describe a novel pathogenic effect of p.I384N mutation that differs from the previously described substitutions in TUBA1A, and expand both phenotypic and mutational spectrum related to this gene.
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Affiliation(s)
- Riccardo Zocchi
- Unit of Neuromuscular Disorders, Translational Pediatrics and Clinical Genetics, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Emanuele Bellacchio
- Molecular Genetics and Functional Genomics Research Unit, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Michela Piccione
- Research Laboratories, Bambino Gesù Children’s Hospital, IRCSS, Rome, Italy
| | - Raffaella Scardigli
- Consiglio Nazionale delle Ricerche (CNR), Institute of Translational Pharmacology (IFT), Rome, Italy
- European Brain Research Institute (EBRI) “Rita Levi-Montalcini,” Rome, Italy
| | - Valentina D’Oria
- Research Laboratories, Bambino Gesù Children’s Hospital, IRCSS, Rome, Italy
| | - Stefania Petrini
- Research Laboratories, Bambino Gesù Children’s Hospital, IRCSS, Rome, Italy
| | - Kristin Baranano
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Enrico Bertini
- Unit of Neuromuscular Disorders, Translational Pediatrics and Clinical Genetics, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Antonella Sferra
- Unit of Neuromuscular Disorders, Translational Pediatrics and Clinical Genetics, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
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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: 2] [Impact Index Per Article: 2.0] [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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8
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Zaqout S, Mannaa A, Klein O, Krajewski A, Klose J, Luise-Becker L, Elsabagh A, Ferih K, Kraemer N, Ravindran E, Makridis K, Kaindl AM. Proteome changes in autosomal recessive primary microcephaly. Ann Hum Genet 2023; 87:50-62. [PMID: 36448252 DOI: 10.1111/ahg.12489] [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: 03/14/2022] [Revised: 11/16/2022] [Accepted: 11/18/2022] [Indexed: 12/05/2022]
Abstract
BACKGROUND/AIM Autosomal recessive primary microcephaly (MCPH) is a rare and genetically heterogeneous group of disorders characterized by intellectual disability and microcephaly at birth, classically without further organ involvement. MCPH3 is caused by biallelic variants in the cyclin-dependent kinase 5 regulatory subunit-associated protein 2 gene CDK5RAP2. In the corresponding Cdk5rap2 mutant or Hertwig's anemia mouse model, congenital microcephaly as well as defects in the hematopoietic system, germ cells and eyes have been reported. The reduction in brain volume, particularly affecting gray matter, has been attributed mainly to disturbances in the proliferation and survival of early neuronal progenitors. In addition, defects in dendritic development and synaptogenesis exist that affect the excitation-inhibition balance. Here, we studied proteomic changes in cerebral cortices of Cdk5rap2 mutant mice. MATERIAL AND METHODS We used large-gel two-dimensional gel (2-DE) electrophoresis to separate cortical proteins. 2-DE gels were visualized by a trained observer on a light box. Spot changes were considered with respect to presence/absence, quantitative variation and altered mobility. RESULT We identified a reduction in more than 30 proteins that play a role in processes such as cell cytoskeleton dynamics, cell cycle progression, ciliary functions and apoptosis. These proteome changes in the MCPH3 model can be associated with various functional and morphological alterations of the developing brain. CONCLUSION Our results shed light on potential protein candidates for the disease-associated phenotype reported in MCPH3.
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Affiliation(s)
- Sami Zaqout
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Atef Mannaa
- Higher Institute of Engineering and Technology, New Borg AlArab City, Alexandria, Egypt.,Inserm U1192, Laboratoire Protéomique, Réponse Inflammatoire & Spectrométrie de Masse (PRISM), Université de Lille, Lille, France
| | - Oliver Klein
- BIH Center for Regenerative Therapies BCRT, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute of Health, Charité-Universitätsmedizin Berlin (BIH), Berlin, Germany
| | - Angelika Krajewski
- BIH Center for Regenerative Therapies BCRT, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute of Health, Charité-Universitätsmedizin Berlin (BIH), Berlin, Germany
| | - Joachim Klose
- Charité-Universitätsmedizin, Institute of Human Genetics, Berlin, Germany
| | - Lena Luise-Becker
- Charité-Universitätsmedizin Berlin, Institute of Cell Biology and Neurobiology, Berlin, Germany.,Charité-Universitätsmedizin Berlin, Center for Chronically Sick Children (Sozialpädiatrisches Zentrum, SPZ), Berlin, Germany.,Department of Pediatric Neurology, Charité-Universitätsmedizin, Berlin, Germany
| | - Ahmed Elsabagh
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Khaled Ferih
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Nadine Kraemer
- Charité-Universitätsmedizin Berlin, Institute of Cell Biology and Neurobiology, Berlin, Germany.,Charité-Universitätsmedizin Berlin, Center for Chronically Sick Children (Sozialpädiatrisches Zentrum, SPZ), Berlin, Germany.,Department of Pediatric Neurology, Charité-Universitätsmedizin, Berlin, Germany
| | - Ethiraj Ravindran
- Charité-Universitätsmedizin Berlin, Institute of Cell Biology and Neurobiology, Berlin, Germany.,Charité-Universitätsmedizin Berlin, Center for Chronically Sick Children (Sozialpädiatrisches Zentrum, SPZ), Berlin, Germany.,Department of Pediatric Neurology, Charité-Universitätsmedizin, Berlin, Germany
| | - Konstantin Makridis
- Charité-Universitätsmedizin Berlin, Institute of Cell Biology and Neurobiology, Berlin, Germany.,Charité-Universitätsmedizin Berlin, Center for Chronically Sick Children (Sozialpädiatrisches Zentrum, SPZ), Berlin, Germany.,Department of Pediatric Neurology, Charité-Universitätsmedizin, Berlin, Germany
| | - Angela M Kaindl
- Charité-Universitätsmedizin Berlin, Institute of Cell Biology and Neurobiology, Berlin, Germany.,Charité-Universitätsmedizin Berlin, Center for Chronically Sick Children (Sozialpädiatrisches Zentrum, SPZ), Berlin, Germany.,Department of Pediatric Neurology, Charité-Universitätsmedizin, Berlin, Germany
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9
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Leca I, Phillips AW, Ushakova L, Cushion TD, Keays DA. Codon modification of Tuba1a alters mRNA levels and causes a severe neurodevelopmental phenotype in mice. Sci Rep 2023; 13:1215. [PMID: 36681692 PMCID: PMC9867703 DOI: 10.1038/s41598-023-27782-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 01/09/2023] [Indexed: 01/22/2023] Open
Abstract
The tubulinopathies are an umbrella of rare diseases that result from mutations in tubulin genes and are frequently characterised by severe brain malformations. The characteristics of a given disease reflect the expression pattern of the transcript, the function of a given tubulin gene, and the role microtubules play in a particular cell type. Mouse models have proved to be valuable tools that have provided insight into the molecular and cellular mechanisms that underlie the disease state. In this manuscript we compare two Tuba1a mouse models, both of which express wild-type TUBA1A protein but employ different codon usage. We show that modification of the Tuba1a mRNA sequence results in homozygous lethality and a severe neurodevelopmental phenotype. This is associated with a decrease in the number of post-mitotic neurons, PAX6 positive progenitors, and an increase in the number of apoptotic cells. We attribute this to a decrease in the stability of the modified Tuba1a transcript, and the absence of compensation by the other neurogenic tubulins. Our findings highlight the importance of maintaining the wild-type coding sequence when engineering mouse lines and the impact of synonymous genetic variation.
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Affiliation(s)
- Ines Leca
- Vienna Biocenter (VBC), Research Institute of Molecular Pathology (IMP), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria
| | - Alexander William Phillips
- Vienna Biocenter (VBC), Research Institute of Molecular Pathology (IMP), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria
- Department of Biology, Ludwig-Maximilians-University Munich, 82152, Planegg-Martinsried, Germany
| | - Lyubov Ushakova
- Vienna Biocenter (VBC), Research Institute of Molecular Pathology (IMP), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria
| | - Thomas David Cushion
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - David Anthony Keays
- Vienna Biocenter (VBC), Research Institute of Molecular Pathology (IMP), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria.
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK.
- Department of Biology, Ludwig-Maximilians-University Munich, 82152, Planegg-Martinsried, Germany.
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10
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Cushion TD, Leca I, Keays DA. MAPping tubulin mutations. Front Cell Dev Biol 2023; 11:1136699. [PMID: 36875768 PMCID: PMC9975266 DOI: 10.3389/fcell.2023.1136699] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 02/02/2023] [Indexed: 02/17/2023] Open
Abstract
Microtubules are filamentous structures that play a critical role in a diverse array of cellular functions including, mitosis, nuclear translocation, trafficking of organelles and cell shape. They are composed of α/β-tubulin heterodimers which are encoded by a large multigene family that has been implicated in an umbrella of disease states collectively known as the tubulinopathies. De novo mutations in different tubulin genes are known to cause lissencephaly, microcephaly, polymicrogyria, motor neuron disease, and female infertility. The diverse clinical features associated with these maladies have been attributed to the expression pattern of individual tubulin genes, as well as their distinct Functional repertoire. Recent studies, however, have highlighted the impact of tubulin mutations on microtubule-associated proteins (MAPs). MAPs can be classified according to their effect on microtubules and include polymer stabilizers (e.g., tau, MAP2, doublecortin), destabilizers (e.g., spastin, katanin), plus-end binding proteins (e.g., EB1-3, XMAP215, CLASPs) and motor proteins (e.g., dyneins, kinesins). In this review we analyse mutation-specific disease mechanisms that influence MAP binding and their phenotypic consequences, and discuss methods by which we can exploit genetic variation to identify novel MAPs.
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Affiliation(s)
- Thomas D Cushion
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom.,Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Ines Leca
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - David A Keays
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom.,Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria.,Division of Neurobiology, Department Biology II, Ludwig-Maximilians-University Munich, Munich, Germany
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11
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Exploring the Genetic Causality of Discordant Phenotypes in Familial Apparently Balanced Translocation Cases Using Whole Exome Sequencing. Genes (Basel) 2022; 14:genes14010082. [PMID: 36672823 PMCID: PMC9859009 DOI: 10.3390/genes14010082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/23/2022] [Accepted: 12/24/2022] [Indexed: 12/29/2022] Open
Abstract
Familial apparently balanced translocations (ABTs) are usually not associated with a phenotype; however, rarely, ABTs segregate with discordant phenotypes in family members carrying identical rearrangements. The current study was a follow-up investigation of four familial ABTs, where whole exome sequencing (WES) was implemented as a diagnostic tool to identify the underlying genetic aetiology of the patients' phenotypes. Data were analysed using an in-house bioinformatics pipeline alongside VarSome Clinical. WES findings were validated with Sanger sequencing, while the impact of splicing and missense variants was assessed by reverse-transcription PCR and in silico tools, respectively. Novel candidate variants were identified in three families. In family 1, it was shown that the de novo pathogenic STXBP1 variant (NM_003165.6:c.1110+2T>G) affected splicing and segregated with the patient's phenotype. In family 2, a likely pathogenic TUBA1A variant (NM_006009.4:c.875C>T, NP_006000.2:p.(Thr292Ile)) could explain the patient's symptoms. In family 3, an SCN1A variant of uncertain significance (NM_006920.6:c.5060A>G, NP_008851.3:p.(Glu1687Gly)) required additional evidence to sufficiently support causality. This first report of WES application in familial ABT carriers with discordant phenotypes supported our previous findings describing such rearrangements as coincidental. Thus, WES can be recommended as a complementary test to find the monogenic cause of aberrant phenotypes in familial ABT carriers.
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12
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Attard TJ, Welburn JPI, Marsh JA. Understanding molecular mechanisms and predicting phenotypic effects of pathogenic tubulin mutations. PLoS Comput Biol 2022; 18:e1010611. [PMID: 36206299 PMCID: PMC9581425 DOI: 10.1371/journal.pcbi.1010611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 10/19/2022] [Accepted: 09/28/2022] [Indexed: 11/21/2022] Open
Abstract
Cells rely heavily on microtubules for several processes, including cell division and molecular trafficking. Mutations in the different tubulin-α and -β proteins that comprise microtubules have been associated with various diseases and are often dominant, sporadic and congenital. While the earliest reported tubulin mutations affect neurodevelopment, mutations are also associated with other disorders such as bleeding disorders and infertility. We performed a systematic survey of tubulin mutations across all isotypes in order to improve our understanding of how they cause disease, and increase our ability to predict their phenotypic effects. Both protein structural analyses and computational variant effect predictors were very limited in their utility for differentiating between pathogenic and benign mutations. This was even worse for those genes associated with non-neurodevelopmental disorders. We selected tubulin-α and -β disease mutations that were most poorly predicted for experimental characterisation. These mutants co-localise to the mitotic spindle in HeLa cells, suggesting they may exert dominant-negative effects by altering microtubule properties. Our results show that tubulin mutations represent a blind spot for current computational approaches, being much more poorly predicted than mutations in most human disease genes. We suggest that this is likely due to their strong association with dominant-negative and gain-of-function mechanisms.
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Affiliation(s)
- Thomas J. Attard
- Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Julie P. I. Welburn
- Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Joseph A. Marsh
- MRC Human Genetics Unit, Institute of Genetics & Cancer, University of Edinburgh, Edinburgh, United Kingdom
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13
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Simoes C, Graña M, Rodriguez S, Baltar Yanes F, Tapié A, Dell’Oca N, Naya H, Raggio V, Spangenberg L. Novel frameshift mutation in LIS1 gene is a probable cause of lissencephaly: a case report. BMC Pediatr 2022; 22:545. [PMID: 36100855 PMCID: PMC9472359 DOI: 10.1186/s12887-022-03595-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Accepted: 09/02/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Lissencephaly (LIS) is a cortical malformation, characterized by smooth or nearly smooth cerebral surface and a shortage of gyral and sulcal development, which is caused by deficient neuronal migration during embryogenesis. Neuronal migration involves many gene products, among which is the product of the PAFAH1B1 gene, associated with this disease. LIS is a rare disease, characterized by low population frequency, and with non-specific clinical symptoms such as early epilepsy, developmental delay or cerebral palsy-like motor problems. Given that high-throughput sequencing techniques have been improving diagnosis, we have chosen this technique for addressing this patient.
Case presentation
We present the case of a seven years old male patient with an undiagnosed rare disease, with non-specific clinical symptoms possibly compatible with lissencephaly.
The patient was enrolled in a study that included the sequencing of his whole genome. Sequence data was analyzed following a bioinformatic pipeline. The variants obtained were annotated and then subjected to different filters for prioritization. Also mitochondrial genome was analyzed. A novel candidate frameshift insertion in known PAFAH1B1 gene was found, explaining the index case phenotype. The assessment through in silico tools reported that it causes nonsense mediated mechanisms and that it is damaging with high confidence scores. The insertion causes a change in the reading frame, and produces a premature stop codon, severely affecting the protein function and probably the silencing of one allele. The healthy mother did not carry the mutation, and the unaffected father was not available for analysis.
Conclusions
Through this work we found a novel de novo mutation in LIS1/PAFAH1B1 gene, as a likely cause of a rare disease in a young boy with non-specific clinical symptoms. The mutation found correlates with the phenotype studied since the loss of function in the gene product has already been described in this condition. Since there are no other variants in the PAFAH1B1 gene with low population frequency and due to family history, a de novo disease mechanism is proposed.
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14
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Zhang W, Hu L, Huang X, Xie D, Wu J, Fu X, Liang D, Huang S. Whole-exome sequencing identified five novel de novo variants in patients with unexplained intellectual disability. J Clin Lab Anal 2022; 36:e24587. [PMID: 35837997 PMCID: PMC9459325 DOI: 10.1002/jcla.24587] [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: 03/10/2022] [Revised: 05/20/2022] [Accepted: 06/25/2022] [Indexed: 11/30/2022] Open
Abstract
Background Intellectual disability (ID) represents a neurodevelopmental disorder, which is characterized by marked defects in the intellectual function and adaptive behavior, with an onset during the developmental period. ID is mainly caused by genetic factors, and it is extremely genetically heterogeneous. This study aims to identify the genetic cause of ID using trio‐WES analysis. Methods We recruited four pediatric patients with unexplained ID from non‐consanguineous families, who presented at the Department of Pediatrics, Guizhou Provincial People's Hospital. Whole‐exome sequencing (WES) and Sanger sequencing validation were performed in the patients and their unaffected parents. Furthermore, conservative analysis and protein structural and functional prediction were performed on the identified pathogenic variants. Results We identified five novel de novo mutations from four known ID‐causing genes in the four included patients, namely COL4A1 (c.2786T>A, p.V929D and c.2797G>A, p.G933S), TBR1 (c.1639_1640insCCCGCAGTCC, p.Y553Sfs*124), CHD7 (c.7013A>T, p.Q2338L), and TUBA1A (c.1350del, p.E450Dfs*34). These mutations were all predicted to be deleterious and were located at highly conserved domains that might affect the structure and function of these proteins. Conclusion Our findings contribute to expanding the mutational spectrum of ID‐related genes and help to deepen the understanding of the genetic causes and heterogeneity of ID.
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Affiliation(s)
- Wenqiu Zhang
- School of Medicine, Guizhou University, Guiyang, China.,Prenatal Diagnosis Center, Guizhou Provincial People's hospital, Guiyang, China
| | - Li Hu
- Prenatal Diagnosis Center, Guizhou Provincial People's hospital, Guiyang, China
| | - Xinyi Huang
- School of Medical and Life Sciences, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Dan Xie
- School of Medicine, Guizhou University, Guiyang, China.,Prenatal Diagnosis Center, Guizhou Provincial People's hospital, Guiyang, China
| | - Jiangfen Wu
- School of Medicine, Guizhou University, Guiyang, China.,Prenatal Diagnosis Center, Guizhou Provincial People's hospital, Guiyang, China
| | - Xiaoling Fu
- Department of Pediatrics, Guizhou Provincial People's hospital, Guiyang, China
| | - Daiyi Liang
- Department of Neurology, Guizhou Provincial People's hospital, Guiyang, China
| | - Shengwen Huang
- School of Medicine, Guizhou University, Guiyang, China.,Prenatal Diagnosis Center, Guizhou Provincial People's hospital, Guiyang, China.,NHC Key Laboratory of Pulmonary Immunological Diseases, Guizhou Provincial People's Hospital, Guiyang, China
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15
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Weber M, Jaber D, Encha-Razavi F, Julien E, Grevoul-Fesquet J, Steffann J, Melki J, Martinovic J. Broadening the phenotypic spectrum of TUBA1A tubulinopathy to syndromic arthrogryposis multiplex congenita. Am J Med Genet A 2022; 188:2331-2338. [PMID: 35686685 DOI: 10.1002/ajmg.a.62866] [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: 10/14/2021] [Revised: 03/01/2022] [Accepted: 04/28/2022] [Indexed: 11/06/2022]
Abstract
The recent finding that some patients with fetal akinesia deformation sequence (FADS) carry variants in the TUBB2B gene has prompted us to add to the existing literature a first description of two fetal FADS cases carrying TUBA1A variants. Hitherto, only isolated cortical malformations have been described with TUBA1A mutation, including microlissencephaly, lissencephaly, central pachygyria and polymicrogyria-like cortical dysplasia, generalized polymicrogyria cortical dysplasia, and/or the "simplified" gyral pattern. The neuropathology of our fetal cases shows several common features of tubulinopathies, in particular, the dysmorphism of the basal ganglia, as the most pathognomonic sign. The cortical ribbon anomalies were extremely severe and concordant with the complex cortical malformation. In conclusion, we broaden the phenotypic spectrum of TUBA1A variants, to include FADS.
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Affiliation(s)
- Mathilde Weber
- Unit of Embryo-Fetal Pathology, AP-HP, Antoine Béclère Hospital, Clamart, France.,Department of Obstetrics and Gynecology, AP-HP, Antoine Béclère Hospital, Clamart, France
| | - Dana Jaber
- Institut National de la Santé et de la Recherche Médicale (Inserm), UMR-1195, Université Paris Saclay, Le Kremlin Bicêtre, France
| | | | - Emmanuel Julien
- Department of Obstetrics and Gynecology, CH du Mans, Le Mans, France
| | - Julie Grevoul-Fesquet
- Department of Obstetrics and Gynecology, CH Sud Francilien, Corbeil-Essonnes, France
| | - Julie Steffann
- Department of Molecular Genetics, AP-HP, Necker-Enfants Malades Hospital, Paris University, Paris, France
| | - Judith Melki
- Institut National de la Santé et de la Recherche Médicale (Inserm), UMR-1195, Université Paris Saclay, Le Kremlin Bicêtre, France
| | - Jelena Martinovic
- Unit of Embryo-Fetal Pathology, AP-HP, Antoine Béclère Hospital, Clamart, France.,Institut National de la Santé et de la Recherche Médicale (Inserm), UMR-1195, Université Paris Saclay, Le Kremlin Bicêtre, France
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16
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Complementing the phenotypical spectrum of TUBA1A tubulinopathy and its role in early-onset epilepsies. Eur J Hum Genet 2022; 30:298-306. [PMID: 35017693 PMCID: PMC8904761 DOI: 10.1038/s41431-021-01027-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 11/26/2021] [Accepted: 12/09/2021] [Indexed: 12/29/2022] Open
Abstract
TUBA1A tubulinopathy is a rare neurodevelopmental disorder associated with brain malformations as well as early-onset and intractable epilepsy. As pathomechanisms and genotype-phenotype correlations are not completely understood, we aimed to provide further insights into the phenotypic and genetic spectrum. We here present a multicenter case series of ten unrelated individuals from four European countries using systematic MRI re-evaluation, protein structure analysis, and prediction score modeling. In two cases, pregnancy was terminated due to brain malformations. Amongst the eight living individuals, the phenotypic range showed various severity. Global developmental delay and severe motor impairment with tetraparesis was present in 63% and 50% of the subjects, respectively. Epilepsy was observed in 75% of the cases, which showed infantile onset in 83% and a refractory course in 50%. One individual presented a novel TUBA1A-associated electroclinical phenotype with evolvement from early myoclonic encephalopathy to continuous spike-and-wave during sleep. Neuroradiological features comprised a heterogeneous spectrum of cortical and extracortical malformations including rare findings such as cobblestone lissencephaly and subcortical band heterotopia. Two individuals developed hydrocephalus with subsequent posterior infarction. We report four novel and five previously published TUBA1A missense variants whose resulting amino acid substitutions likely affect longitudinal, lateral, and motor protein interactions as well as GTP binding. Assessment of pathogenic and benign variant distributions in synopsis with prediction scores revealed sections of variant enrichment and intolerance to missense variation. We here extend the clinical, neuroradiological, and genetic spectrum of TUBA1A tubulinopathy and provide insights into residue-specific pathomechanisms and genotype-phenotype correlations.
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17
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Buscaglia G, Northington KR, Aiken J, Hoff KJ, Bates EA. Bridging the Gap: The Importance of TUBA1A α-Tubulin in Forming Midline Commissures. Front Cell Dev Biol 2022; 9:789438. [PMID: 35127710 PMCID: PMC8807549 DOI: 10.3389/fcell.2021.789438] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 12/20/2021] [Indexed: 11/13/2022] Open
Abstract
Developing neurons undergo dramatic morphological changes to appropriately migrate and extend axons to make synaptic connections. The microtubule cytoskeleton, made of α/β-tubulin dimers, drives neurite outgrowth, promotes neuronal growth cone responses, and facilitates intracellular transport of critical cargoes during neurodevelopment. TUBA1A constitutes the majority of α-tubulin in the developing brain and mutations to TUBA1A in humans cause severe brain malformations accompanied by varying neurological defects, collectively termed tubulinopathies. Studies of TUBA1A function in mammalian cells have been limited by the presence of multiple genes encoding highly similar tubulin proteins, which leads to α-tubulin antibody promiscuity and makes genetic manipulation challenging. Here, we test mutant tubulin levels and assembly activity and analyze the impact of TUBA1A reduction on growth cone composition, neurite extension, and commissural axon architecture during brain development. We present a novel tagging method for studying and manipulating TUBA1A in cells without impairing tubulin function. Using this tool, we show that a TUBA1A loss-of-function mutation TUBA1A N102D (TUBA1A ND ), reduces TUBA1A protein levels and prevents incorporation of TUBA1A into microtubule polymers. Reduced Tuba1a α-tubulin in heterozygous Tuba1a ND/+ mice leads to grossly normal brain formation except a significant impact on axon extension and impaired formation of forebrain commissures. Neurons with reduced Tuba1a as a result of the Tuba1a ND mutation exhibit slower neuron outgrowth compared to controls. Neurons deficient in Tuba1a failed to localize microtubule associated protein-1b (Map1b) to the developing growth cone, likely impacting stabilization of microtubules. Overall, we show that reduced Tuba1a is sufficient to support neuronal migration and cortex development but not commissure formation, and provide mechanistic insight as to how TUBA1A tunes microtubule function to support neurodevelopment.
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Affiliation(s)
- Georgia Buscaglia
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Kyle R. Northington
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Jayne Aiken
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Cell and Developmental Biology, 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
| | - Emily A. Bates
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
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18
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Vriend I, Oegema R. Genetic causes underlying grey matter heterotopia. Eur J Paediatr Neurol 2021; 35:82-92. [PMID: 34666232 DOI: 10.1016/j.ejpn.2021.09.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 09/21/2021] [Indexed: 11/15/2022]
Abstract
Grey matter heterotopia (GMH) can cause of seizures and are associated with a wide range of neurodevelopmental disorders and syndromes. They are caused by a failure of neuronal migration during fetal development, leading to clusters of neurons that have not reached their final destination in the cerebral cortex. We have performed an extensive literature search in Pubmed, OMIM, and Google scholar and provide an overview of known genetic associations with periventricular nodular heterotopia (PNVH), subcortical band heterotopia (SBH) and other subcortical heterotopia (SUBH). We classified the heterotopias as PVNH, SBH, SUBH or other and collected the genetic information, frequency, imaging features and salient features in tables for every subtype of heterotopia. This resulted in 105 PVNH, 16 SBH and 25 SUBH gene/locus associations, making a total of 146 genes and chromosomal loci. Our study emphasizes the extreme genetic heterogeneity underlying GMH. It will aid the clinician in establishing an differential diagnosis and eventually a molecular diagnosis in GMH patients. A diagnosis enables proper counseling of prognosis and recurrence risks, and enables individualized patient management.
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Affiliation(s)
- Ilona Vriend
- Department of Genetics, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Renske Oegema
- Department of Genetics, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands.
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19
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Peng SW, Peng KP, Tian GX, Cao XY, Liu MH, Dong QY. Ultrasonic Diagnosis of Lissencephaly: Literature Review and A Case Report. JOURNAL OF FETAL MEDICINE 2021. [DOI: 10.1007/s40556-021-00313-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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20
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Shi L, Li M, Qi H, Zhu J, Yang J, Tang J, Wang L. Whole-exome sequencing analysis to identify novel potential pathogenetic mutations in fetuses with abnormal brain structure. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:807. [PMID: 34268420 PMCID: PMC8246198 DOI: 10.21037/atm-21-1477] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 05/08/2021] [Indexed: 12/30/2022]
Abstract
Background Genetic mutations in genes related to the production, migration, or differentiation of cortical neurons can result in malformations of cortical development (MCDs). However, a large number of MCD-related pathogenetic mutations remain unknown. This study aimed to investigate the genetic cause of MCDs and to identify the new MCD-associated mutations through whole‐exome sequencing (WES) in fetuses with abnormal brain structure. Methods Cord venous blood samples were collected from 11 fetuses with MCDs. Whole-genome DNA was extracted from the blood, and WES was performed. Single nucleotide substitutions, insertions, and deletions were detected by bioinformatics analysis. Genetic mutations in genes associated with MCD were identified. Results A total of 1035 genes with high-impact genetic variants in at least 1 fetus were identified. The results of gene ontology enrichment analysis were consistent with those of previous studies and also indicated new potential MCD-related pathogenetic genetic mutations. Genes with high-impact mutations in multiple fetuses, such as CTDSP2 and C-terminal binding protein 2 (CTBP2), were more likely to be the genes affecting normal brain development. Conclusions This study has characterized variations in fetuses with MCDs and identified potential genetic mutations causing MCDs. Our findings extend the mutation spectrum of MCDs and provide a promising source for the identification of MCD-related pathogenetic mutations.
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Affiliation(s)
- Lili Shi
- Medical School of Chinese PLA, Beijing, China.,Department of Ultrasound Medicine, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Ming Li
- Department of Laboratory, Tianyou Hospital Affiliated to Wuhan University of Science & Technology, Wuhan, China
| | - Hong Qi
- Department of Prenatal Diagnosis Center, Haidian Maternal and Child Health Hospital, Beijing, China
| | - Jianjiang Zhu
- Department of Prenatal Diagnosis Center, Haidian Maternal and Child Health Hospital, Beijing, China
| | - Jing Yang
- Department of Obstetrics & Gynecology, Peking University Third Hospital, Beijing, China
| | - Jie Tang
- Department of Ultrasound, First Medical Center of Chinese PLA General Hospital, Medical School of Chinese PLA, Beijing, China
| | - Longxia Wang
- Department of Ultrasound, First Medical Center of Chinese PLA General Hospital, Medical School of Chinese PLA, Beijing, China
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21
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Jurgens JA, Barry BJ, Lemire G, Chan WM, Whitman MC, Shaaban S, Robson CD, MacKinnon S, England EM, McMillan HJ, Kelly C, Pratt BM, O’Donnell-Luria A, MacArthur DG, Boycott KM, Hunter DG, Engle EC. Novel variants in TUBA1A cause congenital fibrosis of the extraocular muscles with or without malformations of cortical brain development. Eur J Hum Genet 2021; 29:816-826. [PMID: 33649541 PMCID: PMC8110841 DOI: 10.1038/s41431-020-00804-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/12/2020] [Accepted: 12/17/2020] [Indexed: 01/31/2023] Open
Abstract
Variants in multiple tubulin genes have been implicated in neurodevelopmental disorders, including malformations of cortical development (MCD) and congenital fibrosis of the extraocular muscles (CFEOM). Distinct missense variants in the beta-tubulin encoding genes TUBB3 and TUBB2B cause MCD, CFEOM, or both, suggesting substitution-specific mechanisms. Variants in the alpha tubulin-encoding gene TUBA1A have been associated with MCD, but not with CFEOM. Using exome sequencing (ES) and genome sequencing (GS), we identified 3 unrelated probands with CFEOM who harbored novel heterozygous TUBA1A missense variants c.1216C>G, p.(His406Asp); c.467G>A, p.(Arg156His); and c.1193T>G, p.(Met398Arg). MRI revealed small oculomotor-innervated muscles and asymmetrical caudate heads and lateral ventricles with or without corpus callosal thinning. Two of the three probands had MCD. Mutated amino acid residues localize either to the longitudinal interface at which α and β tubulins heterodimerize (Met398, His406) or to the lateral interface at which tubulin protofilaments interact (Arg156), and His406 interacts with the motor domain of kinesin-1. This series of individuals supports TUBA1A variants as a cause of CFEOM and expands our knowledge of tubulinopathies.
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Affiliation(s)
- Julie A. Jurgens
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA USA ,Department of Neurology, Boston Children’s Hospital, Boston, MA USA ,Department of Neurology, Harvard Medical School, Boston, MA USA ,Broad Institute of MIT and Harvard, Cambridge, MA USA
| | - Brenda J. Barry
- Department of Neurology, Boston Children’s Hospital, Boston, MA USA ,Howard Hughes Medical Institute, Chevy Chase, MD USA
| | - Gabrielle Lemire
- Children’s Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON Canada
| | - Wai-Man Chan
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA USA ,Department of Neurology, Boston Children’s Hospital, Boston, MA USA ,Department of Neurology, Harvard Medical School, Boston, MA USA ,Broad Institute of MIT and Harvard, Cambridge, MA USA ,Howard Hughes Medical Institute, Chevy Chase, MD USA
| | - Mary C. Whitman
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA USA ,Department of Ophthalmology, Boston Children’s Hospital, Boston, MA USA ,Department of Ophthalmology, Harvard Medical School, Boston, MA USA
| | - Sherin Shaaban
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA USA ,Department of Neurology, Boston Children’s Hospital, Boston, MA USA ,Department of Neurology, Harvard Medical School, Boston, MA USA ,Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT USA
| | - Caroline D. Robson
- Division of Neuroradiology, Department of Radiology, Boston Children’s Hospital, Boston, MA USA ,Department of Radiology, Harvard Medical School, Boston, MA USA
| | - Sarah MacKinnon
- Department of Ophthalmology, Boston Children’s Hospital, Boston, MA USA ,Department of Ophthalmology, Harvard Medical School, Boston, MA USA
| | - Eleina M. England
- Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA USA ,Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA USA ,Division of Genetics and Genomics, Boston Children’s Hospital, Boston, MA USA
| | - Hugh J. McMillan
- Division of Neurology, Department of Pediatrics, Children’s Hospital of Eastern Ontario, Ottawa, ON Canada
| | - Christopher Kelly
- Pediatric Ophthalmology and Physician Informatics, MultiCare Health System, Tacoma, WA USA
| | - Brandon M. Pratt
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA USA ,Department of Neurology, Boston Children’s Hospital, Boston, MA USA ,Department of Neurology, Harvard Medical School, Boston, MA USA
| | | | - Anne O’Donnell-Luria
- Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA USA ,Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA USA ,Division of Genetics and Genomics, Boston Children’s Hospital, Boston, MA USA
| | - Daniel G. MacArthur
- Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA USA ,Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA USA ,Centre for Population Genomics, Garvan Institute of Medical Research and UNSW, Sydney, NSW Australia ,Murdoch Children’s Research Institute, Parkville, VIC Australia
| | - Kym M. Boycott
- Children’s Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON Canada ,Department of Genetics, Children’s Hospital of Eastern Ontario, Ottawa, ON Canada
| | - David G. Hunter
- Department of Ophthalmology, Boston Children’s Hospital, Boston, MA USA ,Department of Ophthalmology, Harvard Medical School, Boston, MA USA
| | - Elizabeth C. Engle
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA USA ,Department of Neurology, Boston Children’s Hospital, Boston, MA USA ,Department of Neurology, Harvard Medical School, Boston, MA USA ,Broad Institute of MIT and Harvard, Cambridge, MA USA ,Howard Hughes Medical Institute, Chevy Chase, MD USA ,Department of Ophthalmology, Boston Children’s Hospital, Boston, MA USA ,Department of Ophthalmology, Harvard Medical School, Boston, MA USA
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22
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Brock S, Cools F, Jansen AC. Neuropathology of genetically defined malformations of cortical development-A systematic literature review. Neuropathol Appl Neurobiol 2021; 47:585-602. [PMID: 33480109 PMCID: PMC8359484 DOI: 10.1111/nan.12696] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 12/31/2020] [Accepted: 01/15/2021] [Indexed: 12/23/2022]
Abstract
AIMS Malformations of cortical development (MCD) include a heterogeneous spectrum of clinical, imaging, molecular and histopathological entities. While the understanding of genetic causes of MCD has improved with the availability of next-generation sequencing modalities, genotype-histopathological correlations remain limited. This is the first systematic review of molecular and neuropathological findings in patients with MCD to provide a comprehensive overview of the literature. METHODS A systematic review was performed between November 2019 and February 2020. A MEDLINE search was conducted for 132 genes previously linked to MCD in order to identify studies reporting macroscopic and/or microscopic findings in patients with a confirmed genetic cause. RESULTS Eighty-one studies were included in this review reporting neuropathological features associated with pathogenic variants in 46 genes (46/132 genes, 34.8%). Four groups emerged, consisting of (1) 13 genes with well-defined histological-genotype correlations, (2) 27 genes for which neuropathological reports were limited, (3) 5 genes with conflicting neuropathological features, and (4) 87 genes for which no histological data were available. Lissencephaly and polymicrogyria were reported most frequently. Associated brain malformations were variably present, with abnormalities of the corpus callosum as most common associated feature. CONCLUSIONS Neuropathological data in patients with MCD with a defined genetic cause are available only for a small number of genes. As each genetic cause might lead to unique histopathological features of MCD, standardised thorough neuropathological assessment and reporting should be encouraged. Histological features can help improve the understanding of the pathogenesis of MCD and generate hypotheses with impact on further research directions.
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Affiliation(s)
- Stefanie Brock
- Department of Pathology, Universitair Ziekenhuis Brussel (UZ Brussel), Brussels, Belgium.,Neurogenetics Research Group, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Filip Cools
- Department of Neonatology, Universitair Ziekenhuis Brussel (UZ Brussel), Brussels, Belgium
| | - Anna C Jansen
- Neurogenetics Research Group, Vrije Universiteit Brussel (VUB), Brussels, Belgium.,Pediatric Neurology Unit, Universitair Ziekenhuis Brussel (UZ Brussel), Brussels, Belgium
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23
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Kolbjer S, Martin DA, Pettersson M, Dahlin M, Anderlid BM. Lissencephaly in an epilepsy cohort: Molecular, radiological and clinical aspects. Eur J Paediatr Neurol 2021; 30:71-81. [PMID: 33453472 DOI: 10.1016/j.ejpn.2020.12.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 12/22/2020] [Accepted: 12/27/2020] [Indexed: 12/15/2022]
Abstract
INTRODUCTION Lissencephaly is a rare malformation of cortical development due to abnormal transmantle migration resulting in absent or reduced gyration. The lissencephaly spectrum consists of agyria, pachygyria and subcortical band heterotopia. In this study we compared genetic aetiology, neuroradiology, clinical phenotype and response to antiepileptic drugs in patients with epilepsy and lissencephaly spectrum malformations. METHODS The study group consisted of 20 patients - 13 males and 7 females, aged 18 months to 21 years at the time of data collection. Genetic testing was performed by oligonucleotide array comparative genomic hybridization (microarray), multiplex ligation-dependent probe amplification (MLPA), targeted gene panels and whole exome/genome sequencing. All neuroradiological investigations were re-evaluated and the malformations were classified by the same neuroradiologist. Clinical features and response to anti-epileptic drugs (AEDs) were evaluated by retrospective review of medical records. RESULTS In eleven patients (55%) mutations in PAFAH1B1 (LIS1) or variable microdeletions of 17p13.3 including the PAFAH1B1 gene were detected. Four patients (20%) had tubulin encoding gene mutations (TUBA1A, TUBG1 and TUBGCP6). Mutations in DCX, DYNC1H1, ADGRG1 and WDR62 were identified in single patients. In one patient, a possibly pathogenic intragenic deletion in TRIO was detected. A clear radiologic distinction could be made between tubulinopathies and PAFAH1B1 related lissencephaly. The majority of the patients had therapy resistant epilepsy and epileptic spasms was the most prominent seizure type. The best therapeutic response to seizure control in our cohort was obtained by the ketogenic diet, vigabatrin, clobazam, phenobarbital and valproate. CONCLUSION The most common genetic aetiologies in our cohort of 20 individuals with epilepsy and lissencephaly spectrum were intragenic deletions or single nucleotide mutations in PAFAH1B1 or larger deletions in 17p13.3, encompassing PAFAH1B1, followed by mutations in tubulin encoding genes. Radiological findings could reliably predict molecular results only in agyria with a posterior to anterior gradient. Radiological and molecular findings did not correlate consistently with severity of clinical outcome or therapeutic response.
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Affiliation(s)
- Sintia Kolbjer
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; Department of Neuropaediatrics, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden.
| | - Daniel A Martin
- Department of Neuroradiology, Karolinska University Hospital, Stockholm, Sweden; Department of Paediatric Radiology, Karolinska University Hospital, Stockholm, Sweden
| | - Maria Pettersson
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Maria Dahlin
- Department of Neuropaediatrics, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden; Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden
| | - Britt-Marie Anderlid
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
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24
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Xie L, Huang J, Dai L, Luo J, Zhang J, Peng Q, Sun J, Zhang W. Loss-of-Function Plays a Major Role in Early Neurogenesis of Tubulin α-1 A (TUBA1A) Mutation-Related Brain Malformations. Mol Neurobiol 2020; 58:1291-1302. [PMID: 33165829 DOI: 10.1007/s12035-020-02193-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 10/30/2020] [Indexed: 11/26/2022]
Abstract
Tubulin α-1 A (TUBA1A) mutations cause a wide spectrum of brain abnormalities. Although many mutations have been identified and functionally verified, there are clearly many more, and the relationship between TUBA1A mutations and brain malformations remains unclear. The aim of this study was to identify a TUBA1A mutation in a fetus with severe brain abnormalities, verify it functionally, and determine the mechanism of the mutation-related pathogenesis. A de novo missense mutation of the TUBA1A gene, c.167C>G p.T56R/P.THR56Arg, was identified by exon sequencing. Computer simulations showed that the mutation results in a disruption of lateral interactions between the microtubules. Transfection of 293T cells with TUBA1A p.T56R showed that the mutated protein is only partially incorporated into the microtubule network, resulting in a decrease in the rate of microtubule re-integration in comparison with the wild-type protein. The mechanism of pathological changes induced by the mutant gene was determined by knockdown and overexpression. It was found that knockdown of TUBA1A reduced the generation of neural progenitor cells, while overexpression of wild-type or mutant TUBA1A promoted neurogenesis. Our identification and functional verification of the novel TUBA1A mutation extends the TUBA1A gene-phenotype database. Loss-of-function of TUBA1A was shown to play an important role in early neurogenesis of TUBA1A mutation-related brain malformations.
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Affiliation(s)
- Liangqun Xie
- Department of Obstetrics, Xiangya Hospital Central South University, 87 Xiangya Road, Changsha, 410008, China
| | - Jingrui Huang
- Department of Obstetrics, Xiangya Hospital Central South University, 87 Xiangya Road, Changsha, 410008, China
| | - Lei Dai
- Department of Obstetrics, Xiangya Hospital Central South University, 87 Xiangya Road, Changsha, 410008, China
| | - Jiefeng Luo
- Department of Obstetrics, Xiangya Hospital Central South University, 87 Xiangya Road, Changsha, 410008, China
| | - Jiejie Zhang
- Department of Obstetrics, Xiangya Hospital Central South University, 87 Xiangya Road, Changsha, 410008, China
| | - Qiaozhen Peng
- Department of Obstetrics, Xiangya Hospital Central South University, 87 Xiangya Road, Changsha, 410008, China
| | - Jingchi Sun
- Department of Obstetrics, Xiangya Hospital Central South University, 87 Xiangya Road, Changsha, 410008, China
| | - Weishe Zhang
- Department of Obstetrics, Xiangya Hospital Central South University, 87 Xiangya Road, Changsha, 410008, China.
- Hunan Engineering Research Center of Early Life Development and Disease Prevention, 87 Xiangya Road, Changsha, 410008, China.
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25
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Fourel G, Boscheron C. Tubulin mutations in neurodevelopmental disorders as a tool to decipher microtubule function. FEBS Lett 2020; 594:3409-3438. [PMID: 33064843 DOI: 10.1002/1873-3468.13958] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 09/28/2020] [Accepted: 10/05/2020] [Indexed: 01/08/2023]
Abstract
Malformations of cortical development (MCDs) are a group of severe brain malformations associated with intellectual disability and refractory childhood epilepsy. Human missense heterozygous mutations in the 9 α-tubulin and 10 β-tubulin isoforms forming the heterodimers that assemble into microtubules (MTs) were found to cause MCDs. However, how a single mutated residue in a given tubulin isoform can perturb the entire microtubule population in a neuronal cell remains a crucial question. Here, we examined 85 MCD-associated tubulin mutations occurring in TUBA1A, TUBB2, and TUBB3 and their location in a three-dimensional (3D) microtubule cylinder. Mutations hitting residues exposed on the outer microtubule surface are likely to alter microtubule association with partners, while alteration of intradimer contacts may impair dimer stability and straightness. Other types of mutations are predicted to alter interdimer and lateral contacts, which are responsible for microtubule cohesion, rigidity, and dynamics. MCD-associated tubulin mutations surprisingly fall into all categories, thus providing unexpected insights into how a single mutation may impair microtubule function and elicit dominant effects in neurons.
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26
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Leca I, Phillips AW, Hofer I, Landler L, Ushakova L, Cushion TD, Dürnberger G, Stejskal K, Mechtler K, Keays DA. A proteomic survey of microtubule-associated proteins in a R402H TUBA1A mutant mouse. PLoS Genet 2020; 16:e1009104. [PMID: 33137126 PMCID: PMC7660477 DOI: 10.1371/journal.pgen.1009104] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 11/12/2020] [Accepted: 09/08/2020] [Indexed: 11/25/2022] Open
Abstract
Microtubules play a critical role in multiple aspects of neurodevelopment, including the generation, migration and differentiation of neurons. A recurrent mutation (R402H) in the α-tubulin gene TUBA1A is known to cause lissencephaly with cerebellar and striatal phenotypes. Previous work has shown that this mutation does not perturb the chaperone-mediated folding of tubulin heterodimers, which are able to assemble and incorporate into the microtubule lattice. To explore the molecular mechanisms that cause the disease state we generated a new conditional mouse line that recapitulates the R402H variant. We show that heterozygous mutants present with laminar phenotypes in the cortex and hippocampus, as well as a reduction in striatal size and cerebellar abnormalities. We demonstrate that homozygous expression of the R402H allele causes neuronal death and exacerbates a cell intrinsic defect in cortical neuronal migration. Microtubule sedimentation assays coupled with quantitative mass spectrometry demonstrated that the binding and/or levels of multiple microtubule associated proteins (MAPs) are perturbed by the R402H mutation including VAPB, REEP1, EZRIN, PRNP and DYNC1l1/2. Consistent with these data we show that the R402H mutation impairs dynein-mediated transport which is associated with a decoupling of the nucleus to the microtubule organising center. Our data support a model whereby the R402H variant is able to fold and incorporate into microtubules, but acts as a gain of function by perturbing the binding of MAPs. Microtubules are polymers composed of tubulin proteins, which play an important role in the development of the human brain. Genetic mutations in tubulin genes are known to cause neurodevelopmental diseases, including lissencephaly which is characterised by an impairment in the migration of neurons. In this study we investigate how a common mutation (R402H) in TUBA1A causes lissencephaly by generating and characterising a mouse with the same variant. We show that affected animals recapitulate multiple aspects of the human disease; including laminar perturbations in the cortex and hippocampus, attributable to defects in neuronal migration at key developmental time points. To characterize the molecular implications of the R402H mutation we purified microtubules from the developing brain, and analysed the proteins present by mass spectrometry. This revealed that the binding of DYNC1I1/2 to microtubules is altered in mice with the R402H mutation. Our results provide insight into the molecular pathology underlying tubulin related disease states, and provide a foundation for the rational design of therapeutic interventions.
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Affiliation(s)
- Ines Leca
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | | | - Iris Hofer
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Lukas Landler
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
- Institute of Zoology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Lyubov Ushakova
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Thomas David Cushion
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Gerhard Dürnberger
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), Vienna, Austria
| | - Karel Stejskal
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), Vienna, Austria
| | - Karl Mechtler
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), Vienna, Austria
| | - David Anthony Keays
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Australia
- Division of Neurobiology, Department Biology II, Ludwig-Maximilians-University Munich, Planegg-Martinsried 82152, Germany
- * E-mail:
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27
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Microtubule Dysfunction: A Common Feature of Neurodegenerative Diseases. Int J Mol Sci 2020; 21:ijms21197354. [PMID: 33027950 PMCID: PMC7582320 DOI: 10.3390/ijms21197354] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 09/24/2020] [Accepted: 10/01/2020] [Indexed: 12/13/2022] Open
Abstract
Neurons are particularly susceptible to microtubule (MT) defects and deregulation of the MT cytoskeleton is considered to be a common insult during the pathogenesis of neurodegenerative disorders. Evidence that dysfunctions in the MT system have a direct role in neurodegeneration comes from findings that several forms of neurodegenerative diseases are associated with changes in genes encoding tubulins, the structural units of MTs, MT-associated proteins (MAPs), or additional factors such as MT modifying enzymes which modulating tubulin post-translational modifications (PTMs) regulate MT functions and dynamics. Efforts to use MT-targeting therapeutic agents for the treatment of neurodegenerative diseases are underway. Many of these agents have provided several benefits when tested on both in vitro and in vivo neurodegenerative model systems. Currently, the most frequently addressed therapeutic interventions include drugs that modulate MT stability or that target tubulin PTMs, such as tubulin acetylation. The purpose of this review is to provide an update on the relevance of MT dysfunctions to the process of neurodegeneration and briefly discuss advances in the use of MT-targeting drugs for the treatment of neurodegenerative disorders.
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28
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Gavrilovici C, Jiang Y, Kiroski I, Teskey GC, Rho JM, Nguyen MD. Postnatal Role of the Cytoskeleton in Adult Epileptogenesis. Cereb Cortex Commun 2020; 1:tgaa024. [PMID: 32864616 PMCID: PMC7446231 DOI: 10.1093/texcom/tgaa024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 06/08/2020] [Accepted: 06/11/2020] [Indexed: 02/07/2023] Open
Abstract
Mutations in cytoskeletal proteins can cause early infantile and childhood epilepsies by misplacing newly born neurons and altering neuronal connectivity. In the adult epileptic brain, cytoskeletal disruption is often viewed as being secondary to aberrant neuronal activity and/or death, and hence simply represents an epiphenomenon. Here, we review the emerging evidence collected in animal models and human studies implicating the cytoskeleton as a potential causative factor in adult epileptogenesis. Based on the emerging evidence, we propose that cytoskeletal disruption may be an important pathogenic mechanism in the mature epileptic brain.
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Affiliation(s)
- Cezar Gavrilovici
- Departments of Neurosciences & Pediatrics, University of California San Diego, Rady Children's Hospital San Diego, San Diego, CA 92123, USA
| | - Yulan Jiang
- Departments of Clinical Neurosciences, Cell Biology & Anatomy, and Biochemistry & Molecular Biology, Hotchkiss Brain Institute, Alberta Children Hospital Research Institute, University of Calgary, Calgary T2N 4N1, Canada
| | - Ivana Kiroski
- Departments of Clinical Neurosciences, Cell Biology & Anatomy, and Biochemistry & Molecular Biology, Hotchkiss Brain Institute, Alberta Children Hospital Research Institute, University of Calgary, Calgary T2N 4N1, Canada
| | - G Campbell Teskey
- Department of Cell Biology & Anatomy, Hotchkiss Brain Institute, Alberta Children Hospital Research Institute, University of Calgary, Calgary T2N 4N1, Canada
| | - Jong M Rho
- Departments of Neurosciences & Pediatrics, University of California San Diego, Rady Children's Hospital San Diego, San Diego, CA 92123, USA
| | - Minh Dang Nguyen
- Departments of Clinical Neurosciences, Cell Biology & Anatomy, and Biochemistry & Molecular Biology, Hotchkiss Brain Institute, Alberta Children Hospital Research Institute, University of Calgary, Calgary T2N 4N1, Canada
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29
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Borys F, Joachimiak E, Krawczyk H, Fabczak H. Intrinsic and Extrinsic Factors Affecting Microtubule Dynamics in Normal and Cancer Cells. Molecules 2020; 25:molecules25163705. [PMID: 32823874 PMCID: PMC7464520 DOI: 10.3390/molecules25163705] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/03/2020] [Accepted: 08/08/2020] [Indexed: 12/18/2022] Open
Abstract
Microtubules (MTs), highly dynamic structures composed of α- and β-tubulin heterodimers, are involved in cell movement and intracellular traffic and are essential for cell division. Within the cell, MTs are not uniform as they can be composed of different tubulin isotypes that are post-translationally modified and interact with different microtubule-associated proteins (MAPs). These diverse intrinsic factors influence the dynamics of MTs. Extrinsic factors such as microtubule-targeting agents (MTAs) can also affect MT dynamics. MTAs can be divided into two main categories: microtubule-stabilizing agents (MSAs) and microtubule-destabilizing agents (MDAs). Thus, the MT skeleton is an important target for anticancer therapy. This review discusses factors that determine the microtubule dynamics in normal and cancer cells and describes microtubule–MTA interactions, highlighting the importance of tubulin isoform diversity and post-translational modifications in MTA responses and the consequences of such a phenomenon, including drug resistance development.
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Affiliation(s)
- Filip Borys
- Laboratory of Cytoskeleton and Cilia Biology Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland;
- Department of Organic Chemistry, Faculty of Chemistry, Warsaw University of Technology, 3 Noakowskiego Street, 00-664 Warsaw, Poland;
| | - Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland;
- Correspondence: (E.J.); (H.F.)
| | - Hanna Krawczyk
- Department of Organic Chemistry, Faculty of Chemistry, Warsaw University of Technology, 3 Noakowskiego Street, 00-664 Warsaw, Poland;
| | - Hanna Fabczak
- Laboratory of Cytoskeleton and Cilia Biology Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland;
- Correspondence: (E.J.); (H.F.)
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30
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Yadav A, Seth B, Chaturvedi RK. Brain Organoids: Tiny Mirrors of Human Neurodevelopment and Neurological Disorders. Neuroscientist 2020; 27:388-426. [PMID: 32723210 DOI: 10.1177/1073858420943192] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Unravelling the complexity of the human brain is a challenging task. Nowadays, modern neurobiologists have developed 3D model systems called "brain organoids" to overcome the technical challenges in understanding human brain development and the limitations of animal models to study neurological diseases. Certainly like most model systems in neuroscience, brain organoids too have limitations, as these minuscule brains lack the complex neuronal circuitry required to begin the operational tasks of human brain. However, researchers are hopeful that future endeavors with these 3D brain tissues could provide mechanistic insights into the generation of circuit complexity as well as reproducible creation of different regions of the human brain. Herein, we have presented the contemporary state of brain organoids with special emphasis on their mode of generation and their utility in modelling neurological disorders, drug discovery, and clinical trials.
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Affiliation(s)
- Anuradha Yadav
- Developmental Toxicology Laboratory, Systems Toxicology and Health Risk Assessment Group, CSIR-Indian Institute of Toxicology Research, Lucknow, Uttar Pradesh, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Brashket Seth
- Developmental Toxicology Laboratory, Systems Toxicology and Health Risk Assessment Group, CSIR-Indian Institute of Toxicology Research, Lucknow, Uttar Pradesh, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Rajnish Kumar Chaturvedi
- Developmental Toxicology Laboratory, Systems Toxicology and Health Risk Assessment Group, CSIR-Indian Institute of Toxicology Research, Lucknow, Uttar Pradesh, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
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Markus SM, Marzo MG, McKenney RJ. New insights into the mechanism of dynein motor regulation by lissencephaly-1. eLife 2020; 9:59737. [PMID: 32692650 PMCID: PMC7373426 DOI: 10.7554/elife.59737] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 07/13/2020] [Indexed: 12/20/2022] Open
Abstract
Lissencephaly (‘smooth brain’) is a severe brain disease associated with numerous symptoms, including cognitive impairment, and shortened lifespan. The main causative gene of this disease – lissencephaly-1 (LIS1) – has been a focus of intense scrutiny since its first identification almost 30 years ago. LIS1 is a critical regulator of the microtubule motor cytoplasmic dynein, which transports numerous cargoes throughout the cell, and is a key effector of nuclear and neuronal transport during brain development. Here, we review the role of LIS1 in cellular dynein function and discuss recent key findings that have revealed a new mechanism by which this molecule influences dynein-mediated transport. In addition to reconciling prior observations with this new model for LIS1 function, we also discuss phylogenetic data that suggest that LIS1 may have coevolved with an autoinhibitory mode of cytoplasmic dynein regulation.
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Affiliation(s)
- Steven M Markus
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, United States
| | - Matthew G Marzo
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, United States
| | - Richard J McKenney
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, United States
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Sferra A, Petrini S, Bellacchio E, Nicita F, Scibelli F, Dentici ML, Alfieri P, Cestra G, Bertini ES, Zanni G. TUBB Variants Underlying Different Phenotypes Result in Altered Vesicle Trafficking and Microtubule Dynamics. Int J Mol Sci 2020; 21:ijms21041385. [PMID: 32085672 PMCID: PMC7073044 DOI: 10.3390/ijms21041385] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/13/2020] [Accepted: 02/14/2020] [Indexed: 11/26/2022] Open
Abstract
Tubulinopathies are rare neurological disorders caused by alterations in tubulin structure and function, giving rise to a wide range of brain abnormalities involving neuronal proliferation, migration, differentiation and axon guidance. TUBB is one of the ten β-tubulin encoding genes present in the human genome and is broadly expressed in the developing central nervous system and the skin. Mutations in TUBB are responsible for two distinct pathological conditions: the first is characterized by microcephaly and complex structural brain malformations and the second, also known as “circumferential skin creases Kunze type” (CSC-KT), is associated to neurological features, excess skin folding and growth retardation. We used a combination of immunocytochemical and cellular approaches to explore, on patients’ derived fibroblasts, the functional consequences of two TUBB variants: the novel mutation (p.N52S), associated with basal ganglia and cerebellar dysgenesis, and the previously reported variant (p.M73T), linked to microcephaly, corpus callosum agenesis and CSC-KT skin phenotype. Our results demonstrate that these variants impair microtubule (MT) function and dynamics. Most importantly, our studies show an altered epidermal growth factor (EGF) and transferrin (Tf) intracellular vesicle trafficking in both patients’ fibroblasts, suggesting a specific role of TUBB in MT-dependent vesicular transport.
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Affiliation(s)
- Antonella Sferra
- Unit of Neuromuscular and Neurodegenerative Disorders, Department Neurosciences, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy; (F.N.); (E.S.B.)
- Correspondence: (A.S.); (G.Z.)
| | - Stefania Petrini
- Confocal Microscopy Core Facility, Research Laboratories, Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy;
| | - Emanuele Bellacchio
- Department of Research Laboratories, Bambino Gesù Children’s Hospital, 00146 Rome, Italy;
| | - Francesco Nicita
- Unit of Neuromuscular and Neurodegenerative Disorders, Department Neurosciences, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy; (F.N.); (E.S.B.)
| | - Francesco Scibelli
- Unit of Child Neuropsychiatry, Department of Neurosciences, Bambino Gesù Children’s Hospital, 00165 Rome, Italy; (F.S.); (P.A.)
| | - Maria Lisa Dentici
- Unit of Medical Genetics, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy;
| | - Paolo Alfieri
- Unit of Child Neuropsychiatry, Department of Neurosciences, Bambino Gesù Children’s Hospital, 00165 Rome, Italy; (F.S.); (P.A.)
| | - Gianluca Cestra
- Institute of Molecular Biology and Pathology (IBPM), National Research Council (CNR) and University of Rome “Sapienza”, Department of Biology and Biotechnology, 00185 Rome, Italy;
| | - Enrico Silvio Bertini
- Unit of Neuromuscular and Neurodegenerative Disorders, Department Neurosciences, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy; (F.N.); (E.S.B.)
| | - Ginevra Zanni
- Unit of Neuromuscular and Neurodegenerative Disorders, Department Neurosciences, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy; (F.N.); (E.S.B.)
- Correspondence: (A.S.); (G.Z.)
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Lee S, Kim SH, Kim B, Lee ST, Choi JR, Kim HD, Lee JS, Kang HC. Clinical Implementation of Targeted Gene Sequencing for Malformation of Cortical Development. Pediatr Neurol 2020; 103:27-34. [PMID: 31481326 DOI: 10.1016/j.pediatrneurol.2019.07.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Revised: 07/16/2019] [Accepted: 07/21/2019] [Indexed: 11/29/2022]
Abstract
BACKGROUND Malformations of cortical development comprise phenotypically heterogeneous conditions, and the diagnostic value of genetic testing in blood still remains to be elucidated. We used targeted gene sequencing to identify malformations of cortical development caused by germline mutations and characteristics associated with pathogenic mutations. METHODS A total of 81 patients with malformations of cortical development were included. Genomic DNA was isolated from peripheral blood. Ninety-six genes were assessed using a targeted next-generation sequencing panel. Single-nucleotide variants and exonic and chromosomal copy number variations were examined with our customized pipeline. RESULTS Genetic causes were identified from blood in 19 (23.5%) patients with malformations of cortical development; 14 patients had pathogenic or likely pathogenic single-nucleotide variants in seven genes, including DCX (n = 5), DEPDC5 (n = 2), PAFAH1B1 (n = 3), TUBA1A (n = 1), TUBA8 (n = 1), TUBB2B (n = 1), and TUBB3 (n = 1). Five patients had pathogenic copy number variations. Multifocal involvement of the lesion (tangential distribution, P < 0.001) and concurrent involvement of multiple structures such as the cortex, white matter, and ventricle (radial distribution, P = 0.003) were more commonly found in patients with identified genetic causes. Intellectual disability was also more commonly associated with pathogenic mutations (P = 0.048). In a multivariable regression analysis, both tangential and radial radiological distribution of malformations of cortical development were independently associated with positive germline test results. CONCLUSION We identified germline mutations in almost one-fourth of our patients with malformations of cortical development by using targeted gene sequencing. Germline abnormalities were more likely found in patients who had multifocal malformations of cortical development.
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Affiliation(s)
- Sangbo Lee
- Division of Pediatric Neurology, Epilepsy Research Institute, Severance Children's Hospital, Department of Pediatrics, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Se Hee Kim
- Division of Pediatric Neurology, Epilepsy Research Institute, Severance Children's Hospital, Department of Pediatrics, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Borahm Kim
- Department of Laboratory Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Seung-Tae Lee
- Department of Laboratory Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Jong Rak Choi
- Department of Laboratory Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Heung Dong Kim
- Division of Pediatric Neurology, Epilepsy Research Institute, Severance Children's Hospital, Department of Pediatrics, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Joon Soo Lee
- Division of Pediatric Neurology, Epilepsy Research Institute, Severance Children's Hospital, Department of Pediatrics, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Hoon-Chul Kang
- Division of Pediatric Neurology, Epilepsy Research Institute, Severance Children's Hospital, Department of Pediatrics, Yonsei University College of Medicine, Seoul, Republic of Korea.
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34
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Labonne JDJ, Driessen TM, Harris ME, Kong IK, Brakta S, Theisen J, Sangare M, Layman LC, Kim CH, Lim J, Kim HG. Comparative Genomic Mapping Implicates LRRK2 for Intellectual Disability and Autism at 12q12, and HDHD1, as Well as PNPLA4, for X-Linked Intellectual Disability at Xp22.31. J Clin Med 2020; 9:jcm9010274. [PMID: 31963867 PMCID: PMC7019335 DOI: 10.3390/jcm9010274] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 11/28/2019] [Accepted: 12/06/2019] [Indexed: 01/01/2023] Open
Abstract
We report a genomic and phenotypic delineation for two chromosome regions with candidate genes for syndromic intellectual disability at 12q12 and Xp22.31, segregating independently in one family with four affected members. Fine mapping of three affected members, along with six unreported small informative CNVs, narrowed down the candidate chromosomal interval to one gene LRRK2 at 12q12. Expression studies revealed high levels of LRRK2 transcripts in the whole human brain, cerebral cortex and hippocampus. RT-qPCR assays revealed that LRRK2 transcripts were dramatically reduced in our microdeletion patient DGDP289A compared to his healthy grandfather with no deletion. The decreased expression of LRRK2 may affect protein–protein interactions between LRRK2 and its binding partners, of which eight have previously been linked to intellectual disability. These findings corroborate with a role for LRRK2 in cognitive development, and, thus, we propose that intellectual disability and autism, displayed in the 12q12 microdeletions, are likely caused by LRRK2. Using another affected member, DGDP289B, with a microdeletion at Xp22.31, in this family, we performed the genomic and clinical delineation with six published and nine unreported cases. We propose HDHD1 and PNPLA4 for X-linked intellectual disability in this region, since their high transcript levels in the human brain substantiate their role in intellectual functioning.
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Affiliation(s)
- Jonathan D. J. Labonne
- Section of Reproductive Endocrinology, Infertility & Genetics, Department of Obstetrics & Gynecology, Augusta University, Augusta, GA 30912, USA (M.E.H.); (S.B.); (J.T.); (L.C.L.)
| | - Terri M. Driessen
- Department of Genetics, Yale University, New Haven, CT 06510, USA; (T.M.D.); (J.L.)
| | - Marvin E. Harris
- Section of Reproductive Endocrinology, Infertility & Genetics, Department of Obstetrics & Gynecology, Augusta University, Augusta, GA 30912, USA (M.E.H.); (S.B.); (J.T.); (L.C.L.)
| | - Il-Keun Kong
- Department of Animal Science, Division of Applied Life Science (BK21plus), Institute of Agriculture and Life Science, Gyeongsang National University, Jinju 52828, Korea;
| | - Soumia Brakta
- Section of Reproductive Endocrinology, Infertility & Genetics, Department of Obstetrics & Gynecology, Augusta University, Augusta, GA 30912, USA (M.E.H.); (S.B.); (J.T.); (L.C.L.)
| | - John Theisen
- Section of Reproductive Endocrinology, Infertility & Genetics, Department of Obstetrics & Gynecology, Augusta University, Augusta, GA 30912, USA (M.E.H.); (S.B.); (J.T.); (L.C.L.)
| | - Modibo Sangare
- Faculty of Medicine and Odontostomatology (FMOS), University of Sciences, Techniques and Technologies of Bamako (USTTB), Bamako, Mali;
| | - Lawrence C. Layman
- Section of Reproductive Endocrinology, Infertility & Genetics, Department of Obstetrics & Gynecology, Augusta University, Augusta, GA 30912, USA (M.E.H.); (S.B.); (J.T.); (L.C.L.)
- Department of Neuroscience and Regenerative Medicine, Augusta University, Augusta, GA 30912, USA
| | - Cheol-Hee Kim
- Department of Biology, Chungnam National University, Daejeon 34134, Korea;
| | - Janghoo Lim
- Department of Genetics, Yale University, New Haven, CT 06510, USA; (T.M.D.); (J.L.)
- Department of Neuroscience, Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale Stem Cell Center, Yale University, New Haven, CT 06510, USA
| | - Hyung-Goo Kim
- Section of Reproductive Endocrinology, Infertility & Genetics, Department of Obstetrics & Gynecology, Augusta University, Augusta, GA 30912, USA (M.E.H.); (S.B.); (J.T.); (L.C.L.)
- Neurological Disorders Research Center, Qatar Biomedical Research Institute, Hamad Bin Khalifa University, Doha P.O. Box 34110, Qatar
- Correspondence:
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35
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Aiken J, Buscaglia G, Aiken AS, Moore JK, Bates EA. Tubulin mutations in brain development disorders: Why haploinsufficiency does not explain TUBA1A tubulinopathies. Cytoskeleton (Hoboken) 2019; 77:40-54. [PMID: 31574570 DOI: 10.1002/cm.21567] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 09/09/2019] [Accepted: 09/17/2019] [Indexed: 12/12/2022]
Abstract
The neuronal cytoskeleton performs incredible feats during nervous system development. Extension of neuronal processes, migration, and synapse formation rely on the proper regulation of microtubules. Mutations that disrupt the primary α-tubulin expressed during brain development, TUBA1A, are associated with a spectrum of human brain malformations. One model posits that TUBA1A mutations lead to a reduction in tubulin subunits available for microtubule polymerization, which represents a haploinsufficiency mechanism. We propose an alternative model for the majority of tubulinopathy mutations, in which the mutant tubulin polymerizes into the microtubule lattice to dominantly "poison" microtubule function. Nine distinct α-tubulin and ten β-tubulin genes have been identified in the human genome. These genes encode similar tubulin proteins, called isotypes. Multiple tubulin isotypes may partially compensate for heterozygous deletion of a tubulin gene, but may not overcome the disruption caused by missense mutations that dominantly alter microtubule function. Here, we describe disorders attributed to haploinsufficiency versus dominant negative mechanisms to demonstrate the hallmark features of each disorder. We summarize literature on mouse models that represent both knockout and point mutants in tubulin genes, with an emphasis on how these mutations might provide insight into the nature of tubulinopathy patient mutations. Finally, we present data from a panel of TUBA1A tubulinopathy mutations generated in yeast α-tubulin that demonstrate that α-tubulin mutants can incorporate into the microtubule network and support viability of yeast growth. This perspective on tubulinopathy mutations draws on previous studies and additional data to provide a fresh perspective on how TUBA1A mutations disrupt neurodevelopment.
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Affiliation(s)
- Jayne Aiken
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado
| | - Georgia Buscaglia
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - A Sophie Aiken
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado
| | - Jeffrey K Moore
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado
| | - Emily A Bates
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
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36
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Pagnamenta AT, Heemeryck P, Martin HC, Bosc C, Peris L, Uszynski I, Gory-Fauré S, Couly S, Deshpande C, Siddiqui A, Elmonairy AA, Jayawant S, Murthy S, Walker I, Loong L, Bauer P, Vossier F, Denarier E, Maurice T, Barbier EL, Deloulme JC, Taylor JC, Blair EM, Andrieux A, Moutin MJ. Defective tubulin detyrosination causes structural brain abnormalities with cognitive deficiency in humans and mice. Hum Mol Genet 2019; 28:3391-3405. [PMID: 31363758 PMCID: PMC6891070 DOI: 10.1093/hmg/ddz186] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 07/23/2019] [Accepted: 07/23/2019] [Indexed: 12/15/2022] Open
Abstract
Reversible detyrosination of tubulin, the building block of microtubules, is crucial for neuronal physiology. Enzymes responsible for detyrosination were recently identified as complexes of vasohibins (VASHs) one or two with small VASH-binding protein (SVBP). Here we report three consanguineous families, each containing multiple individuals with biallelic inactivation of SVBP caused by truncating variants (p.Q28* and p.K13Nfs*18). Affected individuals show brain abnormalities with microcephaly, intellectual disability and delayed gross motor and speech development. Immunoblot testing in cells with pathogenic SVBP variants demonstrated that the encoded proteins were unstable and non-functional, resulting in a complete loss of VASH detyrosination activity. Svbp knockout mice exhibit drastic accumulation of tyrosinated tubulin and a reduction of detyrosinated tubulin in brain tissue. Similar alterations in tubulin tyrosination levels were observed in cultured neurons and associated with defects in axonal differentiation and architecture. Morphological analysis of the Svbp knockout mouse brains by anatomical magnetic resonance imaging showed a broad impact of SVBP loss, with a 7% brain volume decrease, numerous structural defects and a 30% reduction of some white matter tracts. Svbp knockout mice display behavioural defects, including mild hyperactivity, lower anxiety and impaired social behaviour. They do not, however, show prominent memory defects. Thus, SVBP-deficient mice recapitulate several features observed in human patients. Altogether, our data demonstrate that deleterious variants in SVBP cause this neurodevelopmental pathology, by leading to a major change in brain tubulin tyrosination and alteration of microtubule dynamics and neuron physiology.
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Affiliation(s)
- Alistair T Pagnamenta
- NIHR Oxford BRC, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Pierre Heemeryck
- Grenoble Institut Neurosciences, Université Grenoble Alpes, Inserm, U1216, CEA, CNRS, 38000 Grenoble, France
| | - Hilary C Martin
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK
| | - Christophe Bosc
- Grenoble Institut Neurosciences, Université Grenoble Alpes, Inserm, U1216, CEA, CNRS, 38000 Grenoble, France
| | - Leticia Peris
- Grenoble Institut Neurosciences, Université Grenoble Alpes, Inserm, U1216, CEA, CNRS, 38000 Grenoble, France
| | - Ivy Uszynski
- Grenoble Institut Neurosciences, Université Grenoble Alpes, Inserm, U1216, CEA, CNRS, 38000 Grenoble, France
| | - Sylvie Gory-Fauré
- Grenoble Institut Neurosciences, Université Grenoble Alpes, Inserm, U1216, CEA, CNRS, 38000 Grenoble, France
| | - Simon Couly
- MMDN, Université de Montpellier, INSERM, EPHE, UMR_S1198, Montpellier, France
| | - Charu Deshpande
- South East Thames Regional Genetics Unit, Guys and St Thomas NHS Trust, London, UK
| | - Ata Siddiqui
- Department of Neuroradiology, Kings College Hospital, Denmark Hill, London SE5 9RS, UK
| | - Alaa A Elmonairy
- Ministry of Health, Kuwait Medical Genetics Center, Sulaibikhat 80901, Kuwait
| | | | | | - Sandeep Jayawant
- Department of Paediatric Neurology, John Radcliffe Hospital, Oxford, UK
| | | | - Ian Walker
- Clinical Biochemistry, Wexham Park Hospital, Slough, UK
| | - Lucy Loong
- Oxford Centre for Genomic Medicine, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | | | - Frédérique Vossier
- Grenoble Institut Neurosciences, Université Grenoble Alpes, Inserm, U1216, CEA, CNRS, 38000 Grenoble, France
| | - Eric Denarier
- Grenoble Institut Neurosciences, Université Grenoble Alpes, Inserm, U1216, CEA, CNRS, 38000 Grenoble, France
| | - Tangui Maurice
- MMDN, Université de Montpellier, INSERM, EPHE, UMR_S1198, Montpellier, France
| | - Emmanuel L Barbier
- Grenoble Institut Neurosciences, Université Grenoble Alpes, Inserm, U1216, CEA, CNRS, 38000 Grenoble, France
| | - Jean-Christophe Deloulme
- Grenoble Institut Neurosciences, Université Grenoble Alpes, Inserm, U1216, CEA, CNRS, 38000 Grenoble, France
| | - Jenny C Taylor
- NIHR Oxford BRC, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Edward M Blair
- Oxford Centre for Genomic Medicine, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Annie Andrieux
- Grenoble Institut Neurosciences, Université Grenoble Alpes, Inserm, U1216, CEA, CNRS, 38000 Grenoble, France
| | - Marie-Jo Moutin
- Grenoble Institut Neurosciences, Université Grenoble Alpes, Inserm, U1216, CEA, CNRS, 38000 Grenoble, France
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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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38
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Vasung L, Rezayev A, Yun HJ, Song JW, van der Kouwe A, Stewart N, Palani A, Shiohama T, Chouinard-Decorte F, Levman J, Takahashi E. Structural and Diffusion MRI Analyses With Histological Observations in Patients With Lissencephaly. Front Cell Dev Biol 2019; 7:124. [PMID: 31355197 PMCID: PMC6637974 DOI: 10.3389/fcell.2019.00124] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 06/26/2019] [Indexed: 12/11/2022] Open
Abstract
The development of cortical convolutions, gyri and sulci, is a complex process that takes place during prenatal development. Lissencephaly, a rare genetic condition characterized by the lack of cortical convolutions, offers a model to look into biological processes that lead to the development of convolutions. Retrospective, qualitative, and quantitative analyses of structural magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) were performed in patients with lissencephaly (N = 10) and age-/sex-matched controls (N = 10). In order to identify microstructural correlates of structural MRI and DTI findings, postmortem brains of patients with lissencephaly (N = 4) and age-matched controls (N = 4) were also examined with histology. Patients with lissencephaly had significantly smaller gyrification index and volumes of hemispheric white and gray matter, compared to the age-/sex-matched control group. However, there was no significant difference between groups in the subcortical gray matter volumes. Although the majority of patients with lissencephaly had a preserved normal-like appearance of major fissures and primary sulci, the spatial distribution of agyric cortical regions was different in patients with lissencephaly-1 (LIS1) and doublecortin (DCX) mutations. Lastly, in patients with lissencephaly, the spatiotemporal distribution of projection pathways was preserved while short- to medium-range cortico-cortical pathways were absent or fewer in number. Our results indicate that in the patients with lissencephaly cortical system is affected more than the subcortical one.
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Affiliation(s)
- Lana Vasung
- Division of Newborn Medicine, Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States
- Fetal Neonatal Neuroimaging and Developmental Science Center, Boston, MA, United States
| | - Arthur Rezayev
- Division of Newborn Medicine, Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States
- Fetal Neonatal Neuroimaging and Developmental Science Center, Boston, MA, United States
| | - Hyuk Jin Yun
- Division of Newborn Medicine, Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States
- Fetal Neonatal Neuroimaging and Developmental Science Center, Boston, MA, United States
| | - Jae W. Song
- Division of Neuroradiology, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Andre van der Kouwe
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Boston, MA, United States
| | - Natalie Stewart
- Division of Newborn Medicine, Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States
- Fetal Neonatal Neuroimaging and Developmental Science Center, Boston, MA, United States
| | - Arthi Palani
- Division of Newborn Medicine, Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States
- Fetal Neonatal Neuroimaging and Developmental Science Center, Boston, MA, United States
| | - Tadashi Shiohama
- Division of Newborn Medicine, Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States
- Fetal Neonatal Neuroimaging and Developmental Science Center, Boston, MA, United States
- Department of Pediatrics, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Francois Chouinard-Decorte
- Ludmer Centre for Neuroinformatics, McGill Centre for Integrative Neuroscience, Department of Biomedical Engineering, Montreal Neurological Institute and Hospital, McGill University, Montreal, QC, Canada
| | - Jacob Levman
- Division of Newborn Medicine, Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States
- Fetal Neonatal Neuroimaging and Developmental Science Center, Boston, MA, United States
- Department of Mathematics, Statistics, and Computer Science, St. Francis Xavier University, Antigonish, NS, Canada
| | - Emi Takahashi
- Division of Newborn Medicine, Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States
- Fetal Neonatal Neuroimaging and Developmental Science Center, Boston, MA, United States
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Epilepsy in Tubulinopathy: Personal Series and Literature Review. Cells 2019; 8:cells8070669. [PMID: 31269740 PMCID: PMC6678821 DOI: 10.3390/cells8070669] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 06/25/2019] [Accepted: 06/28/2019] [Indexed: 11/17/2022] Open
Abstract
Mutations in tubulin genes are responsible for a large spectrum of brain malformations secondary to abnormal neuronal migration, organization, differentiation and axon guidance and maintenance. Motor impairment, intellectual disability and epilepsy are the main clinical symptoms. In the present study 15 patients from a personal cohort and 75 from 21 published studies carrying mutations in TUBA1A, TUBB2B and TUBB3 tubulin genes were evaluated with the aim to define a clinical and electrophysiological associated pattern. Epilepsy shows a wide range of severity without a specific pattern. Mutations in TUBA1A (60%) and TUBB2B (74%) and TUBB3 (25%) genes are associated with epilepsy. The accurate analysis of the Electroencephalogram (EEG) pattern in wakefulness and sleep in our series allows us to detect significant abnormalities of the background activity in 100% of patients. The involvement of white matter and of the inter-hemispheric connection structures typically observed in tubulinopathies is evidenced by the high percentage of asynchronisms in the organization of sleep activity recorded. In addition to asymmetries of the background activity, excess of slowing, low amplitude and Magnetic Resonance (MR) imaging confirm the presence of extensive brain malformations involving subcortical and midline structures. In conclusion, epilepsy in tubulinopathies when present has a favorable evolution over time suggesting a not particularly aggressive therapeutic approach.
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Aiken J, Moore JK, Bates EA. TUBA1A mutations identified in lissencephaly patients dominantly disrupt neuronal migration and impair dynein activity. Hum Mol Genet 2019; 28:1227-1243. [PMID: 30517687 DOI: 10.1093/hmg/ddy416] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 11/16/2018] [Accepted: 11/27/2018] [Indexed: 02/06/2023] Open
Abstract
The microtubule cytoskeleton supports diverse cellular morphogenesis and migration processes during brain development. Mutations in tubulin genes are associated with severe human brain malformations known as 'tubulinopathies'; however, it is not understood how molecular-level changes in microtubule subunits lead to brain malformations. In this study, we demonstrate that missense mutations affecting arginine at position 402 (R402) of TUBA1A α-tubulin selectively impair dynein motor activity and severely and dominantly disrupt cortical neuronal migration. TUBA1A is the most commonly affected tubulin gene in tubulinopathy patients, and mutations altering R402 account for 30% of all reported TUBA1A mutations. We show for the first time that ectopic expression of TUBA1A-R402C and TUBA1A-R402H patient alleles is sufficient to dominantly disrupt cortical neuronal migration in the developing mouse brain, strongly supporting a causal role in the pathology of brain malformation. To isolate the precise molecular impact of R402 mutations, we generated analogous R402C and R402H mutations in budding yeast α-tubulin, which exhibit a simplified microtubule cytoskeleton. We find that R402 mutant tubulins assemble into microtubules that support normal kinesin motor activity but fail to support the activity of dynein motors. Importantly, the level of dynein impairment scales with the expression level of the mutant in the cell, suggesting a 'poisoning' mechanism in which R402 mutant α-tubulin acts dominantly by populating microtubules with defective binding sites for dynein. Based on our results, we propose a new model for the molecular pathology of tubulinopathies that may also extend to other tubulin-related neuropathies.
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Affiliation(s)
- Jayne Aiken
- Department of Cell and Developmental Biology
| | | | - Emily A Bates
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
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41
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Tubulin heterogeneity regulates functions and dynamics of microtubules and plays a role in the development of drug resistance in cancer. Biochem J 2019; 476:1359-1376. [DOI: 10.1042/bcj20190123] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 04/21/2019] [Accepted: 04/24/2019] [Indexed: 01/01/2023]
Abstract
Abstract
Microtubules, composed of αβ-tubulin heterodimers, exhibit diverse structural and functional properties in different cell types. The diversity in the microtubule structure originates from tubulin heterogeneities, namely tubulin isotypes and their post-translational modifications (PTMs). These heterogeneities confer differential stability to microtubules and provide spatial cues for the functioning of the cell. Furthermore, the altered expressions of tubulin isotypes and PTMs are prominent factors for the development of resistance against some cancer drugs. In this review, we summarize our current knowledge of the tubulin isotypes and PTMs and how, together, they control the cellular functions of the microtubules. We also describe how cancer cells use this tubulin heterogeneity to acquire resistance against clinical agents and discuss existing attempts to counter the developed resistance.
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Abstract
Mutations causing dysfunction of the tubulins and microtubule-associated proteins, otherwise known as tubulinopathies, are a group of recently described entities, that lead to complex brain malformations. An understanding of the fundamental principles of operation of the cytoskeleton and compounds in particular microtubules, actin, and microtubule-associated proteins, can assist in the interpretation of the imaging findings of tubulinopathies. Somewhat consistent morphological imaging patterns have been described in tubulinopathies such as dysmorphic basal ganglia-the hallmark (found in 75% of cases), callosal dysgenesis, cerebellar hypoplasia/dysplasia, and cortical malformations, most notably lissencephaly. Recognizing the common imaging phenotypes present in tubulinopathies can prove invaluable in directing the genetic workup for a patient with brain malformations.
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Hebebrand M, Hüffmeier U, Trollmann R, Hehr U, Uebe S, Ekici AB, Kraus C, Krumbiegel M, Reis A, Thiel CT, Popp B. The mutational and phenotypic spectrum of TUBA1A-associated tubulinopathy. Orphanet J Rare Dis 2019; 14:38. [PMID: 30744660 PMCID: PMC6371496 DOI: 10.1186/s13023-019-1020-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 02/03/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The TUBA1A-associated tubulinopathy is clinically heterogeneous with brain malformations, microcephaly, developmental delay and epilepsy being the main clinical features. It is an autosomal dominant disorder mostly caused by de novo variants in TUBA1A. RESULTS In three individuals with developmental delay we identified heterozygous de novo missense variants in TUBA1A using exome sequencing. While the c.1307G > A, p.(Gly436Asp) variant was novel, the two variants c.518C > T, p.(Pro173Leu) and c.641G > A, p.(Arg214His) were previously described. We compared the variable phenotype observed in these individuals with a carefully conducted review of the current literature and identified 166 individuals, 146 born and 20 fetuses with a TUBA1A variant. In 107 cases with available clinical information we standardized the reported phenotypes according to the Human Phenotype Ontology. The most commonly reported features were developmental delay (98%), anomalies of the corpus callosum (96%), microcephaly (76%) and lissencephaly (agyria-pachygyria) (70%), although reporting was incomplete in the different studies. We identified a total of 121 specific variants, including 15 recurrent ones. Missense variants cluster in the C-terminal region around the most commonly affected amino acid position Arg402 (13.3%). In a three-dimensional protein model, 38.6% of all disease-causing variants including those in the C-terminal region are predicted to affect the binding of microtubule-associated proteins or motor proteins. Genotype-phenotype analysis for recurrent variants showed an overrepresentation of certain clinical features. However, individuals with these variants are often reported in the same publication. CONCLUSIONS With 166 individuals, we present the most comprehensive phenotypic and genotypic standardized synopsis for clinical interpretation of TUBA1A variants. Despite this considerable number, a detailed genotype-phenotype characterization is limited by large inter-study variability in reporting.
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Affiliation(s)
- Moritz Hebebrand
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany
| | - Ulrike Hüffmeier
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany
| | - Regina Trollmann
- Department of Pediatrics, Division of Neuropediatrics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Ute Hehr
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
| | - Steffen Uebe
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany
| | - Arif B Ekici
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany
| | - Cornelia Kraus
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany
| | - Mandy Krumbiegel
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany
| | - André Reis
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany
| | - Christian T Thiel
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany.
| | - Bernt Popp
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany
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Buchsbaum IY, Cappello S. Neuronal migration in the CNS during development and disease: insights from in vivo and in vitro models. Development 2019; 146:146/1/dev163766. [DOI: 10.1242/dev.163766] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
ABSTRACT
Neuronal migration is a fundamental process that governs embryonic brain development. As such, mutations that affect essential neuronal migration processes lead to severe brain malformations, which can cause complex and heterogeneous developmental and neuronal migration disorders. Our fragmented knowledge about the aetiology of these disorders raises numerous issues. However, many of these can now be addressed through studies of in vivo and in vitro models that attempt to recapitulate human-specific mechanisms of cortical development. In this Review, we discuss the advantages and limitations of these model systems and suggest that a complementary approach, using combinations of in vivo and in vitro models, will broaden our knowledge of the molecular and cellular mechanisms that underlie defective neuronal positioning in the human cerebral cortex.
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Affiliation(s)
- Isabel Yasmin Buchsbaum
- Developmental Neurobiology, Max Planck Institute of Psychiatry, 80804 Munich, Germany
- Graduate School of Systemic Neurosciences, Ludwig-Maximilians-University Munich, 82152 Planegg, Germany
| | - Silvia Cappello
- Developmental Neurobiology, Max Planck Institute of Psychiatry, 80804 Munich, Germany
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Abstract
PURPOSE OF REVIEW This article provides an overview of the most common nervous system malformations and serves as a reference for the latest advances in diagnosis and treatment. RECENT FINDINGS Major advances have occurred in recognizing the genetic basis of nervous system malformations. Environmental causes of nervous system malformations, such as perinatal infections including Zika virus, are also reviewed. Treatment for nervous system malformations begins prior to birth with prevention. Folic acid supplementation reduces the risk of neural tube defects and is an important part of health maintenance for pregnant women. Fetal surgery is now available for prenatal repair of myelomeningocele and has been demonstrated to improve outcomes. SUMMARY Each type of nervous system malformation is relatively uncommon, but, collectively, they constitute a large population of neurologic patients. The diagnosis of nervous system malformations begins with radiographic characterization. Genetic studies, including chromosomal microarray, targeted gene sequencing, and next-generation sequencing, are increasingly important aspects of the assessment. A genetic diagnosis may identify an associated medical condition and is necessary for family planning. Treatment consists primarily of supportive therapies for developmental delays and epilepsy, but prenatal surgery for myelomeningocele offers a glimpse of future possibilities. Prognosis depends on multiple clinical factors, including the examination findings, imaging characteristics, and genetic results. Treatment is best conducted in a multidisciplinary setting with neurology, neurosurgery, developmental pediatrics, and genetics working together as a comprehensive team.
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Clinical and Functional Characterization of the Recurrent TUBA1A p.(Arg2His) Mutation. Brain Sci 2018; 8:brainsci8080145. [PMID: 30087272 PMCID: PMC6119949 DOI: 10.3390/brainsci8080145] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 07/06/2018] [Accepted: 07/17/2018] [Indexed: 12/25/2022] Open
Abstract
The TUBA1A gene encodes tubulin alpha-1A, a protein that is highly expressed in the fetal brain. Alpha- and beta-tubulin subunits form dimers, which then co-assemble into microtubule polymers: dynamic, scaffold-like structures that perform key functions during neurogenesis, neuronal migration, and cortical organisation. Mutations in TUBA1A have been reported to cause a range of brain malformations. We describe four unrelated patients with the same de novo missense mutation in TUBA1A, c.5G>A, p.(Arg2His), as found by next generation sequencing. Detailed comparison revealed similar brain phenotypes with mild variability. Shared features included developmental delay, microcephaly, hypoplasia of the cerebellar vermis, dysplasia or thinning of the corpus callosum, small pons, and dysmorphic basal ganglia. Two of the patients had bilateral perisylvian polymicrogyria. We examined the effects of the p.(Arg2His) mutation by computer-based protein structure modelling and heterologous expression in HEK-293 cells. The results suggest the mutation subtly impairs microtubule function, potentially by affecting inter-dimer interaction. Based on its sequence context, c.5G>A is likely to be a common recurrent mutation. We propose that the subtle functional effects of p.(Arg2His) may allow for other factors (such as genetic background or environmental conditions) to influence phenotypic outcome, thus explaining the mild variability in clinical manifestations.
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Tan AP, Chong WK, Mankad K. Comprehensive genotype-phenotype correlation in lissencephaly. Quant Imaging Med Surg 2018; 8:673-693. [PMID: 30211035 DOI: 10.21037/qims.2018.08.08] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Malformations of cortical development (MCD) are a heterogenous group of disorders with diverse genotypic and phenotypic variations. Lissencephaly is a subtype of MCD caused by defect in neuronal migration, which occurs between 12 and 24 weeks of gestation. The continuous advancement in the field of molecular genetics in the last decade has led to identification of at least 19 lissencephaly-related genes, most of which are related to microtubule structural proteins (tubulin) or microtubule-associated proteins (MAPs). The aim of this review article is to bring together current knowledge of gene mutations associated with lissencephaly and to provide a comprehensive genotype-phenotype correlation. Illustrative cases will be presented to facilitate the understanding of the described genotype-phenotype correlation.
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Affiliation(s)
- Ai Peng Tan
- Department of Diagnostic Imaging, National University Health System, Singapore.,Yong Loo Lin School of Medicine, National University of Singapore (NUS), Singapore
| | - Wui Khean Chong
- Department of Neuroradiology, Great Ormond Street Hospital NHS Foundation Trust, London, UK
| | - Kshitij Mankad
- Department of Neuroradiology, Great Ormond Street Hospital NHS Foundation Trust, London, UK
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48
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Reyes-Capó DP, Chen F, Wilson B, Tarshish B, Ventura CV, Read SP, Negron CI, Berrocal AM. Aggressive Posterior Retinopathy of Prematurity and a
TUBA1A
Mutation inde Morsier Syndrome. Ophthalmic Surg Lasers Imaging Retina 2018; 49:629-632. [DOI: 10.3928/23258160-20180803-12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 02/27/2018] [Indexed: 11/20/2022]
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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: 76] [Impact Index Per Article: 12.7] [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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Lasser M, Tiber J, Lowery LA. The Role of the Microtubule Cytoskeleton in Neurodevelopmental Disorders. Front Cell Neurosci 2018; 12:165. [PMID: 29962938 PMCID: PMC6010848 DOI: 10.3389/fncel.2018.00165] [Citation(s) in RCA: 126] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 05/28/2018] [Indexed: 12/28/2022] Open
Abstract
Neurons depend on the highly dynamic microtubule (MT) cytoskeleton for many different processes during early embryonic development including cell division and migration, intracellular trafficking and signal transduction, as well as proper axon guidance and synapse formation. The coordination and support from MTs is crucial for newly formed neurons to migrate appropriately in order to establish neural connections. Once connections are made, MTs provide structural integrity and support to maintain neural connectivity throughout development. Abnormalities in neural migration and connectivity due to genetic mutations of MT-associated proteins can lead to detrimental developmental defects. Growing evidence suggests that these mutations are associated with many different neurodevelopmental disorders, including intellectual disabilities (ID) and autism spectrum disorders (ASD). In this review article, we highlight the crucial role of the MT cytoskeleton in the context of neurodevelopment and summarize genetic mutations of various MT related proteins that may underlie or contribute to neurodevelopmental disorders.
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Affiliation(s)
- Micaela Lasser
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Jessica Tiber
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Laura Anne Lowery
- Department of Biology, Boston College, Chestnut Hill, MA, United States
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