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Passchier EMJ, Bisseling Q, Helman G, van Spaendonk RML, Simons C, Olsthoorn RCL, van der Veen H, Abbink TEM, van der Knaap MS, Min R. Megalencephalic leukoencephalopathy with subcortical cysts: a variant update and review of the literature. Front Genet 2024; 15:1352947. [PMID: 38487253 PMCID: PMC10938252 DOI: 10.3389/fgene.2024.1352947] [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: 12/09/2023] [Accepted: 01/29/2024] [Indexed: 03/17/2024] Open
Abstract
The leukodystrophy megalencephalic leukoencephalopathy with subcortical cysts (MLC) is characterized by infantile-onset macrocephaly and chronic edema of the brain white matter. With delayed onset, patients typically experience motor problems, epilepsy and slow cognitive decline. No treatment is available. Classic MLC is caused by bi-allelic recessive pathogenic variants in MLC1 or GLIALCAM (also called HEPACAM). Heterozygous dominant pathogenic variants in GLIALCAM lead to remitting MLC, where patients show a similar phenotype in early life, followed by normalization of white matter edema and no clinical regression. Rare patients with heterozygous dominant variants in GPRC5B and classic MLC were recently described. In addition, two siblings with bi-allelic recessive variants in AQP4 and remitting MLC have been identified. The last systematic overview of variants linked to MLC dates back to 2006. We provide an updated overview of published and novel variants. We report on genetic variants from 508 patients with MLC as confirmed by MRI diagnosis (258 from our database and 250 extracted from 64 published reports). We describe 151 unique MLC1 variants, 29 GLIALCAM variants, 2 GPRC5B variants and 1 AQP4 variant observed in these MLC patients. We include experiments confirming pathogenicity for some variants, discuss particularly notable variants, and provide an overview of recent scientific and clinical insight in the pathophysiology of MLC.
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Affiliation(s)
- Emma M. J. Passchier
- Department of Child Neurology, Amsterdam Leukodystrophy Center, Emma Children’s Hospital, Amsterdam University Medical Center, Amsterdam Neuroscience, Amsterdam, Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, Amsterdam, Netherlands
| | - Quinty Bisseling
- Department of Child Neurology, Amsterdam Leukodystrophy Center, Emma Children’s Hospital, Amsterdam University Medical Center, Amsterdam Neuroscience, Amsterdam, Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, Amsterdam, Netherlands
| | - Guy Helman
- Translational Bioinformatics, Murdoch Children’s Research Institute, The Royal Children’s Hospital, Parkville, VIC, Australia
| | | | - Cas Simons
- Translational Bioinformatics, Murdoch Children’s Research Institute, The Royal Children’s Hospital, Parkville, VIC, Australia
- Centre for Population Genomics, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | | | - Hieke van der Veen
- Department of Child Neurology, Amsterdam Leukodystrophy Center, Emma Children’s Hospital, Amsterdam University Medical Center, Amsterdam Neuroscience, Amsterdam, Netherlands
- Department of Complex Trait Genetics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, Amsterdam, Netherlands
| | - Truus E. M. Abbink
- Department of Child Neurology, Amsterdam Leukodystrophy Center, Emma Children’s Hospital, Amsterdam University Medical Center, Amsterdam Neuroscience, Amsterdam, Netherlands
| | - Marjo S. van der Knaap
- Department of Child Neurology, Amsterdam Leukodystrophy Center, Emma Children’s Hospital, Amsterdam University Medical Center, Amsterdam Neuroscience, Amsterdam, Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, Amsterdam, Netherlands
| | - Rogier Min
- Department of Child Neurology, Amsterdam Leukodystrophy Center, Emma Children’s Hospital, Amsterdam University Medical Center, Amsterdam Neuroscience, Amsterdam, Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, Amsterdam, Netherlands
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2
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Vitrac A, Leblond CS, Rolland T, Cliquet F, Mathieu A, Maruani A, Delorme R, Schön M, Grabrucker AM, van Ravenswaaij-Arts C, Phelan K, Tabet AC, Bourgeron T. Dissecting the 22q13 region to explore the genetic and phenotypic diversity of patients with Phelan-McDermid syndrome. Eur J Med Genet 2023; 66:104732. [PMID: 36822569 DOI: 10.1016/j.ejmg.2023.104732] [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: 12/09/2022] [Revised: 02/14/2023] [Accepted: 02/19/2023] [Indexed: 02/25/2023]
Abstract
SHANK3-related Phelan-McDermid syndrome (PMS) is caused by a loss of the distal part of chromosome 22, including SHANK3, or by a pathological SHANK3 variant. There is an important genetic and phenotypic diversity among patients who can present with developmental delay, language impairments, autism, epilepsy, and other symptoms. SHANK3, encoding a synaptic scaffolding protein, is deleted in the majority of patients with PMS and is considered a major gene involved in the neurological impairments of the patients. However, differences in deletion size can influence clinical features, and in some rare cases, deletions at the 22q13 locus in individuals with SHANK3-unrelated PMS do not encompass SHANK3. These individuals with SHANK3-unrelated PMS still display a PMS-like phenotype. This suggests the participation of other 22q13 genes in the pathogenesis of PMS. Here, we review the biological function and potential implication in PMS symptoms of 110 genes located in the 22q13 region, focusing on 35 genes with evidence for association with neurodevelopmental disorders, including 13 genes for epilepsy and 11 genes for microcephaly and/or macrocephaly. Our review is restricted to the 22q13 region, but future large-scale studies using whole genome sequencing and deep-phenotyping are warranted to develop predictive models of clinical trajectories and to target specific medical and educational care for each individual with PMS.
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Affiliation(s)
- Aline Vitrac
- Génétique Humaine et Fonctions Cognitives, Institut Pasteur, UMR3571 CNRS, Université de Paris Cité, IUF, 75015, Paris, France.
| | - Claire S Leblond
- Génétique Humaine et Fonctions Cognitives, Institut Pasteur, UMR3571 CNRS, Université de Paris Cité, IUF, 75015, Paris, France
| | - Thomas Rolland
- Génétique Humaine et Fonctions Cognitives, Institut Pasteur, UMR3571 CNRS, Université de Paris Cité, IUF, 75015, Paris, France
| | - Freddy Cliquet
- Génétique Humaine et Fonctions Cognitives, Institut Pasteur, UMR3571 CNRS, Université de Paris Cité, IUF, 75015, Paris, France
| | - Alexandre Mathieu
- Génétique Humaine et Fonctions Cognitives, Institut Pasteur, UMR3571 CNRS, Université de Paris Cité, IUF, 75015, Paris, France
| | - Anna Maruani
- Department of Child and Adolescent Psychiatry, Hôpital Robert Debré, APHP, Paris, France
| | - Richard Delorme
- Department of Child and Adolescent Psychiatry, Hôpital Robert Debré, APHP, Paris, France
| | - Michael Schön
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Andreas M Grabrucker
- Bernal Institute, University of Limerick, Limerick, Ireland; Dept. of Biological Sciences, University of Limerick, Limerick, Ireland; Health Research Institute HRI, University of Limerick, Limerick, Ireland
| | - Conny van Ravenswaaij-Arts
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, Netherlands
| | - Katy Phelan
- Genetics Laboratory, Florida Cancer Specialists & Research Institute, Fort Myers, FL, 33916, USA
| | | | - Thomas Bourgeron
- Génétique Humaine et Fonctions Cognitives, Institut Pasteur, UMR3571 CNRS, Université de Paris Cité, IUF, 75015, Paris, France.
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3
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Gilbert A, Elorza-Vidal X, Rancillac A, Chagnot A, Yetim M, Hingot V, Deffieux T, Boulay AC, Alvear-Perez R, Cisternino S, Martin S, Taïb S, Gelot A, Mignon V, Favier M, Brunet I, Declèves X, Tanter M, Estevez R, Vivien D, Saubaméa B, Cohen-Salmon M. Megalencephalic leukoencephalopathy with subcortical cysts is a developmental disorder of the gliovascular unit. eLife 2021; 10:71379. [PMID: 34723793 PMCID: PMC8598235 DOI: 10.7554/elife.71379] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 10/27/2021] [Indexed: 12/20/2022] Open
Abstract
Absence of the astrocyte-specific membrane protein MLC1 is responsible for megalencephalic leukoencephalopathy with subcortical cysts (MLC), a rare type of leukodystrophy characterized by early-onset macrocephaly and progressive white matter vacuolation that lead to ataxia, spasticity, and cognitive decline. During postnatal development (from P5 to P15 in the mouse), MLC1 forms a membrane complex with GlialCAM (another astrocytic transmembrane protein) at the junctions between perivascular astrocytic processes. Perivascular astrocytic processes along with blood vessels form the gliovascular unit. It was not previously known how MLC1 influences the physiology of the gliovascular unit. Here, using the Mlc1 knock-out mouse model of MLC, we demonstrated that MLC1 controls the postnatal development and organization of perivascular astrocytic processes, vascular smooth muscle cell contractility, neurovascular coupling, and intraparenchymal interstitial fluid clearance. Our data suggest that MLC is a developmental disorder of the gliovascular unit, and perivascular astrocytic processes and vascular smooth muscle cell maturation defects are primary events in the pathogenesis of MLC and therapeutic targets for this disease.
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Affiliation(s)
- Alice Gilbert
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Research in Biology (CIRB), College de France, CNRS, Paris, France.,École doctorale Cerveau Cognition Comportement "ED3C" N°158, Pierre and Marie Curie University, Paris, France
| | - Xabier Elorza-Vidal
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Research in Biology (CIRB), College de France, CNRS, Paris, France
| | - Armelle Rancillac
- Neuroglial Interactions in Cerebral Physiopathology Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, Labex Memolife, Université PSL, Paris, France
| | - Audrey Chagnot
- Normandie University, UNICAEN, INSERM, GIP Cyceron, Institut Blood and Brain, Physiopathology and Imaging of Neurological Disorders, Caen, France
| | - Mervé Yetim
- Normandie University, UNICAEN, INSERM, GIP Cyceron, Institut Blood and Brain, Physiopathology and Imaging of Neurological Disorders, Caen, France
| | - Vincent Hingot
- Physics for Medicine Paris, ESPCI Paris, PSL University, Paris, France
| | - Thomas Deffieux
- Physics for Medicine Paris, ESPCI Paris, PSL University, Paris, France
| | - Anne-Cécile Boulay
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Research in Biology (CIRB), College de France, CNRS, Paris, France
| | - Rodrigo Alvear-Perez
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Research in Biology (CIRB), College de France, CNRS, Paris, France
| | | | - Sabrina Martin
- Molecular Control of the Neurovascular Development Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, Labex Memolife, Université PSL, Paris, France
| | - Sonia Taïb
- Molecular Control of the Neurovascular Development Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, Labex Memolife, Université PSL, Paris, France
| | - Aontoinette Gelot
- Service d'anatomie et cytologie pathologie de l'hôpital Armand Trousseau, Paris, France
| | - Virginie Mignon
- Cellular and Molecular Imaging Facility, US25 INSERM, UMS3612 CNRS, Faculty of Pharmacy, University of Paris, Paris, France
| | | | - Isabelle Brunet
- Molecular Control of the Neurovascular Development Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, Labex Memolife, Université PSL, Paris, France
| | - Xavier Declèves
- Université de Paris, Faculté de Santé, Paris, France.,Biologie du médicament et toxicologie, Assistance Publique - hôpitaux de Paris, APHP, Hôpital Cochin, Paris, France
| | - Mickael Tanter
- Physics for Medicine Paris, ESPCI Paris, PSL University, Paris, France
| | - Raul Estevez
- Unitat de Fisiología, Departament de Ciències Fisiològiques, IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.,Centro de Investigación en Red de Enfermedades Raras (CIBERER), Barcelona, Spain
| | - Denis Vivien
- Normandie University, UNICAEN, INSERM, GIP Cyceron, Institut Blood and Brain, Physiopathology and Imaging of Neurological Disorders, Caen, France
| | - Bruno Saubaméa
- Université de Paris, Faculté de Santé, Paris, France.,Cellular and Molecular Imaging Facility, US25 INSERM, UMS3612 CNRS, Faculty of Pharmacy, University of Paris, Paris, France
| | - Martine Cohen-Salmon
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Research in Biology (CIRB), College de France, CNRS, Paris, France
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4
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Wilson CS, Dohare P, Orbeta S, Nalwalk JW, Huang Y, Ferland RJ, Sah R, Scimemi A, Mongin AA. Late adolescence mortality in mice with brain-specific deletion of the volume-regulated anion channel subunit LRRC8A. FASEB J 2021; 35:e21869. [PMID: 34469026 PMCID: PMC8639177 DOI: 10.1096/fj.202002745r] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 07/27/2021] [Accepted: 08/09/2021] [Indexed: 11/11/2022]
Abstract
The leucine-rich repeat-containing family 8 member A (LRRC8A) is an essential subunit of the volume-regulated anion channel (VRAC). VRAC is critical for cell volume control, but its broader physiological functions remain under investigation. Recent studies in the field indicate that Lrrc8a disruption in the brain astrocytes reduces neuronal excitability, impairs synaptic plasticity and memory, and protects against cerebral ischemia. In the present work, we generated brain-wide conditional LRRC8A knockout mice (LRRC8A bKO) using NestinCre -driven Lrrc8aflox/flox excision in neurons, astrocytes, and oligodendroglia. LRRC8A bKO animals were born close to the expected Mendelian ratio and developed without overt histological abnormalities, but, surprisingly, all died between 5 and 9 weeks of age with a seizure phenotype, which was confirmed by video and EEG recordings. Brain slice electrophysiology detected changes in the excitability of pyramidal cells and modified GABAergic inputs in the hippocampal CA1 region of LRRC8A bKO. LRRC8A-null hippocampi showed increased immunoreactivity of the astrocytic marker GFAP, indicating reactive astrogliosis. We also found decreased whole-brain protein levels of the GABA transporter GAT-1, the glutamate transporter GLT-1, and the astrocytic enzyme glutamine synthetase. Complementary HPLC assays identified reduction in the tissue levels of the glutamate and GABA precursor glutamine. Together, these findings suggest that VRAC provides vital control of brain excitability in mouse adolescence. VRAC deletion leads to a lethal phenotype involving progressive astrogliosis and dysregulation of astrocytic uptake and supply of amino acid neurotransmitters and their precursors.
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Affiliation(s)
- Corinne S Wilson
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Preeti Dohare
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Shaina Orbeta
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Julia W Nalwalk
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Yunfei Huang
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Russell J Ferland
- Department of Biomedical Sciences, University of New England College of Osteopathic Medicine, Biddeford, Maine, USA
| | - Rajan Sah
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Annalisa Scimemi
- Department of Biology, University at Albany, State University of New York, Albany, New York, USA
| | - Alexander A Mongin
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
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5
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Baldwin KT, Tan CX, Strader ST, Jiang C, Savage JT, Elorza-Vidal X, Contreras X, Rülicke T, Hippenmeyer S, Estévez R, Ji RR, Eroglu C. HepaCAM controls astrocyte self-organization and coupling. Neuron 2021; 109:2427-2442.e10. [PMID: 34171291 PMCID: PMC8547372 DOI: 10.1016/j.neuron.2021.05.025] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 04/19/2021] [Accepted: 05/19/2021] [Indexed: 10/21/2022]
Abstract
Astrocytes extensively infiltrate the neuropil to regulate critical aspects of synaptic development and function. This process is regulated by transcellular interactions between astrocytes and neurons via cell adhesion molecules. How astrocytes coordinate developmental processes among one another to parse out the synaptic neuropil and form non-overlapping territories is unknown. Here we identify a molecular mechanism regulating astrocyte-astrocyte interactions during development to coordinate astrocyte morphogenesis and gap junction coupling. We show that hepaCAM, a disease-linked, astrocyte-enriched cell adhesion molecule, regulates astrocyte competition for territory and morphological complexity in the developing mouse cortex. Furthermore, conditional deletion of Hepacam from developing astrocytes significantly impairs gap junction coupling between astrocytes and disrupts the balance between synaptic excitation and inhibition. Mutations in HEPACAM cause megalencephalic leukoencephalopathy with subcortical cysts in humans. Therefore, our findings suggest that disruption of astrocyte self-organization mechanisms could be an underlying cause of neural pathology.
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Affiliation(s)
- Katherine T Baldwin
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA.
| | - Christabel X Tan
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Samuel T Strader
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Changyu Jiang
- Department of Anesthesiology and Center for Translational Pain Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | - Justin T Savage
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Xabier Elorza-Vidal
- Unitat de Fisiología, Departament de Ciències Fisiològiques, IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Spain
| | - Ximena Contreras
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Thomas Rülicke
- Institute of Laboratory Animal Science, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Simon Hippenmeyer
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Raúl Estévez
- Unitat de Fisiología, Departament de Ciències Fisiològiques, IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain
| | - Ru-Rong Ji
- Department of Anesthesiology and Center for Translational Pain Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | - Cagla Eroglu
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA; Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA; Duke Institute for Brain Sciences (DIBS), Durham, NC 27710, USA; Duke University Regeneration Next Initiative, Durham, NC 27710, USA.
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6
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Megalencephalic Leukoencephalopathy with Subcortical Cysts Protein-1 (MLC1) Counteracts Astrocyte Activation in Response to Inflammatory Signals. Mol Neurobiol 2019; 56:8237-8254. [DOI: 10.1007/s12035-019-01657-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 05/20/2019] [Indexed: 01/08/2023]
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Min R, van der Knaap MS. Genetic defects disrupting glial ion and water homeostasis in the brain. Brain Pathol 2019; 28:372-387. [PMID: 29740942 PMCID: PMC8028498 DOI: 10.1111/bpa.12602] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 03/02/2018] [Indexed: 12/23/2022] Open
Abstract
Electrical activity of neurons in the brain, caused by the movement of ions between intracellular and extracellular compartments, is the basis of all our thoughts and actions. Maintaining the correct ionic concentration gradients is therefore crucial for brain functioning. Ion fluxes are accompanied by the displacement of osmotically obliged water. Since even minor brain swelling leads to severe brain damage and even death, brain ion and water movement has to be tightly regulated. Glial cells, in particular astrocytes, play a key role in ion and water homeostasis. They are endowed with specific channels, pumps and carriers to regulate ion and water flow. Glial cells form a large panglial syncytium to aid the uptake and dispersal of ions and water, and make extensive contacts with brain fluid barriers for disposal of excess ions and water. Genetic defects in glial proteins involved in ion and water homeostasis disrupt brain functioning, thereby leading to neurological diseases. Since white matter edema is often a hallmark disease feature, many of these diseases are characterized as leukodystrophies. In this review we summarize our current understanding of inherited glial diseases characterized by disturbed brain ion and water homeostasis by integrating findings from MRI, genetics, neuropathology and animal models for disease. We discuss how mutations in different glial proteins lead to disease, and highlight the similarities and differences between these diseases. To come to effective therapies for this group of diseases, a better mechanistic understanding of how glial cells shape ion and water movement in the brain is crucial.
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Affiliation(s)
- Rogier Min
- Department of Child Neurology, Amsterdam Neuroscience, VU University Medical Center, Amsterdam, The Netherlands.,Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, The Netherlands
| | - Marjo S van der Knaap
- Department of Child Neurology, Amsterdam Neuroscience, VU University Medical Center, Amsterdam, The Netherlands.,Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, The Netherlands
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8
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Dubey M, Brouwers E, Hamilton EM, Stiedl O, Bugiani M, Koch H, Kole MH, Boschert U, Wykes RC, Mansvelder HD, van der Knaap MS, Min R. Seizures and disturbed brain potassium dynamics in the leukodystrophy megalencephalic leukoencephalopathy with subcortical cysts. Ann Neurol 2018; 83:636-649. [PMID: 29466841 PMCID: PMC5900999 DOI: 10.1002/ana.25190] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 01/12/2018] [Accepted: 02/18/2018] [Indexed: 12/26/2022]
Abstract
OBJECTIVE Loss of function of the astrocyte-specific protein MLC1 leads to the childhood-onset leukodystrophy "megalencephalic leukoencephalopathy with subcortical cysts" (MLC). Studies on isolated cells show a role for MLC1 in astrocyte volume regulation and suggest that disturbed brain ion and water homeostasis is central to the disease. Excitability of neuronal networks is particularly sensitive to ion and water homeostasis. In line with this, reports of seizures and epilepsy in MLC patients exist. However, systematic assessment and mechanistic understanding of seizures in MLC are lacking. METHODS We analyzed an MLC patient inventory to study occurrence of seizures in MLC. We used two distinct genetic mouse models of MLC to further study epileptiform activity and seizure threshold through wireless extracellular field potential recordings. Whole-cell patch-clamp recordings and K+ -sensitive electrode recordings in mouse brain slices were used to explore the underlying mechanisms of epilepsy in MLC. RESULTS An early onset of seizures is common in MLC. Similarly, in MLC mice, we uncovered spontaneous epileptiform brain activity and a lowered threshold for induced seizures. At the cellular level, we found that although passive and active properties of individual pyramidal neurons are unchanged, extracellular K+ dynamics and neuronal network activity are abnormal in MLC mice. INTERPRETATION Disturbed astrocyte regulation of ion and water homeostasis in MLC causes hyperexcitability of neuronal networks and seizures. These findings suggest a role for defective astrocyte volume regulation in epilepsy. Ann Neurol 2018;83:636-649.
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Affiliation(s)
- Mohit Dubey
- Department of Child Neurology, Amsterdam NeuroscienceVU University Medical CenterAmsterdamThe Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam NeuroscienceVU UniversityAmsterdamThe Netherlands
- Present address:
Current address for Mohit Dubey: Department of Axonal SignalingNetherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and SciencesAmsterdamThe Netherlands
| | - Eelke Brouwers
- Department of Child Neurology, Amsterdam NeuroscienceVU University Medical CenterAmsterdamThe Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam NeuroscienceVU UniversityAmsterdamThe Netherlands
| | - Eline M.C. Hamilton
- Department of Child Neurology, Amsterdam NeuroscienceVU University Medical CenterAmsterdamThe Netherlands
| | - Oliver Stiedl
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Amsterdam NeuroscienceVU UniversityAmsterdamThe Netherlands
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam NeuroscienceVU UniversityAmsterdamThe Netherlands
| | - Marianna Bugiani
- Department of Child Neurology, Amsterdam NeuroscienceVU University Medical CenterAmsterdamThe Netherlands
- Department of PathologyVU University Medical CenterAmsterdamThe Netherlands
| | - Henner Koch
- Department of NeurologyUniversity of Tübingen, Hertie Institute for Clinical Brain ResearchTübingenGermany
| | - Maarten H.P. Kole
- Department of Axonal SignalingNetherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and SciencesAmsterdamThe Netherlands
- Cell Biology, Faculty of ScienceUtrecht UniversityUtrechtThe Netherlands
| | - Ursula Boschert
- Translational Innovation Platform Immunology/Neurology, EMD Serono Research & Development InstituteBillericaMA
| | - Robert C. Wykes
- Department of Clinical & Experimental Epilepsy, UCL Institute of NeurologyUniversity College LondonLondonUnited Kingdom
| | - Huibert D. Mansvelder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam NeuroscienceVU UniversityAmsterdamThe Netherlands
| | - Marjo S. van der Knaap
- Department of Child Neurology, Amsterdam NeuroscienceVU University Medical CenterAmsterdamThe Netherlands
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Amsterdam NeuroscienceVU UniversityAmsterdamThe Netherlands
| | - Rogier Min
- Department of Child Neurology, Amsterdam NeuroscienceVU University Medical CenterAmsterdamThe Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam NeuroscienceVU UniversityAmsterdamThe Netherlands
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9
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Cao B, Yan H, Guo M, Xie H, Wu Y, Gu Q, Xiao J, Shang J, Yang Y, Xiong H, Niu Z, Wu X, Jiang Y, Wang J. Ten Novel Mutations in Chinese Patients with Megalencephalic Leukoencephalopathy with Subcortical Cysts and a Long-Term Follow-Up Research. PLoS One 2016; 11:e0157258. [PMID: 27322623 PMCID: PMC4913951 DOI: 10.1371/journal.pone.0157258] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 05/26/2016] [Indexed: 11/21/2022] Open
Abstract
Objective Megalencephalic leukoencephalopathy with subcortical cysts (MLC, OMIM 604004) is a rare neurological deterioration disease. We aimed to clarify clinical and genetic features of Chinese MLC patients. Methods Clinical information and peripheral venous blood of 20 patients and their families were collected, Sanger-sequencing and Multiple Ligation-dependent Probe Amplification were performed to make genetic analysis. Splicing-site mutation was confirmed with RT-PCR. UPD was detected by haplotype analysis. Follow-up study was performed through telephone for 27 patients. Results Out of 20 patients, macrocephaly, classic MRI features, motor development delay and cognitive impairment were detected in 20(100%), 20(100%), 17(85%) and 4(20%) patients, respectively. 20(100%) were clinically diagnosed with MLC. 19(95%) were genetically diagnosed with 10 novel mutations in MLC1, MLC1 and GlialCAM mutations were identified in 15 and 4 patients, respectively. Deletion mutation from exon4 to exon9 and a homozygous point mutation due to maternal UPD of chromosome22 in MLC1 were found firstly. c.598-2A>C in MLC1 leads to the skip of exon8. c.772-1G>C in MLC1 accounting for 15.5%(9/58) alleles in Chinese patients might be a founder or a hot-spot mutation. Out of 27 patients in the follow-up study, head circumference was ranged from 56cm to 61cm in patients older than 5yeas old, with a median of 57cm. Motor development delay and cognitive impairment were detected in 22(81.5%) and 5(18.5%) patients, respectively. Motor and cognitive deterioration was found in 5 (18.5%) and 2 patients (7.4%), respectively. Improvements and MRI recovery were first found in Chinese patients. Rate of seizures (45.5%), transient motor retrogress (45.5%) and unconsciousness (13.6%) after head trauma was much higher than that after fever (18.2%, 9.1%, 0%, respectively). Significance It’s a clinical and genetic analysis and a follow-up study for largest sample of Chinese MLC patients, identifying 10 novel mutations, expanding mutation spectrums and discovering clinical features of Chinese MLC patients.
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Affiliation(s)
- Binbin Cao
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Huifang Yan
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Mangmang Guo
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
- Department of Pediatrics, Beijing Tian Tan Hospital, Capital Medical University Beijing 100050, China
| | - Han Xie
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Ye Wu
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Qiang Gu
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Jiangxi Xiao
- Department of Radiology, Peking University First Hospital, Beijing 100034, China
| | - Jing Shang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
- Department of Neurology, Shanxi Dayi Hospital, Taiyuan 030000, Shanxi Province, China
| | - Yanling Yang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Hui Xiong
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Zhengping Niu
- Department of Neurology, First Hospital of Shanxi Medical University, Taiyuan 030001, Shanxi Province, China
| | - Xiru Wu
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Yuwu Jiang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
- * E-mail: (YWJ); (JMW)
| | - Jingmin Wang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
- * E-mail: (YWJ); (JMW)
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10
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Koç K, Koç P, Karaali K, Olgaç Dündar N, Şenol U, Canan A. Magnetic resonance imaging findings of two sisters with Van der Knaap leukoencephalopathy. Neuroradiol J 2015; 28:519-22. [PMID: 26427893 DOI: 10.1177/1971400915609335] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Megalencephalic leukoencephalopathy with subcortical cysts, or Van der Knaap leukoencephalopathy, is a rare disease which is characterised by macrocephaly and neurological disorders with autosomal recessive inheritance. Magnetic resonance imaging is very helpful for determining distinctive findings and distinguishing other diseases. We present the radiological findings of two sisters (aged 6 and 10 years) diagnosed with Van der Knaap leukoencephalopathy.
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Affiliation(s)
- Koray Koç
- Antalya Ataturk State Hospital, Radiology Clinics, Antalya, Turkey
| | - Pınar Koç
- Antalya Training and Research Hospital, Radiology Clinics, Antalya, Turkey
| | - Kamil Karaali
- Akdeniz University, School of Medicine, Department of Radiology, Antalya, Turkey
| | - Nihal Olgaç Dündar
- Akdeniz University, School of Medicine, Department of Pediatry, Antalya, Turkey
| | - Utku Şenol
- Akdeniz University, School of Medicine, Department of Radiology, Antalya, Turkey
| | - Arzu Canan
- Antalya Ataturk State Hospital, Radiology Clinics, Antalya, Turkey
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11
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Nunes RH, Pacheco FT, da Rocha AJ. Magnetic resonance imaging of anterior temporal lobe cysts in children: discriminating special imaging features in a particular group of diseases. Neuroradiology 2014; 56:569-77. [DOI: 10.1007/s00234-014-1356-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 03/19/2014] [Indexed: 11/29/2022]
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12
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Bajaj SK, Misra R, Gupta R, Chandra R, Malik A. Megalencephalic leukoencephalopathy with sub cortical cysts: An inherited dysmyelinating disorder. J Pediatr Neurosci 2013; 8:77-80. [PMID: 23772256 PMCID: PMC3680908 DOI: 10.4103/1817-1745.111438] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Affiliation(s)
- Sunil Kumar Bajaj
- Department of Radiodiagnosis, Safdarjung Hospital and VM Medical College, New Delhi, India
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13
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van der Knaap MS, Boor I, Estévez R. Megalencephalic leukoencephalopathy with subcortical cysts: chronic white matter oedema due to a defect in brain ion and water homoeostasis. Lancet Neurol 2012; 11:973-85. [PMID: 23079554 DOI: 10.1016/s1474-4422(12)70192-8] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is characterised by chronic white matter oedema. The disease has an infantile onset and leads to slow neurological deterioration in most cases, but, surprisingly, some patients recover. The first disease gene, MLC1, identified in 2001, is mutated in 75% of patients. At that time, nothing was known about MLC1 protein function and the pathophysiology of MLC. More recently, HEPACAM (also called GLIALCAM) has been identified as a second disease gene. GlialCAM serves as an escort for MLC1 and the chloride channel CLC2. The defect in MLC1 has been shown to hamper the cell volume regulation of astrocytes. One of the most important consequences involves the potassium siphoning process, which is essential in brain ion and water homoeostasis. An understanding of the mechanisms of white matter oedema in MLC is emerging. Further insight into the specific function of MLC1 is necessary to find treatment targets.
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Affiliation(s)
- Marjo S van der Knaap
- Department of Pediatrics/Child Neurology, VU University Medical Centre, Amsterdam, Netherlands.
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14
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Biochemical characterization of MLC1 protein in astrocytes and its association with the dystrophin-glycoprotein complex. Mol Cell Neurosci 2007; 37:480-93. [PMID: 18165104 DOI: 10.1016/j.mcn.2007.11.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Revised: 10/31/2007] [Accepted: 11/07/2007] [Indexed: 11/23/2022] Open
Abstract
MLC1 gene mutations have been associated with megalencephalic leukoencephalopathy with subcortical cysts (MLC), a rare neurologic disorder in children. The MLC1 gene encodes a membrane protein (MLC1) with unknown function which is mainly expressed in astrocytes. Using a newly developed anti-human MLC1 polyclonal antibody, we have investigated the biochemical properties and localization of MLC1 in cultured astrocytes and brain tissue and searched for evidence of a relationship between MLC1 and proteins of the dystrophin-glycoprotein complex (DGC). Cultured astrocytes express two MLC1 components showing different solubilisation properties and subcellular distribution. Most importantly, we show that the membrane-associated component of MLC1 (60-64 kDa) localizes in astrocytic lipid rafts together with dystroglycan, syntrophin and caveolin-1, and co-fractionates with the DGC in whole rat brain tissue. In the human brain, MLC1 protein is expressed in astrocyte processes and ependymal cells, where it colocalizes with dystroglycan and syntrophin. These data indicate that the DGC may be involved in the organization and function of the MLC1 protein in astrocyte membranes.
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15
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Jocic-Jakubi B, Martinović Z, Kozić D. Epileptic encephalopathy with bilateral continuous spike-waves during slow sleep in a child with vacuolating megalencephalic leukoencephalopathy. Eur J Paediatr Neurol 2007; 11:181-4. [PMID: 17276710 DOI: 10.1016/j.ejpn.2006.12.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2006] [Revised: 12/12/2006] [Indexed: 11/19/2022]
Abstract
This case report describes the clinical evolution of a symptomatic epileptic encephalopathy with bilateral continuous spike-waves during slow wave sleep (BCSWS) in a 3-year-old girl. Her epilepsy with focal motor seizures during sleep was later complicated by myoclonic, atonic and clonic seizures culminating in BCSWS. The clinical picture, clinical course and magnetic resonance imaging findings were characterstic of primary white matter disease, probably, vacuolated megalencephalic leukoencephalopathy with subcortical cysts (MLC). To the best of our knowledge, this is the first reported case of BSCWS in a patient with leukodystrophies or MLC. This case report indicates that epileptic encephalopathy with BSCWS may be a cause of neurological or neuropsychological deterioration in MLC.
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Affiliation(s)
- Bosanka Jocic-Jakubi
- Clinic of Mental Health and Child Neuropsychiatry, Medical School, University of Nis, Serbia.
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16
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Teijido O, Casaroli-Marano R, Kharkovets T, Aguado F, Zorzano A, Palacín M, Soriano E, Martínez A, Estévez R. Expression patterns of MLC1 protein in the central and peripheral nervous systems. Neurobiol Dis 2007; 26:532-45. [PMID: 17434314 DOI: 10.1016/j.nbd.2007.01.016] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2006] [Revised: 01/12/2007] [Accepted: 01/28/2007] [Indexed: 10/23/2022] Open
Abstract
Mutations in MLC1 cause megalencephalic leukoencephalopathy with subcortical cysts (MLC), a disorder characterized clinically by macrocephaly, deterioration of motor functions, epilepsy and mental decline. Recent studies have detected MLC1 mRNA and protein in astroglial processes. In addition, our group previously reported MLC1 expression in some neurons in the adult mouse brain. Here we performed an exhaustive study of the expression pattern of MLC1 in the developing mouse brain by means of optic and electron microscopy. In the central nervous system, MLC1 was detected mainly in axonal tracts early in development. In addition, MLC1 was also observed in the peripheral nervous system and in several sensory epithelia, as retina or saccula maculae. Post-embedding immunogold experiments indicated that MLC1 is localized in astrocyte-astrocyte junctions, but not in the perivascular membrane, indicating that MLC1 is not a component of the dystrophin-glycoprotein complex. In neurons, MLC1 is located at the plasma membrane and vesicular structures. Our data provide a mouse MLC1 expression map that could be useful to understand the phenotype of MLC patients, and suggested that MLC disease is caused by an astrocytic and a neuronal dysfunction.
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Affiliation(s)
- Oscar Teijido
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona and Institute for Research in Biomedicine, Barcelona Science Park, Josep Samitier 1-5. Barcelona, E-08028, Spain
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17
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Gorospe JR, Maletkovic J. Alexander disease and megalencephalic leukoencephalopathy with subcortical cysts: Leukodystrophies arising from astrocyte dysfunction. ACTA ACUST UNITED AC 2006; 12:113-22. [PMID: 16807904 DOI: 10.1002/mrdd.20101] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- J Rafael Gorospe
- Center for Genetic Medicine, Children's National Medical Center, Washington, District of Columbia 20010, USA.
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18
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Riel-Romero RMS, Smith CD, Pettigrew AL. Megalencephalic leukoencephalopathy with subcortical cysts in two siblings owing to two novel mutations: case reports and review of the literature. J Child Neurol 2005; 20:230-4. [PMID: 15832614 DOI: 10.1177/088307380502000301] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Megalencephalic leukoencephalopathy with subcortical cysts is a rare leukodystrophy characterized by macrocephaly and a slowly progressive clinical course marked by spasticity and cognitive decline. We report two full siblings with neuroimaging studies and clinical courses typical for megalencephalic leukoencephalopathy with subcortical cysts, in whom a pair of novel mutations in the MLC1 gene was identified. We review the current knowledge of this disorder in relation to the patients reported.
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Affiliation(s)
- Rosario Maria S Riel-Romero
- Department of Neurology, Louisiana State University Health Sciences Center, School of Medicine, Shreveport, LA 71130-3932, USA.
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19
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Teijido O, Martínez A, Pusch M, Zorzano A, Soriano E, Del Río JA, Palacín M, Estévez R. Localization and functional analyses of the MLC1 protein involved in megalencephalic leukoencephalopathy with subcortical cysts. Hum Mol Genet 2004; 13:2581-94. [PMID: 15367490 DOI: 10.1093/hmg/ddh291] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Mutations in the MLC1 gene are responsible for one form of the neurological disorder megalencephalic leukoencephalopathy with subcortical cysts (MLC). The disease is a type of vacuolating myelinopathy. The biochemical properties and the function of the MLC1 protein are unknown. To characterize MLC1, we generated polyclonal antibodies. The MLC1 protein was detected in the brain, assembled into higher molecular complexes, as assessed by assembly-dependent trafficking assays. In situ hybridization and immunohistochemistry were used to determine MLC1 localization within the adult mouse brain. MLC1 was expressed in neurons, detected preferentially in particular axonal tracts. This expression pattern correlates with the major phenotype observed in the disease. In addition, it was expressed in some astrocytes, concentrating in Bergmann glia, the astrocyte end-feet membranes adjacent to blood vessels and in astrocyte-astrocyte membrane contact regions. Other neuronal barriers, such as the ependyma and the pia mater, were also positive for MLC1 expression. MLC1 was detected in vivo and in heterologous systems at the plasma membrane. MLC mutations impaired folding, and the defect was corrected in vitro by addition of curcumin, a Ca(2+)-ATPase inhibitor. In summary, this study provides an explanation as to why mutations in MLC1 provoke the disease and points to a possible therapy for some patients.
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Affiliation(s)
- Oscar Teijido
- Department of Biochemistry and Molecular Biology, Josep Samitier 1-5. Barcelona E-08028, Spain
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