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Shukla A, Kaur P, Narayanan DL, do Rosario MC, Kadavigere R, Girisha KM. Genetic disorders with central nervous system white matter abnormalities: An update. Clin Genet 2021; 99:119-132. [PMID: 33047326 PMCID: PMC9951823 DOI: 10.1111/cge.13863] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 09/21/2020] [Accepted: 10/07/2020] [Indexed: 12/21/2022]
Abstract
Several genetic disorders have variable degree of central nervous system white matter abnormalities. We retrieved and reviewed 422 genetic conditions with prominent and consistent involvement of white matter from the literature. We herein describe the current definitions, classification systems, clinical spectrum, neuroimaging findings, genomics, and molecular mechanisms of these conditions. Though diagnosis for most of these disorders relies mainly on genomic tests, specifically exome sequencing, we collate several clinical and neuroimaging findings still relevant in diagnosis of clinically recognizable disorders. We also review the current understanding of pathophysiology and therapeutics of these disorders.
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Affiliation(s)
- Anju Shukla
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Parneet Kaur
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Dhanya Lakshmi Narayanan
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Michelle C do Rosario
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Rajagopal Kadavigere
- Department of Radiodiagnosis, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Katta Mohan Girisha
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
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Di Bella D, Magri S, Benzoni C, Farina L, Maccagnano C, Sarto E, Moscatelli M, Baratta S, Ciano C, Piacentini SHMJ, Draghi L, Mauro E, Pareyson D, Gellera C, Taroni F, Salsano E. Hypomyelinating leukodystrophies in adults: Clinical and genetic features. Eur J Neurol 2020; 28:934-944. [PMID: 33190326 DOI: 10.1111/ene.14646] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 11/07/2020] [Accepted: 11/10/2020] [Indexed: 01/07/2023]
Abstract
BACKGROUND AND PURPOSE Little is known about hypomyelinating leukodystrophies (HLDs) in adults. The aim of this study was to investigate HLD occurrence, clinical features, and etiology among undefined leukoencephalopathies in adulthood. METHODS We recruited the patients with cerebral hypomyelinating magnetic resonance imaging pattern (mild T2 hyperintensity with normal or near-normal T1 signal) from our cohort of 62 adult index cases with undefined leukoencephalopathies, reviewed their clinical features, and used a leukoencephalopathy-targeted next generation sequencing panel. RESULTS We identified 25/62 patients (~40%) with hypomyelination. Cardinal manifestations were spastic gait and varying degree of cognitive impairment. Etiology was determined in 44% (definite, 10/25; likely, 1/25). Specifically, we found pathogenic variants in the POLR3A (n = 2), POLR1C (n = 1), RARS1 (n = 1), and TUBB4A (n = 1) genes, which are typically associated with severe early-onset HLDs, and in the GJA1 gene (n = 1), which is associated with oculodentodigital dysplasia. Duplication of a large chromosome X region encompassing PLP1 and a pathogenic GJC2 variant were found in two patients, both females, with early-onset HLDs persisting into adulthood. Finally, we found likely pathogenic variants in PEX3 (n = 1) and PEX13 (n = 1) and potentially relevant variants of unknown significance in TBCD (n = 1), which are genes associated with severe, early-onset diseases with central hypomyelination/dysmyelination. CONCLUSIONS A hypomyelinating pattern characterizes a relevant number of undefined leukoencephalopathies in adulthood. A comprehensive genetic screening allows definite diagnosis in about half of patients, and demonstrates the involvement of many disease-causing genes, including genes associated with severe early-onset HLDs, and genes causing peroxisome biogenesis disorders.
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Affiliation(s)
- Daniela Di Bella
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Stefania Magri
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Chiara Benzoni
- Unit of Rare Neurodegenerative and Neurometabolic Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Laura Farina
- Unit of Neuroradiology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.,Neuroimaging Laboratory, IRCCS Fondazione Santa Lucia, Rome, Italy
| | - Carmelo Maccagnano
- Unit of Neuroradiology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Elisa Sarto
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Marco Moscatelli
- Unit of Neuroradiology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Silvia Baratta
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Claudia Ciano
- Unit of Neurophysiology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | | | - Lara Draghi
- Unit of Neuropsychology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Elena Mauro
- Unit of Rare Neurodegenerative and Neurometabolic Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Davide Pareyson
- Unit of Rare Neurodegenerative and Neurometabolic Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Cinzia Gellera
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Franco Taroni
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Ettore Salsano
- Unit of Rare Neurodegenerative and Neurometabolic Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.,Neuroscience PhD Program, University of Milano-Bicocca, Monza, Italy
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Konno T, Kasanuki K, Ikeuchi T, Dickson DW, Wszolek ZK. CSF1R-related leukoencephalopathy: A major player in primary microgliopathies. Neurology 2018; 91:1092-1104. [PMID: 30429277 DOI: 10.1212/wnl.0000000000006642] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 07/27/2018] [Indexed: 12/22/2022] Open
Abstract
Since the discovery of CSF1R gene mutations in families with hereditary diffuse leukoencephalopathy with spheroids in 2012, more than 70 different mutations have been identified around the world. Through the analyses of mutation carriers, CSF1R-related leukoencephalopathy has been distinctly characterized clinically, radiologically, and pathologically. Typically, patients present with frontotemporal dementia-like phenotype in their 40s-50s, accompanied by motor symptoms, including pyramidal and extrapyramidal signs. Women tend to develop the clinical symptoms at a younger age than men. On brain imaging, in addition to white matter abnormalities, thinning of the corpus callosum, diffusion-restricted lesions in the white matter, and brain calcifications are hallmarks. Primary axonopathy followed by demyelination was suggested by pathology. Haploinsufficiency of colony-stimulating factor-1 receptor (CSF1R) is evident in a patient with a frameshift mutation, facilitating the establishment of Csf1r haploinsufficient mouse model. These mice develop clinical, radiologic, and pathologic phenotypes consistent with those of human patients with CSF1R mutations. In vitro, perturbation of CSF1R signaling is shown in cultured cells expressing mutant CSF1R. However, the underlying mechanisms by which CSF1R mutations selectively lead to white matter degeneration remains to be elucidated. Given that CSF1R mainly expresses in microglia, CSF1R-related leukoencephalopathy is representative of primary microgliopathies, of which microglia have a pivotal and primary role in pathogenesis. In this review, we address the current knowledge of CSF1R-related leukoencephalopathy and discuss the putative pathophysiology, with a focus on microglia, as well as future research directions.
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Affiliation(s)
- Takuya Konno
- From the Departments of Neurology (T.K., Z.K.W.) and Neuroscience (K.K., D.W.D.), Mayo Clinic, Jacksonville, FL; and Department of Molecular Genetics (T.I.), Brain Research Institute, Niigata University, Niigata, Japan. Dr. Konno is currently with the Department of Neurology, Brain Research Institute, Niigata University, Niigata, Japan.
| | - Koji Kasanuki
- From the Departments of Neurology (T.K., Z.K.W.) and Neuroscience (K.K., D.W.D.), Mayo Clinic, Jacksonville, FL; and Department of Molecular Genetics (T.I.), Brain Research Institute, Niigata University, Niigata, Japan. Dr. Konno is currently with the Department of Neurology, Brain Research Institute, Niigata University, Niigata, Japan
| | - Takeshi Ikeuchi
- From the Departments of Neurology (T.K., Z.K.W.) and Neuroscience (K.K., D.W.D.), Mayo Clinic, Jacksonville, FL; and Department of Molecular Genetics (T.I.), Brain Research Institute, Niigata University, Niigata, Japan. Dr. Konno is currently with the Department of Neurology, Brain Research Institute, Niigata University, Niigata, Japan
| | - Dennis W Dickson
- From the Departments of Neurology (T.K., Z.K.W.) and Neuroscience (K.K., D.W.D.), Mayo Clinic, Jacksonville, FL; and Department of Molecular Genetics (T.I.), Brain Research Institute, Niigata University, Niigata, Japan. Dr. Konno is currently with the Department of Neurology, Brain Research Institute, Niigata University, Niigata, Japan
| | - Zbigniew K Wszolek
- From the Departments of Neurology (T.K., Z.K.W.) and Neuroscience (K.K., D.W.D.), Mayo Clinic, Jacksonville, FL; and Department of Molecular Genetics (T.I.), Brain Research Institute, Niigata University, Niigata, Japan. Dr. Konno is currently with the Department of Neurology, Brain Research Institute, Niigata University, Niigata, Japan.
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Ashrafi MR, Tavasoli AR. Childhood leukodystrophies: A literature review of updates on new definitions, classification, diagnostic approach and management. Brain Dev 2017; 39:369-385. [PMID: 28117190 DOI: 10.1016/j.braindev.2017.01.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 12/29/2016] [Accepted: 01/04/2017] [Indexed: 12/29/2022]
Abstract
Childhood leukodystrophies are a growing category of neurological disorders in pediatric neurology practice. With the help of new advanced genetic studies such as whole exome sequencing (WES) and whole genome sequencing (WGS), the list of childhood heritable white matter disorders has been increased to more than one hundred disorders. During the last three decades, the basic concepts and definitions, classification, diagnostic approach and medical management of these disorders much have changed. Pattern recognition based on brain magnetic resonance imaging (MRI), has played an important role in this process. We reviewed the last Global Leukodystrophy Initiative (GLIA) expert opinions in definition, new classification, diagnostic approach and medical management including emerging treatments for pediatric leukodystrophies.
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Affiliation(s)
- Mahmoud Reza Ashrafi
- Department of Child Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran.
| | - Ali Reza Tavasoli
- Department of Child Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran.
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