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Fink JK. The hereditary spastic paraplegias. Handb Clin Neurol 2023; 196:59-88. [PMID: 37620092 DOI: 10.1016/b978-0-323-98817-9.00022-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/26/2023]
Abstract
The hereditary spastic paraplegias (HSPs) are a group of more than 90 genetic disorders in which lower extremity spasticity and weakness are either the primary neurologic impairments ("uncomplicated HSP") or when accompanied by other neurologic deficits ("complicated HSP"), important features of the clinical syndrome. Various genetic types of HSP are inherited such as autosomal dominant, autosomal recessive, X-linked, and maternal (mitochondrial) traits. Symptoms that begin in early childhood may be nonprogressive and resemble spastic diplegic cerebral palsy. Symptoms that begin later, typically progress insidiously over a number of years. Genetic testing is able to confirm the diagnosis for many subjects. Insights from gene discovery indicate that abnormalities in diverse molecular processes underlie various forms of HSP, including disturbance in axon transport, endoplasmic reticulum morphogenesis, vesicle transport, lipid metabolism, and mitochondrial function. Pathologic studies in "uncomplicated" HSP have shown axon degeneration particularly involving the distal ends of corticospinal tracts and dorsal column fibers. Treatment is limited to symptom reduction including amelioration of spasticity, reducing urinary urgency, proactive physical therapy including strengthening, stretching, balance, and agility exercise.
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Affiliation(s)
- John K Fink
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States.
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2
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Parodi L, Barbier M, Jacoupy M, Pujol C, Lejeune FX, Lallemant-Dudek P, Esteves T, Pennings M, Kamsteeg EJ, Guillaud-Bataille M, Banneau G, Coarelli G, Oumoussa BM, Fraidakis MJ, Stevanin G, Depienne C, van de Warrenburg B, Brice A, Durr A. The mitochondrial seryl-tRNA synthetase SARS2 modifies onset in spastic paraplegia type 4. Genet Med 2022; 24:2308-2317. [PMID: 36056923 DOI: 10.1016/j.gim.2022.07.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 07/24/2022] [Accepted: 07/25/2022] [Indexed: 11/25/2022] Open
Abstract
PURPOSE Hereditary spastic paraplegia type 4 is extremely variable in age at onset; the same variant can cause onset at birth or in the eighth decade. We recently discovered that missense variants in SPAST, which influences microtubule dynamics, are associated with earlier onset and more severe disease than truncating variants, but even within the early and late-onset groups there remained significant differences in onset. Given the rarity of the condition, we adapted an extreme phenotype approach to identify genetic modifiers of onset. METHODS We performed a genome-wide association study on 134 patients bearing truncating pathogenic variants in SPAST, divided into early- and late-onset groups (aged ≤15 and ≥45 years, respectively). A replication cohort of 419 included patients carrying either truncating or missense variants. Finally, age at onset was analyzed in the merged cohort (N = 553). RESULTS We found 1 signal associated with earlier age at onset (rs10775533, P = 8.73E-6) in 2 independent cohorts and in the merged cohort (N = 553, Mantel-Cox test, P < .0001). Western blotting in lymphocytes of 20 patients showed that this locus tends to upregulate SARS2 expression in earlier-onset patients. CONCLUSION SARS2 overexpression lowers the age of onset in hereditary spastic paraplegia type 4. Lowering SARS2 or improving mitochondrial function could thus present viable approaches to therapy.
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Affiliation(s)
- Livia Parodi
- Paris Brain Institute (Institut du Cerveau, ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Paris, France
| | - Mathieu Barbier
- Paris Brain Institute (Institut du Cerveau, ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Paris, France
| | - Maxime Jacoupy
- Paris Brain Institute (Institut du Cerveau, ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Paris, France
| | - Claire Pujol
- Paris Brain Institute (Institut du Cerveau, ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Paris, France; Pasteur Institute, Centre National de la Recherche Scientifique UMR 3691, Paris, France
| | - François-Xavier Lejeune
- Paris Brain Institute (Institut du Cerveau, ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Paris, France
| | - Pauline Lallemant-Dudek
- Paris Brain Institute (Institut du Cerveau, ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Paris, France
| | - Typhaine Esteves
- Paris Brain Institute (Institut du Cerveau, ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Paris, France; Université de Bordeaux, CNRS, EPHE, INCIA, UMR 5287, Bordeaux, France
| | - Maartje Pennings
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Erik-Jan Kamsteeg
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | | | - Guillaume Banneau
- Département de Génétique, AP-HP, GH Pitié-Salpêtrière, Sorbonne Université, Paris, France
| | - Giulia Coarelli
- Paris Brain Institute (Institut du Cerveau, ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Paris, France
| | - Badreddine Mohand Oumoussa
- Sorbonne Université, Inserm, UMS Production et Analyse des données en Sciences de la vie et en Santé, PASS, Plateforme Post-génomique de la Pitié-Salpêtrière, P3S, Paris, France
| | - Matthew J Fraidakis
- Rare Neurological Diseases Unit, Department of Neurology, Attikon University Hospital, Medical School of the University of Athens, Athens, Greece
| | - Giovanni Stevanin
- Paris Brain Institute (Institut du Cerveau, ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Paris, France; Université de Bordeaux, CNRS, EPHE, INCIA, UMR 5287, Bordeaux, France
| | - Christel Depienne
- Paris Brain Institute (Institut du Cerveau, ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Paris, France; Institut für Humangenetik, Universitätsklinikum Essen, Essen, Germany
| | - Bart van de Warrenburg
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Alexis Brice
- Paris Brain Institute (Institut du Cerveau, ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Paris, France
| | - Alexandra Durr
- Paris Brain Institute (Institut du Cerveau, ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Paris, France.
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Li JL, Lee NC, Chen PS, Lee GH, Wu RM. Leukoencephalopathy with Brainstem and Spinal Cord Involvement and Lactate Elevation: A Novel DARS2 Mutation and Intra-Familial Heterogeneity. Mov Disord Clin Pract 2021; 8:1116-1122. [PMID: 34631948 PMCID: PMC8485606 DOI: 10.1002/mdc3.13281] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 05/28/2021] [Accepted: 06/27/2021] [Indexed: 11/06/2022] Open
Abstract
Background Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL) is characterized by slowly progressive spastic gait, cerebellar symptoms, and posterior cord dysfunction. DARS2, which encodes mitochondrial aspartyl tRNA synthase, is associated with the rare disease. Cases The proband had gait disturbance since age 56, while her younger brother had the gait problem since his 20s and needed cane‐assistance at age 45. Both cases showed typical demyelinating features of LBSL on the magnetic resonance imaging (MRI) involving the periventricular white matter, brainstem, cerebellum and spinal cord. Sequencing of both cases showed compound heterozygous mutations: c.228‐16C>A and c.508C>T in DARS2. The c.228‐16C>A is a common mutation in splicing site of intron 2, which causes alternative splicing defect of exon 3, while the c.508C>T at the exon 6 is novel. Our patients are unique in the relative late onset and the apparent difference in disease progression. Literature Review Literatures from PubMed were reviewed. Five families showed intra‐familial heterogeneity on age at onset or clinical severity. Conclusion We identified a family of LBSL with compound heterozygous mutations, and c.508C>T at the exon 6 is a novel one. Clinical heterogeneity was observed in the family and other literatures. Further research for underlying mechanism is required.
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Affiliation(s)
- Jeng-Lin Li
- Department of Neurology National Taiwan University Hospital Taipei Taiwan
| | - Ni-Chung Lee
- Department of Medical Genetics National Taiwan University Hospital Taipei Taiwan
| | - Pin-Shiuan Chen
- Department of Neurology National Taiwan University Hospital Taipei Taiwan
| | - Gin Hoong Lee
- Department of Neurology National Taiwan University Hospital Taipei Taiwan.,Department of Medical Education National Taiwan University Hospital Taipei Taiwan
| | - Ruey-Meei Wu
- Department of Neurology National Taiwan University Hospital Taipei Taiwan.,Department of Neurology, College of Medicine National Taiwan University Taipei Taiwan
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Pauly MG, Hellenbroich Y, Grundmann-Hauser K, Hinrichs F, Lohmann K, Brüggemann N. Compound Heterozygous DARS2 Mutations as a Mimic of Hereditary Spastic Paraplegia. Mov Disord Clin Pract 2021; 8:972-976. [PMID: 34405109 DOI: 10.1002/mdc3.13258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/30/2021] [Accepted: 05/11/2021] [Indexed: 11/09/2022] Open
Affiliation(s)
- Martje G Pauly
- Institute of Neurogenetics University of Lübeck Lübeck Germany.,Institute of Systems Motor Science University of Lübeck Lübeck Germany.,Department of Neurology University Hospital Schleswig Holstein Lübeck Germany
| | | | - Kathrin Grundmann-Hauser
- Institute of Medical Genetics and Applied Genomics University Hospital of Tübingen Tübingen Germany
| | - Frauke Hinrichs
- Institute of Neurogenetics University of Lübeck Lübeck Germany
| | - Katja Lohmann
- Institute of Neurogenetics University of Lübeck Lübeck Germany
| | - Norbert Brüggemann
- Institute of Neurogenetics University of Lübeck Lübeck Germany.,Department of Neurology University Hospital Schleswig Holstein Lübeck Germany.,Center for Brain, Behavior and Metabolism University of Lübeck Lübeck Germany
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Yazici Gencdal I, Dincer A, Obuz O, Yapici Z. Leukoencephalopathy With Brain Stem and Spinal Cord Involvement and Lactate Elevation (LBSL): A Case With Long-term Follow-up. Neurologist 2020; 25:144-7. [PMID: 32925487 DOI: 10.1097/NRL.0000000000000286] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Leukoencephalopathy with brain stem and spinal cord involvement and lactate elevation (LBSL) is caused by a recessive mutation in the DARS2 gene and can be recognized by specific magnetic resonance imaging patterns. CASE REPORT A girl who developed leg tremors at age 4 years was diagnosed at age 17 years with LBSL -after evolution of ataxia and sensory loss. Examination at age 29 revealed mild spastic gait, ataxia, and sensory loss, and she did not require assistance to walk. CONCLUSION This report illustrates the clinical and magnetic resonance imaging characteristics of a slowly progressive long-term course of childhood-onset LBSL.
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Yahia A, Stevanin G. The History of Gene Hunting in Hereditary Spinocerebellar Degeneration: Lessons From the Past and Future Perspectives. Front Genet 2021; 12:638730. [PMID: 33833777 PMCID: PMC8021710 DOI: 10.3389/fgene.2021.638730] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 03/02/2021] [Indexed: 01/02/2023] Open
Abstract
Hereditary spinocerebellar degeneration (SCD) encompasses an expanding list of rare diseases with a broad clinical and genetic heterogeneity, complicating their diagnosis and management in daily clinical practice. Correct diagnosis is a pillar for precision medicine, a branch of medicine that promises to flourish with the progressive improvements in studying the human genome. Discovering the genes causing novel Mendelian phenotypes contributes to precision medicine by diagnosing subsets of patients with previously undiagnosed conditions, guiding the management of these patients and their families, and enabling the discovery of more causes of Mendelian diseases. This new knowledge provides insight into the biological processes involved in health and disease, including the more common complex disorders. This review discusses the evolution of the clinical and genetic approaches used to diagnose hereditary SCD and the potential of new tools for future discoveries.
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Affiliation(s)
- Ashraf Yahia
- Department of Biochemistry, Faculty of Medicine, University of Khartoum, Khartoum, Sudan
- Department of Biochemistry, Faculty of Medicine, National University, Khartoum, Sudan
- Institut du Cerveau, INSERM U1127, CNRS UMR7225, Sorbonne Université, Paris, France
- Ecole Pratique des Hautes Etudes, EPHE, PSL Research University, Paris, France
| | - Giovanni Stevanin
- Institut du Cerveau, INSERM U1127, CNRS UMR7225, Sorbonne Université, Paris, France
- Ecole Pratique des Hautes Etudes, EPHE, PSL Research University, Paris, France
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Muthiah A, Housley GD, Klugmann M, Fröhlich D. The Leukodystrophies HBSL and LBSL-Correlates and Distinctions. Front Cell Neurosci 2021; 14:626610. [PMID: 33574740 PMCID: PMC7870476 DOI: 10.3389/fncel.2020.626610] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 12/21/2020] [Indexed: 12/16/2022] Open
Abstract
Aminoacyl-tRNA synthetases (ARSs) accurately charge tRNAs with their respective amino acids. As such, they are vital for the initiation of cytosolic and mitochondrial protein translation. These enzymes have become increasingly scrutinized in recent years for their role in neurodegenerative disorders caused by the mutations of ARS-encoding genes. This review focuses on two such genes-DARS1 and DARS2-which encode cytosolic and mitochondrial aspartyl-tRNA synthetases, and the clinical conditions associated with mutations of these genes. We also describe attempts made at modeling these conditions in mice, which have both yielded important mechanistic insights. Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL) is a disease caused by a range of mutations in the DARS2 gene, initially identified in 2003. Ten years later, hypomyelination with brainstem and spinal cord involvement and leg spasticity (HBSL), caused by mutations of cytosolic DARS1, was discovered. Multiple parallels have been drawn between the two conditions. The Magnetic Resonance Imaging (MRI) patterns are strikingly similar, but still set these two conditions apart from other leukodystrophies. Clinically, both conditions are characterized by lower limb spasticity, often associated with other pyramidal signs. However, perhaps due to earlier detection, a wider range of symptoms, including peripheral neuropathy, as well as visual and hearing changes have been described in LBSL patients. Both HBSL and LBSL are spectrum disorders lacking genotype to phenotype correlation. While the fatal phenotype of Dars1 or Dars2 single gene deletion mouse mutants revealed that the two enzymes lack functional redundancy, further pursuit of disease modeling are required to shed light onto the underlying disease mechanism, and enable examination of experimental treatments, including gene therapies.
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Affiliation(s)
| | | | | | - Dominik Fröhlich
- Translational Neuroscience Facility and Department of Physiology, School of Medical Sciences, UNSW Sydney, Kensington, NSW, Australia
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Luca P, Alessia G, Camilla REM, Antonio N, Diego M, Federica D, Daria D, Rosalba C, Carlo DV, Daniela L. Spinal cord involvement in Kearns-Sayre syndrome: a neuroimaging study. Neuroradiology 2020; 62:1315-1321. [PMID: 32700106 PMCID: PMC7479017 DOI: 10.1007/s00234-020-02501-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 07/14/2020] [Indexed: 12/18/2022]
Abstract
Purpose Spinal cord involvement in Kearns-Sayre (KSS) syndrome could be more frequent than commonly thought. Our aims were to evaluate the involvement of the spinal cord in patients with KSS by means of MRI and to investigate possible correlations of spinal and brain disease with patient disability. Methods Eleven patients with KSS disease and spinal cord MRI were retrospectively recruited. The severity of spinal disease was defined as follows: grade 0 (none), grade 1 (focal), and grade 2 (extensive). We calculated a radiologic score of brain involvement based on typical features. We performed a chi-square test to correlate spinal cord and brain MRI involvement to patient disability. For significant variables, a contingency coefficient, phi factor, and Cramer’s V were also computed. Results Spinal cord lesions were detected in 6/11 patients, showing four patterns: involvement of gray matter, gray matter and posterior columns, posterior columns, and anterior columns. The severity of spinal disease was grade 1 in two and grade 2 in four patients. All patients showed brain involvement (9-point average for patients with spinal involvement and 10 for the others). A significant correlation was found between disability score and spinal cord involvement (χ2 = 7.64; p = 0.022) or brain score (χ2 = 26.85; p = 0.043). Significance for brain score-disability correlation increased with the spinal cord as a cofactor (χ2 = 24.51; p = 0.017, phi factor = 1.201, Cramer’s V = 0.849, contingency effect = 0.767; p = 0.017). Conclusion Spinal cord lesions are common in KSS. Patients with spinal disease show higher disability than patients without spinal cord lesions, supporting the inclusion of dedicated acquisitions to routine MRI of the brain in patients with KSS.
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Affiliation(s)
- Pasquini Luca
- Neuroradiology Unit, Imaging Department, Bambino Gesù Children's Hospital, P.zza Sant'Onofrio 4, 00165, Rome, Italy. .,Neuroradiology Unit, NESMOS Department, Sant'Andrea Hospital, La Sapienza University, Rome, Italy.
| | - Guarnera Alessia
- Neuroradiology Unit, Imaging Department, Bambino Gesù Children's Hospital, P.zza Sant'Onofrio 4, 00165, Rome, Italy.,Neuroradiology Unit, NESMOS Department, Sant'Andrea Hospital, La Sapienza University, Rome, Italy
| | - Rossi-Espagnet Maria Camilla
- Neuroradiology Unit, Imaging Department, Bambino Gesù Children's Hospital, P.zza Sant'Onofrio 4, 00165, Rome, Italy.,Neuroradiology Unit, NESMOS Department, Sant'Andrea Hospital, La Sapienza University, Rome, Italy
| | - Napolitano Antonio
- Medical Physics Department, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Martinelli Diego
- Division of Metabolism, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - Deodato Federica
- Division of Metabolism, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - Diodato Daria
- Unit of Muscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, IRCCS Bambino Gesù Children's Hospital, 00146, Rome, Italy
| | - Carrozzo Rosalba
- Unit of Muscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, IRCCS Bambino Gesù Children's Hospital, 00146, Rome, Italy
| | - Dionisi-Vici Carlo
- Division of Metabolism, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - Longo Daniela
- Neuroradiology Unit, Imaging Department, Bambino Gesù Children's Hospital, P.zza Sant'Onofrio 4, 00165, Rome, Italy
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Lin TK, Chang YY, Lin HY, Liou CW, Wang PW, Chuang JH, Chen SD, Chuang YC, Huang ST, Hsu TY, Peng CH, Lan MY. Mitochondrial dysfunctions in leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL). PLoS One 2019; 14:e0224173. [PMID: 31671122 DOI: 10.1371/journal.pone.0224173] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 10/07/2019] [Indexed: 02/07/2023] Open
Abstract
Several inherited human diseases have been linked to mitochondrial aminoacyl-tRNA synthetases (mtARSs). Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL) is a leukodystrophy caused by mutations in the DARS2 gene which encodes mitochondrial aspartyl-tRNA synthetase. As mitochondrial ARSs are key components of the mitochondrial translation apparatus, we investigated the effects of DARS2 mutations on mitochondrial functions and mitochondrial morphology in an LBSL patient. In fibroblasts from the patient with LBSL, biosynthesis of respiratory chain complex proteins encoded by mitochondrial DNA was decreased, while those encoded by nuclear DNA were not. Cellular oxygen consumption rates and respiratory control ratio were decreased in the LBSL patient; in addition, fragmentation of mitochondria was increased, while their tubular elongation and interconnectivity were decreased. Taken together, these findings suggest that DARS2 mutations impair translations of mitochondrial DNA-encoded respiratory chain complex proteins, consequently causing dysfunction of cellular respiration and impediment of mitochondrial dynamics, which highlights the role of mtARSs in the maintenance of normal mitochondrial bioenergetics and dynamics.
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Abstract
This review aims at summarising and discussing the current status concerning the clinical presentation, pathogenesis, diagnosis, and treatment of spinal cord affection in mitochondrial disorders (MIDs). A literature search using the database Pubmed was carried out by application of appropriate search terms and their combinations. Involvement of the spinal cord in MIDs is more frequent than anticipated. It occurs in specific and non-specific MIDs. Among the specific MIDs it has been most frequently described in LBSL, LS, MERRF, KSS, IOSCA, MIRAS, and PCH and only rarely in MELAS, CPEO, and LHON. Clinically, spinal cord involvement manifests as monoparesis, paraparesis, quadruparesis, sensory disturbances, hypotonia, spasticity, urinary or defecation dysfunction, spinal column deformities, or as transverse syndrome. Diagnosing spinal cord involvement in MIDs requires a thoroughly taken history, clinical exam, and imaging studies. Additionally, transcranial magnetic stimulation, somato-sensory-evoked potentials, and cerebro-spinal fluid can be supportive. Treatment is generally not at variance compared to the underlying MID but occasionally surgical stabilisation of the spinal column may be necessary. It is concluded that spinal cord involvement in MIDs is more frequent than anticipated but may be missed if cerebral manifestations prevail. Spinal cord involvement in MIDs may strongly determine the mobility of these patients.
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Affiliation(s)
- Josef Finsterer
- Department of Neurology, Krankenanstalt Rudolfstiftung, Vienna, Austria
| | - Sinda Zarrouk-Mahjoub
- Pasteur Institute of Tunis, University of Tunis El Manar and Genomics Platform, Pasteur Institute of Tunis, Tunis, Tunisia
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Shimojima K, Higashiguchi T, Kishimoto K, Miyatake S, Miyake N, Takanashi JI, Matsumoto N, Yamamoto T. A novel DARS2 mutation in a Japanese patient with leukoencephalopathy with brainstem and spinal cord involvement but no lactate elevation. Hum Genome Var 2017; 4:17051. [PMID: 29138691 DOI: 10.1038/hgv.2017.51] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 09/19/2017] [Accepted: 09/21/2017] [Indexed: 11/13/2022] Open
Abstract
The mitochondrial aspartyl-tRNA synthetase 2 gene (DARS2) is responsible for leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL). A Japanese patient with LBSL showed compound heterozygous DARS2 mutations c.358_359delinsTC (p.Gly120Ser) and c.228-15C>G (splicing error). This provides further evidence that most patients with LBSL show compound heterozygous mutations in DARS2 in association with a common splicing mutation in the splicing acceptor site of intron 2.
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Meyer-Schuman R, Antonellis A. Emerging mechanisms of aminoacyl-tRNA synthetase mutations in recessive and dominant human disease. Hum Mol Genet 2017; 26:R114-R127. [PMID: 28633377 PMCID: PMC5886470 DOI: 10.1093/hmg/ddx231] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 06/09/2017] [Accepted: 06/12/2017] [Indexed: 12/29/2022] Open
Abstract
Aminoacyl-tRNA synthetases (ARSs) are responsible for charging amino acids to cognate tRNA molecules, which is the essential first step of protein translation. Interestingly, mutations in genes encoding ARS enzymes have been implicated in a broad spectrum of human inherited diseases. Bi-allelic mutations in ARSs typically cause severe, early-onset, recessive diseases that affect a wide range of tissues. The vast majority of these mutations show loss-of-function effects and impair protein translation. However, it is not clear how a subset cause tissue-specific phenotypes. In contrast, dominant ARS-mediated diseases specifically affect the peripheral nervous system-most commonly causing axonal peripheral neuropathy-and usually manifest later in life. These neuropathies are linked to heterozygosity for missense mutations in five ARS genes, which points to a shared mechanism of disease. However, it is not clear if a loss-of-function mechanism or a toxic gain-of-function mechanism is responsible for ARS-mediated neuropathy, or if a combination of these mechanisms operate on a mutation-specific basis. Here, we review our current understanding of recessive and dominant ARS-mediated disease. We also propose future directions for defining the molecular mechanisms of ARS mutations toward designing therapies for affected patient populations.
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Affiliation(s)
- Rebecca Meyer-Schuman
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Anthony Antonellis
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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Finsterer J, Zarrouk-Mahjoub S. Phenotypic spectrum of DARS2 mutations. J Neurol Sci 2017; 376:117-118. [PMID: 28431594 DOI: 10.1016/j.jns.2017.03.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 02/28/2017] [Accepted: 03/07/2017] [Indexed: 12/13/2022]
Affiliation(s)
| | - Sinda Zarrouk-Mahjoub
- University of Tunis El Manar, Genomics Platform, Pasteur Institute of Tunis, Tunisia
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