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Synofzik M, Rugarli E, Reid E, Schüle R. Ataxia and spastic paraplegia in mitochondrial disease. HANDBOOK OF CLINICAL NEUROLOGY 2023; 194:79-98. [PMID: 36813322 DOI: 10.1016/b978-0-12-821751-1.00009-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Degenerative ataxias and hereditary spastic paraplegias (HSPs) form a continuous, often overlapping disease spectrum sharing not only phenotypic features and underlying genes, but also cellular pathways and disease mechanisms. Mitochondrial metabolism presents a major molecular theme underlying both multiple ataxias and HSPs, thus indicating a heightened vulnerability of Purkinje cells, spinocerebellar tracts, and motor neurons to mitochondrial dysfunction, which is of particular interest for translational approaches. Mitochondrial dysfunction might be the primary (upstream) or secondary (downstream) result of a genetic defect, with underlying genetic defects in nuclear-encoded genes being much more frequent than in mtDNA genes in both, ataxias and HSPs. Here, we outline the substantial number of ataxias, spastic ataxias and HSPs caused by mutated genes implicated in (primary or secondary) mitochondrial dysfunction, highlighting several key "mitochondrial" ataxias and HSPs which are of particular interest for their frequency, pathogenesis and translational opportunities. We then showcase prototypic mitochondrial mechanisms by which disruption of these ataxia and HSP genes contributes to Purkinje cells or corticospinal neuron dysfunction, thus elucidating hypotheses on Purkinje cells and corticospinal neuron vulnerability to mitochondrial dysfunction.
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Affiliation(s)
- Matthis Synofzik
- Department of Neurodegenerative Diseases, Center for Neurology & Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany; German Center of Neurodegenerative Diseases (DZNE), Tübingen, Germany.
| | - Elena Rugarli
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, and Center for Molecular Medicine, University of Cologne, Cologne, Germany
| | - Evan Reid
- Cambridge Institute for Medical Research and Department of Medical Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Rebecca Schüle
- Department of Neurodegenerative Diseases, Center for Neurology & Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany; German Center of Neurodegenerative Diseases (DZNE), Tübingen, Germany
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2
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Fluctuating ataxia caused by mitochondrial tRNA (Lys) gene m.8363G > A variant. Neurol Sci 2022; 43:6589-6591. [DOI: 10.1007/s10072-022-06246-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 06/21/2022] [Indexed: 11/25/2022]
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3
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Mitochondrial Neurodegeneration. Cells 2022; 11:cells11040637. [PMID: 35203288 PMCID: PMC8870525 DOI: 10.3390/cells11040637] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 01/28/2022] [Accepted: 02/06/2022] [Indexed: 01/27/2023] Open
Abstract
Mitochondria are cytoplasmic organelles, which generate energy as heat and ATP, the universal energy currency of the cell. This process is carried out by coupling electron stripping through oxidation of nutrient substrates with the formation of a proton-based electrochemical gradient across the inner mitochondrial membrane. Controlled dissipation of the gradient can lead to production of heat as well as ATP, via ADP phosphorylation. This process is known as oxidative phosphorylation, and is carried out by four multiheteromeric complexes (from I to IV) of the mitochondrial respiratory chain, carrying out the electron flow whose energy is stored as a proton-based electrochemical gradient. This gradient sustains a second reaction, operated by the mitochondrial ATP synthase, or complex V, which condensates ADP and Pi into ATP. Four complexes (CI, CIII, CIV, and CV) are composed of proteins encoded by genes present in two separate compartments: the nuclear genome and a small circular DNA found in mitochondria themselves, and are termed mitochondrial DNA (mtDNA). Mutations striking either genome can lead to mitochondrial impairment, determining infantile, childhood or adult neurodegeneration. Mitochondrial disorders are complex neurological syndromes, and are often part of a multisystem disorder. In this paper, we divide the diseases into those caused by mtDNA defects and those that are due to mutations involving nuclear genes; from a clinical point of view, we discuss pediatric disorders in comparison to juvenile or adult-onset conditions. The complementary genetic contributions controlling organellar function and the complexity of the biochemical pathways present in the mitochondria justify the extreme genetic and phenotypic heterogeneity of this new area of inborn errors of metabolism known as ‘mitochondrial medicine’.
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Kauppila LA, Ten Holter SE, van de Warrenburg B, Bloem BR. A Guide for the Differential Diagnosis of Multiple System Atrophy in Clinical Practice. JOURNAL OF PARKINSON'S DISEASE 2022; 12:2015-2027. [PMID: 36057832 PMCID: PMC9661336 DOI: 10.3233/jpd-223392] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Accepted: 08/11/2022] [Indexed: 06/15/2023]
Abstract
Multiple system atrophy (MSA) is a sporadic and progressive neurodegenerative disorder with a complex differential diagnosis. A range of disorders- also of nondegenerative etiology- can mimic MSA, expanding its differential diagnosis. Both misdiagnosis and diagnostic delays are relatively common in clinical practice. A correct diagnosis is vital for daily clinical practice, in order to facilitate proper counselling and to timely install therapies in treatable disorders that mimic MSA. A correct diagnosis is also essential for including properly classified individuals into research studies that aim to better understand the pathophysiology of MSA, to develop specific biomarkers or to evaluate novel symptomatic or disease-modifying therapies. Here, we offer some practical guidance to support the diagnostic process, by highlighting conditions that may be considered as MSA lookalikes, by emphasizing some key clinical aspects of these mimics, and by discussing several useful ancillary diagnostic tests.
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Affiliation(s)
- Linda Azevedo Kauppila
- CNS – Campus Neurológico, Lisbon, Portugal
- Department of Neurology, Center of Expertise for Parkinson & Movement Disorders, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Susanne E.M. Ten Holter
- Department of Neurology, Center of Expertise for Parkinson & Movement Disorders, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Bart van de Warrenburg
- Department of Neurology, Center of Expertise for Parkinson & Movement Disorders, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Bastiaan R. Bloem
- Department of Neurology, Center of Expertise for Parkinson & Movement Disorders, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
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Flickinger J, Fan J, Wellik A, Ganetzky R, Goldstein A, Muraresku CC, Glanzman AM, Ballance E, Leonhardt K, McCormick EM, Soreth B, Nguyen S, Gornish J, George‐Sankoh I, Peterson J, MacMullen LE, Vishnubhatt S, McBride M, Haas R, Falk MJ, Xiao R, Zolkipli‐Cunningham Z. Development of a Mitochondrial Myopathy‐Composite Assessment Tool. JCSM CLINICAL REPORTS 2021. [DOI: 10.1002/crt2.41] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Affiliation(s)
- Jean Flickinger
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia PA 19104 USA
- Department of Physical Therapy Children's Hospital of Philadelphia Philadelphia PA USA
| | - Jiaxin Fan
- Department of Biostatistics, Epidemiology and Informatics University of Pennsylvania Perelman School of Medicine Philadelphia PA USA
| | - Amanda Wellik
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia PA 19104 USA
| | - Rebecca Ganetzky
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia PA 19104 USA
- Department of Pediatrics University of Pennsylvania Perelman School of Medicine Philadelphia PA USA
| | - Amy Goldstein
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia PA 19104 USA
- Department of Pediatrics University of Pennsylvania Perelman School of Medicine Philadelphia PA USA
| | - Colleen C. Muraresku
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia PA 19104 USA
| | - Allan M. Glanzman
- Department of Physical Therapy Children's Hospital of Philadelphia Philadelphia PA USA
| | - Elizabeth Ballance
- Department of Physical Therapy Children's Hospital of Philadelphia Philadelphia PA USA
| | - Kristin Leonhardt
- Department of Physical Therapy Children's Hospital of Philadelphia Philadelphia PA USA
| | - Elizabeth M. McCormick
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia PA 19104 USA
| | - Brianna Soreth
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia PA 19104 USA
| | - Sara Nguyen
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia PA 19104 USA
| | - Jennifer Gornish
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia PA 19104 USA
| | - Ibrahim George‐Sankoh
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia PA 19104 USA
| | - James Peterson
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia PA 19104 USA
| | - Laura E. MacMullen
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia PA 19104 USA
| | - Shailee Vishnubhatt
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia PA 19104 USA
| | - Michael McBride
- Cardiovascular Exercise Physiology Laboratory, Division of Cardiology Children's Hospital of Philadelphia Philadelphia PA USA
| | - Richard Haas
- Metabolic and Mitochondrial Disease Center La Jolla CA USA
- Department of Neurosciences University of California San Diego School of Medicine La Jolla CA USA
| | - Marni J. Falk
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia PA 19104 USA
- Department of Pediatrics University of Pennsylvania Perelman School of Medicine Philadelphia PA USA
| | - Rui Xiao
- Department of Biostatistics, Epidemiology and Informatics University of Pennsylvania Perelman School of Medicine Philadelphia PA USA
- Department of Pediatrics University of Pennsylvania Perelman School of Medicine Philadelphia PA USA
| | - Zarazuela Zolkipli‐Cunningham
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia PA 19104 USA
- Department of Pediatrics University of Pennsylvania Perelman School of Medicine Philadelphia PA USA
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6
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Mei C, Dong H, Nisenbaum E, Thielhelm T, Nourbakhsh A, Yan D, Smeal M, Lundberg Y, Hoffer ME, Angeli S, Telischi F, Nie G, Blanton SH, Liu X. Genetics and the Individualized Therapy of Vestibular Disorders. Front Neurol 2021; 12:633207. [PMID: 33613440 PMCID: PMC7892966 DOI: 10.3389/fneur.2021.633207] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 01/13/2021] [Indexed: 02/06/2023] Open
Abstract
Background: Vestibular disorders (VDs) are a clinically divergent group of conditions that stem from pathology at the level of the inner ear, vestibulocochlear nerve, or central vestibular pathway. No etiology can be identified in the majority of patients with VDs. Relatively few families have been reported with VD, and so far, no causative genes have been identified despite the fact that more than 100 genes have been identified for inherited hearing loss. Inherited VDs, similar to deafness, are genetically heterogeneous and follow Mendelian inheritance patterns with all modes of transmission, as well as multifactorial inheritance. With advances in genetic sequencing, evidence of familial clustering in VD has begun to highlight the genetic causes of these disorders, potentially opening up new avenues of treatment, particularly in Meniere's disease and disorders with comorbid hearing loss, such as Usher syndrome. In this review, we aim to present recent findings on the genetics of VDs, review the role of genetic sequencing tools, and explore the potential for individualized medicine in the treatment of these disorders. Methods: A search of the PubMed database was performed for English language studies relevant to the genetic basis of and therapies for vestibular disorders, using search terms including but not limited to: “genetics,” “genomics,” “vestibular disorders,” “hearing loss with vestibular dysfunction,” “individualized medicine,” “genome-wide association studies,” “precision medicine,” and “Meniere's syndrome.” Results: Increasing numbers of studies on vestibular disorder genetics have been published in recent years. Next-generation sequencing and new genetic tools are being utilized to unearth the significance of the genomic findings in terms of understanding disease etiology and clinical utility, with growing research interest being shown for individualized gene therapy for some disorders. Conclusions: The genetic knowledge base for vestibular disorders is still in its infancy. Identifying the genetic causes of balance problems is imperative in our understanding of the biology of normal function of the vestibule and the disease etiology and process. There is an increasing effort to use new and efficient genetic sequencing tools to discover the genetic causes for these diseases, leading to the hope for precise and personalized treatment for these patients.
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Affiliation(s)
- Christine Mei
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Hongsong Dong
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States.,Shenzhen Second People's Hospital, Shenzhen, China
| | - Eric Nisenbaum
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Torin Thielhelm
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Aida Nourbakhsh
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Denise Yan
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Molly Smeal
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Yesha Lundberg
- Department of Otolaryngology, Boys Town National Research Hospital, Omaha, NE, United States
| | - Michael E Hoffer
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Simon Angeli
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Fred Telischi
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Guohui Nie
- Shenzhen Second People's Hospital, Shenzhen, China
| | - Susan H Blanton
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Xuezhong Liu
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
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La Rosa P, Petrillo S, Bertini ES, Piemonte F. Oxidative Stress in DNA Repeat Expansion Disorders: A Focus on NRF2 Signaling Involvement. Biomolecules 2020; 10:biom10050702. [PMID: 32369911 PMCID: PMC7277112 DOI: 10.3390/biom10050702] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 04/24/2020] [Accepted: 04/27/2020] [Indexed: 12/13/2022] Open
Abstract
DNA repeat expansion disorders are a group of neuromuscular and neurodegenerative diseases that arise from the inheritance of long tracts of nucleotide repetitions, located in the regulatory region, introns, or inside the coding sequence of a gene. Although loss of protein expression and/or the gain of function of its transcribed mRNA or translated product represent the major pathogenic effect of these pathologies, mitochondrial dysfunction and imbalance in redox homeostasis are reported as common features in these disorders, deeply affecting their severity and progression. In this review, we examine the role that the redox imbalance plays in the pathological mechanisms of DNA expansion disorders and the recent advances on antioxidant treatments, particularly focusing on the expression and the activity of the transcription factor NRF2, the main cellular regulator of the antioxidant response.
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Benussi A, Pascual-Leone A, Borroni B. Non-Invasive Cerebellar Stimulation in Neurodegenerative Ataxia: A Literature Review. Int J Mol Sci 2020; 21:ijms21061948. [PMID: 32178459 PMCID: PMC7139863 DOI: 10.3390/ijms21061948] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 03/08/2020] [Accepted: 03/11/2020] [Indexed: 12/16/2022] Open
Abstract
Cerebellar ataxias are a heterogenous group of degenerative disorders for which we currently lack effective and disease-modifying interventions. The field of non-invasive brain stimulation has made much progress in the development of specific stimulation protocols to modulate cerebellar excitability and try to restore the physiological activity of the cerebellum in patients with ataxia. In light of limited evidence-based pharmacologic and non-pharmacologic treatment options for patients with ataxia, several different non-invasive brain stimulation protocols have emerged, particularly employing repetitive transcranial magnetic stimulation (rTMS) or transcranial direct current stimulation (tDCS) techniques. In this review, we summarize the most relevant rTMS and tDCS therapeutic trials and discuss their implications in the care of patients with degenerative ataxias.
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Affiliation(s)
- Alberto Benussi
- Neurology Unit, Department of Clinical and Experimental Sciences, University of Brescia, 25123 Brescia, Italy;
| | - Alvaro Pascual-Leone
- Arthur and Hinda Marcus Institute for Aging Brain, Hebrew SeniorLife and Department of Neurology, Harvard Medical School, Boston, MA 02131, USA;
- Guttmann Brain Health Institute, Institute Guttmann, Universitat Autonoma, 08027 Barcelona, Spain
| | - Barbara Borroni
- Neurology Unit, Department of Clinical and Experimental Sciences, University of Brescia, 25123 Brescia, Italy;
- Correspondence: ; Tel.: +39-030-3995632
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9
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Srivastava S, Butala A, Mahida S, Richter J, Mu W, Poretti A, Vernon H, VanGerpen J, Atwal PS, Middlebrooks EH, Zee DS, Naidu S. Expansion of the clinical spectrum associated with AARS2-related disorders. Am J Med Genet A 2019; 179:1556-1564. [PMID: 31099476 DOI: 10.1002/ajmg.a.61188] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 04/21/2019] [Accepted: 04/23/2019] [Indexed: 12/14/2022]
Abstract
Biallelic pathogenic variants in AARS2, a gene encoding the mitochondrial alanyl-tRNA synthetase, result in a spectrum of findings ranging from infantile cardiomyopathy to adult-onset progressive leukoencephalopathy. In this article, we present three unrelated individuals with novel compound heterozygous pathogenic AARS2 variants underlying diverse clinical presentations. Patient 1 is a 51-year-old man with adult-onset progressive cognitive, psychiatric, and motor decline and leukodystrophy. Patient 2 is a 34-year-old man with childhood-onset progressive tremor followed by the development of polyneuropathy, ataxia, and mild cognitive and psychiatric decline without leukodystrophy on imaging. Patient 3 is a 57-year-old woman with childhood-onset tremor and nystagmus which preceded dystonia, chorea, ataxia, depression, and cognitive decline marked by cerebellar atrophy and white matter disease. These cases expand the clinical heterogeneity of AARS2-related disorders, given that the first and third case represent some of the oldest known survivors of this disease, the second is adult-onset AARS2-related neurological decline without leukodystrophy, and the third is biallelic AARS2-related disorder involving a partial gene deletion.
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Affiliation(s)
| | - Ankur Butala
- Department of Neurology, The Johns Hopkins Hospital, Baltimore, Maryland
| | - Sonal Mahida
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts
| | - John Richter
- Department of Neurology, Mayo Clinic, Jacksonville, Florida
| | - Weiyi Mu
- Institute of Genetic Medicine, The Johns Hopkins Hospital, Baltimore, Maryland
| | - Andrea Poretti
- Department of Neurogenetics, Hugo W. Moser Research Institute at Kennedy Krieger Institute, Baltimore, Maryland.,Department of Neurology and Pediatrics, The Johns Hopkins Hospital, Baltimore, Maryland
| | - Hilary Vernon
- Institute of Genetic Medicine, The Johns Hopkins Hospital, Baltimore, Maryland
| | - Jay VanGerpen
- Department of Neurology, Mayo Clinic, Jacksonville, Florida
| | | | - Erik H Middlebrooks
- Department of Radiology and Neurosurgery, Mayo Clinic, Jacksonville, Florida
| | - David S Zee
- Department of Neurology, The Johns Hopkins Hospital, Baltimore, Maryland.,Department of Ophthalmology, Otolaryngology, Head and Neck Surgery and Neuroscience, The Johns Hopkins Hospital, Baltimore, Maryland
| | - SakkuBai Naidu
- Department of Neurogenetics, Hugo W. Moser Research Institute at Kennedy Krieger Institute, Baltimore, Maryland.,Department of Neurology and Pediatrics, The Johns Hopkins Hospital, Baltimore, Maryland
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Barca E, Emmanuele V, DiMauro S, Toscano A, Quinzii CM. Anti-Oxidant Drugs: Novelties and Clinical Implications in Cerebellar Ataxias. Curr Neuropharmacol 2019; 17:21-32. [PMID: 29119930 PMCID: PMC6341493 DOI: 10.2174/1570159x15666171109125643] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2017] [Revised: 01/01/1970] [Accepted: 11/07/2017] [Indexed: 12/06/2022] Open
Abstract
BACKGROUND Hereditary cerebellar ataxias are a group of disorders characterized by heterogeneous clinical manifestations, progressive clinical course, and diverse genetic causes. No disease modifying treatments are yet available for many of these disorders. Oxidative stress has been recurrently identified in different progressive cerebellar diseases, and it represents a widely investigated target for treatment. OBJECTIVE To review the main aspects and new perspectives of antioxidant therapy in cerebellar ataxias ranging from bench to bedside. METHOD This article is a summary of the state-of-the-art on the use of antioxidant molecules in cerebellar ataxia treatments. It also briefly summarizes aspects of oxidative stress production and general characteristics of antioxidant compounds. RESULTS Antioxidants represent a vast category of compounds; old drugs have been extensively studied and modified in order to achieve better biological effects. Despite the vast body of literature present on the use of antioxidants in cerebellar ataxias, for the majority of these disorders conclusive results on the efficacy are still missing. CONCLUSION Antioxidant therapy in cerebellar ataxias is a promising field of investigations. To achieve the success in identifying the correct treatment more work needs to be done. In particular, a combined effort is needed by basic scientists in developing more efficient molecules, and by clinical researchers together with patients communities, to run clinical trials in order to identify conclusive treatments strategies.
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Affiliation(s)
- Emanuele Barca
- Address correspondence to this author at the Department of Neurology, Columbia University Medical Center, 630 W 168 Street, P&S 4-424/A, New York, NY 10032, USA; Tel: +1-212-305-1637; Fax: +1-212-305-3986; E-mail:
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11
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Impaired Mitochondrial Fatty Acid Synthesis Leads to Neurodegeneration in Mice. J Neurosci 2018; 38:9781-9800. [PMID: 30266742 DOI: 10.1523/jneurosci.3514-17.2018] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 08/31/2018] [Accepted: 09/19/2018] [Indexed: 01/07/2023] Open
Abstract
There has been a growing interest toward mitochondrial fatty acid synthesis (mtFAS) since the recent discovery of a neurodegenerative human disorder termed MEPAN (mitochondrial enoyl reductase protein associated neurodegeneration), which is caused by mutations in the mitochondrial enoyl-CoA/ACP (acyl carrier protein) reductase (MECR) carrying out the last step of mtFAS. We show here that MECR protein is highly expressed in mouse Purkinje cells (PCs). To elucidate mtFAS function in neural tissue, here, we generated a mouse line with a PC-specific knock-out (KO) of Mecr, leading to inactivation of mtFAS confined to this cell type. Both sexes were studied. The mitochondria in KO PCs displayed abnormal morphology, loss of protein lipoylation, and reduced respiratory chain enzymatic activities by the time these mice were 6 months of age, followed by nearly complete loss of PCs by 9 months of age. These animals exhibited balancing difficulties ∼7 months of age and ataxic symptoms were evident from 8-9 months of age on. Our data show that impairment of mtFAS results in functional and ultrastructural changes in mitochondria followed by death of PCs, mimicking aspects of the clinical phenotype. This KO mouse represents a new model for impaired mitochondrial lipid metabolism and cerebellar ataxia with a distinct and well trackable cellular phenotype. This mouse model will allow the future investigation of the feasibility of metabolite supplementation approaches toward the prevention of neurodegeneration due to dysfunctional mtFAS.SIGNIFICANCE STATEMENT We have recently reported a novel neurodegenerative disorder in humans termed MEPAN (mitochondrial enoyl reductase protein associated neurodegeneration) (Heimer et al., 2016). The cause of neuron degeneration in MEPAN patients is the dysfunction of the highly conserved mitochondrial fatty acid synthesis (mtFAS) pathway due to mutations in MECR, encoding mitochondrial 2-enoyl-CoA/ACP reductase. The report presented here describes the analysis of the first mouse model suffering from mtFAS-defect-induced neurodegenerative changes due to specific disruption of the Mecr gene in Purkinje cells. Our work sheds a light on the mechanisms of neurodegeneration caused by mtFAS deficiency and provides a test bed for future treatment approaches.
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12
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Movement disorders in mitochondrial disease: a clinicopathological correlation. Curr Opin Neurol 2018; 31:472-483. [DOI: 10.1097/wco.0000000000000583] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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13
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Yamada T, Adachi Y, Yanagawa T, Iijima M, Sesaki H. p62/sequestosome-1 knockout delays neurodegeneration induced by Drp1 loss. Neurochem Int 2018; 117:77-81. [PMID: 28527629 PMCID: PMC5847479 DOI: 10.1016/j.neuint.2017.05.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2017] [Revised: 05/16/2017] [Accepted: 05/16/2017] [Indexed: 12/14/2022]
Abstract
Purkinje neurons, one of the largest neurons in the brain, are critical for controlling body movements, and the dysfunction and degeneration of these cells cause ataxia. Purkinje neurons require a very efficient energy supply from mitochondria because of their large size and extensive dendritic arbors. We have previously shown that mitochondrial division mediated by dynamin-related protein 1 (Drp1) is critical for the development and survival of Purkinje neurons. Drp1 deficiency has been associated with one of the major types of ataxia: autosomal recessive spastic ataxia of Charlevoix Saguenay. Using post-mitotic Purkinje neuron-specific Drp1 knockout (KO) in mice, we investigated the molecular mechanisms that mediate the progressive degeneration of Drp1-KO Purkinje neurons in vivo. In these Purkinje neurons, p62/sequestosome-1, a multi-functional adaptor protein that balances apoptotic cell death and cell survival, was recruited to large mitochondria resulting from unopposed fusion in the absence of mitochondrial division. To test the role of p62 in Drp1-deficient neurodegeneration, we created mice lacking both Drp1 and p62 and found that the additional loss of p62 significantly extended the survival of Purkinje neurons lacking Drp1. These results provide insights into the neurodegenerative mechanisms of mitochondrial ataxia and a critical foundation for therapeutic interventions for this disease.
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Affiliation(s)
- Tatsuya Yamada
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yoshihiro Adachi
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Toru Yanagawa
- Department of Oral and Maxillofacial Surgery, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan
| | - Miho Iijima
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Hiromi Sesaki
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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14
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Abstract
The approach to identifying a genetic cause in patients with cerebellar disorders relies on history, examination, consultation, and testing, combined with specialized expertise because they are rare and genetically diverse. Cerebellar disorders can be caused by a variety of DNA alterations including single-nucleotide changes, small insertions or deletions, larger copy number variants, and nucleotide repeat expansions, exhibiting autosomal-recessive, autosomal-dominant (inherited and de novo), X-linked, and mitochondrial modes of inheritance. Imaging findings and a variety of neurologic and nonneurologic clinical features can help direct genetic testing and choose the most appropriate strategy. Clinical and genetic diagnoses are complementary, each providing distinct information for the care of the patient. In this chapter, we provide an overview of inheritance modes for different cerebellar disorders and the variety of genetic testing and tools that are currently available to reach a genetic diagnosis, including conventional and next-generation sequencing, classic, molecular and virtual cytogenetics, testing for repeat expansions, and other techniques. Practical examples are presented in both the text and accompanying vignettes.
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Affiliation(s)
- Enza Maria Valente
- Neurogenetics Unit, IRCCS Santa Lucia Foundation, Rome, Italy; Department of Molecular Medicine, University of Pavia, Pavia, Italy.
| | - Sara Nuovo
- Neurogenetics Unit, IRCCS Santa Lucia Foundation, Rome, Italy; Department of Medicine and Surgery, University of Salerno, Salerno, Italy
| | - Dan Doherty
- Department of Pediatrics, University of Washington and Seattle Children's Research Institute, Seattle, WA, United States
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Lv ZY, Xu XM, Cao XF, Wang Q, Sun DF, Tian WJ, Yang Y, Wang YZ, Hao YL. Mitochondrial mutations in 12S rRNA and 16S rRNA presenting as chronic progressive external ophthalmoplegia (CPEO) plus: A case report. Medicine (Baltimore) 2017; 96:e8869. [PMID: 29310369 PMCID: PMC5728770 DOI: 10.1097/md.0000000000008869] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
RATIONALE Chronic progressive external ophthalmoplegia (CPEO) is a classical mitochondrial ocular disorder characterized by bilateral progressive ptosis and ophthalmoplegia. Kearns -Sayre syndrome (KSS) is a multisystem disorder with PEO, cardiac conduction block, and pigmentary retinopathy. A few individuals with CPEO have other manifestations of KSS, but do not meet all the clinical diagnosis criteria, and this is called "CPEO plus." PATIENT CONCERNS We report a 48-year-old woman exhibiting limb weakness, ptosis, ophthalmoparesis, and cerebellar dysfunctions. DIAGNOSES The patient was diagnosed as exhibiting CPEO plus syndrome. INTERVENTIONS The patient underwent clinical, genetic, histological, and histochemical analysis. She was treated orally with CoQ10, vitamin Bs, L-carnitine, and vitamin E. OUTCOMES The patient's serum creatine kinase levels, electrocardiography, and nerve conduction study results were normal; an electromyogram revealed myopathic findings. Magnetic resonance imaging showed global brain atrophy, particularly in the brainstem and cerebellum areas. A muscle biopsy showed the presence of abundant ragged red fibers. Sequencing of the mitochondrial DNA from the skeletal muscle biopsy revealed C960del mutation in 12S rRNA and homozygous mutation C2835T in 16S rRNA. She took medicines on schedule, the clinical features were similar as 2 years ago. LESSONS This is the first report of 2 rRNA mutations in a patient with MRI findings showing global brain atrophy, particularly in brainstem and cerebellum areas. Early recognition and appropriate treatment is crucial. This case highlights the cerebellar ataxia can occur in CPEO plus.
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Schreglmann SR, Riederer F, Galovic M, Ganos C, Kägi G, Waldvogel D, Jaunmuktane Z, Schaller A, Hidding U, Krasemann E, Michels L, Baumann CR, Bhatia K, Jung HH. Movement disorders in genetically confirmed mitochondrial disease and the putative role of the cerebellum. Mov Disord 2017; 33:146-155. [PMID: 28901595 DOI: 10.1002/mds.27174] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 07/24/2017] [Accepted: 07/30/2017] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Mitochondrial disease can present as a movement disorder. Data on this entity's epidemiology, genetics, and underlying pathophysiology, however, is scarce. OBJECTIVE The objective of this study was to describe the clinical, genetic, and volumetric imaging data from patients with mitochondrial disease who presented with movement disorders. METHODS In this retrospective analysis of all genetically confirmed mitochondrial disease cases from three centers (n = 50), the prevalence and clinical presentation of video-documented movement disorders was assessed. Voxel-based morphometry from high-resolution MRI was employed to compare cerebral and cerebellar gray matter volume between mitochondrial disease patients with and without movement disorders and healthy controls. RESULTS Of the 50 (30%) patients with genetically confirmed mitochondrial disease, 15 presented with hypokinesia (parkinsonism 3/15), hyperkinesia (dystonia 5/15, myoclonus 3/15, chorea 2/15), and ataxia (3/15). In 3 patients, mitochondrial disease presented as adult-onset isolated dystonia. In comparison to healthy controls and mitochondrial disease patients without movement disorders, patients with hypo- and hyperkinetic movement disorders had significantly more cerebellar atrophy and an atrophy pattern predominantly involving cerebellar lobules VI and VII. CONCLUSION This series provides clinical, genetic, volumetric imaging, and histologic data that indicate major involvement of the cerebellum in mitochondrial disease when it presents with hyper- and hypokinetic movement disorders. As a working hypothesis addressing the particular vulnerability of the cerebellum to energy deficiency, this adds substantially to the pathophysiological understanding of movement disorders in mitochondrial disease. Furthermore, it provides evidence that mitochondrial disease can present as adult-onset isolated dystonia. © 2017 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Sebastian R Schreglmann
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London (UCL) Institute of Neurology, Queen Square, London, UK.,Department of Neurology, University Hospital Zurich, Zurich, Switzerland.,Department of Neurology, Kantonsspital St. Gallen, St. Gallen, Switzerland
| | - Franz Riederer
- Department of Neurology, University Hospital Zurich, Zurich, Switzerland.,Neurological Center Rosenhuegel and Karl Landsteiner Institute for Epilepsy Research and Cognitive Neurology, Vienna, Austria
| | - Marian Galovic
- Department of Neurology, Kantonsspital St. Gallen, St. Gallen, Switzerland.,UK National Institute for Health Research, University College London Hospitals Biomedical Research Centre.,Department of Clinical and Experimental Epilepsy, University College London (UCL) Institute of Neurology, London, UK, Epilepsy Society, Chalfont St. Peter, UK
| | - Christos Ganos
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London (UCL) Institute of Neurology, Queen Square, London, UK.,Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Georg Kägi
- Department of Neurology, Kantonsspital St. Gallen, St. Gallen, Switzerland
| | - Daniel Waldvogel
- Department of Neurology, University Hospital Zurich, Zurich, Switzerland
| | - Zane Jaunmuktane
- Department of Molecular Neuroscience, University College London (UCL) Institute of Neurology and Division of Neuropathology, The National Hospital for Neurology and Neurosurgery, London, UK
| | - Andre Schaller
- Department of Genetics, Inselspital Bern, Bern, Switzerland
| | - Ute Hidding
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ernst Krasemann
- Department of Human Genetics, Medizinisches Versorgungszentrum (MVZ) Labor Fenner GmbH, Hamburg, Germany
| | - Lars Michels
- Clinic of Neuroradiology, University Hospital Zurich, Zurich, Switzerland
| | | | - Kailash Bhatia
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London (UCL) Institute of Neurology, Queen Square, London, UK
| | - Hans H Jung
- Department of Neurology, University Hospital Zurich, Zurich, Switzerland
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17
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Stucki DM, Ruegsegger C, Steiner S, Radecke J, Murphy MP, Zuber B, Saxena S. Mitochondrial impairments contribute to Spinocerebellar ataxia type 1 progression and can be ameliorated by the mitochondria-targeted antioxidant MitoQ. Free Radic Biol Med 2016; 97:427-440. [PMID: 27394174 DOI: 10.1016/j.freeradbiomed.2016.07.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 06/23/2016] [Accepted: 07/05/2016] [Indexed: 12/29/2022]
Abstract
Spinocerebellar ataxia type 1 (SCA1), due to an unstable polyglutamine expansion within the ubiquitously expressed Ataxin-1 protein, leads to the premature degeneration of Purkinje cells (PCs), decreasing motor coordination and causing death within 10-15 years of diagnosis. Currently, there are no therapies available to slow down disease progression. As secondary cellular impairments contributing to SCA1 progression are poorly understood, here, we focused on identifying those processes by performing a PC specific proteome profiling of Sca1(154Q/2Q) mice at a symptomatic stage. Mass spectrometry analysis revealed prominent alterations in mitochondrial proteins. Immunohistochemical and serial block-face scanning electron microscopy analyses confirmed that PCs underwent age-dependent alterations in mitochondrial morphology. Moreover, colorimetric assays demonstrated impairment of the electron transport chain complexes (ETC) and decrease in ATPase activity. Subsequently, we examined whether the mitochondria-targeted antioxidant MitoQ could restore mitochondrial dysfunction and prevent SCA1-associated pathology in Sca1(154Q/2Q) mice. MitoQ treatment both presymptomatically and when symptoms were evident ameliorated mitochondrial morphology and restored the activities of the ETC complexes. Notably, MitoQ slowed down the appearance of SCA1-linked neuropathology such as lack of motor coordination as well as prevented oxidative stress-induced DNA damage and PC loss. Our work identifies a central role for mitochondria in PC degeneration in SCA1 and provides evidence for the supportive use of mitochondria-targeted therapeutics in slowing down disease progression.
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Affiliation(s)
- David M Stucki
- Institute of Cell Biology, University of Bern, Bern, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Céline Ruegsegger
- Institute of Cell Biology, University of Bern, Bern, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Silvio Steiner
- Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - Julika Radecke
- Institute of Anatomy, University of Bern, Bern, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Michael P Murphy
- Medical Research Council, Mitochondrial Biology Unit, Cambridge, United Kingdom
| | - Benoît Zuber
- Institute of Anatomy, University of Bern, Bern, Switzerland
| | - Smita Saxena
- Institute of Cell Biology, University of Bern, Bern, Switzerland.
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18
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19
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Guo C, Sun L, Chen X, Zhang D. Oxidative stress, mitochondrial damage and neurodegenerative diseases. Neural Regen Res 2014; 8:2003-14. [PMID: 25206509 PMCID: PMC4145906 DOI: 10.3969/j.issn.1673-5374.2013.21.009] [Citation(s) in RCA: 397] [Impact Index Per Article: 39.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2013] [Accepted: 05/15/2013] [Indexed: 12/11/2022] Open
Abstract
Oxidative stress and mitochondrial damage have been implicated in the pathogenesis of several neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis. Oxidative stress is characterized by the overproduction of reactive oxygen species, which can induce mitochondrial DNA mutations, damage the mitochondrial respiratory chain, alter membrane permeability, and influence Ca2+ homeostasis and mitochondrial defense systems. All these changes are implicated in the development of these neurodegenerative diseases, mediating or amplifying neuronal dysfunction and triggering neurodegeneration. This paper summarizes the contribution of oxidative stress and mitochondrial damage to the onset of neurodegenerative eases and discusses strategies to modify mitochondrial dysfunction that may be attractive therapeutic interventions for the treatment of various neurodegenerative diseases.
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Affiliation(s)
- Chunyan Guo
- Department of Pharmacy, Hebei North University, Zhangjiakou 075000, Hebei Province, China
| | - Li Sun
- Life Science Research Center, Hebei North University, Zhangjiakou 075000, Hebei Province, China
| | - Xueping Chen
- Department of Human Anatomy and Cell Science, University of Manitoba, Manitoba R3E 0J9, Canada
| | - Danshen Zhang
- Hebei University of Science and Technology, Shijiazhuang 050018, Hebei Province, China
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Abstract
PURPOSE OF REVIEW Recent advances in next generation sequencing techniques (NGS) are increasing the number of novel genes associated with cerebellar and vestibular disorders. We have summarized clinical and molecular genetics findings in neuro-otolology during the last 2 years. RECENT FINDINGS Whole-exome and targeted sequencing have defined the genetic basis of dizziness including new genes causing ataxia: GBA2, TGM6, ANO10 and SYT14. Novel mutations in KCNA1 and CACNA1A genes are associated with episodic ataxia type 1 and type 2, respectively. Moreover, new variants in genes such as COCH, MYO7A and POU4F3 are associated with nonsyndromic deafness and vestibular dysfunction. Several susceptibility loci have been linked to familial vestibular migraine, suggesting genetic heterogeneity, but no specific gene has been identified. Finally, loci for complex and heterogeneous diseases such as bilateral vestibular hypofunction or familial Ménière disease have not been identified yet, despite their strong familial aggregation. SUMMARY Cerebellar and vestibular disorders leading to dizziness or episodic vertigo may show overlapping clinical features. A deep phenotyping including a complete familial history is a key step in performing a reliable molecular genetic diagnosis using NGS. Personalized molecular medicine will be essential to understand disease mechanisms as well as to improve their diagnosis and treatment.
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21
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Lieber DS, Hershman SG, Slate NG, Calvo SE, Sims KB, Schmahmann JD, Mootha VK. Next generation sequencing with copy number variant detection expands the phenotypic spectrum of HSD17B4-deficiency. BMC MEDICAL GENETICS 2014; 15:30. [PMID: 24602372 PMCID: PMC4015298 DOI: 10.1186/1471-2350-15-30] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 02/25/2014] [Indexed: 11/10/2022]
Abstract
Background D-bifunctional protein deficiency, caused by recessive mutations in HSD17B4, is a severe, infantile-onset disorder of peroxisomal fatty acid oxidation. Few affected patients survive past two years of age. Compound heterozygous mutations in HSD17B4 have also been reported in two sisters diagnosed with Perrault syndrome (MIM # 233400), who presented in adolescence with ovarian dysgenesis, hearing loss, and ataxia. Case presentation An adult male presented with cerebellar ataxia, peripheral neuropathy, hearing loss, and azoospermia. The clinical presentation, in combination with biochemical findings in serum, urine, and muscle biopsy, suggested a mitochondrial disorder. Commercial genetic testing of 18 ataxia and mitochondrial disease genes was negative. Targeted exome sequencing followed by analysis of single nucleotide variants and small insertions/deletions failed to reveal a genetic basis of disease. Application of a computational algorithm to infer copy number variants (CNVs) from exome data revealed a heterozygous 12 kb deletion of exons 10–13 of HSD17B4 that was compounded with a rare missense variant (p.A196V) at a highly conserved residue. Retrospective review of patient records revealed mildly elevated ratios of pristanic:phytanic acid and arachidonic:docosahexaenoic acid, consistent with dysfunctional peroxisomal fatty acid oxidation. Conclusion Our case expands the phenotypic spectrum of HSD17B4-deficiency, representing the first male case reported with infertility. Furthermore, it points to crosstalk between mitochondria and peroxisomes in HSD17B4-deficiency and Perrault syndrome.
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Affiliation(s)
| | | | | | | | | | - Jeremy D Schmahmann
- Ataxia Unit, Cognitive Behavioral Neurology Unit, Laboratory for Neuroanatomy and Cerebellar Neurobiology, Department of Neurology, Massachusetts General Hospital & Harvard Medical School, Boston, MA 02114 USA,
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Morino H, Miyamoto R, Ohnishi S, Maruyama H, Kawakami H. Exome sequencing reveals a novel TTC19 mutation in an autosomal recessive spinocerebellar ataxia patient. BMC Neurol 2014; 14:5. [PMID: 24397319 PMCID: PMC3890717 DOI: 10.1186/1471-2377-14-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 01/02/2014] [Indexed: 12/30/2022] Open
Abstract
Background Spinocerebellar ataxias (SCAs) are heterogeneous diseases characterized by progressive cerebellar ataxia associated with dysarthria, oculomotor abnormalities, and mental impairment. To identify the causative gene, we performed exome sequencing on a Japanese patient clinically diagnosed with recessive SCA. Method The patient is a 37-year-old Japanese woman with consanguineous parents. The head magnetic resonance imaging (MRI) showed cerebellar atrophy and T1 low/T2 high intensity at the bilateral inferior olives. Single-nucleotide polymorphism (SNP) genotyping and next-generation sequencing were performed, and the variants obtained were filtered and prioritized. Results After these manipulations, we identified a homozygous nonsense mutation of the TTC19 gene (p.Q277*). TTC19 has been reported to be a causative gene of a neurodegenerative disease in Italian and Portuguese families and to be involved in the pathogenesis of mitochondrial respiratory chain complex III (cIII) deficiency. This report is the first description of a TTC19 mutation in an Asian population. Clinical symptoms and neuroimaging are consistent with previous reports. The head MRI already showed abnormal features four years before her blood lactate and pyruvate levels were elevated. Conclusions We should consider the genetic analysis of TTC19 when we observe such characteristic MRI abnormalities. Genes associated with mitochondrial function cause many types of SCAs; the mutation we identified should help to elucidate the pathology of these disorders.
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Affiliation(s)
- Hiroyuki Morino
- Department of Epidemiology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8553, Japan.
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DaRe JT, Vasta V, Penn J, Tran NTB, Hahn SH. Targeted exome sequencing for mitochondrial disorders reveals high genetic heterogeneity. BMC MEDICAL GENETICS 2013; 14:118. [PMID: 24215330 PMCID: PMC3827825 DOI: 10.1186/1471-2350-14-118] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 11/06/2013] [Indexed: 12/11/2022]
Abstract
Background Mitochondrial disorders are difficult to diagnose due to extreme genetic and phenotypic heterogeneities. Methods We explored the utility of targeted next-generation sequencing for the diagnosis of mitochondrial disorders in 148 patients submitted for clinical testing. A panel of 447 nuclear genes encoding mitochondrial respiratory chain complexes, and other genes inducing secondary mitochondrial dysfunction or that cause diseases which mimic mitochondrial disorders were tested. Results We identified variants considered to be possibly disease-causing based on family segregation data and/or variants already known to cause disease in twelve genes in thirteen patients. Rare or novel variants of unknown significance were identified in 45 additional genes for various metabolic, genetic or neurogenetic disorders. Conclusions Primary mitochondrial defects were confirmed only in four patients indicating that majority of patients with suspected mitochondrial disorders are presumably not the result of direct impairment of energy production. Our results support that clinical and routine laboratory ascertainment for mitochondrial disorders are challenging due to significant overlapping non-specific clinical symptoms and lack of specific biomarkers. While next-generation sequencing shows promise for diagnosing suspected mitochondrial disorders, the challenges remain as the underlying genetic heterogeneity may be greater than suspected and it is further confounded by the similarity of symptoms with other conditions as we report here.
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Affiliation(s)
| | | | | | | | - Si Houn Hahn
- Seattle Children's Hospital Research Institute, 1900 9th Ave, Seattle, WA 98101, USA.
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Su SL, Wang WF, Wu SL, Wu HM, Chang JC, Huang CS, Cheng WL, Soong BW, Lee YC, Li JY, Kuo SJ, Chen M, Huang CN, Liu CS. FGF21 in ataxia patients with spinocerebellar atrophy and mitochondrial disease. Clin Chim Acta 2012; 414:225-7. [PMID: 23031666 DOI: 10.1016/j.cca.2012.09.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Revised: 09/19/2012] [Accepted: 09/19/2012] [Indexed: 12/13/2022]
Abstract
BACKGROUND Serum fibroblast growth factor 21 (FGF21) was proven to be a useful biomarker for the presence of mitochondrial neuromuscular disease. METHODS In the present study, we used the difference in the serum FGF21 level to differentiate between ataxia patients with hereditary spinocerebellar atrophy (SCA-ataxia) and those with mitochondrial syndrome (Mito-ataxia). Patients with SCA-ataxia (SCA2, SCA3) and Mito-ataxia (MELAS, MERRF, LHON, maternal inherited hearing impairment mtDNA A1555G mutation) were recruited in this study. All SCA-ataxia patients revealed a consistent pattern of cerebellar atrophy. On the contrary, some of the Mito-ataxia patients exhibited a vascular lesion with cerebellar infarction. RESULTS Extremely higher levels of serum FGF21 were found in the Mito-ataxia patients with MERRF and MELAS diseases, but not in patients with SCA-ataxia or LHON/mtDNA A1555G mutation. The positive trend between the mtDNA heteroplasmy and serum FGF21 was indicated in either MERRF (P=0.003, r=0.923) or MELAS (P=0.070, r=0.566) patients. CONCLUSION Serum FGF21 can be applied as the first molecular screening among patients suspected to be victims of hereditary ataxia with neuromuscular degeneration prior to mass genetic screening.
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Affiliation(s)
- Shih-Li Su
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Changhua Christian Hospital, Changhua 500, Taiwan
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Federico A, Cardaioli E, Da Pozzo P, Formichi P, Gallus GN, Radi E. Mitochondria, oxidative stress and neurodegeneration. J Neurol Sci 2012; 322:254-62. [PMID: 22669122 DOI: 10.1016/j.jns.2012.05.030] [Citation(s) in RCA: 517] [Impact Index Per Article: 43.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 05/10/2012] [Accepted: 05/12/2012] [Indexed: 02/06/2023]
Abstract
Mitochondria are involved in ATP supply to cells through oxidative phosphorylation (OXPHOS), synthesis of key molecules and response to oxidative stress, as well as in apoptosis. They contain many redox enzymes and naturally occurring inefficiencies of oxidative phosphorylation generate reactive oxygen species (ROS). CNS functions depend heavily on efficient mitochondrial function, since brain tissue has a high energy demand. Mutations in mitochondrial DNA (mtDNA), generation and presence of ROS and environmental factors may contribute to energy failure and lead to neurodegenerative diseases. Many rare metabolic disorders have been associated with mitochondrial dysfunction. More than 300 pathogenic mtDNA mutations involve proteins that regulate OXPHOS and mitochondrial structural integrity, and have also been described in neurodegenerative diseases with autosomal inheritance. Mitochondria may have an important role in ageing-related neurodegenerative disorders like Parkinson's disease (PD), Alzheimer's disease (AD), Huntington's disease (HD) and amyotrophic lateral sclerosis (ALS). In primary mitochondrial and neurodegenerative disorders, there is strong evidence that mitochondrial dysfunction occurs early and has a primary role in pathogenesis. In the present review, we discuss several mitochondrial diseases as models of neurodegeneration.
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Affiliation(s)
- Antonio Federico
- Department of Neurological, Neurosurgical and Behavioural Sciences, Medical School, University of Siena, Italy.
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