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Pizzamiglio C, Hanna MG, Pitceathly RDS. Primary mitochondrial diseases. HANDBOOK OF CLINICAL NEUROLOGY 2024; 204:53-76. [PMID: 39322395 DOI: 10.1016/b978-0-323-99209-1.00004-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/27/2024]
Abstract
Primary mitochondrial diseases (PMDs) are a heterogeneous group of hereditary disorders characterized by an impairment of the mitochondrial respiratory chain. They are the most common group of genetic metabolic disorders, with a prevalence of 1 in 4,300 people. The presence of leukoencephalopathy is recognized as an important feature in many PMDs and can be a manifestation of mutations in both mitochondrial DNA (classic syndromes such as mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes; myoclonic epilepsy with ragged-red fibers [RRFs]; Leigh syndrome; and Kearns-Sayre syndrome) and nuclear DNA (mutations in maintenance genes such as POLG, MPV17, and TYMP; Leigh syndrome; and mitochondrial aminoacyl-tRNA synthetase disorders). In this chapter, PMDs associated with white matter involvement are outlined, including details of clinical presentations, brain MRI features, and elements of differential diagnoses. The current approach to the diagnosis of PMDs and management strategies are also discussed. A PMD diagnosis in a subject with leukoencephalopathy should be considered in the presence of specific brain MRI features (for example, cyst-like lesions, bilateral basal ganglia lesions, and involvement of both cerebral hemispheres and cerebellum), in addition to a complex neurologic or multisystem disorder. Establishing a genetic diagnosis is crucial to ensure appropriate genetic counseling, multidisciplinary team input, and eligibility for clinical trials.
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Affiliation(s)
- Chiara Pizzamiglio
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom; NHS Highly Specialised Service for Rare Mitochondrial Disorders, Queen Square Centre for Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - Michael G Hanna
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom; NHS Highly Specialised Service for Rare Mitochondrial Disorders, Queen Square Centre for Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - Robert D S Pitceathly
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom; NHS Highly Specialised Service for Rare Mitochondrial Disorders, Queen Square Centre for Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, London, United Kingdom.
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2
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Conti F, Di Martino S, Drago F, Bucolo C, Micale V, Montano V, Siciliano G, Mancuso M, Lopriore P. Red Flags in Primary Mitochondrial Diseases: What Should We Recognize? Int J Mol Sci 2023; 24:16746. [PMID: 38069070 PMCID: PMC10706469 DOI: 10.3390/ijms242316746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 11/22/2023] [Accepted: 11/23/2023] [Indexed: 12/18/2023] Open
Abstract
Primary mitochondrial diseases (PMDs) are complex group of metabolic disorders caused by genetically determined impairment of the mitochondrial oxidative phosphorylation (OXPHOS). The unique features of mitochondrial genetics and the pivotal role of mitochondria in cell biology explain the phenotypical heterogeneity of primary mitochondrial diseases and the resulting diagnostic challenges that follow. Some peculiar features ("red flags") may indicate a primary mitochondrial disease, helping the physician to orient in this diagnostic maze. In this narrative review, we aimed to outline the features of the most common mitochondrial red flags offering a general overview on the topic that could help physicians to untangle mitochondrial medicine complexity.
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Affiliation(s)
- Federica Conti
- Department of Biomedical and Biotechnological Science, School of Medicine, University of Catania, 95123 Catania, Italy; (F.C.); (S.D.M.); (C.B.); (V.M.)
| | - Serena Di Martino
- Department of Biomedical and Biotechnological Science, School of Medicine, University of Catania, 95123 Catania, Italy; (F.C.); (S.D.M.); (C.B.); (V.M.)
| | - Filippo Drago
- Department of Biomedical and Biotechnological Science, School of Medicine, University of Catania, 95123 Catania, Italy; (F.C.); (S.D.M.); (C.B.); (V.M.)
| | - Claudio Bucolo
- Department of Biomedical and Biotechnological Science, School of Medicine, University of Catania, 95123 Catania, Italy; (F.C.); (S.D.M.); (C.B.); (V.M.)
- Center for Research in Ocular Pharmacology-CERFO, University of Catania, 95213 Catania, Italy
| | - Vincenzo Micale
- Department of Biomedical and Biotechnological Science, School of Medicine, University of Catania, 95123 Catania, Italy; (F.C.); (S.D.M.); (C.B.); (V.M.)
| | - Vincenzo Montano
- Neurological Institute, Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy (P.L.)
| | - Gabriele Siciliano
- Neurological Institute, Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy (P.L.)
| | - Michelangelo Mancuso
- Neurological Institute, Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy (P.L.)
| | - Piervito Lopriore
- Neurological Institute, Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy (P.L.)
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3
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Viti F, De Giorgio R, Ceccherini I, Ahluwalia A, Alves MM, Baldo C, Baldussi G, Bonora E, Borrelli O, Dall'Oglio L, De Coppi P, De Filippo C, de Santa Barbara P, Diamanti A, Di Lorenzo C, Di Maulo R, Galeone A, Gandullia P, Hashmi SK, Lacaille F, Lancon L, Leone S, Mahé MM, Molnar MJ, Palmitelli A, Perin S, Prato AP, Thapar N, Vassalli M, Heuckeroth RO. Multi-disciplinary Insights from the First European Forum on Visceral Myopathy 2022 Meeting. Dig Dis Sci 2023; 68:3857-3871. [PMID: 37650948 PMCID: PMC10517037 DOI: 10.1007/s10620-023-08066-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Accepted: 07/28/2023] [Indexed: 09/01/2023]
Abstract
Visceral myopathy is a rare, life-threatening disease linked to identified genetic mutations in 60% of cases. Mostly due to the dearth of knowledge regarding its pathogenesis, effective treatments are lacking. The disease is most commonly diagnosed in children with recurrent or persistent disabling episodes of functional intestinal obstruction, which can be life threatening, often requiring long-term parenteral or specialized enteral nutritional support. Although these interventions are undisputedly life-saving as they allow affected individuals to avoid malnutrition and related complications, they also seriously compromise their quality of life and can carry the risk of sepsis and thrombosis. Animal models for visceral myopathy, which could be crucial for advancing the scientific knowledge of this condition, are scarce. Clearly, a collaborative network is needed to develop research plans to clarify genotype-phenotype correlations and unravel molecular mechanisms to provide targeted therapeutic strategies. This paper represents a summary report of the first 'European Forum on Visceral Myopathy'. This forum was attended by an international interdisciplinary working group that met to better understand visceral myopathy and foster interaction among scientists actively involved in the field and clinicians who specialize in care of people with visceral myopathy.
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Affiliation(s)
- Federica Viti
- Institute of Biophysics, National Research Council, Via De Marini, 6, 16149, Genoa, Italy.
| | - Roberto De Giorgio
- Department of Translational Medicine, University of Ferrara, Ferrara, Italy
| | | | - Arti Ahluwalia
- Centro di Ricerca 'E. Piaggio' and Department of Information Engineering, University of Pisa, Pisa, Italy
| | - Maria M Alves
- Department of Clinical Genetics, Erasmus University Medical Center - Sophia Children's Hospital, Rotterdam, The Netherlands
| | - Chiara Baldo
- IRCCS Istituto Giannina Gaslini Pediatric Hospital, Genoa, Italy
| | - Giannina Baldussi
- 'Uniti per la P.I.P.O.' Patient Advocacy Organization, Brescia, Italy
| | - Elena Bonora
- Unit of Medical Genetics, Department of Medical and Surgical Sciences, University of Bologna, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Osvaldo Borrelli
- Department of Gastroenterology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Luigi Dall'Oglio
- Digestive Surgery and Endoscopy, Bambino Gesù Children's Research Hospital IRCCS, Rome, Italy
| | - Paolo De Coppi
- Pediatric Surgery, Great Ormond Street Hospital for Children, London, UK
| | - Carlotta De Filippo
- Institute of Agricultural Biology and Biotechnology of the National Research Council, Pisa, Italy
| | - Pascal de Santa Barbara
- Physiology and Experimental Medicine of the Heart and Muscles (PhyMedExp), University of Montpellier, INSERM, CNRS, Montpellier, France
| | | | - Carlo Di Lorenzo
- Division of Pediatric Gastroenterology, Hepatology and Nutrition, Nationwide Children's Hospital, Columbus, OH, USA
| | | | | | - Paolo Gandullia
- IRCCS Istituto Giannina Gaslini Pediatric Hospital, Genoa, Italy
| | - Sohaib K Hashmi
- Department of Pediatrics, The Children's Hospital of Philadelphia Research Institute and the Perelman School of Medicine at the University of Pennsylvania, Abramson Research Center, Philadelphia, PA, USA
| | - Florence Lacaille
- Pediatric Gastroenterology-Hepatology-Nutrition, Necker-Enfants Malades Hospital, Paris, France
| | - Laurence Lancon
- 'Association des POIC' Patient Advocacy Organization, Marseille, France
| | - Salvatore Leone
- AMICI ETS, Associazione Nazionale per le Malattie Infiammatorie Croniche dell'Intestino, Milan, Italy
| | - Maxime M Mahé
- Nantes Université, INSERM, TENS, The Enteric Nervous System in Gut and Brain Diseases, IMAD, Nantes, France
| | | | | | - Silvia Perin
- Unit of Pediatric Surgery, Department of Women and Child Health, University of Padua, Padua, Italy
| | - Alessio Pini Prato
- Unit of Pediatric Surgery, 'St. Antonio e Biagio e Cesare Arrigo' Hospital, Alessandria, Italy
| | - Nikhil Thapar
- Stem Cell and Regenerative Medicine, GOS Institute of Child Health, University College London, London, UK
- Gastroenterology, Hepatology and Liver Transplant, Queensland Children's Hospital, Brisbane, Australia
- School of Medicine, University of Queensland, Brisbane, Australia
- Woolworths Centre for Child Nutrition Research, Queensland University of Technology, Brisbane, Australia
| | - Massimo Vassalli
- James Watt School of Engineering, University of Glasgow, Glasgow, UK
| | - Robert O Heuckeroth
- Department of Pediatrics, The Children's Hospital of Philadelphia Research Institute and the Perelman School of Medicine at the University of Pennsylvania, Abramson Research Center, Philadelphia, PA, USA
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Magistrati M, Gilea AI, Gerra MC, Baruffini E, Dallabona C. Drug Drop Test: How to Quickly Identify Potential Therapeutic Compounds for Mitochondrial Diseases Using Yeast Saccharomyces cerevisiae. Int J Mol Sci 2023; 24:10696. [PMID: 37445873 DOI: 10.3390/ijms241310696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 06/22/2023] [Accepted: 06/25/2023] [Indexed: 07/15/2023] Open
Abstract
Mitochondrial diseases (MDs) refer to a group of clinically and genetically heterogeneous pathologies characterized by defective mitochondrial function and energy production. Unfortunately, there is no effective treatment for most MDs, and current therapeutic management is limited to relieving symptoms. The yeast Saccharomyces cerevisiae has been efficiently used as a model organism to study mitochondria-related disorders thanks to its easy manipulation and well-known mitochondrial biogenesis and metabolism. It has been successfully exploited both to validate alleged pathogenic variants identified in patients and to discover potential beneficial molecules for their treatment. The so-called "drug drop test", a phenotype-based high-throughput screening, especially if coupled with a drug repurposing approach, allows the identification of molecules with high translational potential in a cost-effective and time-saving manner. In addition to drug identification, S. cerevisiae can be used to point out the drug's target or pathway. To date, drug drop tests have been successfully carried out for a variety of disease models, leading to very promising results. The most relevant aspect is that studies on more complex model organisms confirmed the effectiveness of the drugs, strengthening the results obtained in yeast and demonstrating the usefulness of this screening as a novel approach to revealing new therapeutic molecules for MDs.
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Affiliation(s)
- Martina Magistrati
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Alexandru Ionut Gilea
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Maria Carla Gerra
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Enrico Baruffini
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Cristina Dallabona
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
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Finsterer J. Diagnosing mitochondrial, neurogastrointestinal leukoencephalopathy requires mutations in TYMP1, POLG1, LIG1, or RRM2B. J Med Case Rep 2023; 17:162. [PMID: 37055871 PMCID: PMC10103436 DOI: 10.1186/s13256-023-03916-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 01/20/2023] [Indexed: 04/15/2023] Open
Affiliation(s)
- Josef Finsterer
- Neurology and Neurophysiology Center, Postfach 20, 1180, Vienna, Austria.
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Altuntaş C, Uzunhan TA, Ertürk B, Petmezci MT, Çakar NE, Noyan B, Dokucu Aİ, Önal H. A very early onset MNGIE-like syndrome with POLG1 mutation and accompanying leukoencephalopathy. Clin Neurol Neurosurg 2023; 229:107712. [PMID: 37084649 DOI: 10.1016/j.clineuro.2023.107712] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 03/29/2023] [Accepted: 04/03/2023] [Indexed: 04/23/2023]
Abstract
Mitochondrial neurogastrointestinal encephalopathy (MNGIE) is a well-known mitochondrial depletion syndrome. Since Van Goethem et al. described MNGIE syndrome with pathogenic POLG1 mutations in 2003, POLG1 gene became a target for MNGIE patients. Cases with POLG1 mutations strikingly differ from classic MNGIE patients due to a lack of leukoencephalopathy. Here we present a female patient with very early onset disease and leukoencephalopathy compatible with classic MNGIE disease who turned out to have homozygous POLG1 mutation compatible with MNGIE-like syndrome, mitochondrial depletion syndrome type 4b.
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Affiliation(s)
- Cansu Altuntaş
- Istinye University Medical Faculty, Pediatric Gastroenterology Department, Istanbul, Turkey.
| | - Tugce Aksu Uzunhan
- Prof Dr Cemil Taşçıoğlu City Hospital, Pediatric Neurology Department, Istanbul, Turkey
| | - Biray Ertürk
- Prof Dr Cemil Taşçıoğlu City Hospital, Medical Genetics Department, Istanbul, Turkey
| | - Mey Talip Petmezci
- Prof Dr Cemil Taşçıoğlu City Hospital, Pediatric Intensive Care Department, Istanbul, Turkey
| | - Nafiye Emel Çakar
- Prof Dr Cemil Taşçıoğlu City Hospital, Pediatric Metabolic Diseases Department, Istanbul, Turkey
| | - Bilge Noyan
- University of Health Sciences Başakşehir Çam Sakura City Hospital, Pediatric Metabolic Diseases Department, Istanbul, Turkey
| | - Ali İhsan Dokucu
- Prof Dr Cemil Taşçıoğlu City Hospital, Pediatric Surgery Department, Istanbul, Turkey
| | - Hasan Önal
- University of Health Sciences Başakşehir Çam Sakura City Hospital, Pediatric Metabolic Diseases Department, Istanbul, Turkey
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Ammar M, Safi W, Tlili A, Alila-Fersi O, Frikha F, Chouchen J, Mnif F, Kharrat M, Maalej M, Felhi R, Abid M, Mnif-Feki M, Kacem FH, Fakhfakh F, Mkaouar-Rebai E. A novel TYMP mutation in a family with MNGIE syndrome: Molecular docking, dynamic simulation and computational investigations. Int J Dev Neurosci 2022; 82:626-638. [PMID: 35841120 DOI: 10.1002/jdn.10215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 06/27/2022] [Accepted: 07/02/2022] [Indexed: 11/11/2022] Open
Abstract
Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE; OMIM 603041) is a rare inherited metabolic disorder mostly caused by mutations in TYMP gene encoding thymidine phosphorylase (TP) protein that affects the mitochondrial nucleotide metabolism. TP, functionally active as a homodimer, is involved in the salvage pathway of pyrimidine nucleosides. MNGIE-like syndrome having an overlapping phenotype of MNGIE was also described and has been associated with mutations in POLG and RRM2B genes. In the present study, we report the molecular investigation of a consanguineous family including two patients with clinical features suggestive of MNGIE syndrome. Bioinformatics analyses were carried out in addition to mtDNA deletion screening and copy number quantification in the blood of the two patients. Whole exome sequencing and Sanger sequencing analyses revealed the segregation in the affected family a novel mutation c.1205T>A (p.L402Q) within the exon 9 of the TYMP gene. In addition, mtDNA analysis revealed the absence of mtDNA deletions and a decrease of the copy number in the blood of the two patients of the studied family. The p.Leu402Gln mutation was located in a conserved amino acid within the α/β domain of the TP protein and several software supported its pathogenicity. In addition, and based on docking and molecular dynamic simulation analyses, results revealed that L402Q caused a conformational change in TP mutated structure and could therefore alter its flexibility and stability. These changes prevent also the formation of stable homodimer leading to non-functional protein with partial or complete loss of its catalytic activity.
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Affiliation(s)
- Marwa Ammar
- Laboratory of Molecular and Functional Genetics, Faculty of Sciences. University of Sfax, Tunisia
| | - Wajdi Safi
- Department of Endocrinology Diabetology, CHU Hedi Chaker, Sfax, Tunisia
| | - Abdelaziz Tlili
- Department of Applied Biology, College of Sciences, University of Sharjah, Sharjah, United Arab Emirates
| | - Olfa Alila-Fersi
- Laboratory of Molecular and Functional Genetics, Faculty of Sciences. University of Sfax, Tunisia
| | - Fakher Frikha
- Laboratory of Molecular and Cellular Screening Processes, Center of Biotechnology of Sfax, University of Sfax, Tunisia
| | - Jihen Chouchen
- Department of Applied Biology, College of Sciences, University of Sharjah, Sharjah, United Arab Emirates
| | - Fatma Mnif
- Department of Endocrinology Diabetology, CHU Hedi Chaker, Sfax, Tunisia
| | - Marwa Kharrat
- Laboratory of Molecular and Functional Genetics, Faculty of Sciences. University of Sfax, Tunisia
| | - Marwa Maalej
- Laboratory of Molecular and Functional Genetics, Faculty of Sciences. University of Sfax, Tunisia
| | - Rahma Felhi
- Laboratory of Molecular and Functional Genetics, Faculty of Sciences. University of Sfax, Tunisia
| | - Mohamed Abid
- Department of Endocrinology Diabetology, CHU Hedi Chaker, Sfax, Tunisia
| | - Mouna Mnif-Feki
- Department of Endocrinology Diabetology, CHU Hedi Chaker, Sfax, Tunisia
| | - Faten Hadj Kacem
- Department of Endocrinology Diabetology, CHU Hedi Chaker, Sfax, Tunisia
| | - Faiza Fakhfakh
- Laboratory of Molecular and Functional Genetics, Faculty of Sciences. University of Sfax, Tunisia
| | - Emna Mkaouar-Rebai
- Laboratory of Molecular and Functional Genetics, Faculty of Sciences. University of Sfax, Tunisia
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Saccharomyces cerevisiae as a Tool for Studying Mutations in Nuclear Genes Involved in Diseases Caused by Mitochondrial DNA Instability. Genes (Basel) 2021; 12:genes12121866. [PMID: 34946817 PMCID: PMC8701800 DOI: 10.3390/genes12121866] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/20/2021] [Accepted: 11/23/2021] [Indexed: 01/03/2023] Open
Abstract
Mitochondrial DNA (mtDNA) maintenance is critical for oxidative phosphorylation (OXPHOS) since some subunits of the respiratory chain complexes are mitochondrially encoded. Pathological mutations in nuclear genes involved in the mtDNA metabolism may result in a quantitative decrease in mtDNA levels, referred to as mtDNA depletion, or in qualitative defects in mtDNA, especially in multiple deletions. Since, in the last decade, most of the novel mutations have been identified through whole-exome sequencing, it is crucial to confirm the pathogenicity by functional analysis in the appropriate model systems. Among these, the yeast Saccharomyces cerevisiae has proved to be a good model for studying mutations associated with mtDNA instability. This review focuses on the use of yeast for evaluating the pathogenicity of mutations in six genes, MPV17/SYM1, MRM2/MRM2, OPA1/MGM1, POLG/MIP1, RRM2B/RNR2, and SLC25A4/AAC2, all associated with mtDNA depletion or multiple deletions. We highlight the techniques used to construct a specific model and to measure the mtDNA instability as well as the main results obtained. We then report the contribution that yeast has given in understanding the pathogenic mechanisms of the mutant variants, in finding the genetic suppressors of the mitochondrial defects and in the discovery of molecules able to improve the mtDNA stability.
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Bender F, Timmann D, van de Warrenburg BP, Adarmes-Gómez AD, Bender B, Thieme A, Synofzik M, Schöls L. Natural History of Polymerase Gamma-Related Ataxia. Mov Disord 2021; 36:2642-2652. [PMID: 34288125 DOI: 10.1002/mds.28713] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 05/31/2021] [Accepted: 06/16/2021] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Mutations in the mitochondrial DNA polymerase gamma are causing a wide phenotypic spectrum including ataxia as one of the most common presentations. OBJECTIVE The objective of this study was to determine the course of disease of polymerase gamma-related ataxia. METHODS In a prospective natural history study, we assessed 24 adult ataxia patients with biallelic polymerase gamma mutations for (1) severity of cerebellar dysfunction using the Scale for the Assessment and Rating of Ataxia score, (2) presence of nonataxia signs using the Inventory of Non-Ataxia Symptoms, (3) gray- and white-matter changes in brain MRI, and (4) findings in nerve conduction studies. RESULTS Assessment included follow-up visits up to 11.6 years. The Scale for the Assessment and Rating of Ataxia showed a mean annual increase of 1.02 ± 0.78 points/year. Disease progression was faster in patients with age at onset ≤ 30 years (1.5 Scale for the Assessment and Rating of Ataxia points/year) than with later onset (0.5 points/year); P = 0.008. The Inventory of Non-Ataxia Symptoms count increased by 0.30 ± 0.4 points/year. External ophthalmoplegia, brain stem oculomotor signs, areflexia, and sensory deficits were the most common nonataxic features. On MRI cerebellar atrophy was mild. T2 signal alterations affected mostly cerebellar white matter, middle cerebellar peduncles, thalamus, brain stem, and occipital and frontal white matter. Within 4 years, progression was primarily observed in the context of repeated epileptic seizures. Nerve conduction studies revealed axonal sensory peripheral neuropathy with mild motor nerve involvement. Exploratory sample size calculation implied 38 patients per arm as sufficient to detect a reduction of progression by 50% in hypothetical interventions within a 1-year trial. CONCLUSION The results recommend the Scale for the Assessment and Rating of Ataxia as a primary outcome measure for future interventional trials in polymerase gamma-related ataxia. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Friedemann Bender
- Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research & Center of Neurology, University of Tuebingen, Tuebingen, Germany.,German Center for Neurodegenerative Diseases (DZNE), Tuebingen, Germany
| | - Dagmar Timmann
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Bart P van de Warrenburg
- Department of Neurology, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
| | - Astrid D Adarmes-Gómez
- Unidad de Trastornos del Movimiento, Servicio de Neurología y Neurofisiología Clínica, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Benjamin Bender
- Department of Diagnostics and Interventional Neuroradiology, University of Tuebingen, Tuebingen, Germany
| | - Andreas Thieme
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Matthis Synofzik
- Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research & Center of Neurology, University of Tuebingen, Tuebingen, Germany.,German Center for Neurodegenerative Diseases (DZNE), Tuebingen, Germany
| | - Ludger Schöls
- Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research & Center of Neurology, University of Tuebingen, Tuebingen, Germany.,German Center for Neurodegenerative Diseases (DZNE), Tuebingen, Germany
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10
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Smirnov AA, Kiriltseva MM, Lyubchenko ME, Nazarov VD, Botina AV, Burakov AN, Lapin SV. Peroral endoscopic myotomy in a pregnant woman diagnosed with mitochondrial disease: A case report. World J Gastrointest Endosc 2021; 13:155-160. [PMID: 34046152 PMCID: PMC8134852 DOI: 10.4253/wjge.v13.i5.155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 03/06/2021] [Accepted: 04/26/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Achalasia is a primary esophageal motility disease characterized by impairment of normal esophageal peristalsis and absence of relaxation of the lower esophageal sphincter. Sometimes is can be a part of some genetic disorders. One of the causes of gastrointestinal motility disorders, including achalasia, is mitochondrial defects.
CASE SUMMARY We report about a pregnant woman with a history of symptoms associated with inherited mitochondrial disease, which was confirmed by genetic tests, and who was treated via peroral endoscopic myotomy.
CONCLUSION Peroral endoscopic myotomy is possible treatment option for a pregnant woman with achalasia caused by mitochondrial disease.
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Affiliation(s)
- Alexander A Smirnov
- Department of Endoscopy, Pavlov First Saint Petersburg State Medical University, Saint Petersburg 197022, Russia
| | - Maya M Kiriltseva
- Department of Endoscopy, Pavlov First Saint Petersburg State Medical University, Saint Petersburg 197022, Russia
| | - Mariya E Lyubchenko
- Department of Endoscopy, Pavlov First Saint Petersburg State Medical University, Saint Petersburg 197022, Russia
| | - Vladimir D Nazarov
- Center for Molecular Medicine, Pavlov First Saint Petersburg State Medical University, Saint Petersburg 197022, Russia
| | - Anna V Botina
- Department of Pathology, Pavlov First Saint Petersburg State Medical University, Saint Petersburg 197022, Russia
| | - Aleksandr N Burakov
- Department of Endoscopy, Pavlov First Saint Petersburg State Medical University, Saint Petersburg 197022, Russia
| | - Sergey V Lapin
- Center for Molecular Medicine, Pavlov First Saint Petersburg State Medical University, Saint Petersburg 197022, Russia
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Lu JQ, Tarnopolsky MA. Mitochondrial neuropathy and neurogenic features in mitochondrial myopathy. Mitochondrion 2020; 56:52-61. [PMID: 33220502 DOI: 10.1016/j.mito.2020.11.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 10/25/2020] [Accepted: 11/02/2020] [Indexed: 01/21/2023]
Abstract
Mitochondrial diseases (MIDs) involve multiple organs including peripheral nerves and skeletal muscle. Mitochondrial neuropathy (MN) and mitochondrial myopathy (MM) are commonly associated and linked at the neuromuscular junction (NMJ). Herein we review MN in connection with neurogenic features of MM, and pathological evidence for the involvement of the peripheral nerve and NMJ in MID patients traditionally assumed to have predominantly MM. MN is not uncommon, but still likely under-reported, and muscle biopsies of MM commonly exhibit neurogenic features. Pathological examination remains the gold standard to assess the nerve and muscle changes in patients with MIDs. Ultrastructural studies by electron microscopy are often necessary to fully characterize the pathology of mitochondrial cytopathy in MN and MM.
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Affiliation(s)
- Jian-Qiang Lu
- Department of Pathology and Molecular Medicine/Neuropathology, McMaster University, Hamilton, Ontario, Canada.
| | - Mark A Tarnopolsky
- Department of Medicine/Neurology, McMaster University, Hamilton, Ontario, Canada; Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada
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12
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Maghbooli M, Ghaffarpour M, Ghazizadeh T, Shalbaf NA, MalekMahmoudi G. Clinicogenetical Variants of Progressive External Ophthalmoplegia - An Especial Review of Non-ophthalmic Manifestations. Neurol India 2020; 68:760-768. [PMID: 32859811 DOI: 10.4103/0028-3886.293454] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Progressive external ophthalmoplegia (PEO) is a slowly progressive myopathy characterized by extraocular muscles involvement, leading to frozen eyes without diplopia. The pattern of inheritance may be mitochondrial, autosomal dominant or, rarely, autosomal recessive. Sporadic forms were also reported. Muscular involvement other than extraocular muscles may occur with varying degrees of weakness, but this mostly happens many years after the disease begins. There are also scattered data about systemic signs besides ophthalmoplegia. This article aims to review non-ophthalmic findings of PEO from a clinicogenetical point of view.
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Affiliation(s)
- Mehdi Maghbooli
- Department of Neurology, Zanjan University of Medical Sciences, Vali-e-Asr Hospital, Zanjan, Iran
| | - Majid Ghaffarpour
- Department of Neurology, Tehran University of Medical Sciences, Iranian Center of Neurological Research, Tehran, Iran
| | - Taher Ghazizadeh
- Department of Neurology, Zanjan University of Medical Sciences, Vali-e-Asr Hospital, Zanjan, Iran
| | - Nazanin Azizi Shalbaf
- Department of Neurology, Zanjan University of Medical Sciences, Vali-e-Asr Hospital, Zanjan, Iran
| | - Ghazal MalekMahmoudi
- Department of Neurology, Zanjan University of Medical Sciences, Vali-e-Asr Hospital, Zanjan, Iran
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13
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Hikmat O, Naess K, Engvall M, Klingenberg C, Rasmussen M, Tallaksen CM, Brodtkorb E, Ostergaard E, de Coo IFM, Pias-Peleteiro L, Isohanni P, Uusimaa J, Darin N, Rahman S, Bindoff LA. Simplifying the clinical classification of polymerase gamma (POLG) disease based on age of onset; studies using a cohort of 155 cases. J Inherit Metab Dis 2020; 43:726-736. [PMID: 32391929 DOI: 10.1002/jimd.12211] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 01/02/2020] [Accepted: 01/03/2020] [Indexed: 01/14/2023]
Abstract
BACKGROUND Variants in POLG are one of the most common causes of inherited mitochondrial disease. Phenotypic classification of POLG disease has evolved haphazardly making it complicated and difficult to implement in everyday clinical practise. The aim of our study was to simplify the classification and facilitate better clinical recognition. METHODS A multinational, retrospective study using data from 155 patients with POLG variants recruited from seven European countries. RESULTS We describe the spectrum of clinical features associated with POLG variants in the largest known cohort of patients. While clinical features clearly form a continuum, stratifying patients simply according to age of onset-onset prior to age 12 years; onset between 12 and 40 years and onset after the age of 40 years, permitted us to identify clear phenotypic and prognostic differences. Prior to 12 years of age, liver involvement (87%), seizures (84%), and feeding difficulties (84%) were the major features. For those with onset between 12 and 40 years, ataxia (90%), peripheral neuropathy (84%), and seizures (71%) predominated, while for those with onset over 40 years, ptosis (95%), progressive external ophthalmoplegia (89%), and ataxia (58%) were the major clinical features. The earlier the onset the worse the prognosis. Patients with epilepsy and those with compound heterozygous variants carried significantly worse prognosis. CONCLUSION Based on our data, we propose a simplified POLG disease classification, which can be used to guide diagnostic investigations and predict disease course.
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Affiliation(s)
- Omar Hikmat
- Department of Pediatrics, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Medicine (K1), University of Bergen, Bergen, Norway
| | - Karin Naess
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Martin Engvall
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Claus Klingenberg
- Department of Paediatric and Adolescent Medicine, University Hospital of North Norway, Tromso, Norway
- Paediatric Research Group, Department of Clinical Medicine, UiT - The Arctic University of Norway, Tromso, Norway
| | - Magnhild Rasmussen
- Women and Children's Division, Department of Clinical Neurosciences for Children, Oslo University Hospital, Oslo, Norway
- Unit for Congenital and Hereditary Neuromuscular Disorders, Department of Neurology, Oslo University Hospital, Oslo, Norway
| | - Chantal Me Tallaksen
- Department of Neurology, Oslo University Hospital, Oslo, Norway
- Faculty of Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Eylert Brodtkorb
- Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway
- Department of Neurology and Clinical Neurophysiology, St. Olav's University Hospital, Trondheim, Norway
| | - Elsebet Ostergaard
- Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - I F M de Coo
- Department of Neurology, Medical Spectrum Twente, Enschede, The Netherlands
- Department of Genetics and Cell Biology, University of Maastricht, Maastricht, The Netherlands
| | | | - Pirjo Isohanni
- Department of Pediatric Neurology, Children's Hospital and Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Johanna Uusimaa
- PEDEGO Research Unit, University of Oulu, Oulu, Finland
- Biocenter Oulu, University of Oulu, Oulu, Finland
- Department of Pediatric Neurology, Clinic for Children and Adolescents, Medical Research Center, Oulu University Hospital, Oulu, Finland
| | - Niklas Darin
- Department of Pediatrics, The Queen Silvia Children's Hospital, University of Gothenburg, Gothenburg, Sweden
| | - Shamima Rahman
- Mitochondrial Research Group, UCL Great Ormond Street Institute of Child Health, London, UK
- Metabolic Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Laurence A Bindoff
- Department of Clinical Medicine (K1), University of Bergen, Bergen, Norway
- Department of Neurology, Haukeland University Hospital, Bergen, Norway
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14
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Habibzadeh P, Silawi M, Dastsooz H, Bahramjahan S, Ezzatzadegan Jahromi S, Ostovan VR, Yavarian M, Mofatteh M, Faghihi MA. Clinical and molecular characterization of a patient with mitochondrial Neurogastrointestinal Encephalomyopathy. BMC Gastroenterol 2020; 20:142. [PMID: 32384880 PMCID: PMC7206720 DOI: 10.1186/s12876-020-01280-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 04/21/2020] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a rare autosomal recessive disorder caused by mutations in TYMP gene, encoding nuclear thymidine phosphorylase (TP). MNGIE mainly presents with gastrointestinal symptoms and is mostly misdiagnosed in many patients as malabsorption syndrome, inflammatory bowel disease, anorexia nervosa, and intestinal pseudo-obstruction. Up to date, more than 80 pathogenic and likely pathogenic mutations associated with the disease have been reported in patients from a wide range of ethnicities. The objective of this study was to investigate the underlying genetic abnormalities in a 25-year-old woman affected with MNGIE. CASE PRESENTATION The patient was a 25-year-old female referred to our center with the chief complaint of severe abdominal pain and diarrhea for 2 years that had worsened from 2 months prior to admission. The clinical and para-clinical findings were in favor of mitochondrial neurogastrointestinal encephalomyopathy syndrome. Subsequent genetic studies revealed a novel, private, homozygous nonsense mutation in TYMP gene (c. 1013 C > A, p.S338X). Sanger sequencing confirmed the new mutation in the proband. Multiple sequence alignment showed high conservation of amino acids of this protein across different species. CONCLUSION The detected new nonsense mutation in the TYMP gene would be very important for genetic counseling and subsequent early diagnosis and initiation of proper therapy. This novel pathogenic variant would help us establish future genotype-phenotype correlations and identify different pathways related to this disorder.
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Affiliation(s)
- Parham Habibzadeh
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad Silawi
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Hassan Dastsooz
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Italian Institute for Genomic Medicine (IIGM), University of Turin, Turin, Italy
| | - Shima Bahramjahan
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | | | - Vahid Reza Ostovan
- Clinical Neurology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Majid Yavarian
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad Mofatteh
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Mohammad Ali Faghihi
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, Miami, USA
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15
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Abstract
The POLG gene encodes the mitochondrial DNA polymerase that is responsible for replication of the mitochondrial genome. Mutations in POLG can cause early childhood mitochondrial DNA (mtDNA) depletion syndromes or later-onset syndromes arising from mtDNA deletions. POLG mutations are the most common cause of inherited mitochondrial disorders, with as many as 2% of the population carrying these mutations. POLG-related disorders comprise a continuum of overlapping phenotypes with onset from infancy to late adulthood. The six leading disorders caused by POLG mutations are Alpers-Huttenlocher syndrome, which is one of the most severe phenotypes; childhood myocerebrohepatopathy spectrum, which presents within the first 3 years of life; myoclonic epilepsy myopathy sensory ataxia; ataxia neuropathy spectrum; autosomal recessive progressive external ophthalmoplegia; and autosomal dominant progressive external ophthalmoplegia. This Review describes the clinical features, pathophysiology, natural history and treatment of POLG-related disorders, focusing particularly on the neurological manifestations of these conditions.
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16
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Homozygous R627W mutations in POLG cause mitochondrial DNA depletion leading to encephalopathy, seizures and stroke-like episodes. Mitochondrion 2019; 48:78-83. [DOI: 10.1016/j.mito.2019.08.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 08/05/2019] [Accepted: 08/14/2019] [Indexed: 01/21/2023]
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17
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Huang H, Yang X, Liu L, Xu Y. Leukoencephalopathy in Mitochondrial Neurogastrointestinal Encephalomyopathy-Like Syndrome with Polymerase-Gamma Mutations. Ann Indian Acad Neurol 2019; 22:325-327. [PMID: 31359948 PMCID: PMC6613405 DOI: 10.4103/aian.aian_34_18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) syndrome, caused by mutations in the thymidine phosphorylase gene, manifests as a multisystemic disorder characterized by severe gastrointestinal dysmotility, cachexia, ptosis and ophthalmoparesis, peripheral neuropathy, and leukoencephalopathy. These clinical manifestations, with the exception of leukoencephalopathy, are mimicked by MNGIE-like syndrome, linked to polymerase-gamma (POLG) gene. Here, we report a 49-year-old Chinese man with MNGIE-like syndrome involved leukoencephalopathy and was associated with novel POLG mutations. This case expands the clinical spectrum of MNGIE-like syndrome.
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Affiliation(s)
- Hongyan Huang
- Department of Neurology, West China Hospital, Sichuan University, Sichuan Province, PR China
| | - Xinglong Yang
- Department of Geriatric Neurology, The First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, PR China
| | - Ling Liu
- Department of Neurology, West China Hospital, Sichuan University, Sichuan Province, PR China
| | - Yanming Xu
- Department of Neurology, West China Hospital, Sichuan University, Sichuan Province, PR China
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18
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Piekutowska-Abramczuk D, Kaliszewska M, Sułek A, Jurkowska N, Ołtarzewski M, Jabłońska E, Trubicka J, Głowacka A, Ciara E, Kowalski P, Langiewicz-Wojciechowska K, Tesarova M, Zeman J, Kierdaszuk B, Kuczyński D, Chmielewski D, Szymańska E, Bakuła A, Łusakowska A, Lipowska M, Brodacki B, Pera J, Dorobek M, Rydzanicz M, Płoski R, Chrzanowska KH, Bartnik E, Placha G, Kamińska A, Kostera-Pruszczyk A, Krajewska-Walasek M, Tońska K, Pronicka E. The frequency of mitochondrial polymerase gamma related disorders in a large Polish population cohort. Mitochondrion 2019; 47:179-187. [DOI: 10.1016/j.mito.2018.11.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 10/02/2018] [Accepted: 11/02/2018] [Indexed: 02/06/2023]
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19
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Lynch DS, Wade C, Paiva ARBD, John N, Kinsella JA, Merwick Á, Ahmed RM, Warren JD, Mummery CJ, Schott JM, Fox NC, Houlden H, Adams ME, Davagnanam I, Murphy E, Chataway J. Practical approach to the diagnosis of adult-onset leukodystrophies: an updated guide in the genomic era. J Neurol Neurosurg Psychiatry 2019; 90:543-554. [PMID: 30467211 PMCID: PMC6581077 DOI: 10.1136/jnnp-2018-319481] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Revised: 09/24/2018] [Accepted: 10/07/2018] [Indexed: 12/13/2022]
Abstract
Adult-onset leukodystrophies and genetic leukoencephalopathies comprise a diverse group of neurodegenerative disorders of white matter with a wide age of onset and phenotypic spectrum. Patients with white matter abnormalities detected on MRI often present a diagnostic challenge to both general and specialist neurologists. Patients typically present with a progressive syndrome including various combinations of cognitive impairment, movement disorders, ataxia and upper motor neuron signs. There are a number of important and treatable acquired causes for this imaging and clinical presentation. There are also a very large number of genetic causes which due to their relative rarity and sometimes variable and overlapping presentations can be difficult to diagnose. In this review, we provide a structured approach to the diagnosis of inherited disorders of white matter in adults. We describe clinical and radiological clues to aid diagnosis, and we present an overview of both common and rare genetic white matter disorders. We provide advice on testing for acquired causes, on excluding small vessel disease mimics, and detailed advice on metabolic and genetic testing available to the practising neurologist. Common genetic leukoencephalopathies discussed in detail include CSF1R, AARS2, cerebral arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), and mitochondrial and metabolic disorders.
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Affiliation(s)
- David S Lynch
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK .,Department of Neurology, Royal Free Hospital, London, UK
| | - Charles Wade
- Department of Neurology, Royal Free Hospital, London, UK
| | | | - Nevin John
- Department of Neuroinflammation, UCL Institute of Neurology, London, UK
| | - Justin A Kinsella
- Department of Neurology, St Vincent's University Hospital University College Dublin, Dublin, Ireland
| | - Áine Merwick
- Department of Neurology, Beaumont Hospital and Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Rebekah M Ahmed
- Memory and Cognition Clinic, Department of Clinical Neurosciences, Royal Prince Alfred Hospital and the Brain and Mind Centre, University of Sydney, Camperdown, New South Wales, Australia
| | - Jason D Warren
- Dementia Research Centre, UCL Institute of Neurology, London, UK
| | | | | | - Nick C Fox
- Dementia Research Centre, UCL Institute of Neurology, London, UK
| | - Henry Houlden
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Matthew E Adams
- Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, London, UK
| | - Indran Davagnanam
- Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, London, UK.,Brain Repair & Rehabilitation, UCL Institute of Neurology, London, UK
| | - Elaine Murphy
- Charles Dent Metabolic Unit, National Hospital for Neurology and Neurosurgery Queen Square, London, UK
| | - Jeremy Chataway
- Department of Neuroinflammation, UCL Institute of Neurology, London, UK
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20
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Yasuda K, Murase N, Yoshinaga K, Ohtani R, Goto YI, Takahashi R, Nakamura M. Leukoencephalopathy with a case of heterozygous POLG mutation mimicking mitochondrial neurogastrointestinal encephalomyopathy (MNGIE). J Clin Neurosci 2019; 61:302-304. [DOI: 10.1016/j.jocn.2018.10.054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 10/06/2018] [Indexed: 01/21/2023]
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21
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Durrani S, Chen BC, Yakob Y, Hian LS, Afroze B. Mitochondrial Neurogastrointestinal Encephalomyopathy Disease in Three Siblings from Pakistan with a Novel Mutation. J Pediatr Genet 2019; 8:15-19. [PMID: 30775048 DOI: 10.1055/s-0038-1661411] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 05/24/2018] [Indexed: 01/21/2023]
Abstract
Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a rare multisystem autosomal recessive disorder. The disease is clinically heterogeneous with gastrointestinal symptoms of intestinal dysmotility and cachexia as well as neurological symptoms of ophthalmoplegia, neuropathy, sensorineural hearing impairment, and diffuse leukoencephalopathy being most prominent. MNGIE is caused by mutations in TYMP , a gene that encodes thymidine phosphorylase (TP)-a cytosolic enzyme. Mutations in TYMP lead to very low TP catalytic activity, resulting in dramatically increased thymidine and deoxyuridine in plasma. We describe the clinical, biochemical, and neuroimaging findings of three boys with MNGIE from a Pakistani family with a novel homozygous mutation, c.798_801dupCGCG p. (Ala268Argfs*?), in exon 7 of TYMP .
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Affiliation(s)
| | - Bee Chin Chen
- Unit of Biochemical Genetics, Department of Genetics, Kuala Lumpur Hospital, Kuala Lumpur, Malaysia
| | - Yusnita Yakob
- Unit of Molecular Diagnostics and Protein, Institute for Medical Research, Kuala Lumpur, Malaysia
| | - Lua Seok Hian
- Unit of Molecular Diagnostics and Protein, Institute for Medical Research, Kuala Lumpur, Malaysia
| | - Bushra Afroze
- Department of Paediatrics and Child Health, Aga Khan University Hospital, Karachi, Pakistan
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22
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Filosto M, Cotti Piccinelli S, Caria F, Gallo Cassarino S, Baldelli E, Galvagni A, Volonghi I, Scarpelli M, Padovani A. Mitochondrial Neurogastrointestinal Encephalomyopathy (MNGIE-MTDPS1). J Clin Med 2018; 7:jcm7110389. [PMID: 30373120 PMCID: PMC6262582 DOI: 10.3390/jcm7110389] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 10/14/2018] [Accepted: 10/24/2018] [Indexed: 12/12/2022] Open
Abstract
Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE-MTDPS1) is a devastating autosomal recessive disorder due to mutations in TYMP, which cause a loss of function of thymidine phosphorylase (TP), nucleoside accumulation in plasma and tissues, and mitochondrial dysfunction. The clinical picture includes progressive gastrointestinal dysmotility, cachexia, ptosis and ophthalmoparesis, peripheral neuropathy, and diffuse leukoencephalopathy, which usually lead to death in early adulthood. Other two MNGIE-type phenotypes have been described so far, which are linked to mutations in POLG and RRM2B genes. Therapeutic options are currently available in clinical practice (allogeneic hematopoietic stem cell transplantation and carrier erythrocyte entrapped thymidine phosphorylase therapy) and newer, promising therapies are expected in the near future. Since successful treatment is strictly related to early diagnosis, it is essential that clinicians be warned about the clinical features and diagnostic procedures useful to suspect diagnosis of MNGIE-MTDPS1. The aim of this review is to promote the knowledge of the disease as well as the involved mechanisms and the diagnostic processes in order to reach an early diagnosis.
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Affiliation(s)
- Massimiliano Filosto
- Center for Neuromuscular Diseases, Unit of Neurology, ASST Spedali Civili and University of Brescia, 25100 Brescia, Italy.
| | - Stefano Cotti Piccinelli
- Center for Neuromuscular Diseases, Unit of Neurology, ASST Spedali Civili and University of Brescia, 25100 Brescia, Italy.
| | - Filomena Caria
- Center for Neuromuscular Diseases, Unit of Neurology, ASST Spedali Civili and University of Brescia, 25100 Brescia, Italy.
| | - Serena Gallo Cassarino
- Center for Neuromuscular Diseases, Unit of Neurology, ASST Spedali Civili and University of Brescia, 25100 Brescia, Italy.
| | - Enrico Baldelli
- Center for Neuromuscular Diseases, Unit of Neurology, ASST Spedali Civili and University of Brescia, 25100 Brescia, Italy.
| | - Anna Galvagni
- Center for Neuromuscular Diseases, Unit of Neurology, ASST Spedali Civili and University of Brescia, 25100 Brescia, Italy.
| | - Irene Volonghi
- Center for Neuromuscular Diseases, Unit of Neurology, ASST Spedali Civili and University of Brescia, 25100 Brescia, Italy.
| | - Mauro Scarpelli
- Department of Neuroscience, Unit of Neurology, Azienda Ospedaliera Universitaria Integrata Verona, 37100 Verona, Italy.
| | - Alessandro Padovani
- Center for Neuromuscular Diseases, Unit of Neurology, ASST Spedali Civili and University of Brescia, 25100 Brescia, Italy.
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23
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AlJabri MF, Kamal NM, Halabi A, Korbi H, Alsayyali MM, Alzahrani YA. Lethal neonatal mitochondrial phenotype caused by a novel polymerase subunit gamma mutation: A case report. Medicine (Baltimore) 2018; 97:e12591. [PMID: 30290626 PMCID: PMC6200512 DOI: 10.1097/md.0000000000012591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
RATIONALE Polymerase subunit gamma (POLG) is a gene that codes for the catalytic subunit of the mitochondrial DNA polymerase, which is involved in the replication of mitochondrial DNA. Mutations in these genes are associated with a range of clinical syndromes characterized by secondary mtDNA defect including mtDNA mutation and mtDNA depletion which may culminate in complete failure of energy production (respiratory changes complex 1 defect) as in this case. PATIENT CONCERNS We herein report a full term Saudi female neonate born to consanguineous parents, who was noticed immediately after birth to have severe hypotonia, poor respiratory effort, and dysmorphic features. She had 3 siblings who died with same clinical scenario in neonatal period. DIAGNOSES Molecular genetic testing revealed a novel compound heterozygous mutation of POLG gene c.680G>A (p.Arg227Gin) and c.3098C>T (p.Ala1033Val). INTERVENTIONS The patient remained in neonatal intensive care unit with multidisciplinary team management and was ventilator dependent until she passed away. OUTCOMES The detected mutation had led to complete failure of energy production (respiratory changes complex 1 defect) until she died at the age of 5 months. LESSONS Mitochondrial respiratory chain defect should be considered in patients with severe neonatal hypotonia,encephalopathy, and respiratory failure especially in highly consanguineous population.
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Affiliation(s)
| | - Naglaa M. Kamal
- Pediatric Hepatology, Faculty of Medicine, Cairo University, Egypt
- Pediatric Hepatology
| | | | | | | | - Yahea A. Alzahrani
- Neuroradiology, College of Medicine, Taif University, Taif, Saudi Arabia
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24
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Alves CAPF, Gonçalves FG, Grieb D, Lucato LT, Goldstein AC, Zuccoli G. Neuroimaging of Mitochondrial Cytopathies. Top Magn Reson Imaging 2018; 27:219-240. [PMID: 30086109 DOI: 10.1097/rmr.0000000000000173] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Mitochondrial diseases are a complex and heterogeneous group of genetic disorders that occur as a result of either nuclear DNA or mitochondrial DNA pathogenic variants, leading to a decrease in oxidative phosphorylation and cellular energy (ATP) production. Increasing knowledge about molecular, biochemical, and genetic abnormalities related to mitochondrial dysfunction has expanded the neuroimaging phenotypes of mitochondrial disorders. As a consequence of this growing field, the imaging recognition patterns of mitochondrial cytopathies are continually evolving. In this review, we describe the main neuroimaging characteristics of pediatric mitochondrial diseases, ranging from classical to more recent and challenging features. Due to the increased knowledge about the imaging findings of mitochondrial cytopathies, the pediatric neuroradiologist plays a crucial role in the diagnosis and evaluation of these patients.
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Affiliation(s)
| | | | - Dominik Grieb
- Department of Radiology and Neuroradiology, Sana Kliniken Duisburg, Germany
| | - Leandro Tavares Lucato
- Neuroradiology Section, Hospital das Clínicas- HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP, Brazil
| | - Amy C Goldstein
- Division of Human Genetics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA
| | - Giulio Zuccoli
- Department of Radiology, University of Pittsburgh School of Medicine, Director of Pediatric Neuroradiology, Children Hospital of Pittsburgh, Pittsburgh, PA
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25
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The clinical spectrum and natural history of early-onset diseases due to DNA polymerase gamma mutations. Genet Med 2017; 19:1217-1225. [DOI: 10.1038/gim.2017.35] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 02/16/2017] [Accepted: 02/17/2017] [Indexed: 12/26/2022] Open
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26
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Wang HF, Wang J, Wang YL, Fan JJ, Mo GL, Gong FY, Chai ZM, Zhang J, Meng HX, Li CX, Guo JH, Pu CQ. A novel thymidine phosphorylase mutation in a Chinese MNGIE patient. Acta Neurol Belg 2017; 117:259-267. [PMID: 27709505 DOI: 10.1007/s13760-016-0701-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 09/19/2016] [Indexed: 01/06/2023]
Abstract
Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is an autosomal recessive disorder associated with mitochondrial alterations. MNGIE is characterized by severe gastrointestinal dysmotility, cachexia, ophthalmoplegia, ptosis, peripheral neuropathy, and leukoencephalopathy. The condition is caused by mutation of the TYMP gene. We studied the clinical and biochemical characteristics of a family with MNGIE. The proband was a 48-year-old male presenting with diarrhea and progressive weight loss. He also had ptosis and exhibited eyeball fixation. His blood and cerebrospinal fluid lactate levels were elevated. Magnetic resonance imaging of the brain revealed diffuse leukoencephalopathy. Ragged red fibers and cytochrome c oxidase-deficient fibers were apparent on muscle biopsy. His vision and ptosis deteriorated significantly during follow-up. Our clinical diagnosis of MNGIE was confirmed by TYMP gene analysis. We discovered a homozygous TYMP c.1193-1216 dup-GGGCGCTGCCGCTGGCGCTGGTGC mutation (a duplication). Some of the family members were heterozygous for the mutation but had no clinical features. We predicted the function of this mutation using PredictProtein and found that the secondary structure had changed in the region of the helix and strand, the transmembrane region, and the protein-protein binding sites. The family described herein exhibited biochemically, genetically, and functionally confirmed MNGIE syndrome.
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Affiliation(s)
- Hui-Fang Wang
- Department of Neurology, ShanXi Medical Univeristy of First Hospital, No. 85, Jiefang South Road, Taiyuan, 030001, ShanXi, People's Republic of China
- Department of Neurology, Chinese People's Liberation Army General Hospital, No. 28, Fuxing Road, Beijing, 100853, People's Republic of China
| | - Juan Wang
- Department of Neurology, ShanXi Medical Univeristy of First Hospital, No. 85, Jiefang South Road, Taiyuan, 030001, ShanXi, People's Republic of China
| | - Yan-Ling Wang
- Department of Neurology, ShanXi Medical Univeristy of First Hospital, No. 85, Jiefang South Road, Taiyuan, 030001, ShanXi, People's Republic of China
| | - Jian-Jian Fan
- Department of Neurology, ShanXi Medical Univeristy of First Hospital, No. 85, Jiefang South Road, Taiyuan, 030001, ShanXi, People's Republic of China
| | - Gui-Lin Mo
- Department of Molecular Genetics, Guangzhou Kingmed Center for Clinical Laboratory Co., Ltd., Guangzhou, 510330, Guangdong, People's Republic of China
| | - Feng-Yin Gong
- Department of Endocrinology, Key Laboratory of Endocrinology of the Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, 100730, People's Republic of China
| | - Zhi-Ming Chai
- Department of Neurology, ShanXi Medical Univeristy of First Hospital, No. 85, Jiefang South Road, Taiyuan, 030001, ShanXi, People's Republic of China
| | - Jin Zhang
- Department of Neurology, ShanXi Medical Univeristy of First Hospital, No. 85, Jiefang South Road, Taiyuan, 030001, ShanXi, People's Republic of China
| | - Hua-Xing Meng
- Department of Neurology, ShanXi Medical Univeristy of First Hospital, No. 85, Jiefang South Road, Taiyuan, 030001, ShanXi, People's Republic of China
| | - Chang-Xin Li
- Department of Neurology, ShanXi Medical Univeristy of First Hospital, No. 85, Jiefang South Road, Taiyuan, 030001, ShanXi, People's Republic of China
| | - Jun-Hong Guo
- Department of Neurology, ShanXi Medical Univeristy of First Hospital, No. 85, Jiefang South Road, Taiyuan, 030001, ShanXi, People's Republic of China.
| | - Chuan-Qiang Pu
- Department of Neurology, Chinese People's Liberation Army General Hospital, No. 28, Fuxing Road, Beijing, 100853, People's Republic of China.
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El-Hattab AW, Craigen WJ, Scaglia F. Mitochondrial DNA maintenance defects. Biochim Biophys Acta Mol Basis Dis 2017; 1863:1539-1555. [PMID: 28215579 DOI: 10.1016/j.bbadis.2017.02.017] [Citation(s) in RCA: 185] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 01/31/2017] [Accepted: 02/14/2017] [Indexed: 01/12/2023]
Abstract
The maintenance of mitochondrial DNA (mtDNA) depends on a number of nuclear gene-encoded proteins including a battery of enzymes forming the replisome needed to synthesize mtDNA. These enzymes need to be in balanced quantities to function properly that is in part achieved by exchanging intramitochondrial contents through mitochondrial fusion. In addition, mtDNA synthesis requires a balanced supply of nucleotides that is achieved by nucleotide recycling inside the mitochondria and import from the cytosol. Mitochondrial DNA maintenance defects (MDMDs) are a group of diseases caused by pathogenic variants in the nuclear genes involved in mtDNA maintenance resulting in impaired mtDNA synthesis leading to quantitative (mtDNA depletion) and qualitative (multiple mtDNA deletions) defects in mtDNA. Defective mtDNA leads to organ dysfunction due to insufficient mtDNA-encoded protein synthesis, resulting in an inadequate energy production to meet the needs of affected organs. MDMDs are inherited as autosomal recessive or dominant traits, and are associated with a broad phenotypic spectrum ranging from mild adult-onset ophthalmoplegia to severe infantile fatal hepatic failure. To date, pathogenic variants in 20 nuclear genes known to be crucial for mtDNA maintenance have been linked to MDMDs, including genes encoding enzymes of mtDNA replication machinery (POLG, POLG2, TWNK, TFAM, RNASEH1, MGME1, and DNA2), genes encoding proteins that function in maintaining a balanced mitochondrial nucleotide pool (TK2, DGUOK, SUCLG1, SUCLA2, ABAT, RRM2B, TYMP, SLC25A4, AGK, and MPV17), and genes encoding proteins involved in mitochondrial fusion (OPA1, MFN2, and FBXL4).
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Affiliation(s)
- Ayman W El-Hattab
- Division of Clinical Genetics and Metabolic Disorders, Pediatrics Department, Tawam Hospital, Al-Ain, United Arab Emirates
| | - William J Craigen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
| | - Fernando Scaglia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
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28
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Ng YS, Feeney C, Schaefer AM, Holmes CE, Hynd P, Alston CL, Grady JP, Roberts M, Maguire M, Bright A, Taylor RW, Yiannakou Y, McFarland R, Turnbull DM, Gorman GS. Pseudo-obstruction, stroke, and mitochondrial dysfunction: A lethal combination. Ann Neurol 2016; 80:686-692. [PMID: 27453452 PMCID: PMC5215534 DOI: 10.1002/ana.24736] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 06/28/2016] [Accepted: 07/14/2016] [Indexed: 12/28/2022]
Abstract
OBJECTIVES The m.3243A>G MTTL1 mutation is the most common cause of mitochondrial disease; yet there is limited awareness of intestinal pseudo-obstruction (IPO) in this disorder. We aimed to determine the prevalence, severity, and clinical outcome of patients with m.3243A>G-related mitochondrial disease manifesting with IPO. METHODS In this large, observational cohort study, we assessed the clinical, molecular, and radiological characteristics of patients with genetically determined m.3243A>G-related mitochondrial disease, who presented with severe symptoms suggestive of bowel obstruction in the absence of an occluding lesion. RESULTS Between January 2009 and June 2015, 226 patients harbouring the m.3243A>G mutation were recruited to the Medical Research Council Centre Mitochondrial Disease Patient Cohort, Newcastle. Thirty patients (13%) presented acutely with IPO. Thirteen of these patients had a preceding history of stroke-like episodes, whereas 1 presented 27 years previously with their first stroke-like episode. Eight patients developed IPO concomitantly during an acute stroke-like episode. Regression analysis suggested stroke was the strongest predictor for development of IPO, in addition to cardiomyopathy, low body mass index and high urinary mutation load. Poor clinical outcome was observed in 6 patients who underwent surgical procedures. INTERPRETATION Our findings suggest, in this common mitochondrial disease, that IPO is an under-recognized, often misdiagnosed clinical entity. Poor clinical outcome associated with stroke and acute surgical intervention highlights the importance of the neurologist having a high index of suspicion, particularly in the acute setting, to instigate timely coordination of appropriate care and management with other specialists. Ann Neurol 2016;80:686-692.
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Affiliation(s)
- Yi Shiau Ng
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Catherine Feeney
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Andrew M Schaefer
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Carol Ellen Holmes
- Department of Radiology, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom
| | - Paula Hynd
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Charlotte L Alston
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - John P Grady
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Mark Roberts
- The Greater Manchester Neuroscience Centre, Salford Royal NHS Foundation Trust, Salford, United Kingdom
| | - Mellisa Maguire
- Department of Neurology, The Leeds Teaching Hospitals NHS Trust, West Yorkshire, United Kingdom
| | - Alexandra Bright
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Robert W Taylor
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Yan Yiannakou
- Department of Gastroenterology, County Durham and Darlington NHS Foundation Trust, Durham, United Kingdom
| | - Robert McFarland
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Doug M Turnbull
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Gráinne S Gorman
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
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Li M, Mislak AC, Foli Y, Agbosu E, Bose V, Bhandari S, Szymanski MR, Shumate CK, Yin YW, Anderson KS, Paintsil E. The DNA Polymerase Gamma R953C Mutant Is Associated with Antiretroviral Therapy-Induced Mitochondrial Toxicity. Antimicrob Agents Chemother 2016; 60:5608-11. [PMID: 27381400 PMCID: PMC4997837 DOI: 10.1128/aac.00976-16] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 07/01/2016] [Indexed: 01/11/2023] Open
Abstract
We found a heterozygous C2857T mutation (R953C) in polymerase gamma (Pol-γ) in an HIV-infected patient with mitochondrial toxicity. The R953C Pol-γ mutant binding affinity for dCTP is 8-fold less than that of the wild type. The R953C mutant shows a 4-fold decrease in discrimination of analog nucleotides relative to the wild type. R953 is located on the "O-helix" that forms the substrate deoxynucleoside triphosphate (dNTP) binding site; the interactions of R953 with E1056 and Y986 may stabilize the O-helix and affect polymerase activity.
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Affiliation(s)
- Min Li
- Department of Pediatrics, Yale School of Medicine, New Haven, Connecticut, USA
| | - Andrea C Mislak
- Department of Pharmacology, Yale School of Medicine, New Haven, Connecticut, USA
| | - Yram Foli
- Department of Pediatrics, Yale School of Medicine, New Haven, Connecticut, USA
| | - Esinam Agbosu
- Department of Pediatrics, Yale School of Medicine, New Haven, Connecticut, USA
| | - Vivek Bose
- Department of Pediatrics, Yale School of Medicine, New Haven, Connecticut, USA
| | - Shreya Bhandari
- Department of Pediatrics, Yale School of Medicine, New Haven, Connecticut, USA
| | - Michal R Szymanski
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Christie K Shumate
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Y Whitney Yin
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Karen S Anderson
- Department of Pharmacology, Yale School of Medicine, New Haven, Connecticut, USA
| | - Elijah Paintsil
- Department of Pediatrics, Yale School of Medicine, New Haven, Connecticut, USA Department of Pharmacology, Yale School of Medicine, New Haven, Connecticut, USA Department of Epidemiology & Public Health, Yale School of Medicine, New Haven, Connecticut, USA
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30
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The wide POLG-related spectrum: An integrated view. J Neurol Sci 2016; 368:70-6. [PMID: 27538604 DOI: 10.1016/j.jns.2016.06.062] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 06/05/2016] [Accepted: 06/27/2016] [Indexed: 01/21/2023]
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31
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Rajakulendran S, Pitceathly RDS, Taanman JW, Costello H, Sweeney MG, Woodward CE, Jaunmuktane Z, Holton JL, Jacques TS, Harding BN, Fratter C, Hanna MG, Rahman S. A Clinical, Neuropathological and Genetic Study of Homozygous A467T POLG-Related Mitochondrial Disease. PLoS One 2016; 11:e0145500. [PMID: 26735972 PMCID: PMC4703200 DOI: 10.1371/journal.pone.0145500] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 12/06/2015] [Indexed: 02/06/2023] Open
Abstract
Mutations in the nuclear gene POLG (encoding the catalytic subunit of DNA polymerase gamma) are an important cause of mitochondrial disease. The most common POLG mutation, A467T, appears to exhibit considerable phenotypic heterogeneity. The mechanism by which this single genetic defect results in such clinical diversity remains unclear. In this study we evaluate the clinical, neuropathological and mitochondrial genetic features of four unrelated patients with homozygous A467T mutations. One patient presented with the severe and lethal Alpers-Huttenlocher syndrome, which was confirmed on neuropathology, and was found to have a depletion of mitochondrial DNA (mtDNA). Of the remaining three patients, one presented with mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS), one with a phenotype in the Myoclonic Epilepsy, Myopathy and Sensory Ataxia (MEMSA) spectrum and one with Sensory Ataxic Neuropathy, Dysarthria and Ophthalmoplegia (SANDO). All three had secondary accumulation of multiple mtDNA deletions. Complete sequence analysis of muscle mtDNA using the MitoChip resequencing chip in all four cases demonstrated significant variation in mtDNA, including a pathogenic MT-ND5 mutation in one patient. These data highlight the variable and overlapping clinical and neuropathological phenotypes and downstream molecular defects caused by the A467T mutation, which may result from factors such as the mtDNA genetic background, nuclear genetic modifiers and environmental stressors.
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Affiliation(s)
- Sanjeev Rajakulendran
- UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery and the MRC Centre for Neuromuscular Diseases, Queen Square, London WC1N 3BG, United Kingdom
| | - Robert D. S. Pitceathly
- UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, United Kingdom and Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King’s College London SE5 8AF, United Kingdom
| | - Jan-Willem Taanman
- Department of Clinical Neurosciences, UCL Institute of Neurology, London NW3 2PF, United Kingdom
| | - Harry Costello
- Mitochondrial Research Group, Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, United Kingdom
| | - Mary G. Sweeney
- Department of Neurogenetics, UCL Institute of Neurology and National Hospital for Neurology, Queen Square, London WC1N 3BG, United Kingdom
| | - Cathy E. Woodward
- Department of Neurogenetics, UCL Institute of Neurology and National Hospital for Neurology, Queen Square, London WC1N 3BG, United Kingdom
| | - Zane Jaunmuktane
- Division of Neuropathology, UCL Institute of Neurology and National Hospital for Neurology, Queen Square, London WC1N 3BG, United Kingdom
| | - Janice L. Holton
- Division of Neuropathology, UCL Institute of Neurology and National Hospital for Neurology, Queen Square, London WC1N 3BG, United Kingdom
| | - Thomas S. Jacques
- Developmental Biology and Cancer Programme, UCL Institute of Child Health and Department of Histopathology, Great Ormond Street Hospital for Children Foundation Trust, London WC1N 1EH, United Kingdom
| | - Brian N. Harding
- Division of Neuropathology, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Carl Fratter
- Oxford Medical Genetics Laboratories, Oxford University Hospitals NHS Trust, Churchill Hospital, Oxford OX3 7LE, United Kingdom
| | - Michael G. Hanna
- UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery and the MRC Centre for Neuromuscular Diseases, Queen Square, London WC1N 3BG, United Kingdom
| | - Shamima Rahman
- Mitochondrial Research Group, Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, United Kingdom
- Metabolic Unit, Great Ormond Street Hospital, London WC1N 3JH, United Kingdom
- * E-mail:
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32
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Ng YS, Turnbull DM. Mitochondrial disease: genetics and management. J Neurol 2016; 263:179-91. [PMID: 26315846 PMCID: PMC4723631 DOI: 10.1007/s00415-015-7884-3] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 08/18/2015] [Accepted: 08/18/2015] [Indexed: 12/14/2022]
Abstract
Mitochondrial disease is one of the most common groups of genetic diseases with a minimum prevalence of greater than 1 in 5000 in adults. Whilst multi-system involvement is often evident, neurological manifestation is the principal presentation in most cases. The multiple clinical phenotypes and the involvement of both the mitochondrial and nuclear genome make mitochondrial disease particularly challenging for the clinician. In this review article we cover mitochondrial genetics and common neurological presentations associated with adult mitochondrial disease. In addition, specific and supportive treatments are discussed.
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Affiliation(s)
- Yi Shiau Ng
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Doug M Turnbull
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK.
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33
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Introduzione sugli aspetti genetici delle neuropatie. Neurologia 2015. [DOI: 10.1016/s1634-7072(15)72178-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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34
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Scheibye-Knudsen M, Fang EF, Croteau DL, Wilson DM, Bohr VA. Protecting the mitochondrial powerhouse. Trends Cell Biol 2015; 25:158-70. [PMID: 25499735 PMCID: PMC5576887 DOI: 10.1016/j.tcb.2014.11.002] [Citation(s) in RCA: 230] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 11/07/2014] [Accepted: 11/10/2014] [Indexed: 01/21/2023]
Abstract
Mitochondria are the oxygen-consuming power plants of cells. They provide a critical milieu for the synthesis of many essential molecules and allow for highly efficient energy production through oxidative phosphorylation. The use of oxygen is, however, a double-edged sword that on the one hand supplies ATP for cellular survival, and on the other leads to the formation of damaging reactive oxygen species (ROS). Different quality control pathways maintain mitochondria function including mitochondrial DNA (mtDNA) replication and repair, fusion-fission dynamics, free radical scavenging, and mitophagy. Further, failure of these pathways may lead to human disease. We review these pathways and propose a strategy towards a treatment for these often untreatable disorders.
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Affiliation(s)
- Morten Scheibye-Knudsen
- Laboratory of Molecular Gerontology, National Institute on Aging (NIA), National Institutes of Health (NIH), Baltimore, MD 21224, USA
| | - Evandro F Fang
- Laboratory of Molecular Gerontology, National Institute on Aging (NIA), National Institutes of Health (NIH), Baltimore, MD 21224, USA
| | - Deborah L Croteau
- Laboratory of Molecular Gerontology, National Institute on Aging (NIA), National Institutes of Health (NIH), Baltimore, MD 21224, USA
| | - David M Wilson
- Laboratory of Molecular Gerontology, National Institute on Aging (NIA), National Institutes of Health (NIH), Baltimore, MD 21224, USA
| | - Vilhelm A Bohr
- Laboratory of Molecular Gerontology, National Institute on Aging (NIA), National Institutes of Health (NIH), Baltimore, MD 21224, USA.
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35
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Kazamel M, Wong LJ, Milone M. Novel OPA1 mutation featuring spastic paraparesis and intestinal dysmotility. Mol Genet Metab Rep 2014; 1:443-445. [PMID: 27896119 PMCID: PMC5121360 DOI: 10.1016/j.ymgmr.2014.09.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2014] [Revised: 09/26/2014] [Accepted: 09/26/2014] [Indexed: 01/21/2023] Open
Abstract
A 58-year-old man with optic atrophy, spastic paraparesis, axonal sensorimotor peripheral neuropathy and intestinal dysmotility harbors a novel heterozygous missense mutation in the mitochondrial import signal peptide of OPA1. The case underscores the role of OPA1 in the pathogenesis of spastic paraparesis, so far reported only in very few cases, and it adds intestinal dysmotility to the spectrum of adult-onset clinical manifestation of OPA1-associated disease.
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Affiliation(s)
- Mohamed Kazamel
- Department of Neurology, Mayo Clinic, Rochester, MN 55902, USA
| | - Lee-Jun Wong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
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36
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Prasun P, Koeberl DD. Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE)-like phenotype in a patient with a novel heterozygous POLG mutation. J Neurol 2014; 261:1818-9. [DOI: 10.1007/s00415-014-7428-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 06/26/2014] [Accepted: 06/27/2014] [Indexed: 01/21/2023]
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37
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Nogueira C, Almeida LS, Nesti C, Pezzini I, Videira A, Vilarinho L, Santorelli FM. Syndromes associated with mitochondrial DNA depletion. Ital J Pediatr 2014; 40:34. [PMID: 24708634 PMCID: PMC3985578 DOI: 10.1186/1824-7288-40-34] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 03/28/2014] [Indexed: 01/21/2023] Open
Abstract
Mitochondrial dysfunction accounts for a large group of inherited metabolic disorders most of which are due to a dysfunctional mitochondrial respiratory chain (MRC) and, consequently, deficient energy production. MRC function depends on the coordinated expression of both nuclear (nDNA) and mitochondrial (mtDNA) genomes. Thus, mitochondrial diseases can be caused by genetic defects in either the mitochondrial or the nuclear genome, or in the cross-talk between the two. This impaired cross-talk gives rise to so-called nuclear-mitochondrial intergenomic communication disorders, which result in loss or instability of the mitochondrial genome and, in turn, impaired maintenance of qualitative and quantitative mtDNA integrity. In children, most MRC disorders are associated with nuclear gene defects rather than alterations in the mtDNA itself. The mitochondrial DNA depletion syndromes (MDSs) are a clinically heterogeneous group of disorders with an autosomal recessive pattern of transmission that have onset in infancy or early childhood and are characterized by a reduced number of copies of mtDNA in affected tissues and organs. The MDSs can be divided into least four clinical presentations: hepatocerebral, myopathic, encephalomyopathic and neurogastrointestinal. The focus of this review is to offer an overview of these syndromes, listing the clinical phenotypes, together with their relative frequency, mutational spectrum, and possible insights for improving diagnostic strategies.
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Affiliation(s)
| | | | | | | | | | - Laura Vilarinho
- National Institute of Health, Genetics Department, Research and Development Unit, Porto, Portugal.
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38
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Farnum GA, Nurminen A, Kaguni LS. Mapping 136 pathogenic mutations into functional modules in human DNA polymerase γ establishes predictive genotype-phenotype correlations for the complete spectrum of POLG syndromes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:1113-21. [PMID: 24508722 DOI: 10.1016/j.bbabio.2014.01.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 01/28/2014] [Accepted: 01/29/2014] [Indexed: 01/21/2023]
Abstract
We establish the genotype-phenotype correlations for the complete spectrum of POLG syndromes by refining our previously described protocol for mapping pathogenic mutations in the human POLG gene to functional clusters in the catalytic core of the mitochondrial replicase, Pol γ (1). We assigned 136 mutations to five clusters and identify segments of primary sequence that can be used to delimit the boundaries of each cluster. We report that compound heterozygotes with two mutations from different clusters manifested more severe, earlier-onset POLG syndromes, whereas two mutations from the same cluster are less common and generally are associated with less severe, later onset POLG syndromes. We also show that specific cluster combinations are more severe than others and have a higher likelihood to manifest at an earlier age. Our clustering method provides a powerful tool to predict the pathogenic potential and predicted disease phenotype of novel variants and mutations in POLG, the most common nuclear gene underlying mitochondrial disorders. We propose that such a prediction tool would be useful for routine diagnostics for mitochondrial disorders. This article is part of a Special Issue entitled: 18th European Bioenergetic Conference.
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Affiliation(s)
- Gregory A Farnum
- Department of Biochemistry and Molecular Biology and Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, MI 48824-1319, USA
| | - Anssi Nurminen
- Institute of Biosciences and Medical Technology, University of Tampere, 33014 Tampere, Finland
| | - Laurie S Kaguni
- Department of Biochemistry and Molecular Biology and Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, MI 48824-1319, USA; Institute of Biosciences and Medical Technology, University of Tampere, 33014 Tampere, Finland
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Abstract
PURPOSE OF REVIEW The metabolic myopathies result from inborn errors of metabolism affecting intracellular energy production due to defects in glycogen, lipid, adenine nucleotides, and mitochondrial metabolism. This article provides an overview of the most common metabolic myopathies. RECENT FINDINGS Our knowledge of metabolic myopathies has expanded rapidly in recent years, providing us with major advances in the detection of genetic and biochemical defects. New and improved diagnostic tools are now available for some of these disorders, and targeted therapies for specific biochemical deficits have been developed (ie, enzyme replacement therapy for acid maltase deficiency). SUMMARY The diagnostic approach for patients with suspected metabolic myopathy should start with the recognition of a static or dynamic pattern (fixed versus exercise-induced weakness). Individual presentations vary according to age of onset and the severity of each particular biochemical dysfunction. Additional clinical clues include the presence of multisystem disease, family history, and laboratory characteristics. Appropriate investigations, timely treatment, and genetic counseling are discussed for the most common conditions.
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40
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Pareyson D, Piscosquito G, Moroni I, Salsano E, Zeviani M. Peripheral neuropathy in mitochondrial disorders. Lancet Neurol 2013; 12:1011-24. [PMID: 24050734 DOI: 10.1016/s1474-4422(13)70158-3] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Why is peripheral neuropathy common but mild in many mitochondrial disorders, and why is it, in some cases, the predominant or only manifestation? Although this question remains largely unanswered, recent advances in cellular and molecular biology have begun to clarify the importance of mitochondrial functioning and distribution in the peripheral nerve. Mutations in proteins involved in mitochondrial dynamics (ie, fusion and fission) frequently result in a Charcot-Marie-Tooth phenotype. Peripheral neuropathies with different phenotypic presentations occur in mitochondrial diseases associated with abnormalities in mitochondrial DNA replication and maintenance, or associated with defects in mitochondrial respiratory chain complex V. Our knowledge of mitochondrial disorders is rapidly growing as new nuclear genes are identified and new phenotypes described. Early diagnosis of mitochondrial disorders, essential to provide appropriate genetic counselling, has become crucial in a few treatable conditions. Recognising and diagnosing an underlying mitochondrial defect in patients presenting with peripheral neuropathy is therefore of paramount importance.
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Affiliation(s)
- Davide Pareyson
- Clinic of Central and Peripheral Degenerative Neuropathies Unit, Department of Clinical Neurosciences, Milan, Italy.
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Scarpelli M, Ricciardi GK, Beltramello A, Zocca I, Calabria F, Russignan A, Zappini F, Cotelli MS, Padovani A, Tomelleri G, Filosto M, Tonin P. The role of brain MRI in mitochondrial neurogastrointestinal encephalomyopathy. Neuroradiol J 2013; 26:520-30. [PMID: 24199812 DOI: 10.1177/197140091302600505] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 09/08/2013] [Indexed: 12/11/2022] Open
Abstract
Leukoencephalopathy is a hallmark of mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) a devastating disorder characterized by ptosis, ophthalmoparesis, gastrointestinal dysfunction and polyneuropathy. To characterize MNGIE-associated leukoencephalopathy and to correlate it with clinical, biochemical and molecular data, four MNGIE patients with heterogeneous clinical phenotypes (enteropathic arthritis, exercise intolerance, CIDP-like phenotype and typical presentation) were studied by magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS). Diffusion weighted imaging (DWI) with apparent diffusion coefficient (ADC) maps were also obtained. In two patients we also investigated the role of brain MRI in monitoring the evolution of leukoencephalopathy by performing follow-up imaging studies at an interval of one and two years. The extension and distribution of leukoencephalopathy were not clearly linked with age, phenotype or disease severity, and did not seem to be related to TYMP mutations, enzyme activity or pyrimidine levels. In the studied patients MRS revealed reduced N-acetyl-aspartate and increased choline signals. Although DWI appeared normal in all patients but one, ADC maps always showed moderate increased diffusivity. Leukoencephalopathy worsened over a two-year period in two patients, regardless of the clinical course, indicating a lack of correlation between clinical phenotype, size and progression of white matter abnormalities during this period. Brain MRI should be considered a very useful tool to diagnose both classical and atypical MNGIE. Serial MRIs in untreated and treated MNGIE patients will help to establish whether the leukoencephalopathy is a reversible condition or not.
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Affiliation(s)
- Mauro Scarpelli
- Department of Neurological and Movement Sciences, Section of Neurology, University of Verona; Verona, Italy -
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Recent advances in clinical neurogenetics. J Neurol 2013; 260:2451-7. [DOI: 10.1007/s00415-012-6757-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 11/06/2012] [Accepted: 11/09/2012] [Indexed: 11/24/2022]
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Sagnelli A, Piscosquito G, Pareyson D. Inherited neuropathies: an update. J Neurol 2013; 260:2684-90. [PMID: 24061768 DOI: 10.1007/s00415-013-7113-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 09/11/2013] [Accepted: 09/12/2013] [Indexed: 01/21/2023]
Abstract
In this review, progress in hereditary neuropathy research published in the Journal of Neurology over the last 18 months is summarised.
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Affiliation(s)
- Anna Sagnelli
- Clinic of Central and Peripheral Degenerative Neuropathies Unit, Department of Clinical Neurosciences, IRCCS Foundation, "C. Besta" Neurological Institute, via Celoria 11, 20133, Milan, Italy
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Adding to the burden: gastrointestinal symptoms and syndromes in multiple sclerosis. Mult Scler Int 2013; 2013:319201. [PMID: 24163768 PMCID: PMC3791579 DOI: 10.1155/2013/319201] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 08/14/2013] [Indexed: 02/06/2023] Open
Abstract
Background. Multiple sclerosis (MS) patients often suffer from gastrointestinal (GI) symptoms. However, the full extent and prevalence of such symptoms are not clearly established. Thus, we sought to define the prevalence of GI symptoms and syndromes in those with MS. Methods. 218 MS patients completed self-reported demographic and clinical data questionnaires as well as several standardized surveys probing MS severity and GI health. Results. Nearly two thirds (65.6%) of patients endorsed at least one persistent GI symptom. Constipation (36.6%), dysphagia (21.1%), and fecal incontinence (15.1%) were common. Surprisingly, nearly 30% (28.4%) of the patients reported dyspeptic symptoms. Using validated diagnostic algorithms, patients met criteria for functional dysphagia (14.7%), functional dyspepsia (16.5%), functional constipation (31.7%), and IBS (19.3%), among others. Functional dysphagia, functional dyspepsia, and IBS were significantly more common in those with self-identified mood disorders. Conclusions. Constipation, fecal incontinence, and dysphagia are indeed frequent symptoms seen in MS patients. We also noted a ~30% prevalence of dyspepsia in this population. The mechanisms driving this association are not clear and require further study. However, due to this high prevalence, dyspeptic symptoms should be incorporated into the routine assessment of MS patients and, if found, may warrant collaborative referral with a GI specialist.
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El-Hattab AW, Scaglia F. Mitochondrial DNA depletion syndromes: review and updates of genetic basis, manifestations, and therapeutic options. Neurotherapeutics 2013; 10:186-98. [PMID: 23385875 PMCID: PMC3625391 DOI: 10.1007/s13311-013-0177-6] [Citation(s) in RCA: 157] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Mitochondrial DNA (mtDNA) depletion syndromes (MDS) are a genetically and clinically heterogeneous group of autosomal recessive disorders that are characterized by a severe reduction in mtDNA content leading to impaired energy production in affected tissues and organs. MDS are due to defects in mtDNA maintenance caused by mutations in nuclear genes that function in either mitochondrial nucleotide synthesis (TK2, SUCLA2, SUCLG1, RRM2B, DGUOK, and TYMP) or mtDNA replication (POLG and C10orf2). MDS are phenotypically heterogeneous and usually classified as myopathic, encephalomyopathic, hepatocerebral or neurogastrointestinal. Myopathic MDS, caused by mutations in TK2, usually present before the age of 2 years with hypotonia and muscle weakness. Encephalomyopathic MDS, caused by mutations in SUCLA2, SUCLG1, or RRM2B, typically present during infancy with hypotonia and pronounced neurological features. Hepatocerebral MDS, caused by mutations in DGUOK, MPV17, POLG, or C10orf2, commonly have an early-onset liver dysfunction and neurological involvement. Finally, TYMP mutations have been associated with mitochondrial neurogastrointestinal encephalopathy (MNGIE) disease that typically presents before the age of 20 years with progressive gastrointestinal dysmotility and peripheral neuropathy. Overall, MDS are severe disorders with poor prognosis in the majority of affected individuals. No efficacious therapy is available for any of these disorders. Affected individuals should have a comprehensive evaluation to assess the degree of involvement of different systems. Treatment is directed mainly toward providing symptomatic management. Nutritional modulation and cofactor supplementation may be beneficial. Liver transplantation remains controversial. Finally, stem cell transplantation in MNGIE disease shows promising results.
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Affiliation(s)
- Ayman W. El-Hattab
- />Division of Medical Genetics, Department of Pediatrics, The Children’s Hospital, King Fahad Medical City and Faculty of Medicine, King Saud bin Abdulaziz University for Health Science, Riyadh, Kingdom of Saudi Arabia
| | - Fernando Scaglia
- />Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, MS BCM225, Houston, TX 77030 USA
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Abstract
There has been considerable progress during the past 24 years in the molecular genetics of mitochondrial DNA and related nuclear DNA mutations, and more than 100 nerve biopsies from hereditary neuropathies related to mitochondrial cytopathy have been accurately examined. Neuropathies were first reported in diseases related to point mutations of mitochondrial DNA, but they proved to be a prominent feature of the phenotype in mitochondrial disorders caused by defects in nuclear DNA, particularly in 3 genes: polymerase gamma 1 (POLG1), mitofusin 2 (MFN2), and ganglioside-induced differentiation-associated protein 1 (GDAP1). Most patients have sensory-motor neuropathy, sometimes associated with ophthalmoplegia, ataxia, seizures, parkinsonism, myopathy, or visceral disorders. Some cases are caused by consanguinity, but most are sporadic with various phenotypes mimicking a wide range of other etiologies. Histochemistry on muscle biopsy, as well as identification of crystalloid inclusions at electron microscopy, may provide a diagnostic clue to mitochondriopathy, but nerve biopsy is often less informative. Nevertheless, enlarged mitochondria containing distorted or amputated cristae are highly suggestive, particularly when located in the Schwann cell cytoplasm. Also noticeable are clusters of regenerating myelinated fibers surrounded by concentric Schwann cell processes, and such onion bulb-like formations are frequently observed in neuropathies caused by GDAP1 mutations.
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