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Borrelli E, Bandello F, Boon CJF, Carelli V, Lenaers G, Reibaldi M, Sadda SR, Sadun AA, Sarraf D, Yu-Wai-Man P, Barboni P. Mitochondrial retinopathies and optic neuropathies: The impact of retinal imaging on modern understanding of pathogenesis, diagnosis, and management. Prog Retin Eye Res 2024; 101:101264. [PMID: 38703886 DOI: 10.1016/j.preteyeres.2024.101264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 03/18/2024] [Accepted: 04/26/2024] [Indexed: 05/06/2024]
Abstract
Advancements in ocular imaging have significantly broadened our comprehension of mitochondrial retinopathies and optic neuropathies by examining the structural and pathological aspects of the retina and optic nerve in these conditions. This article aims to review the prominent imaging characteristics associated with mitochondrial retinopathies and optic neuropathies, aiming to deepen our insight into their pathogenesis and clinical features. Preceding this exploration, the article provides a detailed overview of the crucial genetic and clinical features, which is essential for the proper interpretation of in vivo imaging. More importantly, we will provide a critical analysis on how these imaging modalities could serve as biomarkers for characterization and monitoring, as well as in guiding treatment decisions. However, these imaging methods have limitations, which will be discussed along with potential strategies to mitigate them. Lastly, the article will emphasize the potential advantages and future integration of imaging techniques in evaluating patients with mitochondrial eye disorders, considering the prospects of emerging gene therapies.
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Affiliation(s)
- Enrico Borrelli
- Department of Surgical Sciences, University of Turin, Turin, Italy; Department of Ophthalmology, "City of Health and Science" Hospital, Turin, Italy.
| | - Francesco Bandello
- Vita-Salute San Raffaele University, Milan, Italy; IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Camiel J F Boon
- Department of Ophthalmology, Amsterdam University Medical Centers, Amsterdam, the Netherlands; Department of Ophthalmology, Leiden University Medical Center, Leiden, the Netherlands
| | - Valerio Carelli
- Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy; IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy
| | - Guy Lenaers
- Equipe MitoLab, Unité MitoVasc, INSERM U1083, Université d'Angers, 49933, Angers, France; Service de Neurologie, CHU d'Angers, 49100, Angers, France
| | - Michele Reibaldi
- Department of Surgical Sciences, University of Turin, Turin, Italy; Department of Ophthalmology, "City of Health and Science" Hospital, Turin, Italy
| | - Srinivas R Sadda
- Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Doheny Eye Institute, Los Angeles, CA, USA
| | - Alfredo A Sadun
- Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Doheny Eye Institute, Los Angeles, CA, USA
| | - David Sarraf
- Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Retinal Disorders and Ophthalmic Genetics Division, Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Patrick Yu-Wai-Man
- John van Geest Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Cambridge Eye Unit, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK; Institute of Ophthalmology, University College London, London, UK
| | - Piero Barboni
- IRCCS San Raffaele Scientific Institute, Milan, Italy; Studio Oculistico d'Azeglio, Bologna, Italy.
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2
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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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3
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Deen D, Alston CL, Hudson G, Taylor RW, Pyle A. Genomic Strategies in Mitochondrial Diagnostics. Methods Mol Biol 2023; 2615:397-425. [PMID: 36807806 DOI: 10.1007/978-1-0716-2922-2_27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Pathogenic variants in both mitochondrial and nuclear genes contribute to the clinical and genetic heterogeneity of mitochondrial diseases. There are now pathogenic variants in over 300 nuclear genes linked to human mitochondrial diseases. Nonetheless, diagnosing mitochondrial disease with a genetic outcome remains challenging. However, there are now many strategies that help us to pinpoint causative variants in patients with mitochondrial disease. This chapter describes some of the approaches and recent advancements in gene/variant prioritization using whole-exome sequencing (WES).
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Affiliation(s)
- Dasha Deen
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Charlotte L Alston
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.,NHS Highly Specialised Services for Rare Mitochondrial Disorders, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Gavin Hudson
- Wellcome Centre for Mitochondrial Research, Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.,NHS Highly Specialised Services for Rare Mitochondrial Disorders, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Angela Pyle
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.
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4
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Genetics of mitochondrial diseases: Current approaches for the molecular diagnosis. HANDBOOK OF CLINICAL NEUROLOGY 2023; 194:141-165. [PMID: 36813310 DOI: 10.1016/b978-0-12-821751-1.00011-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Mitochondrial diseases are a genetically and phenotypically variable set of monogenic disorders. The main characteristic of mitochondrial diseases is a defective oxidative phosphorylation. Both nuclear and mitochondrial DNA encode the approximately 1500 mitochondrial proteins. Since identification of the first mitochondrial disease gene in 1988 a total of 425 genes have been associated with mitochondrial diseases. Mitochondrial dysfunctions can be caused both by pathogenic variants in the mitochondrial DNA or the nuclear DNA. Hence, besides maternal inheritance, mitochondrial diseases can follow all modes of Mendelian inheritance. The maternal inheritance and tissue specificity distinguish molecular diagnostics of mitochondrial disorders from other rare disorders. With the advances made in the next-generation sequencing technology, whole exome sequencing and even whole-genome sequencing are now the established methods of choice for molecular diagnostics of mitochondrial diseases. They reach a diagnostic rate of more than 50% in clinically suspected mitochondrial disease patients. Moreover, next-generation sequencing is delivering a constantly growing number of novel mitochondrial disease genes. This chapter reviews mitochondrial and nuclear causes of mitochondrial diseases, molecular diagnostic methodologies, and their current challenges and perspectives.
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5
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Genetic testing for mitochondrial disease: the United Kingdom best practice guidelines. Eur J Hum Genet 2023; 31:148-163. [PMID: 36513735 PMCID: PMC9905091 DOI: 10.1038/s41431-022-01249-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 11/12/2022] [Accepted: 11/16/2022] [Indexed: 12/15/2022] Open
Abstract
Primary mitochondrial disease describes a diverse group of neuro-metabolic disorders characterised by impaired oxidative phosphorylation. Diagnosis is challenging; >350 genes, both nuclear and mitochondrial DNA (mtDNA) encoded, are known to cause mitochondrial disease, leading to all possible inheritance patterns and further complicated by heteroplasmy of the multicopy mitochondrial genome. Technological advances, particularly next-generation sequencing, have driven a shift in diagnostic practice from 'biopsy first' to genome-wide analyses of blood and/or urine DNA. This has led to the need for a reference framework for laboratories involved in mitochondrial genetic testing to facilitate a consistent high-quality service. In the United Kingdom, consensus guidelines have been prepared by a working group of Clinical Scientists from the NHS Highly Specialised Service followed by national laboratory consultation. These guidelines summarise current recommended technologies and methodologies for the analysis of mtDNA and nuclear-encoded genes in patients with suspected mitochondrial disease. Genetic testing strategies for diagnosis, family testing and reproductive options including prenatal diagnosis are outlined. Importantly, recommendations for the minimum levels of mtDNA testing for the most common referral reasons are included, as well as guidance on appropriate referrals and information on the minimal appropriate gene content of panels when analysing nuclear mitochondrial genes. Finally, variant interpretation and recommendations for reporting of results are discussed, focussing particularly on the challenges of interpreting and reporting mtDNA variants.
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6
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Ait-El-Mkadem Saadi S, Kaphan E, Morales Jaurrieta A, Fragaki K, Chaussenot A, Bannwarth S, Maues De Paula A, Paquis-Flucklinger V, Rouzier C. Splicing variants in NARS2 are associated with milder phenotypes and intra-familial variability. Eur J Med Genet 2022; 65:104643. [DOI: 10.1016/j.ejmg.2022.104643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 10/07/2022] [Accepted: 10/10/2022] [Indexed: 11/03/2022]
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7
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Yuan M, Guo Y, Xia H, Xu H, Deng H, Yuan L. Novel SCN5A and GPD1L Variants Identified in Two Unrelated Han-Chinese Patients With Clinically Suspected Brugada Syndrome. Front Cardiovasc Med 2021; 8:758903. [PMID: 34957250 PMCID: PMC8692717 DOI: 10.3389/fcvm.2021.758903] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Accepted: 10/29/2021] [Indexed: 12/25/2022] Open
Abstract
Brugada syndrome (BrS) is a complexly genetically patterned, rare, malignant, life-threatening arrhythmia disorder. It is autosomal dominant in most cases and characterized by identifiable electrocardiographic patterns, recurrent syncope, nocturnal agonal respiration, and other symptoms, including sudden cardiac death. Over the last 2 decades, a great number of variants have been identified in more than 36 pathogenic or susceptibility genes associated with BrS. The present study used the combined method of whole exome sequencing and Sanger sequencing to identify pathogenic variants in two unrelated Han-Chinese patients with clinically suspected BrS. Minigene splicing assay was used to evaluate the effects of the splicing variant. A novel heterozygous splicing variant c.2437-2A>C in the sodium voltage-gated channel alpha subunit 5 gene (SCN5A) and a novel heterozygous missense variant c.161A>T [p.(Asp54Val)] in the glycerol-3-phosphate dehydrogenase 1 like gene (GPD1L) were identified in these two patients with BrS-1 and possible BrS-2, respectively. Minigene splicing assay indicated the deletion of 15 and 141 nucleotides in exon 16, resulting in critical amino acid deletions. These findings expand the variant spectrum of SCN5A and GPD1L, which can be beneficial to genetic counseling and prenatal diagnosis.
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Affiliation(s)
- Meng Yuan
- Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Yi Guo
- Department of Medical Information, School of Life Sciences, Central South University, Changsha, China
| | - Hong Xia
- Department of Emergency, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Hongbo Xu
- Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Hao Deng
- Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, China.,Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, China.,Disease Genome Research Center, Central South University, Changsha, China
| | - Lamei Yuan
- Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, China.,Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, China.,Disease Genome Research Center, Central South University, Changsha, China
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8
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Ullah F, Rauf W, Khan K, Khan S, Bell KM, de Oliveira VC, Tariq M, Bakhshalizadeh S, Touraine P, Katsanis N, Sinclair A, He S, Tucker EJ, Baig SM, Davis EE. A recessive variant in TFAM causes mtDNA depletion associated with primary ovarian insufficiency, seizures, intellectual disability and hearing loss. Hum Genet 2021; 140:1733-1751. [PMID: 34647195 DOI: 10.1007/s00439-021-02380-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 09/30/2021] [Indexed: 12/25/2022]
Abstract
Mitochondrial disorders are collectively common, genetically heterogeneous disorders in both pediatric and adult populations. They are caused by molecular defects in oxidative phosphorylation, failure of essential bioenergetic supply to mitochondria, and apoptosis. Here, we present three affected individuals from a consanguineous family of Pakistani origin with variable seizures and intellectual disability. Both females display primary ovarian insufficiency (POI), while the male shows abnormal sex hormone levels. We performed whole exome sequencing and identified a recessive missense variant c.694C > T, p.Arg232Cys in TFAM that segregates with disease. TFAM (mitochondrial transcription factor A) is a component of the mitochondrial replisome machinery that maintains mtDNA transcription and replication. In primary dermal fibroblasts, we show depletion of mtDNA and significantly altered mitochondrial function and morphology. Moreover, we observed reduced nucleoid numbers with significant changes in nucleoid size or shape in fibroblasts from an affected individual compared to controls. We also investigated the effect of tfam impairment in zebrafish; homozygous tfam mutants carrying an in-frame c.141_149 deletion recapitulate the mtDNA depletion and ovarian dysgenesis phenotypes observed in affected humans. Together, our genetic and functional data confirm that TFAM plays a pivotal role in gonad development and expands the repertoire of mitochondrial disease phenotypes.
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Affiliation(s)
- Farid Ullah
- National Institute for Biotechnology and Genetic Engineering (NIBGE-C), Faisalabad, Pakistan.,Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan.,Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Waqar Rauf
- National Institute for Biotechnology and Genetic Engineering (NIBGE-C), Faisalabad, Pakistan.,Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan
| | - Kamal Khan
- Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Sheraz Khan
- National Institute for Biotechnology and Genetic Engineering (NIBGE-C), Faisalabad, Pakistan.,Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan.,Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Katrina M Bell
- Department of Pediatrics, University of Melbourne, Melbourne, Australia.,Bioinformatics, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Australia
| | - Vanessa Cristina de Oliveira
- Department of Veterinary Medicine, Faculty of Animal Science and Food Engineering, University of São Paulo, Pirassununga, São Paulo, Brazil
| | - Muhammad Tariq
- National Institute for Biotechnology and Genetic Engineering (NIBGE-C), Faisalabad, Pakistan.,Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan
| | - Shabnam Bakhshalizadeh
- Department of Pediatrics, University of Melbourne, Melbourne, Australia.,Reproductive Development, MurdochChildren's Research Institute, Royal Children's Hospital, Melbourne, Australia
| | - Philippe Touraine
- Department of Endocrinology and Reproductive Medicine, Center for Rare Endocrine and Gynecological Diseases, Sorbonne Université Pitié Salpétrière Hospital, Paris, France
| | - Nicholas Katsanis
- Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA.,Rescindo Therapeutics, Cary, NC, USA
| | - Andrew Sinclair
- Department of Pediatrics, University of Melbourne, Melbourne, Australia.,Reproductive Development, MurdochChildren's Research Institute, Royal Children's Hospital, Melbourne, Australia
| | | | - Elena J Tucker
- Department of Pediatrics, University of Melbourne, Melbourne, Australia.,Reproductive Development, MurdochChildren's Research Institute, Royal Children's Hospital, Melbourne, Australia
| | - Shahid M Baig
- National Institute for Biotechnology and Genetic Engineering (NIBGE-C), Faisalabad, Pakistan.,Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan.,Pakistan Science Foundation, Constitution Avenue, Islamabad, Pakistan.,Department of Biological and Biomedical Sciences, Aga Khan University, Karachi, Pakistan
| | - Erica E Davis
- Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA. .,Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. .,Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
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9
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Klopstock T, Priglinger C, Yilmaz A, Kornblum C, Distelmaier F, Prokisch H. Mitochondrial Disorders. DEUTSCHES ARZTEBLATT INTERNATIONAL 2021; 118:741-748. [PMID: 34158150 DOI: 10.3238/arztebl.m2021.0251] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 11/19/2020] [Accepted: 05/20/2021] [Indexed: 11/27/2022]
Abstract
BACKGROUND Mitochondrial disorders are among the most common heritable diseases, with an overall lifetime risk of approximately one in 1500. Nonetheless, their diagnosis is often missed because of their extreme phenotypic and genotypic heterogeneity. METHODS This review is based on publications retrieved by a selective literature search on the clinical features, genetics, pathogenesis, diagnosis, and treatment of mitochondrial diseases. RESULTS Pathogenic defects of energy metabolism have been described to date in over 400 genes. Only a small number of these genes lie in the mitochondrial DNA; the corresponding diseases are either maternally inherited or of sporadic distribution. The remaining diseaseassociated genes are coded in nuclear DNA and cause diseases that are inherited according to Mendelian rules, mostly autosomal recessive. The most severely involved organs are generally those with the highest energy requirements, including the brain, the sensory epithelia, and the extraocular, cardiac, and skeletal musculature. Typical manifestations include epileptic seizures, stroke-like episodes, hearing loss, retinopathy, external ophthalmoparesis, exercise intolerance, and diabetes mellitus. More than two manifestations of these types should arouse suspicion of a disease of energy metabolism. The severity of mitochondrial disorders ranges from very severe disease, already evident in childhood, to relatively mild disease arising in late adulthood. The diagnosis is usually confirmed with molecular-genetic methods. Symptomatic treatment can improve patients' quality of life. The only disease-modifying treatment that has been approved to date is idebenone for the treatment of Leber hereditary optic neuropathy. Intravitreal gene therapy has also been developed for the treatment of this disease; its approval by the European Medicines Agency is pending. CONCLUSION Patients with mitochondrial diseases have highly varied manifestations and can thus present to physicians in practically any branch of medicine. A correct diagnosis is the prerequisite for genetic counseling and for the initiation of personalized treatment.
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10
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Kishita Y, Shimura M, Kohda M, Fushimi T, Nitta KR, Yatsuka Y, Hirose S, Ideguchi H, Ohtake A, Murayama K, Okazaki Y. Genome sequencing and RNA-seq analyses of mitochondrial complex I deficiency revealed Alu insertion-mediated deletion in NDUFV2. Hum Mutat 2021; 42:1422-1428. [PMID: 34405929 DOI: 10.1002/humu.24274] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 06/25/2021] [Accepted: 07/15/2021] [Indexed: 11/08/2022]
Abstract
Isolated complex I deficiency is the most common cause of pediatric mitochondrial disease. Exome sequencing (ES) has revealed many complex I causative genes. However, there are limitations associated with identifying causative genes by ES analysis. In this study, we performed multiomics analysis to reveal the causal variants. We here report two cases with mitochondrial complex I deficiency. In both cases, ES identified a novel c.580G>A (p.Glu194Lys) variant in NDUFV2. One case additionally harbored c.427C>T (p.Arg143*), but no other variants were observed in the other case. RNA sequencing showed aberrant exon splicing of NDUFV2 in the unsolved case. Genome sequencing revealed a novel heterozygous deletion in NDUFV2, which included one exon and resulted in exon skipping. Detailed examination of the breakpoint revealed that an Alu insertion-mediated rearrangement caused the deletion. Our report reveals that combined use of transcriptome sequencing and GS was effective for diagnosing cases that were unresolved by ES.
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Affiliation(s)
- Yoshihito Kishita
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan.,Department of Life Science, Faculty of Science and Engineering, Kindai University, Osaka, Japan
| | - Masaru Shimura
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Masakazu Kohda
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Takuya Fushimi
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Kazuhiro R Nitta
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Yukiko Yatsuka
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Shinichi Hirose
- General Medical Research Center, School of Medicine, Fukuoka University, Fukuoka, Japan
| | - Hiroshi Ideguchi
- Department of Pediatrics, Fukuoka Sanno Hospital, Fukuoka, Japan
| | - Akira Ohtake
- Department of Pediatrics & Clinical Genomics, Faculty of Medicine, Saitama Medical University, Saitama, Japan.,Center for Intractable Diseases, Saitama Medical University Hospital, Saitama, Japan
| | - Kei Murayama
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan.,Department of Metabolism, Chiba Children's Hospital, Chiba, Japan.,Center for Medical Genetics, Chiba Children's Hospital, Chiba, Japan
| | - Yasushi Okazaki
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan.,Laboratory for Comprehensive Genomic Analysis, RIKEN Centre for Integrative Medical Sciences, Kanagawa, Japan
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11
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Zanfardino P, Doccini S, Santorelli FM, Petruzzella V. Tackling Dysfunction of Mitochondrial Bioenergetics in the Brain. Int J Mol Sci 2021; 22:8325. [PMID: 34361091 PMCID: PMC8348117 DOI: 10.3390/ijms22158325] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/29/2021] [Accepted: 07/30/2021] [Indexed: 12/15/2022] Open
Abstract
Oxidative phosphorylation (OxPhos) is the basic function of mitochondria, although the landscape of mitochondrial functions is continuously growing to include more aspects of cellular homeostasis. Thanks to the application of -omics technologies to the study of the OxPhos system, novel features emerge from the cataloging of novel proteins as mitochondrial thus adding details to the mitochondrial proteome and defining novel metabolic cellular interrelations, especially in the human brain. We focussed on the diversity of bioenergetics demand and different aspects of mitochondrial structure, functions, and dysfunction in the brain. Definition such as 'mitoexome', 'mitoproteome' and 'mitointeractome' have entered the field of 'mitochondrial medicine'. In this context, we reviewed several genetic defects that hamper the last step of aerobic metabolism, mostly involving the nervous tissue as one of the most prominent energy-dependent tissues and, as consequence, as a primary target of mitochondrial dysfunction. The dual genetic origin of the OxPhos complexes is one of the reasons for the complexity of the genotype-phenotype correlation when facing human diseases associated with mitochondrial defects. Such complexity clinically manifests with extremely heterogeneous symptoms, ranging from organ-specific to multisystemic dysfunction with different clinical courses. Finally, we briefly discuss the future directions of the multi-omics study of human brain disorders.
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Affiliation(s)
- Paola Zanfardino
- Department of Medical Basic Sciences, Neurosciences and Sense Organs, University of Bari Aldo Moro, 70124 Bari, Italy;
| | - Stefano Doccini
- IRCCS Fondazione Stella Maris, Calambrone, 56128 Pisa, Italy;
| | | | - Vittoria Petruzzella
- Department of Medical Basic Sciences, Neurosciences and Sense Organs, University of Bari Aldo Moro, 70124 Bari, Italy;
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12
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Braun F, Hentschel A, Sickmann A, Marteau T, Hertel S, Förster F, Prokisch H, Wagner M, Wortmann S, Della Marina A, Kölbel H, Roos A, Schara-Schmidt U. Muscular and Molecular Pathology Associated with SPATA5 Deficiency in a Child with EHLMRS. Int J Mol Sci 2021; 22:ijms22157835. [PMID: 34360601 PMCID: PMC8345956 DOI: 10.3390/ijms22157835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 07/09/2021] [Accepted: 07/20/2021] [Indexed: 11/16/2022] Open
Abstract
Mutations in the SPATA5 gene are associated with epilepsy, hearing loss and mental retardation syndrome (EHLMRS). While SPATA5 is ubiquitously expressed and is attributed a role within mitochondrial morphogenesis during spermatogenesis, there is only limited knowledge about the associated muscular and molecular pathology. This study reports on a comprehensive workup of muscular pathology, including proteomic profiling and microscopic studies, performed on an 8-year-old girl with typical clinical presentation of EHLMRS, where exome analysis revealed two clinically relevant, compound-heterozygous variants in SPATA5. Proteomic profiling of a quadriceps biopsy showed the dysregulation of 82 proteins, out of which 15 were localized in the mitochondrion, while 19 were associated with diseases presenting with phenotypical overlap to EHLMRS. Histological staining of our patient’s muscle biopsy hints towards mitochondrial pathology, while the identification of dysregulated proteins attested to the vulnerability of the cell beyond the mitochondria. Through our study we provide insights into the molecular etiology of EHLMRS and provide further evidence for a muscle pathology associated with SPATA5 deficiency, including a pathological histochemical pattern accompanied by dysregulated protein expression.
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Affiliation(s)
- Frederik Braun
- Centre for Neuromuscular Disorders, Centre for Translational Neuro- and Behavioral Sciences, Department of Pediatric Neurology, University Duisburg-Essen, 45147 Essen, Germany; (T.M.); (S.H.); (F.F.); (A.D.M.); (H.K.); (A.R.); (U.S.-S.)
- Correspondence:
| | - Andreas Hentschel
- Leibniz-Institut für Analytische Wissenschaften—ISAS e.V., 44139 Dortmund, Germany; (A.H.); (A.S.)
| | - Albert Sickmann
- Leibniz-Institut für Analytische Wissenschaften—ISAS e.V., 44139 Dortmund, Germany; (A.H.); (A.S.)
| | - Theodore Marteau
- Centre for Neuromuscular Disorders, Centre for Translational Neuro- and Behavioral Sciences, Department of Pediatric Neurology, University Duisburg-Essen, 45147 Essen, Germany; (T.M.); (S.H.); (F.F.); (A.D.M.); (H.K.); (A.R.); (U.S.-S.)
| | - Swantje Hertel
- Centre for Neuromuscular Disorders, Centre for Translational Neuro- and Behavioral Sciences, Department of Pediatric Neurology, University Duisburg-Essen, 45147 Essen, Germany; (T.M.); (S.H.); (F.F.); (A.D.M.); (H.K.); (A.R.); (U.S.-S.)
| | - Fabian Förster
- Centre for Neuromuscular Disorders, Centre for Translational Neuro- and Behavioral Sciences, Department of Pediatric Neurology, University Duisburg-Essen, 45147 Essen, Germany; (T.M.); (S.H.); (F.F.); (A.D.M.); (H.K.); (A.R.); (U.S.-S.)
| | - Holger Prokisch
- Institute of Human Genetics, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, 81675 Munich, Germany; (H.P.); (M.W.); (S.W.)
- Helmholtz Zentrum München—German Research Center for Environmental Health, Institute of Neurogenomics, 85764 Neuherberg, Germany
| | - Matias Wagner
- Institute of Human Genetics, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, 81675 Munich, Germany; (H.P.); (M.W.); (S.W.)
- Helmholtz Zentrum München—German Research Center for Environmental Health, Institute of Neurogenomics, 85764 Neuherberg, Germany
| | - Saskia Wortmann
- Institute of Human Genetics, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, 81675 Munich, Germany; (H.P.); (M.W.); (S.W.)
| | - Adela Della Marina
- Centre for Neuromuscular Disorders, Centre for Translational Neuro- and Behavioral Sciences, Department of Pediatric Neurology, University Duisburg-Essen, 45147 Essen, Germany; (T.M.); (S.H.); (F.F.); (A.D.M.); (H.K.); (A.R.); (U.S.-S.)
| | - Heike Kölbel
- Centre for Neuromuscular Disorders, Centre for Translational Neuro- and Behavioral Sciences, Department of Pediatric Neurology, University Duisburg-Essen, 45147 Essen, Germany; (T.M.); (S.H.); (F.F.); (A.D.M.); (H.K.); (A.R.); (U.S.-S.)
| | - Andreas Roos
- Centre for Neuromuscular Disorders, Centre for Translational Neuro- and Behavioral Sciences, Department of Pediatric Neurology, University Duisburg-Essen, 45147 Essen, Germany; (T.M.); (S.H.); (F.F.); (A.D.M.); (H.K.); (A.R.); (U.S.-S.)
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON K1H 5B2, Canada
| | - Ulrike Schara-Schmidt
- Centre for Neuromuscular Disorders, Centre for Translational Neuro- and Behavioral Sciences, Department of Pediatric Neurology, University Duisburg-Essen, 45147 Essen, Germany; (T.M.); (S.H.); (F.F.); (A.D.M.); (H.K.); (A.R.); (U.S.-S.)
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13
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Biochemical consequences of two clinically relevant ND-gene mutations in Escherichia coli respiratory complex I. Sci Rep 2021; 11:12641. [PMID: 34135385 PMCID: PMC8209014 DOI: 10.1038/s41598-021-91631-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 05/28/2021] [Indexed: 11/28/2022] Open
Abstract
NADH:ubiquinone oxidoreductase (respiratory complex I) plays a major role in energy metabolism by coupling electron transfer from NADH to quinone with proton translocation across the membrane. Complex I deficiencies were found to be the most common source of human mitochondrial dysfunction that manifest in a wide variety of neurodegenerative diseases. Seven subunits of human complex I are encoded by mitochondrial DNA (mtDNA) that carry an unexpectedly large number of mutations discovered in mitochondria from patients’ tissues. However, whether or how these genetic aberrations affect complex I at a molecular level is unknown. Here, we used Escherichia coli as a model system to biochemically characterize two mutations that were found in mtDNA of patients. The V253AMT-ND5 mutation completely disturbed the assembly of complex I, while the mutation D199GMT-ND1 led to the assembly of a stable complex capable to catalyze redox-driven proton translocation. However, the latter mutation perturbs quinone reduction leading to a diminished activity. D199MT-ND1 is part of a cluster of charged amino acid residues that are suggested to be important for efficient coupling of quinone reduction and proton translocation. A mechanism considering the role of D199MT-ND1 for energy conservation in complex I is discussed.
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14
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Rossmann MP, Dubois SM, Agarwal S, Zon LI. Mitochondrial function in development and disease. Dis Model Mech 2021; 14:269120. [PMID: 34114603 PMCID: PMC8214736 DOI: 10.1242/dmm.048912] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Mitochondria are organelles with vital functions in almost all eukaryotic cells. Often described as the cellular ‘powerhouses’ due to their essential role in aerobic oxidative phosphorylation, mitochondria perform many other essential functions beyond energy production. As signaling organelles, mitochondria communicate with the nucleus and other organelles to help maintain cellular homeostasis, allow cellular adaptation to diverse stresses, and help steer cell fate decisions during development. Mitochondria have taken center stage in the research of normal and pathological processes, including normal tissue homeostasis and metabolism, neurodegeneration, immunity and infectious diseases. The central role that mitochondria assume within cells is evidenced by the broad impact of mitochondrial diseases, caused by defects in either mitochondrial or nuclear genes encoding for mitochondrial proteins, on different organ systems. In this Review, we will provide the reader with a foundation of the mitochondrial ‘hardware’, the mitochondrion itself, with its specific dynamics, quality control mechanisms and cross-organelle communication, including its roles as a driver of an innate immune response, all with a focus on development, disease and aging. We will further discuss how mitochondrial DNA is inherited, how its mutation affects cell and organismal fitness, and current therapeutic approaches for mitochondrial diseases in both model organisms and humans. Summary: Mitochondria have a plethora of functions beyond metabolism. This Review discusses the emerging and multifaceted roles of mitochondria in different model organisms and human disease biology.
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Affiliation(s)
- Marlies P Rossmann
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 01238, USA.,Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Howard Hughes Medical Institute, Boston, MA 02115, USA
| | - Sonia M Dubois
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Suneet Agarwal
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Leonard I Zon
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 01238, USA.,Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Howard Hughes Medical Institute, Boston, MA 02115, USA
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15
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Poole OV, Pizzamiglio C, Murphy D, Falabella M, Macken WL, Bugiardini E, Woodward CE, Labrum R, Efthymiou S, Salpietro V, Chelban V, Kaiyrzhanov R, Maroofian R, Amato AA, Gregory A, Hayflick SJ, Jonvik H, Wood N, Houlden H, Vandrovcova J, Hanna MG, Pittman A, Pitceathly RD. Mitochondrial DNA Analysis from Exome Sequencing Data Improves Diagnostic Yield in Neurological Diseases. Ann Neurol 2021; 89:1240-1247. [PMID: 33704825 PMCID: PMC8494076 DOI: 10.1002/ana.26063] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 03/05/2021] [Accepted: 03/08/2021] [Indexed: 12/18/2022]
Abstract
A rapidly expanding catalog of neurogenetic disorders has encouraged a diagnostic shift towards early clinical whole exome sequencing (WES). Adult primary mitochondrial diseases (PMDs) frequently exhibit neurological manifestations that overlap with other nervous system disorders. However, mitochondrial DNA (mtDNA) is not routinely analyzed in standard clinical WES bioinformatic pipelines. We reanalyzed 11,424 exomes, enriched with neurological diseases, for pathogenic mtDNA variants. Twenty-four different mtDNA mutations were detected in 64 exomes, 11 of which were considered disease causing based on the associated clinical phenotypes. These findings highlight the diagnostic uplifts gained by analyzing mtDNA from WES data in neurological diseases. ANN NEUROL 2021;89:1240-1247.
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Affiliation(s)
- Olivia V. Poole
- Department of Neuromuscular DiseasesUCL Queen Square Institute of Neurology and The National Hospital for Neurology and NeurosurgeryLondonUK
| | - Chiara Pizzamiglio
- Department of Neuromuscular DiseasesUCL Queen Square Institute of Neurology and The National Hospital for Neurology and NeurosurgeryLondonUK
| | - David Murphy
- Department of Clinical and Movement NeurosciencesUCL Queen Square Institute of Neurology and The National Hospital for Neurology and NeurosurgeryLondonUK
| | - Micol Falabella
- Department of Neuromuscular DiseasesUCL Queen Square Institute of NeurologyLondonUK
| | - William L. Macken
- Department of Neuromuscular DiseasesUCL Queen Square Institute of Neurology and The National Hospital for Neurology and NeurosurgeryLondonUK
| | - Enrico Bugiardini
- Department of Neuromuscular DiseasesUCL Queen Square Institute of Neurology and The National Hospital for Neurology and NeurosurgeryLondonUK
| | - Cathy E. Woodward
- Neurogenetics UnitThe National Hospital for Neurology and NeurosurgeryLondonUK
| | - Robyn Labrum
- Neurogenetics UnitThe National Hospital for Neurology and NeurosurgeryLondonUK
| | - Stephanie Efthymiou
- Department of Neuromuscular DiseasesUCL Queen Square Institute of Neurology and The National Hospital for Neurology and NeurosurgeryLondonUK
| | - Vincenzo Salpietro
- Department of Neuromuscular DiseasesUCL Queen Square Institute of Neurology and The National Hospital for Neurology and NeurosurgeryLondonUK
| | - Viorica Chelban
- Department of Neuromuscular DiseasesUCL Queen Square Institute of Neurology and The National Hospital for Neurology and NeurosurgeryLondonUK
| | - Rauan Kaiyrzhanov
- Department of Neuromuscular DiseasesUCL Queen Square Institute of Neurology and The National Hospital for Neurology and NeurosurgeryLondonUK
| | - Reza Maroofian
- Department of Neuromuscular DiseasesUCL Queen Square Institute of Neurology and The National Hospital for Neurology and NeurosurgeryLondonUK
| | | | - Anthony A. Amato
- Department of NeurologyBrigham and Women's Hospital and Harvard Medical SchoolBostonMA
| | - Allison Gregory
- Departments of Molecular and Medical Genetics, Pediatrics, and NeurologyOregon Health and Science UniversityPortlandOR
| | - Susan J. Hayflick
- Departments of Molecular and Medical Genetics, Pediatrics, and NeurologyOregon Health and Science UniversityPortlandOR
| | | | - Hallgeir Jonvik
- Department of Clinical and Movement NeurosciencesUCL Queen Square Institute of Neurology and The National Hospital for Neurology and NeurosurgeryLondonUK
| | - Nicholas Wood
- Department of Clinical and Movement NeurosciencesUCL Queen Square Institute of Neurology and The National Hospital for Neurology and NeurosurgeryLondonUK
| | - Henry Houlden
- Department of Neuromuscular DiseasesUCL Queen Square Institute of Neurology and The National Hospital for Neurology and NeurosurgeryLondonUK
| | - Jana Vandrovcova
- Department of Neuromuscular DiseasesUCL Queen Square Institute of Neurology and The National Hospital for Neurology and NeurosurgeryLondonUK
| | - Michael G. Hanna
- Department of Neuromuscular DiseasesUCL Queen Square Institute of Neurology and The National Hospital for Neurology and NeurosurgeryLondonUK
| | - Alan Pittman
- Genetics Research CentreSt. George's, University of LondonLondonUK
| | - Robert D.S. Pitceathly
- Department of Neuromuscular DiseasesUCL Queen Square Institute of Neurology and The National Hospital for Neurology and NeurosurgeryLondonUK
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16
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A Yeast-Based Screening Unravels Potential Therapeutic Molecules for Mitochondrial Diseases Associated with Dominant ANT1 Mutations. Int J Mol Sci 2021; 22:ijms22094461. [PMID: 33923309 PMCID: PMC8123201 DOI: 10.3390/ijms22094461] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 04/15/2021] [Accepted: 04/22/2021] [Indexed: 12/19/2022] Open
Abstract
Mitochondrial diseases result from inherited or spontaneous mutations in mitochondrial or nuclear DNA, leading to an impairment of the oxidative phosphorylation responsible for the synthesis of ATP. To date, there are no effective pharmacological therapies for these pathologies. We performed a yeast-based screening to search for therapeutic drugs to be used for treating mitochondrial diseases associated with dominant mutations in the nuclear ANT1 gene, which encodes for the mitochondrial ADP/ATP carrier. Dominant ANT1 mutations are involved in several degenerative mitochondrial pathologies characterized by the presence of multiple deletions or depletion of mitochondrial DNA in tissues of affected patients. Thanks to the presence in yeast of the AAC2 gene, orthologue of human ANT1, a yeast mutant strain carrying the M114P substitution equivalent to adPEO-associated L98P mutation was created. Five molecules were identified for their ability to suppress the defective respiratory growth phenotype of the haploid aac2M114P. Furthermore, these molecules rescued the mtDNA mutability in the heteroallelic AAC2/aac2M114P strain, which mimics the human heterozygous condition of adPEO patients. The drugs were effective in reducing mtDNA instability also in the heteroallelic strain carrying the R96H mutation equivalent to the more severe de novo dominant missense mutation R80H, suggesting a general therapeutic effect on diseases associated with dominant ANT1 mutations.
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17
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Macken WL, Vandrovcova J, Hanna MG, Pitceathly RDS. Applying genomic and transcriptomic advances to mitochondrial medicine. Nat Rev Neurol 2021; 17:215-230. [PMID: 33623159 DOI: 10.1038/s41582-021-00455-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/06/2021] [Indexed: 02/07/2023]
Abstract
Next-generation sequencing (NGS) has increased our understanding of the molecular basis of many primary mitochondrial diseases (PMDs). Despite this progress, many patients with suspected PMD remain without a genetic diagnosis, which restricts their access to in-depth genetic counselling, reproductive options and clinical trials, in addition to hampering efforts to understand the underlying disease mechanisms. Although they represent a considerable improvement over their predecessors, current methods for sequencing the mitochondrial and nuclear genomes have important limitations, and molecular diagnostic techniques are often manual and time consuming. However, recent advances in genomics and transcriptomics offer realistic solutions to these challenges. In this Review, we discuss the current genetic testing approach for PMDs and the opportunities that exist for increased use of whole-genome NGS of nuclear and mitochondrial DNA (mtDNA) in the clinical environment. We consider the possible role for long-read approaches in sequencing of mtDNA and in the identification of novel nuclear genomic causes of PMDs. We examine the expanding applications of RNA sequencing, including the detection of cryptic variants that affect splicing and gene expression and the interpretation of rare and novel mitochondrial transfer RNA variants.
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Affiliation(s)
- William L Macken
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK
| | - Jana Vandrovcova
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK
| | - Michael G Hanna
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK
| | - Robert D S Pitceathly
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK.
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18
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Ceccatelli Berti C, di Punzio G, Dallabona C, Baruffini E, Goffrini P, Lodi T, Donnini C. The Power of Yeast in Modelling Human Nuclear Mutations Associated with Mitochondrial Diseases. Genes (Basel) 2021; 12:300. [PMID: 33672627 PMCID: PMC7924180 DOI: 10.3390/genes12020300] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 02/16/2021] [Accepted: 02/17/2021] [Indexed: 12/17/2022] Open
Abstract
The increasing application of next generation sequencing approaches to the analysis of human exome and whole genome data has enabled the identification of novel variants and new genes involved in mitochondrial diseases. The ability of surviving in the absence of oxidative phosphorylation (OXPHOS) and mitochondrial genome makes the yeast Saccharomyces cerevisiae an excellent model system for investigating the role of these new variants in mitochondrial-related conditions and dissecting the molecular mechanisms associated with these diseases. The aim of this review was to highlight the main advantages offered by this model for the study of mitochondrial diseases, from the validation and characterisation of novel mutations to the dissection of the role played by genes in mitochondrial functionality and the discovery of potential therapeutic molecules. The review also provides a summary of the main contributions to the understanding of mitochondrial diseases emerged from the study of this simple eukaryotic organism.
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Affiliation(s)
| | | | | | | | | | | | - Claudia Donnini
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy; (C.C.B.); (G.d.P.); (C.D.); (E.B.); (P.G.); (T.L.)
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19
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Akiyama N, Shimura M, Yamazaki T, Harashima H, Fushimi T, Tsuruoka T, Ebihara T, Ichimoto K, Matsunaga A, Saito-Tsuruoka M, Yatsuka Y, Kishita Y, Kohda M, Namba A, Kamei Y, Okazaki Y, Kosugi S, Ohtake A, Murayama K. Prenatal diagnosis of severe mitochondrial diseases caused by nuclear gene defects: a study in Japan. Sci Rep 2021; 11:3531. [PMID: 33574353 PMCID: PMC7878886 DOI: 10.1038/s41598-021-81015-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 12/28/2020] [Indexed: 12/05/2022] Open
Abstract
Prenatal diagnoses of mitochondrial diseases caused by defects in nuclear DNA (nDNA) or mitochondrial DNA have been reported in several countries except for Japan. The present study aimed to clarify the status of prenatal genetic diagnosis of mitochondrial diseases caused by nDNA defects in Japan. A comprehensive genomic analysis was performed to diagnose more than 400 patients, of which, 13 families (16 cases) had requested prenatal diagnoses. Eight cases diagnosed with wild type homozygous or heterozygous variants same as either of the heterozygous parents continued the pregnancy and delivered healthy babies. Another eight cases were diagnosed with homozygous, compound heterozygous, or hemizygous variants same as the proband. Of these, seven families chose to terminate the pregnancy, while one decided to continue the pregnancy. Neonatal- or infantile-onset mitochondrial diseases show severe phenotypes and lead to lethality. Therefore, such diseases could be candidates for prenatal diagnosis with careful genetic counseling, and prenatal testing could be a viable option for families.
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Affiliation(s)
- Nana Akiyama
- Center for Medical Genetics, Chiba Children's Hospital, Chiba, Japan.,Department of Medical Genetics/Medical Ethics, Kyoto University School of Public Health, Kyoto, Japan
| | - Masaru Shimura
- Department of Metabolism, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba, 266-0007, Japan
| | - Taro Yamazaki
- Department of Pediatrics, Faculty of Medicine, Saitama Medical University, Saitama, Japan
| | - Hiroko Harashima
- Department of Pediatrics, Faculty of Medicine, Saitama Medical University, Saitama, Japan.,Department of Clinical Genomics, Faculty of Medicine, Saitama Medical University, Saitama, Japan
| | - Takuya Fushimi
- Department of Metabolism, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba, 266-0007, Japan
| | - Tomoko Tsuruoka
- Department of Neonatology, Chiba Children's Hospital, Chiba, Japan
| | - Tomohiro Ebihara
- Department of Neonatology, Chiba Children's Hospital, Chiba, Japan
| | - Keiko Ichimoto
- Department of Metabolism, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba, 266-0007, Japan
| | - Ayako Matsunaga
- Department of Metabolism, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba, 266-0007, Japan
| | - Megumi Saito-Tsuruoka
- Department of Clinical Genomics, Faculty of Medicine, Saitama Medical University, Saitama, Japan.,Center for Intractable Diseases, Saitama Medical University Hospital, Saitama, Japan
| | - Yukiko Yatsuka
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Yoshihito Kishita
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan.,Department of Life Science, Faculty of Science and Engineering, Kindai University, Osaka, Japan
| | - Masakazu Kohda
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Akira Namba
- Department of Clinical Genomics, Faculty of Medicine, Saitama Medical University, Saitama, Japan.,Center for Intractable Diseases, Saitama Medical University Hospital, Saitama, Japan.,Department of Obstetrics and Gynecology, Saitama Medical University Hospital, Saitama, Japan
| | - Yoshimasa Kamei
- Department of Obstetrics and Gynecology, Saitama Medical University Hospital, Saitama, Japan
| | - Yasushi Okazaki
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Shinji Kosugi
- Department of Medical Genetics/Medical Ethics, Kyoto University School of Public Health, Kyoto, Japan
| | - Akira Ohtake
- Department of Pediatrics, Faculty of Medicine, Saitama Medical University, Saitama, Japan. .,Department of Clinical Genomics, Faculty of Medicine, Saitama Medical University, Saitama, Japan. .,Center for Intractable Diseases, Saitama Medical University Hospital, Saitama, Japan.
| | - Kei Murayama
- Center for Medical Genetics, Chiba Children's Hospital, Chiba, Japan. .,Department of Metabolism, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba, 266-0007, Japan. .,Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan.
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20
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Gilhooley MJ, Owen N, Moosajee M, Yu Wai Man P. From Transcriptomics to Treatment in Inherited Optic Neuropathies. Genes (Basel) 2021; 12:147. [PMID: 33499292 PMCID: PMC7912133 DOI: 10.3390/genes12020147] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/13/2021] [Accepted: 01/20/2021] [Indexed: 02/06/2023] Open
Abstract
Inherited optic neuropathies, including Leber Hereditary Optic Neuropathy (LHON) and Dominant Optic Atrophy (DOA), are monogenetic diseases with a final common pathway of mitochondrial dysfunction leading to retinal ganglion cell (RGC) death and ultimately loss of vision. They are, therefore, excellent models with which to investigate this ubiquitous disease process-implicated in both common polygenetic ocular diseases (e.g., Glaucoma) and late-onset central nervous system neurodegenerative diseases (e.g., Parkinson disease). In recent years, cellular and animal models of LHON and DOA have matured in parallel with techniques (such as RNA-seq) to determine and analyze the transcriptomes of affected cells. This confluence leaves us at a particularly exciting time with the potential for the identification of novel pathogenic players and therapeutic targets. Here, we present a discussion of the importance of inherited optic neuropathies and how transcriptomic techniques can be exploited in the development of novel mutation-independent, neuroprotective therapies.
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Affiliation(s)
- Michael James Gilhooley
- Institute of Ophthalmology, University College London, Bath Street, London EC1V 9EL, UK; (N.O.); (M.M.); (P.Y.W.M.)
- Moorfields Eye Hospital NHS Foundation Trust, 162 City Road, London EC1V 2PD, UK
| | - Nicholas Owen
- Institute of Ophthalmology, University College London, Bath Street, London EC1V 9EL, UK; (N.O.); (M.M.); (P.Y.W.M.)
| | - Mariya Moosajee
- Institute of Ophthalmology, University College London, Bath Street, London EC1V 9EL, UK; (N.O.); (M.M.); (P.Y.W.M.)
- Moorfields Eye Hospital NHS Foundation Trust, 162 City Road, London EC1V 2PD, UK
- The Francis Crick Institute, 1 Midland Road, Somers Town, London NW1 1AT, UK
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
| | - Patrick Yu Wai Man
- Institute of Ophthalmology, University College London, Bath Street, London EC1V 9EL, UK; (N.O.); (M.M.); (P.Y.W.M.)
- Moorfields Eye Hospital NHS Foundation Trust, 162 City Road, London EC1V 2PD, UK
- Department of Clinical Neurosciences, University of Cambridge, Robinson Way, Cambridge CB2 0PY, UK
- MRC Mitochondrial Biology Unit, University of Cambridge, Robinson Way, Cambridge CB2 0PY, UK
- Cambridge Eye Unit, Addenbrooke’s Hospital, Hills Road, Cambridge CB2 0QQ, UK
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21
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Association Study Between Genetic Variation in Whole Mitochondrial Genome and Ischemic Stroke. J Mol Neurosci 2021; 71:2152-2162. [PMID: 33447902 DOI: 10.1007/s12031-020-01778-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 12/11/2020] [Indexed: 10/22/2022]
Abstract
Mitochondrial DNA (mtDNA) affects the mitochondrial function, which is potentially related to susceptibility to ischemic stroke (IS). However, study on IS genetics by whole mitochondrial genome sequencing has not been extensively explored. Therefore, a two-stage study was designed to explore the relationship between the whole mitochondrial genome variants and IS. In the first stage, whole mitochondrial genomes of 52 IS patients and 55 controls were sequenced by next-generation sequencing. Fifty-three mtDNA mutation sites which may be related to the pathogenesis of IS were discovered. Nine unreported mtDNA variation sites were found for the first time. In the second larger Chinese cohort, we confirmed that m.T195C and m.T12338C in the mitochondrial D-loop region were the protective factors of IS, especially m.T195C and m.C311T in the LAA subtype. In conclusion, our study provided population genetic information and a reference for IS-relevant research, with wide applications in diagnosis, therapeutic treatments and prediction of IS.
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22
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Koňaříková E, Marković A, Korandová Z, Houštěk J, Mráček T. Current progress in the therapeutic options for mitochondrial disorders. Physiol Res 2020; 69:967-994. [PMID: 33129249 PMCID: PMC8549882 DOI: 10.33549/physiolres.934529] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 10/02/2020] [Indexed: 12/20/2022] Open
Abstract
Mitochondrial disorders manifest enormous genetic and clinical heterogeneity - they can appear at any age, present with various phenotypes affecting any organ, and display any mode of inheritance. What mitochondrial diseases do have in common, is impairment of respiratory chain activity, which is responsible for more than 90% of energy production within cells. While diagnostics of mitochondrial disorders has been accelerated by introducing Next-Generation Sequencing techniques in recent years, the treatment options are still very limited. For many patients only a supportive or symptomatic therapy is available at the moment. However, decades of basic and preclinical research have uncovered potential target points and numerous compounds or interventions are now subjects of clinical trials. In this review, we focus on current and emerging therapeutic approaches towards the treatment of mitochondrial disorders. We focus on small compounds, metabolic interference, such as endurance training or ketogenic diet and also on genomic approaches.
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Affiliation(s)
- E Koňaříková
- Laboratory of Bioenergetics, Institute of Physiology Czech Acad. Sci., Prague, Czech Republic. ,
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23
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Fernandez-Vizarra E, Zeviani M. Mitochondrial disorders of the OXPHOS system. FEBS Lett 2020; 595:1062-1106. [PMID: 33159691 DOI: 10.1002/1873-3468.13995] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 10/21/2020] [Accepted: 11/01/2020] [Indexed: 12/13/2022]
Abstract
Mitochondrial disorders are among the most frequent inborn errors of metabolism, their primary cause being the dysfunction of the oxidative phosphorylation system (OXPHOS). OXPHOS is composed of the electron transport chain (ETC), formed by four multimeric enzymes and two mobile electron carriers, plus an ATP synthase [also called complex V (cV)]. The ETC performs the redox reactions involved in cellular respiration while generating the proton motive force used by cV to synthesize ATP. OXPHOS biogenesis involves multiple steps, starting from the expression of genes encoded in physically separated genomes, namely the mitochondrial and nuclear DNA, to the coordinated assembly of components and cofactors building each individual complex and eventually the supercomplexes. The genetic cause underlying around half of the diagnosed mitochondrial disease cases is currently known. Many of these cases result from pathogenic variants in genes encoding structural subunits or additional factors directly involved in the assembly of the ETC complexes. Here, we review the historical and most recent findings concerning the clinical phenotypes and the molecular pathological mechanisms underlying this particular group of disorders.
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Affiliation(s)
- Erika Fernandez-Vizarra
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK
| | - Massimo Zeviani
- Venetian Institute of Molecular Medicine, Padova, Italy.,Department of Neurosciences, University of Padova, Italy
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24
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Levy MA, Kerkhof J, Belmonte FR, Kaufman BA, Bhai P, Brady L, Bursztyn LLCD, Tarnopolsky M, Rupar T, Sadikovic B. Validation and clinical performance of a combined nuclear-mitochondrial next-generation sequencing and copy number variant analysis panel in a Canadian population. Am J Med Genet A 2020; 185:486-499. [PMID: 33300680 DOI: 10.1002/ajmg.a.61998] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/12/2020] [Accepted: 11/14/2020] [Indexed: 12/17/2022]
Abstract
Diagnosing mitochondrial disorders is a challenge due to the heterogeneous clinical presentation and large number of associated genes. A custom next generation sequencing (NGS) panel was developed incorporating the full mitochondrial genome (mtDNA) plus 19 nuclear genes involved in structural mitochondrial defects and mtDNA maintenance. This assay is capable of simultaneously detecting small gene sequence variations and larger copy number variants (CNVs) in both the nuclear and mitochondrial components along with heteroplasmy detection down to 5%. We describe technical validations of this panel and its implementation for clinical testing in a Canadian reference laboratory, and report its clinical performance in the initial 950 patients tested. Using this assay, we demonstrate a diagnostic yield of 18.1% of patients with known pathogenic variants. In addition to the common 5 kb mtDNA deletion, we describe significant contribution of pathogenic CNVs in both the mitochondrial genome and nuclear genes in this patient population.
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Affiliation(s)
- Michael A Levy
- Department of Pathology and Laboratory Medicine, Western University, London, Ontario, Canada.,Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, Ontario, Canada
| | - Jennifer Kerkhof
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, Ontario, Canada
| | - Frances R Belmonte
- Division of Cardiology, Center for Metabolism and Mitochondrial Medicine and Vascular Medicine Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Brett A Kaufman
- Division of Cardiology, Center for Metabolism and Mitochondrial Medicine and Vascular Medicine Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Pratibha Bhai
- Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, Ontario, Canada
| | - Lauren Brady
- Division of Neuromuscular and Neurometabolic Disease, Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada
| | | | - Mark Tarnopolsky
- Division of Neuromuscular and Neurometabolic Disease, Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada
| | - Tony Rupar
- Department of Pathology and Laboratory Medicine, Western University, London, Ontario, Canada.,Departments of Biochemistry and Paediatrics, Schulich School of Medicine & Dentistry, Western University, and Biochemical Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, Ontario, Canada
| | - Bekim Sadikovic
- Department of Pathology and Laboratory Medicine, Western University, London, Ontario, Canada.,Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, Ontario, Canada
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25
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Kose M, Canda E, Kagnici M, Aykut A, Adebali O, Durmaz A, Bircan A, Diniz G, Eraslan C, Kose E, Ünalp A, Yılmaz Ü, Ozyilmaz B, Özdemir TR, Atik T, Uçar SK, McFarland R, Taylor RW, Brown GK, Çoker M, Özkınay F. SURF1 related Leigh syndrome: Clinical and molecular findings of 16 patients from Turkey. Mol Genet Metab Rep 2020; 25:100657. [PMID: 33134083 PMCID: PMC7586243 DOI: 10.1016/j.ymgmr.2020.100657] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 10/03/2020] [Accepted: 10/03/2020] [Indexed: 01/09/2023] Open
Abstract
Introduction Pathogenic variants in SURF1, a nuclear-encoded gene encoding a mitochondrial chaperone involved in COX assembly, are one of the most common causes of Leigh syndrome (LS). Material-methods Sixteen patients diagnosed to have SURF1-related LS between 2012 and 2020 were included in the study. Their clinical, biochemical and molecular findings were recorded. 10/16 patients were diagnosed using whole-exome sequencing (WES), 4/16 by Sanger sequencing of SURF1, 1/16 via targeted exome sequencing and 1/16 patient with whole-genome sequencing (WGS). The pathogenicity of SURF1 variants was evaluated by phylogenetic studies and modelling on the 3D structure of the SURF1 protein. Results We identified 16 patients from 14 unrelated families who were either homozygous or compound heterozygous for SURF1 pathogenic variants. Nine different SURF1 variants were detected The c.769G > A was the most common variant with an allelic frequency of 42.8% (12/28), c.870dupT [(p.Lys291*); (8/28 28.5%)], c.169delG [(p.Glu57Lysfs*15), (2/24; 7.1%)], c.532 T > A [(p.Tyr178Asn); (2/28, 7.1%)], c.653_654delCT [(p.Pro218Argfs*29); (4/28, 14.2%)] c.595_597delGGA [(p.Gly199del); (1/28, 3.5%)], c.751 + 1G > A (2/28, 4.1%), c.356C > T [(p.Pro119Leu); (2/28, 3.5%)] were the other detected variants. Two pathogenic variants, C.595_597delGGA and c.356C > T, were detected for the first time. The c.769 G > A variant detected in 6 patients from 5 families was evaluated in terms of phenotype-genotype correlation. There was no definite genotype – phenotype correlation. Conclusions To date, more than 120 patients of LS with SURF1 pathogenic variants have been reported. We shared the clinical, molecular data and natural course of 16 new SURF1 defect patients from our country. This study is the first comprehensive research from Turkey that provides information about disease-causing variants in the SURF1 gene. The identification of common variants and phenotype of the SURF1 gene is important for understanding SURF1 related LS. Synopsis SURF1 gene defects are one of the most important causes of LS; patients have a homogeneous clinical and biochemical phenotype.
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Affiliation(s)
- Melis Kose
- Izmir Katip Çelebi University Faculty of Medicine, Department of Pediatrics, Division of Pediatric Metabolism and Nutrition, Izmir, Turkey.,Ege University Faculty of Medicine, Department of Pediatrics, Division of Nutrition and Metabolism, Izmir, Turkey.,Oxford University Hospitals NHS Foundation Trust, The Churchill Hospital, Oxford Medical Genetics Laboratories, Oxford, UK
| | - Ebru Canda
- Ege University Faculty of Medicine, Department of Pediatrics, Division of Nutrition and Metabolism, Izmir, Turkey
| | - Mehtap Kagnici
- University of Health Sciences, Antalya Training and Research Hospital, Department of Pediatrics, Division of Metabolism and Nutrition, Antalya, Turkey
| | - Ayça Aykut
- Ege University Faculty of Medicine, Department of Medical Genetics, Izmir, Turkey
| | - Ogün Adebali
- Sabanci University, Faculty of Engineering and Natural Sciences, Molecular Biology, Genetics and Bioengineering Program, Adebali Lab, Istanbul, Turkey
| | - Asude Durmaz
- Ege University Faculty of Medicine, Department of Medical Genetics, Izmir, Turkey
| | - Aylin Bircan
- Sabanci University, Faculty of Engineering and Natural Sciences, Molecular Biology, Genetics and Bioengineering Program, Adebali Lab, Istanbul, Turkey
| | - Gulden Diniz
- Izmir Democracy University, Faculty of Medicine, Department of Pathology, İzmir, Turkey
| | - Cenk Eraslan
- Ege University Faculty of Medicine, Department of Radiology, Division of Neuroradiology, Izmir, Turkey
| | - Engin Kose
- Ankara University Faculty of Medicine, Department of Pediatrics, Division of Metabolism and Nutrition, Ankara, Turkey
| | - Aycan Ünalp
- University of Health Sciences, Behçet Uz Children Training and Research Hospital, Department of Pediatrics, Division of Neurology, Izmir, Turkey
| | - Ünsal Yılmaz
- University of Health Sciences, Behçet Uz Children Training and Research Hospital, Department of Pediatrics, Division of Neurology, Izmir, Turkey
| | - Berk Ozyilmaz
- University of Health Sciences Tepecik Training and Research Hospital, Department of Medical Genetics, Izmir, Turkey
| | - Taha Reşid Özdemir
- University of Health Sciences Tepecik Training and Research Hospital, Department of Medical Genetics, Izmir, Turkey
| | - Tahir Atik
- Ege University Faculty of Medicine, Department of Pediatrics, Division of Nutrition and Metabolism, Izmir, Turkey
| | - Sema Kalkan Uçar
- Ege University Faculty of Medicine, Department of Pediatrics, Division of Nutrition and Metabolism, Izmir, Turkey
| | - Robert McFarland
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Garry K Brown
- Oxford University Hospitals NHS Foundation Trust, The Churchill Hospital, Oxford Medical Genetics Laboratories, Oxford, UK
| | - Mahmut Çoker
- Ege University Faculty of Medicine, Department of Pediatrics, Division of Nutrition and Metabolism, Izmir, Turkey
| | - Ferda Özkınay
- Ege University Faculty of Medicine, Department of Pediatrics, Division of Nutrition and Metabolism, Izmir, Turkey.,University of Health Sciences, Antalya Training and Research Hospital, Department of Pediatrics, Division of Metabolism and Nutrition, Antalya, Turkey
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26
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Webb M, Sideris DP. Intimate Relations-Mitochondria and Ageing. Int J Mol Sci 2020; 21:ijms21207580. [PMID: 33066461 PMCID: PMC7589147 DOI: 10.3390/ijms21207580] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 10/05/2020] [Accepted: 10/06/2020] [Indexed: 12/14/2022] Open
Abstract
Mitochondrial dysfunction is associated with ageing, but the detailed causal relationship between the two is still unclear. We review the major phenomenological manifestations of mitochondrial age-related dysfunction including biochemical, regulatory and energetic features. We conclude that the complexity of these processes and their inter-relationships are still not fully understood and at this point it seems unlikely that a single linear cause and effect relationship between any specific aspect of mitochondrial biology and ageing can be established in either direction.
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Affiliation(s)
- Michael Webb
- Mitobridge Inc., an Astellas Company, 1030 Massachusetts Ave, Cambridge, MA 02138, USA
| | - Dionisia P Sideris
- Mitobridge Inc., an Astellas Company, 1030 Massachusetts Ave, Cambridge, MA 02138, USA
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27
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Frazier AE, Compton AG, Kishita Y, Hock DH, Welch AE, Amarasekera SSC, Rius R, Formosa LE, Imai-Okazaki A, Francis D, Wang M, Lake NJ, Tregoning S, Jabbari JS, Lucattini A, Nitta KR, Ohtake A, Murayama K, Amor DJ, McGillivray G, Wong FY, van der Knaap MS, Jeroen Vermeulen R, Wiltshire EJ, Fletcher JM, Lewis B, Baynam G, Ellaway C, Balasubramaniam S, Bhattacharya K, Freckmann ML, Arbuckle S, Rodriguez M, Taft RJ, Sadedin S, Cowley MJ, Minoche AE, Calvo SE, Mootha VK, Ryan MT, Okazaki Y, Stroud DA, Simons C, Christodoulou J, Thorburn DR. Fatal perinatal mitochondrial cardiac failure caused by recurrent de novo duplications in the ATAD3 locus. MED 2020; 2:49-73. [PMID: 33575671 DOI: 10.1016/j.medj.2020.06.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Background In about half of all patients with a suspected monogenic disease, genomic investigations fail to identify the diagnosis. A contributing factor is the difficulty with repetitive regions of the genome, such as those generated by segmental duplications. The ATAD3 locus is one such region, in which recessive deletions and dominant duplications have recently been reported to cause lethal perinatal mitochondrial diseases characterized by pontocerebellar hypoplasia or cardiomyopathy, respectively. Methods Whole exome, whole genome and long-read DNA sequencing techniques combined with studies of RNA and quantitative proteomics were used to investigate 17 subjects from 16 unrelated families with suspected mitochondrial disease. Findings We report six different de novo duplications in the ATAD3 gene locus causing a distinctive presentation including lethal perinatal cardiomyopathy, persistent hyperlactacidemia, and frequently corneal clouding or cataracts and encephalopathy. The recurrent 68 Kb ATAD3 duplications are identifiable from genome and exome sequencing but usually missed by microarrays. The ATAD3 duplications result in the formation of identical chimeric ATAD3A/ATAD3C proteins, altered ATAD3 complexes and a striking reduction in mitochondrial oxidative phosphorylation complex I and its activity in heart tissue. Conclusions ATAD3 duplications appear to act in a dominant-negative manner and the de novo inheritance infers a low recurrence risk for families, unlike most pediatric mitochondrial diseases. More than 350 genes underlie mitochondrial diseases. In our experience the ATAD3 locus is now one of the five most common causes of nuclear-encoded pediatric mitochondrial disease but the repetitive nature of the locus means ATAD3 diagnoses may be frequently missed by current genomic strategies. Funding Australian NHMRC, US Department of Defense, Japanese AMED and JSPS agencies, Australian Genomics Health Alliance and Australian Mito Foundation.
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Affiliation(s)
- Ann E Frazier
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia.,These authors contributed equally: A.E. Frazier, A.G. Compton
| | - Alison G Compton
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia.,These authors contributed equally: A.E. Frazier, A.G. Compton
| | - Yoshihito Kishita
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Juntendo University, Graduate School of Medicine, Tokyo, 113-8421, Japan
| | - Daniella H Hock
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, VIC 3052, Australia
| | - AnneMarie E Welch
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
| | - Sumudu S C Amarasekera
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
| | - Rocio Rius
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
| | - Luke E Formosa
- Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC 3800, Australia
| | - Atsuko Imai-Okazaki
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Juntendo University, Graduate School of Medicine, Tokyo, 113-8421, Japan.,Division of Genomic Medicine Research, Medical Genomics Center, National Center for Global Health and Medicine, Tokyo 162-8655, Japan
| | - David Francis
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
| | - Min Wang
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
| | - Nicole J Lake
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia.,Department of Genetics, Yale School of Medicine, New Haven, CT 06510, USA
| | - Simone Tregoning
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
| | - Jafar S Jabbari
- Australian Genome Research Facility Ltd, Victorian Comprehensive Cancer Centre, Melbourne VIC 3052, Australia
| | - Alexis Lucattini
- Australian Genome Research Facility Ltd, Victorian Comprehensive Cancer Centre, Melbourne VIC 3052, Australia
| | - Kazuhiro R Nitta
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Juntendo University, Graduate School of Medicine, Tokyo, 113-8421, Japan
| | - Akira Ohtake
- Department of Pediatrics & Clinical Genomics, Saitama Medical University Hospital, Saitama, 350-0495, Japan
| | - Kei Murayama
- Department of Metabolism, Chiba Children's Hospital, Chiba, 266-0007, Japan
| | - David J Amor
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
| | - George McGillivray
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
| | - Flora Y Wong
- Ritchie Centre, Hudson Institute of Medical Research; Department of Paediatrics, Monash University; and Monash Newborn, Monash Children's Hospital, Melbourne, VIC 3168, Australia
| | - Marjo S van der Knaap
- Child Neurology, Emma Children's Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, 1081 HV Amsterdam, The Netherlands.,Functional Genomics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit and Amsterdam Neuroscience, 1081 HV Amsterdam, The Netherlands
| | - R Jeroen Vermeulen
- Department of Neurology, Maastricht University Medical Center, 6229 HX, Maastricht, The Netherlands
| | - Esko J Wiltshire
- Department of Paediatrics and Child Health, University of Otago Wellington and Capital and Coast District Health Board, Wellington 6021, New Zealand
| | - Janice M Fletcher
- Department of Genetics and Molecular Pathology, SA Pathology, Adelaide, SA 5000, Australia
| | - Barry Lewis
- Department of Clinical Biochemistry, PathWest Laboratory Medicine Western Australia, Nedlands, WA 6009, Australia
| | - Gareth Baynam
- Western Australian Register of Developmental Anomalies and Genetic Services of Western Australia and King Edward Memorial Hospital for Women Perth, Subiaco, WA 6008, Australia.,Telethon Kids Institute and School of Paediatrics and Child Health, The University of Western Australia, Perth, WA 6009, Australia
| | - Carolyn Ellaway
- Genetic Metabolic Disorders Service, Sydney Children's Hospital Network, The Children's Hospital at Westmead, Sydney, NSW 2145, Australia.,Disciplines of Genomic Medicine and Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW 2145, Australia
| | - Shanti Balasubramaniam
- Genetic Metabolic Disorders Service, Sydney Children's Hospital Network, The Children's Hospital at Westmead, Sydney, NSW 2145, Australia
| | - Kaustuv Bhattacharya
- Genetic Metabolic Disorders Service, Sydney Children's Hospital Network, The Children's Hospital at Westmead, Sydney, NSW 2145, Australia.,Disciplines of Genomic Medicine and Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW 2145, Australia
| | | | - Susan Arbuckle
- Department of Histopathology, The Children's Hospital at Westmead, Sydney Children's Hospital Network, Sydney, NSW 2145, Australia
| | - Michael Rodriguez
- Discipline of Pathology, School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | | | - Simon Sadedin
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
| | - Mark J Cowley
- Children's Cancer Institute, Kensington, NSW 2750, Australia; St Vincent's Clinical School, UNSW Sydney, Darlinghurst, NSW 2010, Australia.,Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia
| | - André E Minoche
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia
| | - Sarah E Calvo
- Broad Institute, Cambridge, MA 02142, USA; Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Harvard Medical School, Boston, MA 02446, USA
| | - Vamsi K Mootha
- Broad Institute, Cambridge, MA 02142, USA; Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Harvard Medical School, Boston, MA 02446, USA
| | - Michael T Ryan
- Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC 3800, Australia
| | - Yasushi Okazaki
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Juntendo University, Graduate School of Medicine, Tokyo, 113-8421, Japan
| | - David A Stroud
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, VIC 3052, Australia
| | - Cas Simons
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072 Australia
| | - John Christodoulou
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia.,Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Disciplines of Genomic Medicine and Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW 2145, Australia
| | - David R Thorburn
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia.,Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Lead contact
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28
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La Morgia C, Maresca A, Caporali L, Valentino ML, Carelli V. Mitochondrial diseases in adults. J Intern Med 2020; 287:592-608. [PMID: 32463135 DOI: 10.1111/joim.13064] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/07/2020] [Accepted: 02/21/2020] [Indexed: 02/07/2023]
Abstract
Mitochondrial medicine is a field that expanded exponentially in the last 30 years. Individually rare, mitochondrial diseases as a whole are probably the most frequent genetic disorder in adults. The complexity of their genotype-phenotype correlation, in terms of penetrance and clinical expressivity, natural history and diagnostic algorithm derives from the dual genetic determination. In fact, in addition to the about 1.500 genes encoding mitochondrial proteins that reside in the nuclear genome (nDNA), we have the 13 proteins encoded by the mitochondrial genome (mtDNA), for which 22 specific tRNAs and 2 rRNAs are also needed. Thus, besides Mendelian genetics, we need to consider all peculiarities of how mtDNA is inherited, maintained and expressed to fully understand the pathogenic mechanisms of these disorders. Yet, from the initial restriction to the narrow field of oxidative phosphorylation dysfunction, the landscape of mitochondrial functions impinging on cellular homeostasis, driving life and death, is impressively enlarged. Finally, from the clinical standpoint, starting from the neuromuscular field, where brain and skeletal muscle were the primary targets of mitochondrial dysfunction as energy-dependent tissues, after three decades virtually any subspecialty of medicine is now involved. We will summarize the key clinical pictures and pathogenic mechanisms of mitochondrial diseases in adults.
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Affiliation(s)
- C La Morgia
- From the, Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy.,IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Italy
| | - A Maresca
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Italy
| | - L Caporali
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Italy
| | - M L Valentino
- From the, Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy.,IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Italy
| | - V Carelli
- From the, Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy.,IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Italy
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29
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Yatsuka Y, Kishita Y, Formosa LE, Shimura M, Nozaki F, Fujii T, Nitta KR, Ohtake A, Murayama K, Ryan MT, Okazaki Y. A homozygous variant in NDUFA8 is associated with developmental delay, microcephaly, and epilepsy due to mitochondrial complex I deficiency. Clin Genet 2020; 98:155-165. [PMID: 32385911 DOI: 10.1111/cge.13773] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 04/22/2020] [Accepted: 05/04/2020] [Indexed: 12/12/2022]
Abstract
Mitochondrial complex I deficiency is caused by pathogenic variants in mitochondrial and nuclear genes associated with complex I structure and assembly. We report the case of a patient with NDUFA8-related mitochondrial disease. The patient presented with developmental delay, microcephaly, and epilepsy. His fibroblasts showed apparent biochemical defects in mitochondrial complex I. Whole-exome sequencing revealed that the patient carried a homozygous variant in NDUFA8. His fibroblasts showed a reduction in the protein expression level of not only NDUFA8, but also the other complex I subunits, consistent with assembly defects. The enzyme activity of complex I and oxygen consumption rate were restored by reintroducing wild-typeNDUFA8 cDNA into patient fibroblasts. The functional properties of the variant in NDUFA8 were also investigated using NDUFA8 knockout cells expressing wild-type or mutated NDUFA8 cDNA. These experiments further supported the pathogenicity of the variant in complex I assembly. This is the first report describing that the loss of NDUFA8, which has not previously been associated with mitochondrial disease, causes severe defect in the assembly of mitochondrial complex I, leading to progressive neurological and developmental abnormalities.
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Affiliation(s)
- Yukiko Yatsuka
- Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan.,Diagnostics and Therapeutics of Intractable Diseases, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Yoshihito Kishita
- Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan.,Diagnostics and Therapeutics of Intractable Diseases, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Luke E Formosa
- Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Masaru Shimura
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Fumihito Nozaki
- Department of Pediatrics, Shiga Medical Center for Children, Moriyama, Japan
| | - Tatsuya Fujii
- Department of Pediatrics, Shiga Medical Center for Children, Moriyama, Japan
| | - Kazuhiro R Nitta
- Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan.,Diagnostics and Therapeutics of Intractable Diseases, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Akira Ohtake
- Center for Intractable Diseases, Saitama Medical University Hospital, Saitama, Japan.,Department of Pediatrics and Clinical Genomics, Faculty of Medicine, Saitama Medical University, Saitama, Japan
| | - Kei Murayama
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Michael T Ryan
- Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Yasushi Okazaki
- Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan.,Diagnostics and Therapeutics of Intractable Diseases, Graduate School of Medicine, Juntendo University, Tokyo, Japan.,Laboratory for Comprehensive Genomic Analysis, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
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30
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The diagnostic utility of genome sequencing in a pediatric cohort with suspected mitochondrial disease. Genet Med 2020; 22:1254-1261. [DOI: 10.1038/s41436-020-0793-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 03/23/2020] [Accepted: 03/24/2020] [Indexed: 12/15/2022] Open
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Gusic M, Schottmann G, Feichtinger RG, Du C, Scholz C, Wagner M, Mayr JA, Lee CY, Yépez VA, Lorenz N, Morales-Gonzalez S, Panneman DM, Rötig A, Rodenburg RJT, Wortmann SB, Prokisch H, Schuelke M. Bi-Allelic UQCRFS1 Variants Are Associated with Mitochondrial Complex III Deficiency, Cardiomyopathy, and Alopecia Totalis. Am J Hum Genet 2020; 106:102-111. [PMID: 31883641 DOI: 10.1016/j.ajhg.2019.12.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 12/05/2019] [Indexed: 01/15/2023] Open
Abstract
Isolated complex III (CIII) deficiencies are among the least frequently diagnosed mitochondrial disorders. Clinical symptoms range from isolated myopathy to severe multi-systemic disorders with early death and disability. To date, we know of pathogenic variants in genes encoding five out of 10 subunits and five out of 13 assembly factors of CIII. Here we describe rare bi-allelic variants in the gene of a catalytic subunit of CIII, UQCRFS1, which encodes the Rieske iron-sulfur protein, in two unrelated individuals. Affected children presented with low CIII activity in fibroblasts, lactic acidosis, fetal bradycardia, hypertrophic cardiomyopathy, and alopecia totalis. Studies in proband-derived fibroblasts showed a deleterious effect of the variants on UQCRFS1 protein abundance, mitochondrial import, CIII assembly, and cellular respiration. Complementation studies via lentiviral transduction and overexpression of wild-type UQCRFS1 restored mitochondrial function and rescued the cellular phenotype, confirming UQCRFS1 variants as causative for CIII deficiency. We demonstrate that mutations in UQCRFS1 can cause mitochondrial disease, and our results thereby expand the clinical and mutational spectrum of CIII deficiencies.
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Affiliation(s)
- Mirjana Gusic
- Institute of Human Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Institute of Human Genetics, Technical University Munich, 81675 Munich, Germany
| | - Gudrun Schottmann
- Charité-Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of Health: NeuroCure Cluster of Excellence, 10117 Berlin, Germany; Charité-Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of Health: Department of Neuropediatrics, 13353 Berlin, Germany
| | - René G Feichtinger
- University Children's Hospital, Salzburger Landeskliniken (SALK) and Paracelsus Medical University (PMU), 5020 Salzburg, Austria
| | - Chen Du
- Institute of Human Genetics, Medizinische Hochschule Hannover, 30625 Hannover, Germany
| | - Caroline Scholz
- Institute of Human Genetics, Medizinische Hochschule Hannover, 30625 Hannover, Germany
| | - Matias Wagner
- Institute of Human Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Institute of Human Genetics, Technical University Munich, 81675 Munich, Germany; Institute of Neurogenomics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Johannes A Mayr
- University Children's Hospital, Salzburger Landeskliniken (SALK) and Paracelsus Medical University (PMU), 5020 Salzburg, Austria
| | - Chae-Young Lee
- Charité-Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of Health: NeuroCure Cluster of Excellence, 10117 Berlin, Germany; Charité-Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of Health: Department of Neuropediatrics, 13353 Berlin, Germany
| | - Vicente A Yépez
- Department of Informatics, Technical University of Munich, 81371 Garching, Germany
| | - Norbert Lorenz
- Department of Pediatric Cardiology, Municipal Hospital Dresden, 01307 Dresden, Germany
| | - Susanne Morales-Gonzalez
- Charité-Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of Health: NeuroCure Cluster of Excellence, 10117 Berlin, Germany; Charité-Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of Health: Department of Neuropediatrics, 13353 Berlin, Germany
| | - Daan M Panneman
- Radboud Center for Mitochondrial Disorders, Department of Pediatrics, Radboud UMC, Nijmegen 6525, the Netherlands
| | - Agnès Rötig
- UMR 1163, Université Paris Descartes, Sorbonne Paris Cité, Institut IMAGINE, 24 Boulevard du Montparnasse, 75015 Paris, France
| | - Richard J T Rodenburg
- Radboud Center for Mitochondrial Disorders, Department of Pediatrics, Radboud UMC, Nijmegen 6525, the Netherlands
| | - Saskia B Wortmann
- Institute of Human Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Institute of Human Genetics, Technical University Munich, 81675 Munich, Germany; University Children's Hospital, Salzburger Landeskliniken (SALK) and Paracelsus Medical University (PMU), 5020 Salzburg, Austria
| | - Holger Prokisch
- Institute of Human Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Institute of Human Genetics, Technical University Munich, 81675 Munich, Germany
| | - Markus Schuelke
- Charité-Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of Health: NeuroCure Cluster of Excellence, 10117 Berlin, Germany; Charité-Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of Health: Department of Neuropediatrics, 13353 Berlin, Germany.
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Stenton SL, Kremer LS, Kopajtich R, Ludwig C, Prokisch H. The diagnosis of inborn errors of metabolism by an integrative "multi-omics" approach: A perspective encompassing genomics, transcriptomics, and proteomics. J Inherit Metab Dis 2020; 43:25-35. [PMID: 31119744 DOI: 10.1002/jimd.12130] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 05/21/2019] [Accepted: 05/21/2019] [Indexed: 12/12/2022]
Abstract
Given the rapidly decreasing cost and increasing speed and accessibility of massively parallel technologies, the integration of comprehensive genomic, transcriptomic, and proteomic data into a "multi-omics" diagnostic pipeline is within reach. Even though genomic analysis has the capability to reveal all possible perturbations in our genetic code, analysis typically reaches a diagnosis in just 35% of cases, with a diagnostic gap arising due to limitations in prioritization and interpretation of detected variants. Here we review the utility of complementing genetic data with transcriptomic data and give a perspective for the introduction of proteomics into the diagnostic pipeline. Together these methodologies enable comprehensive capture of the functional consequence of variants, unobtainable by the analysis of each methodology in isolation. This facilitates functional annotation and reprioritization of candidate genes and variants-a promising approach to shed light on the underlying molecular cause of a patient's disease, increasing diagnostic rate, and allowing actionability in clinical practice.
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Affiliation(s)
- Sarah L Stenton
- Institute of Human Genetics, Technische Universität München, München, Germany
- Institute of Human Genetics, Helmholtz Zentrum München, München, Germany
| | - Laura S Kremer
- Institute of Human Genetics, Technische Universität München, München, Germany
- Institute of Human Genetics, Helmholtz Zentrum München, München, Germany
| | - Robert Kopajtich
- Institute of Human Genetics, Technische Universität München, München, Germany
- Institute of Human Genetics, Helmholtz Zentrum München, München, Germany
| | - Christina Ludwig
- Bavarian Center for Biomolecular Mass Spectrometry (BayBioMS), Technische Universität München, München, Germany
| | - Holger Prokisch
- Institute of Human Genetics, Technische Universität München, München, Germany
- Institute of Human Genetics, Helmholtz Zentrum München, München, Germany
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Thompson K, Collier JJ, Glasgow RIC, Robertson FM, Pyle A, Blakely EL, Alston CL, Oláhová M, McFarland R, Taylor RW. Recent advances in understanding the molecular genetic basis of mitochondrial disease. J Inherit Metab Dis 2020; 43:36-50. [PMID: 31021000 PMCID: PMC7041634 DOI: 10.1002/jimd.12104] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 04/03/2019] [Accepted: 04/24/2019] [Indexed: 12/22/2022]
Abstract
Mitochondrial disease is hugely diverse with respect to associated clinical presentations and underlying genetic causes, with pathogenic variants in over 300 disease genes currently described. Approximately half of these have been discovered in the last decade due to the increasingly widespread application of next generation sequencing technologies, in particular unbiased, whole exome-and latterly, whole genome sequencing. These technologies allow more genetic data to be collected from patients with mitochondrial disorders, continually improving the diagnostic success rate in a clinical setting. Despite these significant advances, some patients still remain without a definitive genetic diagnosis. Large datasets containing many variants of unknown significance have become a major challenge with next generation sequencing strategies and these require significant functional validation to confirm pathogenicity. This interface between diagnostics and research is critical in continuing to expand the list of known pathogenic variants and concomitantly enhance our knowledge of mitochondrial biology. The increasing use of whole exome sequencing, whole genome sequencing and other "omics" techniques such as transcriptomics and proteomics will generate even more data and allow further interrogation and validation of genetic causes, including those outside of coding regions. This will improve diagnostic yields still further and emphasizes the integral role that functional assessment of variant causality plays in this process-the overarching focus of this review.
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Affiliation(s)
- Kyle Thompson
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Jack J. Collier
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Ruth I. C. Glasgow
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Fiona M. Robertson
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Angela Pyle
- Wellcome Centre for Mitochondrial Research, Institute of Genetic MedicineNewcastle UniversityNewcastle upon TyneUK
| | - Emma L. Blakely
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
- NHS Highly Specialised Mitochondrial Diagnostic LaboratoryNewcastle upon Tyne Hospitals NHS Foundation TrustNewcastle upon TyneUK
| | - Charlotte L. Alston
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
- NHS Highly Specialised Mitochondrial Diagnostic LaboratoryNewcastle upon Tyne Hospitals NHS Foundation TrustNewcastle upon TyneUK
| | - Monika Oláhová
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Robert McFarland
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Robert W. Taylor
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
- NHS Highly Specialised Mitochondrial Diagnostic LaboratoryNewcastle upon Tyne Hospitals NHS Foundation TrustNewcastle upon TyneUK
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Ion torrent high throughput mitochondrial genome sequencing (HTMGS). PLoS One 2019; 14:e0224847. [PMID: 31730669 PMCID: PMC6857855 DOI: 10.1371/journal.pone.0224847] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 10/22/2019] [Indexed: 12/13/2022] Open
Abstract
The implementation and popularity of next generation sequencing (NGS) has led to the development of various rapid whole mitochondrial genome sequencing techniques. We summarise an efficient and cost-effective NGS approach for mitochondrial genomic DNA in humans using the Ion Torrent platform, and further discuss our bioinformatics pipeline for streamlined variant calling. Ion 316 chips were utilised with the Ion Torrent semi-conductor platform Personal Genome Machine (PGM) to perform tandem sequencing of mitochondrial genomes from the core pedigree (n = 315) of the Norfolk Island Health Study. Key improvements from commercial methods focus on the initial PCR step, which currently requires extensive optimisation to ensure the accurate and reproducible elongation of each section of the complete mitochondrial genome. Dual-platform barcodes were incorporated into our protocol thereby extending its potential application onto Illumina-based systems. Our bioinformatics pipeline consists of a modified version of GATK best practices tailored for mitochondrial genomic data. When compared with current commercial methods, our method, termed high throughput mitochondrial genome sequencing (HTMGS), allows high multiplexing of samples and the use of alternate library preparation reagents at a lower cost per sample (~1.7 times) when compared to current commercial methodologies. Our HTMGS methodology also provides robust mitochondrial sequencing data (>450X average coverage) that can be applied and modified to suit various study designs. On average, we were able to identify ~30 variants per sample with 572 variants observed across 315 samples. We have developed a high throughput sequencing and analysis method targeting complete mitochondrial genomes; with the potential to be platform agnostic with analysis options that adhere to current best practices.
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Saoura M, Powell CA, Kopajtich R, Alahmad A, AL‐Balool HH, Albash B, Alfadhel M, Alston CL, Bertini E, Bonnen PE, Bratkovic D, Carrozzo R, Donati MA, Di Nottia M, Ghezzi D, Goldstein A, Haan E, Horvath R, Hughes J, Invernizzi F, Lamantea E, Lucas B, Pinnock K, Pujantell M, Rahman S, Rebelo‐Guiomar P, Santra S, Verrigni D, McFarland R, Prokisch H, Taylor RW, Levinger L, Minczuk M. Mutations in ELAC2 associated with hypertrophic cardiomyopathy impair mitochondrial tRNA 3'-end processing. Hum Mutat 2019; 40:1731-1748. [PMID: 31045291 PMCID: PMC6764886 DOI: 10.1002/humu.23777] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 04/09/2019] [Accepted: 04/29/2019] [Indexed: 12/16/2022]
Abstract
Mutations in either the mitochondrial or nuclear genomes are associated with a diverse group of human disorders characterized by impaired mitochondrial respiration. Within this group, an increasing number of mutations have been identified in nuclear genes involved in mitochondrial RNA metabolism, including ELAC2. The ELAC2 gene codes for the mitochondrial RNase Z, responsible for endonucleolytic cleavage of the 3' ends of mitochondrial pre-tRNAs. Here, we report the identification of 16 novel ELAC2 variants in individuals presenting with mitochondrial respiratory chain deficiency, hypertrophic cardiomyopathy (HCM), and lactic acidosis. We provide evidence for the pathogenicity of the novel missense variants by studying the RNase Z activity in an in vitro system. We also modeled the residues affected by a missense mutation in solved RNase Z structures, providing insight into enzyme structure and function. Finally, we show that primary fibroblasts from the affected individuals have elevated levels of unprocessed mitochondrial RNA precursors. Our study thus broadly confirms the correlation of ELAC2 variants with severe infantile-onset forms of HCM and mitochondrial respiratory chain dysfunction. One rare missense variant associated with the occurrence of prostate cancer (p.Arg781His) impairs the mitochondrial RNase Z activity of ELAC2, suggesting a functional link between tumorigenesis and mitochondrial RNA metabolism.
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Affiliation(s)
| | | | - Robert Kopajtich
- Genetics of Mitochondrial Disorders, Institute of Human GeneticsTechnische Universität MünchenMunichGermany
- Genetics of Mitochondrial Disorders, Institute of Human GeneticsHelmholtz Zentrum MünchenNeuherbergGermany
| | - Ahmad Alahmad
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
- Kuwait Medical Genetics CenterKuwait CityKuwait
| | | | | | - Majid Alfadhel
- Genetics Division, Department of Pediatrics, King Abdullah International Medical Research CentreKing Saud bin Abdulaziz University for Health SciencesRiyadhSaudi Arabia
| | - Charlotte L. Alston
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Enrico Bertini
- Department of Neurosciences, Unit of Muscular and Neurodegenerative Disorders, Laboratory of Molecular MedicineBambino Gesu' Children's Research Hospital, IRCCSRomeItaly
| | - Penelope E. Bonnen
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonTexas
| | - Drago Bratkovic
- Metabolic ClinicWomen's and Children's HospitalNorth AdelaideSouth AustraliaAustralia
| | - Rosalba Carrozzo
- Department of Neurosciences, Unit of Muscular and Neurodegenerative Disorders, Laboratory of Molecular MedicineBambino Gesu' Children's Research Hospital, IRCCSRomeItaly
| | | | - Michela Di Nottia
- Department of Neurosciences, Unit of Muscular and Neurodegenerative Disorders, Laboratory of Molecular MedicineBambino Gesu' Children's Research Hospital, IRCCSRomeItaly
| | - Daniele Ghezzi
- Unit of Medical Genetics and NeurogeneticsFondazione IRCCS Istituto Neurologico Carlo BestaMilanItaly
- Department of Pathophysiology and TransplantationUniversity of MilanMilanItaly
| | - Amy Goldstein
- Mitochondrial Medicine Frontier ProgramChildren's Hospital of PhiladelphiaPhiladelphiaUSA
| | - Eric Haan
- Metabolic ClinicWomen's and Children's HospitalNorth AdelaideSouth AustraliaAustralia
| | - Rita Horvath
- Wellcome Centre for Mitochondrial Research, Institute of Genetic MedicineNewcastle UniversityNewcastle upon TyneUK
| | - Joanne Hughes
- National Centre for Inherited Metabolic DisordersTemple Street Children's University HospitalDublinIreland
| | - Federica Invernizzi
- Unit of Medical Genetics and NeurogeneticsFondazione IRCCS Istituto Neurologico Carlo BestaMilanItaly
| | - Eleonora Lamantea
- Unit of Medical Genetics and NeurogeneticsFondazione IRCCS Istituto Neurologico Carlo BestaMilanItaly
| | - Benjamin Lucas
- York CollegeThe City University of New YorkJamaicaNew York
| | | | | | - Shamima Rahman
- Mitochondrial Research GroupUCL Great Ormond Street Institute of Child HealthLondonUK
| | - Pedro Rebelo‐Guiomar
- MRC Mitochondrial Biology UnitUniversity of CambridgeCambridgeUK
- Graduate Program in Areas of Basic and Applied BiologyUniversity of PortoPortoPortugal
| | - Saikat Santra
- Department of Clinical Inherited Metabolic DisordersBirmingham Children's HospitalBirminghamUK
| | - Daniela Verrigni
- Department of Neurosciences, Unit of Muscular and Neurodegenerative Disorders, Laboratory of Molecular MedicineBambino Gesu' Children's Research Hospital, IRCCSRomeItaly
| | - Robert McFarland
- Genetics of Mitochondrial Disorders, Institute of Human GeneticsHelmholtz Zentrum MünchenNeuherbergGermany
| | - Holger Prokisch
- Genetics of Mitochondrial Disorders, Institute of Human GeneticsTechnische Universität MünchenMunichGermany
- Genetics of Mitochondrial Disorders, Institute of Human GeneticsHelmholtz Zentrum MünchenNeuherbergGermany
| | - Robert W. Taylor
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Louis Levinger
- York CollegeThe City University of New YorkJamaicaNew York
| | - Michal Minczuk
- MRC Mitochondrial Biology UnitUniversity of CambridgeCambridgeUK
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Ni Y, Hagras MA, Konstantopoulou V, Mayr JA, Stuchebrukhov AA, Meierhofer D. Mutations in NDUFS1 Cause Metabolic Reprogramming and Disruption of the Electron Transfer. Cells 2019; 8:cells8101149. [PMID: 31557978 PMCID: PMC6829531 DOI: 10.3390/cells8101149] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 09/10/2019] [Accepted: 09/20/2019] [Indexed: 01/07/2023] Open
Abstract
Complex I (CI) is the first enzyme of the mitochondrial respiratory chain and couples the electron transfer with proton pumping. Mutations in genes encoding CI subunits can frequently cause inborn metabolic errors. We applied proteome and metabolome profiling of patient-derived cells harboring pathogenic mutations in two distinct CI genes to elucidate underlying pathomechanisms on the molecular level. Our results indicated that the electron transfer within CI was interrupted in both patients by different mechanisms. We showed that the biallelic mutations in NDUFS1 led to a decreased stability of the entire N-module of CI and disrupted the electron transfer between two iron–sulfur clusters. Strikingly interesting and in contrast to the proteome, metabolome profiling illustrated that the pattern of dysregulated metabolites was almost identical in both patients, such as the inhibitory feedback on the TCA cycle and altered glutathione levels, indicative for reactive oxygen species (ROS) stress. Our findings deciphered pathological mechanisms of CI deficiency to better understand inborn metabolic errors.
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Affiliation(s)
- Yang Ni
- Mass Spectrometry Facility, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany;
- Department of Biology, Chemistry and Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
- Present address: Laboratory of Angiogenesis and Vascular Metabolism, VIB-KU Leuven Center for Cancer Biology, 3000 Leuven, Belgium
| | - Muhammad A. Hagras
- Department of Chemistry, University of California Davis, Davis, CA 95616, USA; (M.A.H.); (A.A.S.)
- Present address: Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Vassiliki Konstantopoulou
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, 1090 Vienna, Austria;
| | - Johannes A. Mayr
- Department of Pediatrics, Paracelsus Medical University Salzburg, 5020 Salzburg, Austria;
| | - Alexei A. Stuchebrukhov
- Department of Chemistry, University of California Davis, Davis, CA 95616, USA; (M.A.H.); (A.A.S.)
| | - David Meierhofer
- Mass Spectrometry Facility, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany;
- Correspondence: ; Tel.: +49-30-8413-1567
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Targeted next generation sequencing identifies novel pathogenic variants and provides molecular diagnoses in a cohort of pediatric and adult patients with unexplained mitochondrial dysfunction. Mitochondrion 2019; 47:309-317. [DOI: 10.1016/j.mito.2019.02.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 01/14/2019] [Accepted: 02/26/2019] [Indexed: 12/28/2022]
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Nicolas E, Tricarico R, Savage M, Golemis EA, Hall MJ. Disease-Associated Genetic Variation in Human Mitochondrial Protein Import. Am J Hum Genet 2019; 104:784-801. [PMID: 31051112 PMCID: PMC6506819 DOI: 10.1016/j.ajhg.2019.03.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 03/19/2019] [Indexed: 12/14/2022] Open
Abstract
Mitochondrial dysfunction has consequences not only for cellular energy output but also for cellular signaling pathways. Mitochondrial dysfunction, often based on inherited gene variants, plays a role in devastating human conditions such as mitochondrial neuropathies, myopathies, cardiovascular disorders, and Parkinson and Alzheimer diseases. Of the proteins essential for mitochondrial function, more than 98% are encoded in the cell nucleus, translated in the cytoplasm, sorted based on the presence of encoded mitochondrial targeting sequences (MTSs), and imported to specific mitochondrial sub-compartments based on the integrated activity of a series of mitochondrial translocases, proteinases, and chaperones. This import process is typically dynamic; as cellular homeostasis is coordinated through communication between the mitochondria and the nucleus, many of the adaptive responses to stress depend on modulation of mitochondrial import. We here describe an emerging class of disease-linked gene variants that are found to impact the mitochondrial import machinery itself or to affect the proteins during their import into mitochondria. As a whole, this class of rare defects highlights the importance of correct trafficking of mitochondrial proteins in the cell and the potential implications of failed targeting on metabolism and energy production. The existence of this variant class could have importance beyond rare neuromuscular disorders, given an increasing body of evidence suggesting that aberrant mitochondrial function may impact cancer risk and therapeutic response.
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Affiliation(s)
- Emmanuelle Nicolas
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Rossella Tricarico
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Michelle Savage
- Cancer Prevention and Control Program, Department of Clinical Genetics, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Erica A Golemis
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Michael J Hall
- Cancer Prevention and Control Program, Department of Clinical Genetics, Fox Chase Cancer Center, Philadelphia, PA 19111, USA.
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Mitochondrial disease genetics update: recent insights into the molecular diagnosis and expanding phenotype of primary mitochondrial disease. Curr Opin Pediatr 2018; 30:714-724. [PMID: 30199403 PMCID: PMC6467265 DOI: 10.1097/mop.0000000000000686] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
PURPOSE OF REVIEW Primary mitochondrial disease (PMD) is a genetically and phenotypically diverse group of inherited energy deficiency disorders caused by impaired mitochondrial oxidative phosphorylation (OXPHOS) capacity. Mutations in more than 350 genes in both mitochondrial and nuclear genomes are now recognized to cause primary mitochondrial disease following every inheritance pattern. Next-generation sequencing technologies have dramatically accelerated mitochondrial disease gene discovery and diagnostic yield. Here, we provide an up-to-date review of recently identified, novel mitochondrial disease genes and/or pathogenic variants that directly impair mitochondrial structure, dynamics, and/or function. RECENT FINDINGS A review of PubMed publications was performed from the past 12 months that identified 16 new PMD genes and/or pathogenic variants, and recognition of expanded phenotypes for a wide variety of mitochondrial disease genes. SUMMARY Broad-based exome sequencing has become the standard first-line diagnostic approach for PMD. This has facilitated more rapid and accurate disease identification, and greatly expanded understanding of the wide spectrum of potential clinical phenotypes. A comprehensive dual-genome sequencing approach to PMD diagnosis continues to improve diagnostic yield, advance understanding of mitochondrial physiology, and provide strong potential to develop precision therapeutics targeted to diverse aspects of mitochondrial disease pathophysiology.
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Biomarkers for mitochondrial energy metabolism diseases. Essays Biochem 2018; 62:443-454. [PMID: 29980631 DOI: 10.1042/ebc20170111] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 05/22/2018] [Accepted: 05/23/2018] [Indexed: 02/06/2023]
Abstract
Biomarkers are an indicator of biologic or pathogenic processes, whose function is indicating the presence/absence of disease or monitoring disease course and its response to treatment. Since mitochondrial disorders (MDs) can represent a diagnostic challenge for clinicians, due to their clinical and genetic heterogeneity, the identification of easily measurable biomarkers becomes a high priority. Given the complexity of MD, in particular the primary mitochondrial respiratory chain (MRC) diseases due to oxidative phosphorylation (OXPHOS) dysfunction, a reliable single biomarker, relevant for the whole disease group, could be extremely difficult to find, most of times leading the physicians to better consider a 'biosignature' for the diagnosis, rather than a single biochemical marker. Serum biomarkers like lactate and pyruvate are largely determined in the diagnostic algorithm of MD, but they are not specific to this group of disorders. The concomitant determination of creatine (Cr), plasma amino acids, and urine organic acids might be helpful to reinforce the biosignature in some cases. In recent studies, serum fibroblast growth factor 21 (sFGF21) and serum growth differentiation factor 15 (sGDF15) appear to be promising molecules in identifying MD. Moreover, new different approaches have been developed to discover new MD biomarkers. This work discusses the most important biomarkers currently used in the diagnosis of MRC diseases, and some approaches under evaluation, discussing both their utility and weaknesses.
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