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Abstract
Leigh syndrome, or subacute necrotizing encephalomyelopathy, was initially recognized as a neuropathological entity in 1951. Bilateral symmetrical lesions, typically extending from the basal ganglia and thalamus through brainstem structures to the posterior columns of the spinal cord, are characterized microscopically by capillary proliferation, gliosis, severe neuronal loss, and relative preservation of astrocytes. Leigh syndrome is a pan-ethnic disorder usually with onset in infancy or early childhood, but late-onset forms occur, including in adult life. Over the last six decades it has emerged that this complex neurodegenerative disorder encompasses more than 100 separate monogenic disorders associated with enormous clinical and biochemical heterogeneity. This chapter discusses clinical, biochemical and neuropathological aspects of the disorder, and postulated pathomechanisms. Known genetic causes, including defects of 16 mitochondrial DNA (mtDNA) genes and approaching 100 nuclear genes, are categorized into disorders of subunits and assembly factors of the five oxidative phosphorylation enzymes, disorders of pyruvate metabolism and vitamin and cofactor transport and metabolism, disorders of mtDNA maintenance, and defects of mitochondrial gene expression, protein quality control, lipid remodeling, dynamics, and toxicity. An approach to diagnosis is presented, together with known treatable causes and an overview of current supportive management options and emerging therapies on the horizon.
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Affiliation(s)
- Shamima Rahman
- Genetics and Genomic Medicine Department, UCL Great Ormond Street Institute of Child Health, London, United Kingdom; Metabolic Medicine Department, Great Ormond Street Hospital for Children, London, United Kingdom.
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Protein Transduction Domain-Mediated Delivery of Recombinant Proteins and In Vitro Transcribed mRNAs for Protein Replacement Therapy of Human Severe Genetic Mitochondrial Disorders: The Case of Sco2 Deficiency. Pharmaceutics 2023; 15:pharmaceutics15010286. [PMID: 36678915 PMCID: PMC9861957 DOI: 10.3390/pharmaceutics15010286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/31/2022] [Accepted: 01/09/2023] [Indexed: 01/19/2023] Open
Abstract
Mitochondrial disorders represent a heterogeneous group of genetic disorders with variations in severity and clinical outcomes, mostly characterized by respiratory chain dysfunction and abnormal mitochondrial function. More specifically, mutations in the human SCO2 gene, encoding the mitochondrial inner membrane Sco2 cytochrome c oxidase (COX) assembly protein, have been implicated in the mitochondrial disorder fatal infantile cardioencephalomyopathy with COX deficiency. Since an effective treatment is still missing, a protein replacement therapy (PRT) was explored using protein transduction domain (PTD) technology. Therefore, the human recombinant full-length mitochondrial protein Sco2, fused to TAT peptide (a common PTD), was produced (fusion Sco2 protein) and successfully transduced into fibroblasts derived from a SCO2/COX-deficient patient. This PRT contributed to effective COX assembly and partial recovery of COX activity. In mice, radiolabeled fusion Sco2 protein was biodistributed in the peripheral tissues of mice and successfully delivered into their mitochondria. Complementary to that, an mRNA-based therapeutic approach has been more recently considered as an innovative treatment option. In particular, a patented, novel PTD-mediated IVT-mRNA delivery platform was developed and applied in recent research efforts. PTD-IVT-mRNA of full-length SCO2 was successfully transduced into the fibroblasts derived from a SCO2/COX-deficient patient, translated in host ribosomes into a nascent chain of human Sco2, imported into mitochondria, and processed to the mature protein. Consequently, the recovery of reduced COX activity was achieved, thus suggesting the potential of this mRNA-based technology for clinical translation as a PRT for metabolic/genetic disorders. In this review, such research efforts will be comprehensibly presented and discussed to elaborate their potential in clinical application and therapeutic usefulness.
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Leigh Syndrome: Spectrum of Molecular Defects and Clinical Features in Russia. Int J Mol Sci 2023; 24:ijms24021597. [PMID: 36675121 PMCID: PMC9865855 DOI: 10.3390/ijms24021597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/03/2023] [Accepted: 01/06/2023] [Indexed: 01/15/2023] Open
Abstract
Leigh syndrome (LS), also known as infantile subacute necrotizing encephalopathy, is the most frequent mitochondrial disorder in children. Recently, more than 80 genes have been associated with LS, which greatly complicates the diagnosis. In this article, we present clinical and molecular findings of 219 patients with LS and give the detailed description of three cases with rare findings in nuclear genes MORC2, NARS2 and VPS13D, demonstrating wide genetic heterogeneity of this mitochondrial disease. The most common cause of LS in Russian patients are pathogenic variants in the SURF1 gene (44.3% of patients). The most frequent pathogenic variant is c.845_846delCT (66.0% of mutant alleles; 128/192), which is also widespread in Eastern Europe. Five main LS genes, SURF1, SCO2, MT-ATP6, MT-ND5 and PDHA1, account for 70% of all LS cases in the Russian Federation. Using next generation sequencing (NGS) technique, we were able to detect pathogenic variants in other nuclear genes: NDUFV1, NDUFS2, NDUFS8, NDUFAF5, NDUFAF6, NDUFA10, SUCLG1, GFM2, COX10, PMPCB, NARS2, PDHB and SLC19A3, including two genes previously associated with Leigh-like phenotypes-MORC2 and VPS13D. We found 49 previously undescribed nucleotide variants, including two deep intronic variants which affect splicing.
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Garza NM, Swaminathan AB, Maremanda KP, Zulkifli M, Gohil VM. Mitochondrial copper in human genetic disorders. Trends Endocrinol Metab 2023; 34:21-33. [PMID: 36435678 PMCID: PMC9780195 DOI: 10.1016/j.tem.2022.11.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Revised: 10/28/2022] [Accepted: 11/04/2022] [Indexed: 11/24/2022]
Abstract
Copper is an essential micronutrient that serves as a cofactor for enzymes involved in diverse physiological processes, including mitochondrial energy generation. Copper enters cells through a dedicated copper transporter and is distributed to intracellular cuproenzymes by copper chaperones. Mitochondria are critical copper-utilizing organelles that harbor an essential cuproenzyme cytochrome c oxidase, which powers energy production. Mutations in copper transporters and chaperones that perturb mitochondrial copper homeostasis result in fatal genetic disorders. Recent studies have uncovered the therapeutic potential of elesclomol, a copper ionophore, for the treatment of copper deficiency disorders such as Menkes disease. Here we review the role of copper in mitochondrial energy metabolism in the context of human diseases and highlight the recent developments in copper therapeutics.
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Affiliation(s)
- Natalie M Garza
- Department of Biochemistry and Biophysics, MS 3474, Texas A&M University, College Station, TX 77843, USA
| | - Abhinav B Swaminathan
- Department of Biochemistry and Biophysics, MS 3474, Texas A&M University, College Station, TX 77843, USA
| | - Krishna P Maremanda
- Department of Biochemistry and Biophysics, MS 3474, Texas A&M University, College Station, TX 77843, USA
| | - Mohammad Zulkifli
- Department of Biochemistry and Biophysics, MS 3474, Texas A&M University, College Station, TX 77843, USA
| | - Vishal M Gohil
- Department of Biochemistry and Biophysics, MS 3474, Texas A&M University, College Station, TX 77843, USA.
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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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Ricciardello A, Tomaiuolo P, Persico AM. Genotype-phenotype correlation in Phelan-McDermid syndrome: A comprehensive review of chromosome 22q13 deleted genes. Am J Med Genet A 2021; 185:2211-2233. [PMID: 33949759 PMCID: PMC8251815 DOI: 10.1002/ajmg.a.62222] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 03/28/2021] [Accepted: 04/04/2021] [Indexed: 12/19/2022]
Abstract
Phelan‐McDermid syndrome (PMS, OMIM #606232), also known as chromosome 22q13 deletion syndrome, is a rare genetic disorder characterized by intellectual disability, hypotonia, delayed or absent speech, motor impairment, autism spectrum disorder, behavioral anomalies, and minor aspecific dysmorphic features. Haploinsufficiency of SHANK3, due to intragenic deletions or point mutations, is sufficient to cause many neurobehavioral features of PMS. However, several additional genes located within larger 22q13 deletions can contribute to the great interindividual variability observed in the PMS phenotype. This review summarizes the phenotypic contributions predicted for 213 genes distributed along the largest 22q13.2‐q13.33 terminal deletion detected in our sample of 63 PMS patients by array‐CGH analysis, spanning 9.08 Mb. Genes have been grouped into four categories: (1) genes causing human diseases with an autosomal dominant mechanism, or (2) with an autosomal recessive mechanism; (3) morphogenetically relevant genes, either involved in human diseases with additive co‐dominant, polygenic, and/or multifactorial mechanisms, or implicated in animal models but not yet documented in human pathology; (4) protein coding genes either functionally nonrelevant, with unknown function, or pathogenic through mechanisms other than haploinsufficiency; piRNAs, noncoding RNAs, miRNAs, novel transcripts and pseudogenes. Our aim is to understand genotype–phenotype correlations in PMS patients and to provide clinicians with a conceptual framework to promote evidence‐based genetic work‐ups, clinical assessments, and therapeutic interventions.
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Affiliation(s)
- Arianna Ricciardello
- Interdepartmental Program "Autism 0-90", "Gaetano Martino" University Hospital, University of Messina, Messina, Italy
| | - Pasquale Tomaiuolo
- Interdepartmental Program "Autism 0-90", "Gaetano Martino" University Hospital, University of Messina, Messina, Italy
| | - Antonio M Persico
- Interdepartmental Program "Autism 0-90", "Gaetano Martino" University Hospital, University of Messina, Messina, Italy
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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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Tsang MHY, Kwong AKY, Chan KLS, Fung JLF, Yu MHC, Mak CCY, Yeung KS, Rodenburg RJT, Smeitink JAM, Chan R, Tsoi T, Hui J, Wong SSN, Tai SM, Chan VCM, Ma CK, Fung STH, Wu SP, Chak WK, Chung BHY, Fung CW. Delineation of molecular findings by whole-exome sequencing for suspected cases of paediatric-onset mitochondrial diseases in the Southern Chinese population. Hum Genomics 2020; 14:28. [PMID: 32907636 PMCID: PMC7488033 DOI: 10.1186/s40246-020-00278-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 08/27/2020] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Mitochondrial diseases (MDs) are a group of clinically and genetically heterogeneous disorders characterized by defects in oxidative phosphorylation. Since clinical phenotypes of MDs may be non-specific, genetic diagnosis is crucial for guiding disease management. In the current study, whole-exome sequencing (WES) was performed for our paediatric-onset MD cohort of a Southern Chinese origin, with the aim of identifying key disease-causing variants in the Chinese patients with MDs. METHODS We recruited Chinese patients who had paediatric-onset MDs and a minimum mitochondrial disease criteria (MDC) score of 3. Patients with positive target gene or mitochondrial DNA sequencing results were excluded. WES was performed, variants with population frequency ≤ 1% were analysed for pathogenicity on the basis of the American College of Medical Genetics and Genomics guidelines. RESULTS Sixty-six patients with pre-biopsy MDC scores of 3-8 were recruited. The overall diagnostic yield was 35% (23/66). Eleven patients (17%) were found to have mutations in MD-related genes, with COQ4 having the highest mutation rate owing to the Chinese-specific founder mutation (4/66, 6%). Twelve patients (12/66, 18%) had mutations in non-MD-related genes: ATP1A3 (n = 3, two were siblings), ALDH5A1, ARX, FA2H, KCNT1, LDHD, NEFL, NKX2-2, TBCK, and WAC. CONCLUSIONS We confirmed that the COQ4:c.370G>A, p.(Gly124Ser) variant, was a founder mutation among the Southern Chinese population. Screening for this mutation should therefore be considered while diagnosing Chinese patients suspected to have MDs. Furthermore, WES has proven to be useful in detecting variants in patients suspected to have MDs because it helps to obtain an unbiased and precise genetic diagnosis for these diseases, which are genetically heterogeneous.
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Affiliation(s)
- Mandy H Y Tsang
- Department of Paediatrics & Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China
| | - Anna K Y Kwong
- Department of Paediatrics & Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China
| | - Kate L S Chan
- Department of Paediatrics & Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China
| | - Jasmine L F Fung
- Department of Paediatrics & Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China
| | - Mullin H C Yu
- Department of Paediatrics & Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China
| | - Christopher C Y Mak
- Department of Paediatrics & Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China
| | - Kit-San Yeung
- Department of Paediatrics & Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China
| | - Richard J T Rodenburg
- Radboud Center for Mitochondrial Medicine, Department of Paediatrics, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Jan A M Smeitink
- Radboud Center for Mitochondrial Medicine, Department of Paediatrics, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Rachel Chan
- Department of Paediatrics, Centro Hospitalar Conde de São Januário (CHCSJ) Hospital, SAR, Macau, China
| | - Thomas Tsoi
- Department of Paediatrics, Centro Hospitalar Conde de São Januário (CHCSJ) Hospital, SAR, Macau, China
| | - Joannie Hui
- Department of Paediatrics and Adolescent Medicine, Hong Kong Children's Hospital, Doctors' Office, 9/F, Tower B, 1 Shing Cheong Road, Kowloon Bay, Kowloon, Hong Kong, SAR, China
| | - Shelia S N Wong
- Department of Paediatrics and Adolescent Medicine, Hong Kong Children's Hospital, Doctors' Office, 9/F, Tower B, 1 Shing Cheong Road, Kowloon Bay, Kowloon, Hong Kong, SAR, China
| | - Shuk-Mui Tai
- Department of Paediatrics & Adolescent Medicine, Pamela Youde Nethersole Eastern Hospital, Hong Kong, SAR, China
| | - Victor C M Chan
- Department of Paediatrics & Adolescent Medicine, Pamela Youde Nethersole Eastern Hospital, Hong Kong, SAR, China
| | - Che-Kwan Ma
- Department of Paediatrics and Adolescent Medicine, United Christian Hospital, Hong Kong, SAR, China
| | - Sharon T H Fung
- Department of Paediatrics, Kwong Wah Hospital, Hong Kong, SAR, China
| | - Shun-Ping Wu
- Department of Paediatrics and Adolescent Medicine, Queen Elizabeth Hospital, Hong Kong, SAR, China
| | - W K Chak
- Department of Paediatrics and Adolescent Medicine, Tuen Mun Hospital, Hong Kong, SAR, China
| | - Brian H Y Chung
- Department of Paediatrics & Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China. .,Department of Paediatrics and Adolescent Medicine, Hong Kong Children's Hospital, Doctors' Office, 9/F, Tower B, 1 Shing Cheong Road, Kowloon Bay, Kowloon, Hong Kong, SAR, China. .,Department of Pediatrics and Adolescent Medicine, Queen Mary Hospital, Room 115, 1/F, New Clinical Building, 102 Pokfulam Road, Hong Kong, SAR, China. .,Department of Paediatrics & Adolescent Medicine, Duchess of Kent Children's Hospital, Hong Kong, SAR, China.
| | - Cheuk-Wing Fung
- Department of Paediatrics & Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China. .,Department of Paediatrics and Adolescent Medicine, Hong Kong Children's Hospital, Doctors' Office, 9/F, Tower B, 1 Shing Cheong Road, Kowloon Bay, Kowloon, Hong Kong, SAR, China.
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Piekutowska-Abramczuk D, Kaliszewska M, Sułek A, Jurkowska N, Ołtarzewski M, Jabłońska E, Trubicka J, Głowacka A, Ciara E, Kowalski P, Langiewicz-Wojciechowska K, Tesarova M, Zeman J, Kierdaszuk B, Kuczyński D, Chmielewski D, Szymańska E, Bakuła A, Łusakowska A, Lipowska M, Brodacki B, Pera J, Dorobek M, Rydzanicz M, Płoski R, Chrzanowska KH, Bartnik E, Placha G, Kamińska A, Kostera-Pruszczyk A, Krajewska-Walasek M, Tońska K, Pronicka E. The frequency of mitochondrial polymerase gamma related disorders in a large Polish population cohort. Mitochondrion 2019; 47:179-187. [DOI: 10.1016/j.mito.2018.11.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 10/02/2018] [Accepted: 11/02/2018] [Indexed: 02/06/2023]
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Natural history of mitochondrial disorders: a systematic review. Essays Biochem 2018; 62:423-442. [DOI: 10.1042/ebc20170108] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 05/09/2018] [Accepted: 05/15/2018] [Indexed: 11/17/2022]
Abstract
The natural history of a disease defines the age of onset, presenting features, clinical phenotype, morbidity and mortality outcomes of disease that is unmodified by treatments. A clear understanding of the natural history of mitochondrial disorders is essential for establishing genotype-phenotype–prognosis correlations. We performed a systematic review of the reported natural history of mitochondrial disease by searching the literature for all published natural history studies containing at least 20 individuals. We defined a phenotype as ‘common’ if it was observed in ≥30% of cases in a study, thereby highlighting common and uncommon phenotypes for each disorder. Thirty-seven natural history studies were identified encompassing 29 mitochondrial disease entities. Fifty-nine percent of disorders had an onset before 18 months and 81% before 18 years. Most disorders had multisystemic involvement and most often affected were the central nervous system, eyes, gastrointestinal system, skeletal muscle, auditory system and the heart. Less frequent involvement was seen for respiratory, renal, endocrine, hepatic, haematological and genitourinary systems. Elevated lactate was the most frequent biochemical abnormality, seen in 72% of disorders. Age of death was <1 y in 13% of disorders, <5 y in 57% and <10 y in 74%. Disorders with high mortality rates were generally associated with earlier deaths. The most robust indicators of poor prognosis were early presentation of disease and truncating mutations. A thorough knowledge of natural history has helped to redefine diagnostic criteria for classical clinical syndromes and to establish a clinical baseline for comparison in single-arm clinical trials of novel therapies.
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Abstract
All known eukaryotes require copper for their development and survival. The essentiality of copper reflects its widespread use as a co-factor in conserved enzymes that catalyze biochemical reactions critical to energy production, free radical detoxification, collagen deposition, neurotransmitter biosynthesis and iron homeostasis. However, the prioritized use of copper poses an organism with a considerable challenge because, in its unbound form, copper can potentiate free radical production and displace iron-sulphur clusters to disrupt protein function. Protective mechanisms therefore evolved to mitigate this challenge and tightly regulate the acquisition, trafficking and storage of copper such that the metal ion is rarely found in its free form in the cell. Findings by a number of groups over the last ten years emphasize that this regulatory framework forms the foundation of a system that is capable of monitoring copper status and reprioritizing copper usage at both the cellular and systemic levels of organization. While the identification of relevant molecular mechanisms and signaling pathways has proven to be difficult and remains a barrier to our full understanding of the regulation of copper homeostasis, mounting evidence points to the mitochondrion as a pivotal hub in this regard in both healthy and diseased states. Here, we review our current understanding of copper handling pathways contained within the organelle and consider plausible mechanisms that may serve to functionally couple their activity to that of other cellular copper handling machinery to maintain copper homeostasis.
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Affiliation(s)
- Zakery N. Baker
- Department of Biochemistry, University of Saskatchewan, Saskatoon, SK Canada S7N 5E5
| | - Paul A. Cobine
- Department of Biological Sciences, Auburn University, Auburn, Alabama 36849, USA
| | - Scot C. Leary
- Department of Biochemistry, University of Saskatchewan, Saskatoon, SK Canada S7N 5E5
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de Souza PVS, Bortholin T, Naylor FGM, Chieia MAT, de Rezende Pinto WBV, Oliveira ASB. Motor neuron disease in inherited neurometabolic disorders. Rev Neurol (Paris) 2017; 174:115-124. [PMID: 29128155 DOI: 10.1016/j.neurol.2017.06.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Revised: 04/29/2017] [Accepted: 06/15/2017] [Indexed: 01/18/2023]
Abstract
Inherited neurometabolic disorders represent a growing group of inborn errors of metabolism that present with major neurological symptoms or a complex spectrum of symptoms dominated by central or peripheral nervous system dysfunction. Many neurological presentations may arise from the same metabolic defect, especially in autosomal-recessive inherited disorders. Motor neuron disease (MND), mainly represented by amyotrophic lateral sclerosis, may also result from various inborn errors of metabolism, some of which may represent potentially treatable conditions, thereby emphasizing the importance of recognizing such diseases. The present review discusses the most important neurometabolic disorders presenting with motor neuron (lower and/or upper) dysfunction as the key clinical and neuropathological feature.
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Affiliation(s)
- P Victor Sgobbi de Souza
- Division of Neuromuscular Diseases, Department of Neurology and Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - T Bortholin
- Division of Neuromuscular Diseases, Department of Neurology and Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - F George Monteiro Naylor
- Division of Neuromuscular Diseases, Department of Neurology and Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - M Antônio Troccoli Chieia
- Division of Neuromuscular Diseases, Department of Neurology and Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - W Bocca Vieira de Rezende Pinto
- Division of Neuromuscular Diseases, Department of Neurology and Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil.
| | - A Souza Bulle Oliveira
- Division of Neuromuscular Diseases, Department of Neurology and Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
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Pronicka E, Piekutowska-Abramczuk D, Ciara E, Trubicka J, Rokicki D, Karkucińska-Więckowska A, Pajdowska M, Jurkiewicz E, Halat P, Kosińska J, Pollak A, Rydzanicz M, Stawinski P, Pronicki M, Krajewska-Walasek M, Płoski R. New perspective in diagnostics of mitochondrial disorders: two years' experience with whole-exome sequencing at a national paediatric centre. J Transl Med 2016; 14:174. [PMID: 27290639 PMCID: PMC4903158 DOI: 10.1186/s12967-016-0930-9] [Citation(s) in RCA: 157] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 05/31/2016] [Indexed: 12/30/2022] Open
Abstract
Background Whole-exome sequencing (WES) has led to an exponential increase in identification of causative variants in mitochondrial disorders (MD). Methods We performed WES in 113 MD suspected patients from Polish paediatric reference centre, in whom routine testing failed to identify a molecular defect. WES was performed using TruSeqExome enrichment, followed by variant prioritization, validation by Sanger sequencing, and segregation with the disease phenotype in the family. Results Likely causative mutations were identified in 67 (59.3 %) patients; these included variants in mtDNA (6 patients) and nDNA: X-linked (9 patients), autosomal dominant (5 patients), and autosomal recessive (47 patients, 11 homozygotes). Novel variants accounted for 50.5 % (50/99) of all detected changes. In 47 patients, changes in 31 MD-related genes (ACAD9, ADCK3, AIFM1, CLPB, COX10, DLD, EARS2, FBXL4, MTATP6, MTFMT, MTND1, MTND3, MTND5, NAXE, NDUFS6, NDUFS7, NDUFV1, OPA1, PARS2, PC, PDHA1, POLG, RARS2, RRM2B, SCO2, SERAC1, SLC19A3, SLC25A12, TAZ, TMEM126B, VARS2) were identified. The ACAD9, CLPB, FBXL4, PDHA1 genes recurred more than twice suggesting higher general/ethnic prevalence. In 19 cases, variants in 18 non-MD related genes (ADAR, CACNA1A, CDKL5, CLN3, CPS1, DMD, DYSF, GBE1, GFAP, HSD17B4, MECP2, MYBPC3, PEX5, PGAP2, PIGN, PRF1, SBDS, SCN2A) were found. The percentage of positive WES results rose gradually with increasing probability of MD according to the Mitochondrial Disease Criteria (MDC) scale (from 36 to 90 % for low and high probability, respectively). The percentage of detected MD-related genes compared with non MD-related genes also grew with the increasing MD likelihood (from 20 to 97 %). Molecular diagnosis was established in 30/47 (63.8 %) neonates and in 17/28 (60.7 %) patients with basal ganglia involvement. Mutations in CLPB, SERAC1, TAZ genes were identified in neonates with 3-methylglutaconic aciduria (3-MGA) as a discriminative feature. New MD-related candidate gene (NDUFB8) is under verification. Conclusions We suggest WES rather than targeted NGS as the method of choice in diagnostics of MD in children, including neonates with 3-MGA aciduria, who died without determination of disease cause and with limited availability of laboratory data. There is a strong correlation between the degree of MD diagnosis by WES and MD likelihood expressed by the MDC scale. Electronic supplementary material The online version of this article (doi:10.1186/s12967-016-0930-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ewa Pronicka
- Department of Medical Genetics, The Children's Memorial Health Institute, 04-730, Warsaw, Poland. .,Department of Paediatrics, Nutrition and Metabolic Diseases,, The Children's Memorial Health Institute, Warsaw, Poland.
| | | | - Elżbieta Ciara
- Department of Medical Genetics, The Children's Memorial Health Institute, 04-730, Warsaw, Poland
| | - Joanna Trubicka
- Department of Medical Genetics, The Children's Memorial Health Institute, 04-730, Warsaw, Poland
| | - Dariusz Rokicki
- Department of Paediatrics, Nutrition and Metabolic Diseases,, The Children's Memorial Health Institute, Warsaw, Poland
| | | | - Magdalena Pajdowska
- Department of Biochemistry and Experimental Medicine, The Children's Memorial Health Institute, Warsaw, Poland
| | - Elżbieta Jurkiewicz
- Department of Radiology, The Children's Memorial Health Institute, Warsaw, Poland
| | - Paulina Halat
- Department of Medical Genetics, The Children's Memorial Health Institute, 04-730, Warsaw, Poland
| | - Joanna Kosińska
- Department of Medical Genetics, Warsaw Medical University, Pawińskiego str, 02-106, Warsaw, Poland
| | - Agnieszka Pollak
- Department of Genetics, Institute of Physiology and Pathology of Hearing, Nadarzyn, Poland
| | - Małgorzata Rydzanicz
- Department of Medical Genetics, Warsaw Medical University, Pawińskiego str, 02-106, Warsaw, Poland
| | - Piotr Stawinski
- Department of Genetics, Institute of Physiology and Pathology of Hearing, Nadarzyn, Poland
| | - Maciej Pronicki
- Department of Pathology, The Children's Memorial Health Institute, Warsaw, Poland
| | | | - Rafał Płoski
- Department of Medical Genetics, Warsaw Medical University, Pawińskiego str, 02-106, Warsaw, Poland.
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14
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Lake NJ, Compton AG, Rahman S, Thorburn DR. Leigh syndrome: One disorder, more than 75 monogenic causes. Ann Neurol 2015; 79:190-203. [PMID: 26506407 DOI: 10.1002/ana.24551] [Citation(s) in RCA: 308] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 10/16/2015] [Accepted: 10/18/2015] [Indexed: 12/19/2022]
Abstract
Leigh syndrome is the most common pediatric presentation of mitochondrial disease. This neurodegenerative disorder is genetically heterogeneous, and to date pathogenic mutations in >75 genes have been identified, encoded by 2 genomes (mitochondrial and nuclear). More than one-third of these disease genes have been characterized in the past 5 years alone, reflecting the significant advances made in understanding its etiological basis. We review the diverse biochemical and genetic etiology of Leigh syndrome and associated clinical, neuroradiological, and metabolic features that can provide clues for diagnosis. We discuss the emergence of genotype-phenotype correlations, insights gleaned into the molecular basis of disease, and available therapeutic options.
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Affiliation(s)
- Nicole J Lake
- Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - Alison G Compton
- Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - Shamima Rahman
- Mitochondrial Research Group, Genetics and Genomic Medicine, Institute of Child Health, University College London and Metabolic Unit, Great Ormond Street Hospital, London, United Kingdom
| | - David R Thorburn
- Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia.,Victorian Clinical Genetic Services, Royal Children's Hospital, Melbourne, Victoria, Australia
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15
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Piekutowska-Abramczuk D, Kocyła-Karczmarewicz B, Małkowska M, Łuczak S, Iwanicka-Pronicka K, Siegmund S, Yang H, Wen Q, Hoang QV, Silverman RH, Kowalski P, Szczypińska O, Czornak K, Zimowski J, Płoski R, Pilch J, Ciara E, Zaremba J, Krajewska-Walasek M, Schon EA, Pronicka E. No Evidence for Association of SCO2 Heterozygosity with High-Grade Myopia or Other Diseases with Possible Mitochondrial Dysfunction. JIMD Rep 2015; 27:63-8. [PMID: 26427993 DOI: 10.1007/8904_2015_468] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 05/14/2015] [Accepted: 05/26/2015] [Indexed: 03/05/2023] Open
Abstract
SCO2 mutations cause recessively inherited cytochrome c oxidase deficiency. Recently Tran-Viet et al. proposed that heterozygosity for pathogenic SCO2 variants, including the common E140K variant, causes high-grade myopia. To investigate the association of SCO2 mutations with myopia, ophthalmic examinations were performed on 35 E140K carriers, one homozygous infant, and on a mouse model of Sco2 deficiency. Additionally, a screen for other putative effects of SCO2 heterozygosity was carried out by comparing the prevalence of the common E140K variant in a population of patients with undiagnosed diseases compatible with SCO2-related pathogenesis to that in a general population sample. High-grade myopia was not identified in any of the studied individuals. Of the carriers, 17 were emmetropic, and 18 possessed refractive errors. Additionally, no significant axial elongation indicative of high-grade myopia was found in mice carrying E129K (corresponding to E140K in humans) knock-in mutations. The prevalence of E140K carriers in the symptomatic cohort was evaluated as 1:103 (CI: 0.44-2.09) and did not differ significantly from the population prevalence (1:147, CI: 0.45-1.04).Our study demonstrates that heterozygosity for pathogenic SCO2 variants is not associated with high-grade myopia in either human patients or in mice.
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Affiliation(s)
| | | | - Maja Małkowska
- Department of Medical Genetics, The Children's Memorial Health Institute, 04-730, Warsaw, Poland
| | - Sylwia Łuczak
- Department of Medical Genetics, The Children's Memorial Health Institute, 04-730, Warsaw, Poland
| | | | - Stephanie Siegmund
- Department of Neurology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Hua Yang
- Department of Neurology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Quan Wen
- Department of Ophthalmology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Quan V Hoang
- Department of Ophthalmology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Ronald H Silverman
- Department of Ophthalmology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Paweł Kowalski
- Department of Medical Genetics, The Children's Memorial Health Institute, 04-730, Warsaw, Poland
| | - Olga Szczypińska
- Department of Medical Genetics, The Children's Memorial Health Institute, 04-730, Warsaw, Poland
| | - Kamila Czornak
- Department of Medical Genetics, The Children's Memorial Health Institute, 04-730, Warsaw, Poland
| | - Janusz Zimowski
- Department of Genetics, Institute of Psychiatry and Neurology, 02-957, Warsaw, Poland
| | - Rafał Płoski
- Department of Medical Genetics, Medical University of Warsaw, 02-106, Warsaw, Poland
| | - Jacek Pilch
- Department of Child Neurology, Medical University of Silesia, 0-055, Katowice, Poland
| | - Elżbieta Ciara
- Department of Medical Genetics, The Children's Memorial Health Institute, 04-730, Warsaw, Poland
| | - Jacek Zaremba
- Department of Genetics, Institute of Psychiatry and Neurology, 02-957, Warsaw, Poland
| | | | - Eric A Schon
- Department of Neurology, Columbia University Medical Center, New York, NY, 10032, USA.,Department of Genetics and Development, Columbia University Medical Center, New York, NY, 10032, USA
| | - Ewa Pronicka
- Department of Medical Genetics, The Children's Memorial Health Institute, 04-730, Warsaw, Poland. .,Department of Pediatrics, Nutrition and Metabolic Diseases, The Children's Memorial Health Institute, 04-730, Warsaw, Poland.
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16
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Finsterer J, Mishra A, Wakil S, Pennuto M, Soraru G. Mitochondrial implications in bulbospinal muscular atrophy (Kennedy disease). Amyotroph Lateral Scler Frontotemporal Degener 2015; 17:112-8. [PMID: 26428534 DOI: 10.3109/21678421.2015.1089910] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
There is increasing evidence that mitochondrial functions are secondarily disturbed in bulbospinal muscular atrophy (BSMA). This review focuses on the relation between BSMA and the effect of the expanded polyglutamine (poly-Q) androgen receptor (AR) on mitochondrial functions. Mitochondrial functions in bulbospinal muscular atrophy (SBMA) are affected on the molecular, clinical, and therapeutic level. On the molecular level there is down-regulation of various nuclear-DNA-encoded mitochondrial proteins by mutant androgen receptor (mAR), colocalization of the mAR with various mitochondrial proteins, association of mAR aggregates with mitochondria resulting in abnormal distribution of mitochondria, mtDNA depletion or multiple mtDNA deletions, mitochondrial membrane depolarization, increase in reactive oxidative species, and activation of the mitochondrial caspase pathway. On the clinical level various mitochondrial disorders mimic SBMA, and on the therapeutic level pioglitazone expresses PPAR-γ, cyclosporine-A restores mitochondrial membrane potentials, coenzyme-Q and idebenone reduce oxidative stress, and geldanamycin up-regulates protective mitochondrial heat shock proteins. In conclusion, in BSMA mitochondrial dysfunction results from various interactions of elongated poly-Q AR with mitochondria, mitochondrial proteins, nuclear or mitochondrial DNA, causing oxidative stress, decreased mitochondrial membrane potential, or activation of the mitochondrial caspase pathway. Additionally, mitochondrial disease may mimic BSMA and therapeutic approaches may depend on modifications of mitochondrial pathways.
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Affiliation(s)
| | | | - Salma Wakil
- c Department of Genetics , King Faisal Specialist Hospital and Research Centre , Riyadh , Saudi Arabia
| | - Maria Pennuto
- d Dulbecco Telethon Institute Laboratory of Neurodegenerative Diseases, Centre for Integrative Biology (CIBIO) , University of Trento , Trento
| | - Gianni Soraru
- e Department of Neurosciences , University of Padova , Italy
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17
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Szymanska-Debinska T, Karkucinska-Wieckowska A, Piekutowska-Abramczuk D, Jurkiewicz E, Iwanicka-Pronicka K, Rokicki D, Pronicki M. Leigh disease due to SCO2 mutations revealed at extended autopsy. J Clin Pathol 2015; 68:397-9. [PMID: 25720770 DOI: 10.1136/jclinpath-2014-202606] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 01/18/2015] [Indexed: 11/04/2022]
Affiliation(s)
| | | | | | - Elżbieta Jurkiewicz
- Department of Nuclear Medicine, The Children's Memorial Health Institute, Warsaw, Poland
| | - Katarzyna Iwanicka-Pronicka
- Department of Medical Genetics, The Children's Memorial Health Institute, Warsaw, Poland Department of Audiology and Phoniatrics, The Children's Memorial Health Institute, Warsaw, Poland
| | - Dariusz Rokicki
- Department of Pediatrics, Nutrition and Metabolic Diseases The Children's Memorial Health Institute, Warsaw, Poland
| | - Maciej Pronicki
- Department of Pathology, The Children's Memorial Health Institute, Warsaw, Poland
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