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Finsterer J. Rare Phenotypic Manifestations of MELAS. Yonsei Med J 2020; 61:904-906. [PMID: 32975067 PMCID: PMC7515779 DOI: 10.3349/ymj.2020.61.10.904] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 09/01/2020] [Accepted: 09/03/2020] [Indexed: 12/17/2022] Open
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Al Khatib I, Shutt TE. Advances Towards Therapeutic Approaches for mtDNA Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1158:217-246. [PMID: 31452143 DOI: 10.1007/978-981-13-8367-0_12] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mitochondria maintain and express their own genome, referred to as mtDNA, which is required for proper mitochondrial function. While mutations in mtDNA can cause a heterogeneous array of disease phenotypes, there is currently no cure for this collection of diseases. Here, we will cover characteristics of the mitochondrial genome important for understanding the pathology associated with mtDNA mutations, and review recent approaches that are being developed to treat and prevent mtDNA disease. First, we will discuss mitochondrial replacement therapy (MRT), where mitochondria from a healthy donor replace maternal mitochondria harbouring mutant mtDNA. In addition to ethical concerns surrounding this procedure, MRT is only applicable in cases where the mother is known or suspected to carry mtDNA mutations. Thus, there remains a need for other strategies to treat patients with mtDNA disease. To this end, we will also discuss several alternative means to reduce the amount of mutant mtDNA present in cells. Such methods, referred to as heteroplasmy shifting, have proven successful in animal models. In particular, we will focus on the approach of targeting engineered endonucleases to specifically cleave mutant mtDNA. Together, these approaches offer hope to prevent the transmission of mtDNA disease and potentially reduce the impact of mtDNA mutations.
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Affiliation(s)
- Iman Al Khatib
- Deparments of Medical Genetics and Biochemistry & Molecular Biology, Cumming School of Medicine, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Timothy E Shutt
- Deparments of Medical Genetics and Biochemistry & Molecular Biology, Cumming School of Medicine, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.
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Brisca G, Fiorillo C, Nesti C, Trucco F, Derchi M, Andaloro A, Assereto S, Morcaldi G, Pedemonte M, Minetti C, Santorelli FM, Bruno C. Early onset cardiomyopathy associated with the mitochondrial tRNALeu(UUR) 3271T>C MELAS mutation. Biochem Biophys Res Commun 2015; 458:601-604. [DOI: 10.1016/j.bbrc.2015.01.157] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 01/29/2015] [Indexed: 11/24/2022]
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Diagnostic approach in infants and children with mitochondrial diseases. Pediatr Neonatol 2015; 56:7-18. [PMID: 25151629 DOI: 10.1016/j.pedneo.2014.03.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 03/27/2014] [Indexed: 01/06/2023] Open
Abstract
Mitochondrial diseases are a heterogeneous group of disorders affecting energy production in the human body. The diagnosis of mitochondrial diseases represents a challenge to clinicians, especially for pediatric cases, which show enormous variation in clinical presentations, as well as biochemical and genetic complexity. Different consensus diagnostic criteria for mitochondrial diseases in infants and children are available. The lack of standardized diagnostic criteria poses difficulties in evaluating diagnostic methodologies. Even though there are many diagnostic tools, none of them are sensitive enough to make a confirmative diagnosis without being used in combination with other tools. The current approach to diagnosing and classifying mitochondrial diseases incorporates clinical, biochemical, neuroradiological findings, and histological criteria, as well as DNA-based molecular diagnostic testing. The confirmation or exclusion of mitochondrial diseases remains a challenge in clinical practice, especially in cases with nonspecific clinical phenotypes. Therefore, follow-up evolution of clinical symptoms/signs and biochemical data is crucial. The purpose of this study is to review the molecular classification scheme and associated phenotypes in infants and children with mitochondrial diseases, in addition to providing an overview of the basic biochemical reactions and genetic characteristics in the mitochondrion, clinical manifestations, and diagnostic methods. A diagnostic algorithm for identifying mitochondrial disorders in pediatric neurology patients is proposed.
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Finsterer J, Zarrouk Mahjoub S. Mitochondrial epilepsy in pediatric and adult patients. Acta Neurol Scand 2013; 128:141-52. [PMID: 23480231 DOI: 10.1111/ane.12122] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2013] [Indexed: 01/04/2023]
Abstract
Few data are available about the difference between epilepsy in pediatric mitochondrial disorders (MIDs) and adult MIDs. This review focuses on the differences between pediatric and adult mitochondrial epilepsy with regard to seizure type, seizure frequency, and underlying MID. A literature search via Pubmed using the keywords 'mitochondrial', 'epilepsy', 'seizures', 'adult', 'pediatric', and all MID acronyms, was carried out. Frequency of mitochondrial epilepsy strongly depends on the type of MID included and is higher in pediatric compared to adult patients. In pediatric patients, mitochondrial epilepsy is more frequent due to mutations in nDNA-located than mtDNA-located genes and vice versa in adults. In pediatric patients, mitochondrial epilepsy is associated with a syndromic phenotype in half of the patients and in adults more frequently with a non-syndromic phenotype. In pediatric patients, focal seizures are more frequent than generalized seizures and vice versa in adults. Electro-clinical syndromes are more frequent in pediatric MIDs compared to adult MIDs. Differences between pediatric and adult mitochondrial epilepsy concern the onset of epilepsy, frequency of epilepsy, seizure type, type of electro-clinical syndrome, frequency of syndromic versus non-syndromic MIDs, and the outcome. To optimize management of mitochondrial epilepsy, it is essential to differentiate between early and late-onset forms.
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Affiliation(s)
| | - S. Zarrouk Mahjoub
- Laboratory of Biochemistry; UR ‘Human Nutrition and Metabolic Disorders’ Faculty of Medicine Monastir; Tunisia
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Selim L, Mehaney D. Mitochondrial encephalopathy with lactic acidosis and stroke-like episodes in a Japanese child: Clinical, radiological and molecular genetic analysis. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2013. [DOI: 10.1016/j.ejmhg.2013.03.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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Tzoulis C, Bindoff LA. Acute mitochondrial encephalopathy reflects neuronal energy failure irrespective of which genome the genetic defect affects. Brain 2012; 135:3627-34. [PMID: 23065482 DOI: 10.1093/brain/aws223] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Mitochondrial dysfunction and disease may arise as a result of mutations in either the mitochondrial genome itself or nuclear encoded genes involved in mitochondrial homeostasis and function. Irrespective of which genome is affected, mitochondrial encephalopathies share clinical and biochemical features suggesting common pathophysiological pathways. Two common paradigms of mitochondrial encephalopathy are mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes caused by maternally transmitted mutations of mitochondrial DNA and mitochondrial spinocerebellar ataxia and epilepsy caused by recessively inherited mutations of the nuclear-encoded DNA polymerase gamma, which replicates and repairs the mitochondrial genome. We studied and compared the disease mechanisms involved in these two syndromes. Despite having different genetic origins, their pathophysiological pathways converge on one critical event, damage to the respiratory chain leading to insufficient energy to maintain cellular homeostasis. In the central nervous system, this appears to cause selective neuronal damage leading to the development of lesions that mimic ischaemic damage, but which lack evidence of decreased tissue perfusion. Although these stroke-like lesions may expand or regress dynamically, the critical factor that dictates prognosis is the presence of epilepsy. Epileptic seizures increase the energy requirements of the metabolically already compromised neurons establishing a vicious cycle resulting in worsening energy failure and neuronal death. We believe that it is this cycle of events that determines outcome and which provides us with a mechanistic structure to understand the pathophysiology of acute mitochondrial encephalopathies and plan future treatments.
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Affiliation(s)
- Charalampos Tzoulis
- Department of Neurology, Haukeland University Hospital, 5021 Bergen, Norway.
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Mutations in mitochondrially encoded complex I enzyme as the second common cause in a cohort of Chinese patients with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes. J Hum Genet 2011; 56:759-64. [DOI: 10.1038/jhg.2011.96] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
Stroke is the second most common cause of death and the most common cause of disability in developed countries. Stroke is a multi-factorial disease caused by a combination of environmental and genetic factors. Numerous epidemiologic studies have documented a significant genetic component in the occurrence of strokes. Genes encoding products involved in lipid metabolism, thrombosis, and inflammation are believed to be potential genetic factors for stroke. Although a large group of candidate genes have been studied, most of the epidemiological results are conflicting. Studies of stroke as a monogenic disease have made huge progress, and animal models serve as an indispensable tool to dissect the complex genetics of stroke. In the present review, we provide insight into the role of in vivo stroke models for the study of stroke genetics.
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Affiliation(s)
- Jin-min Guo
- Department of Pharmacology, School of Pharmacy, Second Military Medical University, Shanghai 200433, China
| | - Ai-jun Liu
- Department of Pharmacology, School of Pharmacy, Second Military Medical University, Shanghai 200433, China
| | - Ding-feng Su
- Department of Pharmacology, School of Pharmacy, Second Military Medical University, Shanghai 200433, China
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Seo HE, Hwang SK, Choe BH, Cho MH, Park SP, Kwon S. Clinical spectrum and prognostic factors of acute necrotizing encephalopathy in children. J Korean Med Sci 2010; 25:449-53. [PMID: 20191046 PMCID: PMC2826728 DOI: 10.3346/jkms.2010.25.3.449] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Accepted: 05/18/2009] [Indexed: 11/20/2022] Open
Abstract
This study was conducted to investigate the etiology, the clinical characteristics and prognosis of acute necrotizing encephalopathy (ANE) in Korean children. Six children (1 yr to 7 yr) patients with ANE were enrolled. They were diagnosed by clinical and radiological characteristics and their clinical data were retrospectively analyzed. In a search of clinically plausible causes, brain MRI in all patients, mitochondrial DNA studies for mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes (MELAS) and myoclonus epilepsy and ragged red fibers (MERRF) in four patients, and genomic typing on HLA DRB/HLA DQB genes in three patients were performed. All had precedent illnesses and the main initial symptoms included mental change (83%), seizures (50%), and focal deficits (50%). MRI revealed increased T2 signal density in the bilateral thalami and/or the brainstem in all patients. Mitochodrial DNA studies for MELAS and MERRF were negative in those children and HLA-DRB1*1401, HLA-DRB3*0202, and HLA-DQB1*0502 seemed to be significant. A high dose steroid was given to all patients, which seemed to be partly effective except for 2 patients. In conclusion, ANE is relatively rare, but can result in serious neurological complication in children. Early detection and appropriate treatment may lead to a better neurological outcome.
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Affiliation(s)
- Hye-Eun Seo
- Department of Pediatrics, School of Medicine, Kyungpook National University, Daegu, Korea
| | - Su-Kyeong Hwang
- Department of Pediatrics, School of Medicine, Kyungpook National University, Daegu, Korea
| | - Byung Ho Choe
- Department of Pediatrics, School of Medicine, Kyungpook National University, Daegu, Korea
| | - Min-Hyun Cho
- Department of Pediatrics, School of Medicine, Kyungpook National University, Daegu, Korea
| | - Sung-Pa Park
- Department of Neurology, School of Medicine, Kyungpook National University, Daegu, Korea
| | - Soonhak Kwon
- Department of Pediatrics, School of Medicine, Kyungpook National University, Daegu, Korea
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Arterial ischemic stroke in children--recent advances. Indian J Pediatr 2008; 75:1149-57. [PMID: 19132317 DOI: 10.1007/s12098-008-0239-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2008] [Accepted: 10/16/2008] [Indexed: 10/21/2022]
Abstract
Childhood stroke syndromes are an important cause of mortality and morbidity. This paper focuses on the recent advances in arterial ischaemic stroke beyond the neonatal period. Vascular risk factors are identified in the majority of children and guide both acute and longer term treatments, as well as determining prognosis. Contrary to popular belief many children have residual impairments encompassing a wide range of domains. National and international collaborations are facilitating an increase in the understanding of childhood stroke and have the eventual aim of conducting trials of potential therapeutic interventions.
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