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Abstract
Mitochondrial optic neuropathies have a leading role in the field of mitochondrial medicine ever since 1988, when the first mutation in mitochondrial DNA was associated with Leber's hereditary optic neuropathy (LHON). Autosomal dominant optic atrophy (DOA) was subsequently associated in 2000 with mutations in the nuclear DNA affecting the OPA1 gene. LHON and DOA are both characterized by selective neurodegeneration of retinal ganglion cells (RGCs) triggered by mitochondrial dysfunction. This is centered on respiratory complex I impairment in LHON and defective mitochondrial dynamics in OPA1-related DOA, leading to distinct clinical phenotypes. LHON is a subacute, rapid, severe loss of central vision involving both eyes within weeks or months, with age of onset between 15 and 35 years old. DOA is a more slowly progressive optic neuropathy, usually apparent in early childhood. LHON is characterized by marked incomplete penetrance and a clear male predilection. The introduction of next-generation sequencing has greatly expanded the genetic causes for other rare forms of mitochondrial optic neuropathies, including recessive and X-linked, further emphasizing the exquisite sensitivity of RGCs to compromised mitochondrial function. All forms of mitochondrial optic neuropathies, including LHON and DOA, can manifest either as pure optic atrophy or as a more severe multisystemic syndrome. Mitochondrial optic neuropathies are currently at the forefront of a number of therapeutic programs, including gene therapy, with idebenone being the only approved drug for a mitochondrial disorder.
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Affiliation(s)
- Valerio Carelli
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy; IRCCS Istituto di Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy.
| | - Chiara La Morgia
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy; IRCCS Istituto di Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy
| | - Patrick Yu-Wai-Man
- John van Geest Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom; Cambridge Eye Unit, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, United Kingdom; Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom; Institute of Ophthalmology, University College London, London, United Kingdom
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Guo H, Guo L, Yuan Y, Liang XY, Bi R. Co-occurrence of m.15992A>G and m.15077G>A Is Associated With a High Penetrance of Maternally Inherited Hypertension in a Chinese Pedigree. Am J Hypertens 2022; 35:96-102. [PMID: 34346491 DOI: 10.1093/ajh/hpab123] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 07/25/2021] [Accepted: 08/03/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Mitochondrial DNA (mtDNA) pathogenic variants have been identified to be associated with maternally inherited essential hypertension (MIEH). However, the distinctive clinical features and molecular pathogenesis of MIEH are not fully understood. METHODS In this study, we collected a Chinese MIEH family with extraordinary higher penetrance of essential hypertension (88.89%) and early ages of onset (31-40 years old), and performed clinical and genetic characterization for this family. The complete mitochondrial genome of the proband was sequenced and analyzed. RESULTS The maternally related members in this family were presented with severe increased blood pressure, left ventricular remodeling, and metabolic abnormalities. Through sequencing the entire mtDNA of the proband and performing systematic analysis of the mtDNA variants with a phylogenic approach, we identified a potentially pathogenic tRNA variant (m.15992A>G in the MT-TP gene) that may account for the MIEH in this family. One nonsynonymous variant (m.15077G>A in the MT-CYB gene) was identified to play a synergistic role with m.15992A>G to cause a high penetrance of MIEH. CONCLUSIONS Our results, together with previous findings, have indicated that tRNA pathogenic variants in the mtDNA could act important roles in the pathogenesis of MIEH through reducing mitochondrial translation and disturbing mitochondrial function.
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Affiliation(s)
- Hao Guo
- Department of Cardiology, 1st Affiliated Hospital of Kunming Medical University, Kunming, China
- Department of Cardiology, Yunnan Key Laboratory of Laboratory Medicine, Kunming, Yunnan, China
| | - Li Guo
- Department of Radiology, 2nd Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China
| | - Yong Yuan
- Department of emergency, 2nd Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China
| | - Xin-yue Liang
- Department of Cardiology, 1st Affiliated Hospital of Kunming Medical University, Kunming, China
- Department of Cardiology, Graduate School of the Kunming Medical University, Kunming, China
| | - Rui Bi
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, and KIZ/CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan, China
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Decreased Volume of Lateral and Medial Geniculate Nuclei in Patients with LHON Disease-7 Tesla MRI Study. J Clin Med 2020; 9:jcm9092914. [PMID: 32927622 PMCID: PMC7565643 DOI: 10.3390/jcm9092914] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 09/04/2020] [Accepted: 09/06/2020] [Indexed: 11/17/2022] Open
Abstract
Leber’s hereditary optic neuropathy (LHON) is a maternally inherited genetic disorder leading to severe and bilateral loss of central vision, with a young male predilection. In recent years, multiple studies examined structural abnormalities in visual white matter tracts such as the optic tract and optic radiation. However, it is still unclear if the disease alters only some parts of the white matter architecture or whether the changes also affect grey matter parts of the visual pathway. This study aimed at improving our understanding of morphometric changes in the lateral (LGN) and medial (MGN) geniculate nuclei and their associations with the clinical picture in LHON by the application of a submillimeter surface-based analysis approach to the ultra-high-field 7T magnetic resonance imaging data. To meet these goals, fifteen LHON patients and fifteen age-matched healthy subjects were examined. A quantitative analysis of the LGN and MGN volume was performed for all individuals. Additionally, morphometric results of LGN and MGN were correlated with variables covering selected aspects of the clinical picture of LHON. In comparison with healthy controls (HC), LHON participants showed a significantly decreased volume of the right LGN and the right MGN. Nevertheless, the volume of the right LGN was strongly correlated with the averaged thickness value of the right retinal nerve fiber layer (RNFL). The abnormalities in the volume of the LHON patients’ thalamic nuclei indicate that the disease can cause changes not only in the white matter areas constituting visual tracts but also in the grey matter structures. Furthermore, the correlation between the changes in the LGN volume and the RNFL, as well as the right optic nerve surface area located proximally to the eyeball, suggest some associations between the atrophy of these structures. However, to fully confirm this observation, longitudinal studies should be conducted.
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Zhang X, Li C, Zhou Y, Huang J, Yu T, Liu X, Shi H, Liu H, Chia S, Huang S, Guo Y, Shoocongdej R, Ji X, Su B. A Matrilineal Genetic Perspective of Hanging Coffin Custom in Southern China and Northern Thailand. iScience 2020; 23:101032. [PMID: 32304863 PMCID: PMC7163074 DOI: 10.1016/j.isci.2020.101032] [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: 10/08/2019] [Revised: 02/06/2020] [Accepted: 03/30/2020] [Indexed: 01/16/2023] Open
Abstract
Hanging Coffin is a unique and ancient burial custom that has been practiced in southern China, Southeast Asia, and near Oceania regions for more than 3,000 years. Here, we conducted mitochondrial whole-genome analyses of 41 human remains sampled from 13 Hanging Coffin sites in southern China and northern Thailand, which were dated between ∼2,500 and 660 years before present. We found that there were genetic connections between the Hanging Coffin people living in different geographic regions. Notably, the matrilineal genetic diversity of the Hanging Coffin people from southern China is much higher than those from northern Thailand, consistent with the hypothesized single origin of the Hanging Coffin custom in southern China about 3,600 years ago, followed by its dispersal in southern China through demic diffusion, whereas the major dispersal pattern in Southeast Asia is cultural assimilation in the past 2,000 years.
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Affiliation(s)
- Xiaoming Zhang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China; Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China
| | - Chunmei Li
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China; Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China
| | - Yanan Zhou
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China; Kunming College of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiahui Huang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China; Kunming College of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tengsong Yu
- Zhaotong Institute of Cultural Relics Protection and Archaeology, Zhaoyang, Yunnan 657200, China
| | - Xu Liu
- Yunnan Institute of Cultural Relics and Archaeology, Kunming 650118, China
| | - Hong Shi
- Yunnan Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming 650500, China; Yunnan Provincial Academy of Science and Technology, Kunming 650228, China
| | - Hong Liu
- International Joint Research Center for Karstology, Yunnan University, Kunming, 650223, China
| | - Stephen Chia
- Center for Global Archaeological Research, University of Science Malaysia, Penang, Malaysia
| | - Shenmin Huang
- Key Laboratory of Environmental Change and Resources Use in Baibu Gulf, Ministry of Education, Nanning Normal University, Nanning, Guangxi 530001, China
| | - Yaozheng Guo
- Youjiang Nationalities Museum, Baise, Guangxi 533000, China
| | - Rasmi Shoocongdej
- Department of Archaeology, Faculty of Archaeology, Silpakorn University, Bangkok 10200, Thailand.
| | - Xueping Ji
- Yunnan Institute of Cultural Relics and Archaeology, Kunming 650118, China; School of Geoscience, Yunnan University, Kunming 650091, China.
| | - Bing Su
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China; Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China.
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Caporali L, Maresca A, Capristo M, Del Dotto V, Tagliavini F, Valentino ML, La Morgia C, Carelli V. Incomplete penetrance in mitochondrial optic neuropathies. Mitochondrion 2017; 36:130-137. [PMID: 28716668 DOI: 10.1016/j.mito.2017.07.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 06/27/2017] [Accepted: 07/13/2017] [Indexed: 01/06/2023]
Abstract
Incomplete penetrance characterizes the two most frequent inherited optic neuropathies, Leber's Hereditary Optic Neuropathy (LHON) and dominant optic atrophy (DOA), due to genetic errors in the mitochondrial DNA (mtDNA) and the nuclear DNA (nDNA), respectively. For LHON, compelling evidence has accumulated on the complex interplay of mtDNA haplogroups and environmental interacting factors, whereas the nDNA remains essentially non informative. However, a compensatory mechanism of activated mitochondrial biogenesis and increased mtDNA copy number, possibly driven by a permissive nDNA background, is documented in LHON; when successful it maintains unaffected the mutation carriers, but in some individuals it might be hampered by tobacco smoking or other environmental factors, resulting in disease onset. In females, mitochondrial biogenesis is promoted and maintained within the compensatory range by estrogens, partially explaining the gender bias in LHON. Concerning DOA, none of the above mechanisms has been fully explored, thus mtDNA haplogroups, environmental factors such as tobacco and alcohol, and further nDNA variants may all participate as protective factors or, on the contrary, favor disease expression and severity. Next generation sequencing, complemented by transcriptomics and proteomics, may provide some answers in the next future, even if the multifactorial model that seems to apply to incomplete penetrance in mitochondrial optic neuropathies remains problematic, and careful stratification of patients will play a key role for data interpretation. The deep understanding of which factors impinge on incomplete penetrance may shed light on the pathogenic mechanisms leading to optic nerve atrophy, on their possible compensation and, thus, on development of therapeutic strategies.
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Affiliation(s)
- Leonardo Caporali
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy
| | - Alessandra Maresca
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy
| | | | - Valentina Del Dotto
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Italy
| | - Francesca Tagliavini
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy
| | - Maria Lucia Valentino
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy; Department of Biomedical and Neuromotor Sciences, University of Bologna, Italy
| | - Chiara La Morgia
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy; Department of Biomedical and Neuromotor Sciences, University of Bologna, Italy
| | - Valerio Carelli
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy; Department of Biomedical and Neuromotor Sciences, University of Bologna, Italy.
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Bi R, Logan I, Yao YG. Leber Hereditary Optic Neuropathy: A Mitochondrial Disease Unique in Many Ways. Handb Exp Pharmacol 2017; 240:309-336. [PMID: 27787713 DOI: 10.1007/164_2016_1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Leber hereditary optic neuropathy (LHON) was the first mitochondrial disease to be identified as being caused by mutations in the mitochondrial DNA (mtDNA). This disease has been studied extensively in the past two decades, particularly in Brazilian, Chinese and European populations; and many primary mutations have been reported. However, the disease is enigmatic with many unique features, and there still are several important questions to be resolved. The incomplete penetrance, the male-biased disease expression and the prevalence in young adults all defy a proper explanation. It has been reported that the development of LHON is affected by the interaction between mtDNA mutations, mtDNA haplogroup background, nuclear genes, environmental factors and epigenetics. Furthermore, with the help of new animal models for LHON that have been created in recent years, we are continuing to learn more about the mechanism of this disease. The stage has now been reached at which there is a good understanding of both the genetic basis of the disease and its epidemiology, but just how the blindness that follows from the death of cells in the optic nerve can be prevented remains to be a pharmacological challenge. In this chapter, we summarize the progress that has been made in various recent studies on LHON, focusing on the molecular pathogenic mechanisms, clinical features, biochemical effects, the pharmacology and its treatment.
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Affiliation(s)
- Rui Bi
- Division of Medical Genetics & Evolutionary Medicine, Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
| | | | - Yong-Gang Yao
- Division of Medical Genetics & Evolutionary Medicine, Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China.
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Whole mitochondrial genome analysis in South Indian patients with Leber's hereditary optic neuropathy. Mitochondrion 2016; 36:21-28. [PMID: 27989883 DOI: 10.1016/j.mito.2016.10.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 10/22/2016] [Accepted: 10/26/2016] [Indexed: 11/27/2022]
Abstract
Leber's hereditary optic neuropathy (LHON) is a mitochondrial DNA (mtDNA) associated neurodegenerative disorder of retinal ganglion cells. In this study, whole mitochondrial genome sequencing of 75 LHON patients and 40 controls was performed to identify the mutation frequency and haplogroup background of South Indian population. Analysis of mtDNA revealed 559 different variants in LHON patients, including 7 pathogenic mutations, 30 private, and 22 other disease associated variants. A significantly higher (p=0.0008) overall variation load per individual was noted among LHON patients versus controls. We reported for the first time, the association of M haplogroup (p=0.028) with LHON in this cohort.
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Yang H, Liu R, Wang CC. Searching the co-occurrence of pathogenic mutations for Leber's hereditary optic neuropathy and hearing loss in more than 26,000 whole mitochondrial genomes. Mitochondrial DNA A DNA Mapp Seq Anal 2015; 27:3399-402. [PMID: 25714144 DOI: 10.3109/19401736.2015.1018239] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The co-occurrence of pathogenic or candidate mutations for Leber's hereditary optic neuropathy (LHON) and hearing loss has long been suggested to be a rare incident. The "rare" is probably caused by inadequate database searches. In this study, we created and released a comprehensive database with detailed information of haplogroup, variants, coding sites, and potential pathogenic mutations for more than 26,000 whole mitochondrial genomes. We found the co-occurrence in more than 200 individuals including not only LHON or hearing loss patients but also individuals sampled from general populations with various haplogroup backgrounds. The results highlighted the significant importance of adequate database searching in the genetic analysis of mitochondrial disorders.
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Affiliation(s)
- Haixin Yang
- a Department of Neurology , Liaocheng People's Hospital , Liaocheng , Shandong , P.R. China and
| | - Rui Liu
- b State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Contemporary Anthropology , Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University , Shanghai , P.R. China
| | - Chuan-Chao Wang
- b State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Contemporary Anthropology , Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University , Shanghai , P.R. China
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Jiang Z, Yu J, Xia B, Zhuo G. Mitochondrial tRNAThr 15891C>G mutation was not associated with Leber's hereditary optic neuropathy in Han Chinese patients. Mitochondrial DNA A DNA Mapp Seq Anal 2014; 27:1564-6. [PMID: 25186221 DOI: 10.3109/19401736.2014.953137] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Mutations in mitochondrial DNA (mtDNA) were the most important causes of Leber's hereditary optic neuropathy (LHON). To date, approximately 25 LHON-associated mtDNA mutations have been identified in various ethnic populations. Three primary mutations, the 3460G > A, 11778G > A and 14484T > C, in genes encoding the subunits of respiratory chain complex I, were the most common LHON-associated mtDNA mutations. Moreover, secondary mutations in mt-tRNA genes have been reported increasingly to be associated with LHON, simply due to the high mutation rates of mt-tRNAs. There is a lack of functional analysis and a poor genetic evaluation of a certain mt-tRNA mutation, which failed to meet the classic pathogenicity scoring system. As a result, how to classify a pathogenic mutation in mt-tRNA gene became important for both geneticist and clinician to diagnosis the LHON or the suspicious of LHON. In this study, we reassessed the role of a point mutation in mt-tRNA(Thr) gene which had been reported to be a mutation associated with LHON, the pathogenicity of this mutation has been discussed in this context.
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Affiliation(s)
- Zhaochang Jiang
- a Department of Pathology , Second affiliated hospital of Zhejiang University , Hangzhou , China
| | - Jinfang Yu
- b Department of Cardiology , Xiaoshan First People's Hospital , Hangzhou , China
| | - Bohou Xia
- c Department of Pharmacy , Hunan University of Traditional Chinese Medicine , Changsha , China , and
| | - Guangchao Zhuo
- d Central Laboratory , Hangzhou First People's Hospital , Hangzhou , China
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Mezghani N, Mnif M, Mkaouar-Rebai E, Kallel N, Charfi N, Abid M, Fakhfakh F. A maternally inherited diabetes and deafness patient with the 12S rRNA m.1555A>G and the ND1 m.3308T>C mutations associated with multiple mitochondrial deletions. Biochem Biophys Res Commun 2013; 431:670-4. [DOI: 10.1016/j.bbrc.2013.01.063] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 01/16/2013] [Indexed: 11/29/2022]
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Nakaso K, Adachi Y, Fusayasu E, Doi K, Imamura K, Yasui K, Nakashima K. Leber's Hereditary Optic Neuropathy with Olivocerebellar Degeneration due to G11778A and T3394C Mutations in the Mitochondrial DNA. J Clin Neurol 2012; 8:230-4. [PMID: 23091534 PMCID: PMC3469805 DOI: 10.3988/jcn.2012.8.3.230] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 10/21/2011] [Accepted: 10/21/2011] [Indexed: 11/30/2022] Open
Abstract
Background Leber's hereditary optic neuropathy (LHON) is a mitochondrial disorder with optic nerve atrophy. Although there are no other associated neurological abnormalities in most cases of LHON, cases of "LHON plus" have been reported. Case Report The proband was a 37-year-old man who had visual and gait disturbances that had first appeared at 10 years of age. He showed horizontal gaze palsy, gaze-evoked nystagmus, dysarthria, and cerebellar ataxia. Brain and orbit MRI disclosed atrophy of the optic nerve and cerebellum, and degenerative changes in the bilateral inferior olivary nucleus. Mutational analyses of mitochondrial DNA identified the coexistence of heteroplasmic G11778A and homoplasmic T3394C mutations. Conclusions These results suggest that the combination of G11778A and T3394C mutations leads to an atypical LHON phenotype.
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Affiliation(s)
- Kazuhiro Nakaso
- Division of Neurology, Department of Brain and Neurosciences, Faculty of Medicine, Tottori University, Yonago, Japan
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Whole mitochondrial genome screening in two families with hearing loss: detection of a novel mutation in the 12S rRNA gene. Biosci Rep 2011; 30:405-11. [PMID: 20055758 DOI: 10.1042/bsr20090120] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Sensorineural hearing loss has been described in association with different mitochondrial multisystemic syndromes, often characterized by an important neuromuscular involvement. Until now, mutations in mitochondrial DNA, especially in the 12S rRNA, the tRNASer(UCN) and the tRNALeu(UUR) genes, were implicated in syndromic or non-syndromic hearing loss either as a primary cause or as predisposing factors. In the present study, we performed a whole mitochondrial genome screening in two unrelated Tunisian families with inherited hearing loss. Results showed the presence of a novel mutation in the mitochondrial 12S rRNA gene in the two probands of these two families who belong to two different haplogroups: L3 and H6a1. The m.735A>G mutation affects a conserved nucleotide of the mitochondrial 12S rRNA gene in primates and other species and had a conservation index of 78.5% (11/14). We also detected known polymorphisms and sic novel mitochondrial variants. The present study confirmed that the mitochondrial 12S rRNA gene is a hot spot for mutations associated with hearing impairment.
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mtDNA m.3635G>A may be classified as a common primary mutation for Leber hereditary optic neuropathy in the Chinese population. Biochem Biophys Res Commun 2010; 403:237-41. [DOI: 10.1016/j.bbrc.2010.11.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Accepted: 11/04/2010] [Indexed: 02/08/2023]
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Yu D, Jia X, Zhang AM, Li S, Zou Y, Zhang Q, Yao YG. Mitochondrial DNA sequence variation and haplogroup distribution in Chinese patients with LHON and m.14484T>C. PLoS One 2010; 5:e13426. [PMID: 20976138 PMCID: PMC2956641 DOI: 10.1371/journal.pone.0013426] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Accepted: 09/22/2010] [Indexed: 12/28/2022] Open
Abstract
Background Leber hereditary optic neuropathy (LHON, MIM 535000) is one of the most common mitochondrial genetic disorders caused by three primary mtDNA mutations (m.3460G>A, m.11778G>A and m. 14484T>C). The clinical expression of LHON is affected by many additional factors, e.g. mtDNA background, nuclear genes, and environmental factors. Hitherto, there is no comprehensive study of Chinese LHON patients with m.14484T>C. Methodology/Principal Findings In this study, we analyzed the mtDNA sequence variations and haplogroup distribution pattern of the largest number of Chinese LHON patients with m.14484T>C to date. We first determined the complete mtDNA sequences in eleven LHON probands with m.14484T>C, to discern the potentially pathogenic mutations that co-segregate with m.14484T>C. We then dissected the matrilineal structure of 52 patients with m.14484T>C (including 14 from unrelated families and 38 sporadic cases) and compared it with the reported Han Chinese from general populations. Complete mtDNA sequencing showed that the eleven matrilines belonged to nine haplogroups including Y2, C4a, M8a, M10a1a, G1a1, G2a1, G2b2, D5a2a1, and D5c. We did not identify putatively pathogenic mutation that was co-segregated with m.14484T>C in these lineages based on the evolutionary analysis. Compared with the reported Han Chinese from general populations, the LHON patients with m.14484T>C had significantly higher frequency of haplogroups C, G, M10, and Y, but a lower frequency of haplogroup F. Intriguingly, we also observed a lower prevalence of F lineages in LHON subjects with m.11778G>A in our previous study, suggesting that this haplogroup may enact similar role during the onset of LHON in the presence of m.14484T>C or m.11778G>A. Conclusions/Significance Our current study provided a comprehensive profile regarding the mtDNA variation and background of Chinese patients with LHON and m.14484T>C. Matrilineal background might affect the expression of LHON in Chinese patients with m.14484T>C.
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Affiliation(s)
- Dandan Yu
- Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Xiaoyun Jia
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - A-Mei Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
- Graduate School of the Chinese Academy of Sciences, Beijing, China
| | - Shiqiang Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Yang Zou
- Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
- Graduate School of the Chinese Academy of Sciences, Beijing, China
| | - Qingjiong Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
- * E-mail: (Y-GY); (QZ)
| | - Yong-Gang Yao
- Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
- * E-mail: (Y-GY); (QZ)
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Yu D, Jia X, Zhang AM, Guo X, Zhang YP, Zhang Q, Yao YG. Molecular characterization of six Chinese families with m.3460G>A and Leber hereditary optic neuropathy. Neurogenetics 2010; 11:349-56. [DOI: 10.1007/s10048-010-0236-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2009] [Accepted: 02/15/2010] [Indexed: 12/19/2022]
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Blood pressure treatment in acute ischemic stroke: a review of studies and recommendations. Curr Opin Neurol 2010; 23:46-52. [PMID: 20038827 DOI: 10.1097/wco.0b013e3283355694] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE OF REVIEW Elevated blood pressure (BP) is frequent in patients with acute ischemic stroke. Pathophysiological data support its usefulness to maintain adequate perfusion of the ischemic penumba. This review article aims to summarize the available evidence from clinical studies that examined the prognostic role of BP during the acute phase of ischemic stroke and intervention studies that assessed the efficacy of active BP alteration. RECENT FINDINGS We found 34 observational studies (33,470 patients), with results being inconsistent among the studies; most studies reported a negative association between increased levels of BP and clinical outcome, whereas a few studies showed clinical improvement with higher BP levels, clinical deterioration with decreased BP, or no association at all. Similarly, the conclusions drawn by the 18 intervention studies included in this review (1637 patients) were also heterogeneous. Very recent clinical data suggest a possible beneficial effect of early treatment with some antihypertensives on late clinical outcome. SUMMARY Observational and interventional studies of management of acute poststroke hypertension yield conflicting results. We discuss different explanations that may account for this and discuss the current guidelines and pathophysiological considerations for the management of acute poststroke hypertension.
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Zhang AM, Zou Y, Guo X, Jia X, Zhang Q, Yao YG. Mitochondrial DNA mutation m.3635G>A may be associated with Leber hereditary optic neuropathy in Chinese. Biochem Biophys Res Commun 2009; 386:392-5. [PMID: 19527690 DOI: 10.1016/j.bbrc.2009.06.051] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Accepted: 06/09/2009] [Indexed: 12/20/2022]
Abstract
Leber hereditary optic neuropathy (LHON) was the first disease to be linked to the presence of a mitochondrial DNA (mtDNA) mutation. Nowadays over 95% of LHON cases are known to be caused by one of three primary mutations (m.11778G>A, m.14484T>C, and m.3460G>A). Reports for other (rare) primary mutations in LHON patients are not infrequent. Among those is the mutation m.3635G>A in the MT-ND1 gene which was reported to be pathogenic in a Russian LHON family. In this study, we report on a Chinese family with clinical features of LHON but without any of the three well-known primary mutations. Analysis of the complete mitochondrial genome in the proband revealed the presence of m.3635G>A and m.6228C>T, along with a full array of other variants that suggest the haplogroup M7b1. Evolutionary analysis indicates that site 3635, but not 6228, is highly conserved in vertebrates. Protein secondary-structure modeling for the MT-ND1 protein harboring amino acid change S110N indicates that mutant m.3635G>A decreases the protein hydrophobicity. Our current observations provide further support for a pathogenic role of m.3635G>A in patients with LHON.
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Affiliation(s)
- A-Mei Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan 650223, China
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Ji Y, Zhang AM, Jia X, Zhang YP, Xiao X, Li S, Guo X, Bandelt HJ, Zhang Q, Yao YG. Mitochondrial DNA haplogroups M7b1'2 and M8a affect clinical expression of leber hereditary optic neuropathy in Chinese families with the m.11778G-->a mutation. Am J Hum Genet 2008; 83:760-8. [PMID: 19026397 DOI: 10.1016/j.ajhg.2008.11.002] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Revised: 10/27/2008] [Accepted: 11/06/2008] [Indexed: 02/01/2023] Open
Abstract
Leber hereditary optic neuropathy (LHON) is the most extensively studied mitochondrial disease, with the majority of the cases being caused by one of three primary mitochondrial DNA (mtDNA) mutations. Incomplete disease penetrance and gender bias are two features of LHON and indicate involvement of additional genetic or environmental factors in the pathogenesis of the disorder. Haplogroups J, K, and H have been shown to influence the clinical expression of LHON in subjects harboring primary mutations in European families. However, whether mtDNA haplogroups would affect the penetrance of LHON in East Asian families has not been evaluated yet. By studying the penetrance of LHON in 1859 individuals from 182 Chinese families (including one from Cambodia) with the m.11778G-->A mutation, we found that haplogroup M7b1'2 significantly increases the risk of visual loss, whereas M8a has a protective effect. Analyses of the complete mtDNA sequences from LHON families with m.11778G-->A narrow the association of disease expression to m.12811T-->C (Y159H) in the NADH dehydrogenase 5 gene (MT-ND5) in haplogroup M7b1'2 and suggest that the specific combination of amino acid changes (A20T-T53I) in the ATP synthase 6 protein (MT-ATP6) caused by m.8584G-->A and m.8684C-->T might account for the beneficial background effect of M8a. Protein secondary-structure prediction for the MT-ATP6 with the two M8a-specific amino acid changes further supported our inferences. These findings will assist in further understanding the pathogenesis of LHON and guide future genetic counseling in East Asian patients with m.11778G-->A.
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