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Logan IS. The discovery of a ten-generation m.C1494T pedigree in the east of England with probable links to King Richard III. Eur J Med Genet 2024; 70:104957. [PMID: 38897372 DOI: 10.1016/j.ejmg.2024.104957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 06/11/2024] [Accepted: 06/16/2024] [Indexed: 06/21/2024]
Abstract
This paper reports the discovery of a m.C1494T pedigree in the east of England made during a search for matrilineal relations of King Richard III. The mitochondrial DNA variant m.C1494T has been associated with aminoglycoside-induced deafness. This variant is very uncommon. although pedigrees with this variant have previously been found in China and Spain. The members of the newly identified pedigree all belong to the mitochondrial haplogroup J1c2c3, which is also the haplogroup of King Richard III. The presence of a few people in the USA from the same haplogroup has previously been noted, and it is now known that one of the people can show his descent from a couple who lived in Nottinghamshire, England, in the late 1700's. The mitochondrial DNA sequence of this man, at present living in the USA, and of his 4th cousin, twice removed, living in Lincoln, England, has shown they belong to haplogroup J1c2c3 and both have the variant m.C1494T; thereby, allowing the production of a multi-generational pedigree originating in the east of England. Fortunately, deafness has not been found in any living member of this large pedigree. It was also noted that the link to the family of King Richard III has not been firmly defined; however the circumstantial evidence is strong as many of his family members lived in this part of England.
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Affiliation(s)
- Ian S Logan
- 22 Parkside Drive, Exmouth, Devon, EX8 4LB, UK.
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2
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Barboni MTS, Sustar Habjan M, Petrovic Pajic S, Hawlina M. Electroretinographic oscillatory potentials in Leber hereditary optic neuropathy. Doc Ophthalmol 2024; 148:133-143. [PMID: 38451375 PMCID: PMC11096212 DOI: 10.1007/s10633-024-09968-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 02/06/2024] [Indexed: 03/08/2024]
Abstract
PURPOSE Leber hereditary optic neuropathy (LHON) affects retinal ganglion cells causing severe vision loss. Pattern electroretinogram and photopic negative response (PhNR) of the light-adapted (LA) full-field electroretinogram (ERG) are typically affected in LHON. In the present study, we evaluated dark-adapted (DA) and LA oscillatory potentials (OPs) of the flash ERG in genetically characterized LHON patients to dissociate slow from fast components of the response. METHODS Seven adult patients (mean age = 28.4 ± 5.6) in whom genetic diagnosis confirmed LHON with mtDNA or nuclear DNAJC30 (arLHON) pathogenic variants were compared to 12 healthy volunteers (mean age = 35.0 ± 12.1). Full-field ERGs were recorded from both eyes. Offline digital filters at 50, 75 and 100 Hz low cutoff frequencies were applied to isolate high-frequency components from the original ERG signals. RESULTS ERG a-waves and b-waves were comparable between LHON patients and controls, while PhNR was significantly reduced (p = 0.009) in LHON patients compared to controls, as expected. OPs derived from DA signals (75 Hz low cutoff frequency) showed reduced peak amplitude for OP2 (p = 0.019). LA OP differences between LHON and controls became significant (OP2: p = 0.047, OP3: p = 0.039 and OP4: p = 0.013) when the 100 Hz low-cutoff frequency filter was applied. CONCLUSIONS Reduced OPs in LHON patients may represent disturbed neuronal interactions in the inner retina with preserved photoreceptoral (a-wave) to bipolar cell (b-wave) activation. Reduced DA OP2 and high-cutoff LA OP alterations may be further explored as functional measures to characterize LHON status and progression.
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Affiliation(s)
| | - Maja Sustar Habjan
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva 46, 1000, Ljubljana, Slovenia
| | - Sanja Petrovic Pajic
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva 46, 1000, Ljubljana, Slovenia
- Clinic for Eye Diseases, University Clinical Center of Serbia, Belgrade, Serbia
| | - Marko Hawlina
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva 46, 1000, Ljubljana, Slovenia.
- Medical Faculty, Department of Ophthalmology, University of Ljubljana, Grablovičeva 46, 1000, Ljubljana, Slovenia.
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3
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Chuenkongkaew WL, Chinkulkitnivat B, Lertrit P, Chirapapaisan N, Kaewsutthi S, Suktitipat B, Mitrpant C. Clinical expression and mitochondrial deoxyribonucleic acid study in twins with 14484 Leber’s hereditary optic neuropathy: A case report. World J Clin Cases 2022; 10:6944-6953. [PMID: 36051150 PMCID: PMC9297404 DOI: 10.12998/wjcc.v10.i20.6944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 01/07/2022] [Accepted: 05/14/2022] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND This study aimed to explore clinical and molecular factors that cause discordance for clinical expression of Leber’s hereditary optic neuropathy (LHON) in a pair of identical twins with the 14484 point mutation.
CASE SUMMARY Twin patients with the 14484 point mutation were studied for zygosity by using the Short Tandem Repeats Typing system. For the monozygotic twins, the radioactive restriction and densitometric analyses were used to quantitate the heteroplasmy level for the 14484 point mutation. The mitochondrial genome was analyzed to determine influential factors by mitochondrial deoxyribonucleic acid (DNA) sequencing, denaturing high-performance liquid chromatography and next generation sequencing. For the dizygotic twins, the nuclear DNA was analyzed. The twins with 14484 LHON were monozygotic with homoplasmy. No difference in the point mutation in mitochondrial DNA was found. No modifying genes that potentially influenced the disparity in phenotypic expression of LHON were detected in these twins.
CONCLUSION This 11-year follow-up of monozygotic twins showed additional genetic modifications and epigenetic factors are possibly associated with discordance for LHON.
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Affiliation(s)
| | - Buakhwan Chinkulkitnivat
- Department of Ophthalmology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Patcharee Lertrit
- Department of Biochemistry, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Niphon Chirapapaisan
- Department of Ophthalmology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Supannee Kaewsutthi
- Department of Biochemistry, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Bhoom Suktitipat
- Department of Biochemistry, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
- Integrative Computational BioScience Center, Mahidol University, Nakhon Pathom 73170, Thailand
| | - Chalermchai Mitrpant
- Department of Biochemistry, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
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4
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Lo Faro V, Nolte IM, Ten Brink JB, Snieder H, Jansonius NM, Bergen AA. Mitochondrial Genome Study Identifies Association Between Primary Open-Angle Glaucoma and Variants in MT-CYB, MT-ND4 Genes and Haplogroups. Front Genet 2021; 12:781189. [PMID: 34976016 PMCID: PMC8719162 DOI: 10.3389/fgene.2021.781189] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 11/29/2021] [Indexed: 11/21/2022] Open
Abstract
Background and purpose: Primary open-angle glaucoma (POAG) is an optic neuropathy characterized by death of retinal ganglion cells and atrophy of the optic nerve head. The susceptibility of the optic nerve to damage has been shown to be mediated by mitochondrial dysfunction. In this study, we aimed to determine a possible association between mitochondrial SNPs or haplogroups and POAG. Methods: Mitochondrial DNA single nucleotide polymorphisms (mtSNPs) were genotyped using the Illumina Infinium Global Screening Array-24 (GSA) 700K array set. Genetic analyses were performed in a POAG case-control study involving the cohorts, Groningen Longitudinal Glaucoma Study-Lifelines Cohort Study and Amsterdam Glaucoma Study, including 721 patients and 1951 controls in total. We excluded samples not passing quality control for nuclear genotypes and samples with low call rate for mitochondrial variation. The mitochondrial variants were analyzed both as SNPs and haplogroups. These were determined with the bioinformatics software HaploGrep, and logistic regression analysis was used for the association, as well as for SNPs. Results: Meta-analysis of the results from both cohorts revealed a significant association between POAG and the allele A of rs2853496 [odds ratio (OR) = 0.64; p = 0.006] within the MT-ND4 gene, and for the T allele of rs35788393 (OR = 0.75; p = 0.041) located in the MT-CYB gene. In the mitochondrial haplogroup analysis, the most significant p-value was reached by haplogroup K (p = 1.2 × 10−05), which increases the risk of POAG with an OR of 5.8 (95% CI 2.7–13.1). Conclusion: We identified an association between POAG and polymorphisms in the mitochondrial genes MT-ND4 (rs2853496) and MT-CYB (rs35788393), and with haplogroup K. The present study provides further evidence that mitochondrial genome variations are implicated in POAG. Further genetic and functional studies are required to substantiate the association between mitochondrial gene polymorphisms and POAG and to define the pathophysiological mechanisms of mitochondrial dysfunction in glaucoma.
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Affiliation(s)
- Valeria Lo Faro
- Department of Ophthalmology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
- Department of Clinical Genetics, Amsterdam University Medical Center (AMC), Amsterdam, Netherlands
| | - Ilja M. Nolte
- Department of Epidemiology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Jacoline B. Ten Brink
- Department of Clinical Genetics, Amsterdam University Medical Center (AMC), Amsterdam, Netherlands
| | - Harold Snieder
- Department of Epidemiology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Nomdo M. Jansonius
- Department of Ophthalmology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Arthur A. Bergen
- Department of Clinical Genetics, Amsterdam University Medical Center (AMC), Amsterdam, Netherlands
- Department of Ophthalmology, Amsterdam UMC, Amsterdam, Netherlands
- *Correspondence: Arthur A. Bergen,
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5
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Chow LS, Paley MNJ. Recent advances on optic nerve magnetic resonance imaging and post-processing. Magn Reson Imaging 2021; 79:76-84. [PMID: 33753137 DOI: 10.1016/j.mri.2021.03.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 03/17/2021] [Accepted: 03/17/2021] [Indexed: 11/27/2022]
Abstract
The optic nerve is known to be one of the largest nerve bundles in the human central nervous system. There have been many studies of optic nerve imaging and post-processing that have provided insights into pathophysiology of optic neuritis related to multiple sclerosis and neuromyelitis optica spectrum disorder, glaucoma, and Leber's hereditary optic neuropathy. There are many challenges in optic nerve imaging, due to the morphology of the nerve through its course to the optic chiasm, its mobility due to eye movements and the high signal from cerebrospinal fluid and orbital fat surrounding the optic nerve. Recently, many advanced and fast imaging sequences have been used with post-processing techniques in attempts to produce higher resolution images of the optic nerve for evaluating various diseases. Magnetic resonance imaging (MRI) is one of the most common imaging methodologies for the optic nerve. This review paper will focus on recent MRI advances in optic nerve imaging and explain several post-processing techniques being used for analysis of optic nerve images. Finally, some challenges and potential for future optic nerve studies will be discussed.
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Affiliation(s)
- Li Sze Chow
- Department of Electrical and Electronic Engineering, Faculty of Engineering and Built Environment, UCSI University, 1, Jalan Puncak Menara Gading, Taman Connaught, 56000 Cheras, Kuala Lumpur, Malaysia.
| | - Martyn N J Paley
- Department of Infection, Immunity and Cardiovascular Disease, The Medical School, The University of Sheffield, Beech Hill Road, Sheffield S10 2RX, UK.
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Oladimeji O, Akinyelu J, Singh M. Nanomedicines for Subcellular Targeting: The Mitochondrial Perspective. Curr Med Chem 2020; 27:5480-5509. [PMID: 31763965 DOI: 10.2174/0929867326666191125092111] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 10/28/2019] [Accepted: 10/30/2019] [Indexed: 01/01/2023]
Abstract
BACKGROUND Over the past decade, there has been a surge in the number of mitochondrialactive therapeutics for conditions ranging from cancer to aging. Subcellular targeting interventions can modulate adverse intracellular processes unique to the compartments within the cell. However, there is a dearth of reviews focusing on mitochondrial nano-delivery, and this review seeks to fill this gap with regards to nanotherapeutics of the mitochondria. METHODS Besides its potential for a higher therapeutic index than targeting at the tissue and cell levels, subcellular targeting takes into account the limitations of systemic drug administration and significantly improves pharmacokinetics. Hence, an extensive literature review was undertaken and salient information was compiled in this review. RESULTS From literature, it was evident that nanoparticles with their tunable physicochemical properties have shown potential for efficient therapeutic delivery, with several nanomedicines already approved by the FDA and others in clinical trials. However, strategies for the development of nanomedicines for subcellular targeting are still emerging, with an increased understanding of dysfunctional molecular processes advancing the development of treatment modules. For optimal delivery, the design of an ideal carrier for subcellular delivery must consider the features of the diseased microenvironment. The functional and structural features of the mitochondria in the diseased state are highlighted and potential nano-delivery interventions for treatment and diagnosis are discussed. CONCLUSION This review provides an insight into recent advances in subcellular targeting, with a focus on en route barriers to subcellular targeting. The impact of mitochondrial dysfunction in the aetiology of certain diseases is highlighted, and potential therapeutic sites are identified.
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Affiliation(s)
- Olakunle Oladimeji
- Nano-Gene and Drug Delivery Group, Discipline of Biochemistry, School of Life Sciences, University of Kwa-Zulu Natal, Private Bag X54001, Durban, South Africa
| | - Jude Akinyelu
- Nano-Gene and Drug Delivery Group, Discipline of Biochemistry, School of Life Sciences, University of Kwa-Zulu Natal, Private Bag X54001, Durban, South Africa
| | - Moganavelli Singh
- Nano-Gene and Drug Delivery Group, Discipline of Biochemistry, School of Life Sciences, University of Kwa-Zulu Natal, Private Bag X54001, Durban, South Africa
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7
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Bozi LHM, Campos JC, Zambelli VO, Ferreira ND, Ferreira JCB. Mitochondrially-targeted treatment strategies. Mol Aspects Med 2019; 71:100836. [PMID: 31866004 DOI: 10.1016/j.mam.2019.100836] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 12/11/2019] [Accepted: 12/13/2019] [Indexed: 12/13/2022]
Abstract
Disruption of mitochondrial function is a common feature of inherited mitochondrial diseases (mitochondriopathies) and many other infectious and non-infectious diseases including viral, bacterial and protozoan infections, inflammatory and chronic pain, neurodegeneration, diabetes, obesity and cardiovascular diseases. Mitochondria therefore become an attractive target for developing new therapies. In this review we describe critical mechanisms involved in the maintenance of mitochondrial functionality and discuss strategies used to identify and validate mitochondrial targets in different diseases. We also highlight the most recent preclinical and clinical findings using molecules targeting mitochondrial bioenergetics, morphology, number, content and detoxification systems in common pathologies.
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Affiliation(s)
- Luiz H M Bozi
- Institute of Biomedical Sciences, University of Sao Paulo, Brazil
| | - Juliane C Campos
- Institute of Biomedical Sciences, University of Sao Paulo, Brazil
| | | | | | - Julio C B Ferreira
- Institute of Biomedical Sciences, University of Sao Paulo, Brazil; Department of Chemical and Systems Biology, School of Medicine, Stanford University, USA.
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8
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Mitochondrial Dysfunction and Multiple Sclerosis. BIOLOGY 2019; 8:biology8020037. [PMID: 31083577 PMCID: PMC6627385 DOI: 10.3390/biology8020037] [Citation(s) in RCA: 98] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 04/08/2019] [Accepted: 04/30/2019] [Indexed: 02/07/2023]
Abstract
In recent years, several studies have examined the potential associations between mitochondrial dysfunction and neurodegenerative diseases such as multiple sclerosis (MS), Parkinson’s disease and Alzheimer’s disease. In MS, neurological disability results from inflammation, demyelination, and ultimately, axonal damage within the central nervous system. The sustained inflammatory phase of the disease leads to ion channel changes and chronic oxidative stress. Several independent investigations have demonstrated mitochondrial respiratory chain deficiency in MS, as well as abnormalities in mitochondrial transport. These processes create an energy imbalance and contribute to a parallel process of progressive neurodegeneration and irreversible disability. The potential roles of mitochondria in neurodegeneration are reviewed. An overview of mitochondrial diseases that may overlap with MS are also discussed, as well as possible therapeutic targets for the treatment of MS and other neurodegenerative conditions.
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9
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Identification and characterization of the novel point mutation m.3634A>G in the mitochondrial MT-ND1 gene associated with LHON syndrome. Biochim Biophys Acta Mol Basis Dis 2016; 1863:182-187. [PMID: 27613247 DOI: 10.1016/j.bbadis.2016.09.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 09/01/2016] [Accepted: 09/05/2016] [Indexed: 11/20/2022]
Abstract
Leber's hereditary optic neuropathy (LHON) is a mitochondrial genetic disease characterized by bilateral acute or subacute progressive central visual loss. Most cases of LHON syndrome are caused by point mutations in the MT-ND1, MT-ND4, and MT-ND6 genes. Here, we report a novel homoplasmic mutation in the MT-ND1 gene (m.3634A>G, p.Ser110Gly) in a patient with the classical clinical features of LHON syndrome. Several observations support the idea that the mutation is pathogenic and involved in the clinical phenotype of the patient: 1) The mutation affected a highly conserved amino acid, 2) A pathogenic mutation in the same amino acid (m.3635G>A, p.Ser110Asn) was previously reported in a patient with LHON syndrome, 3) The mutation is not recorded in the Mitomap or Human Mitochondrial Genome Database, 4) In silico predictors classified the mutation as "probably damaging", and 5) Cybrids carrying the mutation showed decreased Complex I enzyme activity, lower cell proliferation, and decreased mitochondrial membrane potential relative to control cybrids.
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10
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Enriched retinal ganglion cells derived from human embryonic stem cells. Sci Rep 2016; 6:30552. [PMID: 27506453 PMCID: PMC4978994 DOI: 10.1038/srep30552] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 07/04/2016] [Indexed: 12/21/2022] Open
Abstract
Optic neuropathies are characterised by a loss of retinal ganglion cells (RGCs) that lead to vision impairment. Development of cell therapy requires a better understanding of the signals that direct stem cells into RGCs. Human embryonic stem cells (hESCs) represent an unlimited cellular source for generation of human RGCs in vitro. In this study, we present a 45-day protocol that utilises magnetic activated cell sorting to generate enriched population of RGCs via stepwise retinal differentiation using hESCs. We performed an extensive characterization of these stem cell-derived RGCs by examining the gene and protein expressions of a panel of neural/RGC markers. Furthermore, whole transcriptome analysis demonstrated similarity of the hESC-derived RGCs to human adult RGCs. The enriched hESC-RGCs possess long axons, functional electrophysiological profiles and axonal transport of mitochondria, suggestive of maturity. In summary, this RGC differentiation protocol can generate an enriched population of functional RGCs from hESCs, allowing future studies on disease modeling of optic neuropathies and development of cell therapies.
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11
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Ravera S, Panfoli I. Role of myelin sheath energy metabolism in neurodegenerative diseases. Neural Regen Res 2015; 10:1570-1. [PMID: 26692843 PMCID: PMC4660739 DOI: 10.4103/1673-5374.167749] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Silvia Ravera
- Pharmacy Department, Biochemistry Laboratory, University of Genova, Viale Benedetto XV, Genova, Italy
| | - Isabella Panfoli
- Pharmacy Department, Biochemistry Laboratory, University of Genova, Viale Benedetto XV, Genova, Italy
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12
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Consequences of zygote injection and germline transfer of mutant human mitochondrial DNA in mice. Proc Natl Acad Sci U S A 2015; 112:E5689-98. [PMID: 26438859 DOI: 10.1073/pnas.1506129112] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Considerable evidence supports mutations in mitochondrial genes as the cause of maternally inherited diseases affecting tissues that rely primarily on oxidative energy metabolism, usually the nervous system, the heart, and skeletal muscles. Mitochondrial diseases are diverse, and animal models currently are limited. Here we introduced a mutant human mitochondrial gene responsible for Leber hereditary optic neuropathy (LHON) into the mouse germ line using fluorescence imaging for tissue-specific enrichment in the target retinal ganglion cells. A mitochondria-targeted adeno-associated virus (MTS-AAV) containing the mutant human NADH ubiquinone oxidoreductase subunit 4 (ND4) gene followed by mitochondrial-encoded mCherry was microinjected into zygotes. Female founders with mCherry fluorescence on ophthalmoscopy were backcrossed with normal males for eight generations. Mutant human ND4 DNA was 20% of mouse ND4 and did not integrate into the host genome. Translated human ND4 protein assembled into host respiratory complexes, decreasing respiratory chain function and increasing oxidative stress. Swelling of the optic nerve head was followed by progressive demise of ganglion cells and their axons, the hallmarks of human LHON. Early visual loss that began at 3 mo and progressed to blindness 8 mo after birth was reversed by intraocular injection of MTS-AAV expressing wild-type human ND4. The technology of introducing human mitochondrial genes into the mouse germ line has never been described, to our knowledge, and has implications not only for creating animal models recapitulating the counterpart human disorder but more importantly for reversing the adverse effects of the mutant gene using gene therapy to deliver the wild-type allele.
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Zhang X, Yu S, Tu Y, Huang W. Mitochondrial tRNA(Thr) A15951G mutation may not be associated with Leber's Hereditary Optic Neuropathy. Mitochondrial DNA A DNA Mapp Seq Anal 2015; 27:2323-5. [PMID: 26000946 DOI: 10.3109/19401736.2015.1022763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Mutation in mitochondrial DNA (mtDNA) has been found to play an important role in the pathogenesis of Leber's Hereditary Optic Neuropathy (LHON). Three primary mutations, the ND4 G11778A, ND6 T14484C, and ND1 G3460A, have been found to account more than 90% of LHON patients in many families worldwide. In addition to the mutations in genes encoding the respiratory chain complex I, reports concerning the mt-tRNA gene mutations associated with LHON have increased, some pathogenic mutations caused the failure in mt-tRNA metabolism, thereby worsened the mitochondrial dysfunction that is responsible for LHON. Recently, the A15951G mutation in mt-tRNA(Thr) gene has been reported to be a "modified" factor in increasing the penetrance and expressivity of LHON-associated ND4 G11778A mutation in three Chinese families. However, evolutionary conservation analysis of this mutation suggested a poor conservation index and the pathogenicity scoring system showed that this mutation was a neutral polymorphism.
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Affiliation(s)
- Xi Zhang
- a Department of Ophthalmic Endoscopic Surgery , the Eye Hospital of Wenzhou Medical University , Wenzhou , China
| | - Shuaishuai Yu
- b School of Laboratory Medicine and Life Science , Wenzhou Medical University , Wenzhou , China , and
| | - Yunhai Tu
- a Department of Ophthalmic Endoscopic Surgery , the Eye Hospital of Wenzhou Medical University , Wenzhou , China
| | - Wenjie Huang
- c Ward 3, The Eye Hospital of Wenzhou Medical University , Wenzhou , China
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Zhang L, Liu L, Philip AL, Martinez JC, Guttierez JC, Marella M, Patki G, Matsuno-Yagi A, Yagi T, Thomas BB. Long-term evaluation of Leber's hereditary optic neuropathy-like symptoms in rotenone administered rats. Neurosci Lett 2014; 585:171-6. [PMID: 25481764 DOI: 10.1016/j.neulet.2014.12.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 11/27/2014] [Accepted: 12/01/2014] [Indexed: 12/21/2022]
Abstract
Leber's hereditary optic neuropathy (LHON) is an inherited disorder affecting the retinal ganglion cells (RGCs) and their axons that lead to the loss of central vision. This study is aimed at evaluating the LHON symptoms in rats administered with rotenone microspheres into the superior colliculus (SC). Optical coherence tomography (OCT) analysis showed substantial loss of retinal nerve fiber layer (RNFL) thickness in rotenone injected rats. Optokinetic testing in rotenone treated rats showed decrease in head-tracking response. Electrophysiological mapping of the SC surface demonstrated attenuation of visually evoked responses; however, no changes were observed in the ERG data. The progressive pattern of disease manifestation in rotenone administered rats demonstrated several similarities with human disease symptoms. These rats with LHON-like symptoms can serve as a model for future investigators to design and implement reliable tests to assess the beneficial effects of therapeutic interventions for LHON disease.
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Affiliation(s)
- Li Zhang
- Eye Center, Second Affiliated Hospital, Medical School of Zhejiang University, Hangzhou, China; Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, CA,USA
| | - Laura Liu
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan
| | - Ann L Philip
- Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, CA,USA
| | - Juan C Martinez
- Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, CA,USA
| | - Juan C Guttierez
- Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, CA,USA
| | - Mathieu Marella
- Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA,USA
| | - Gaurav Patki
- Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA,USA
| | - Akemi Matsuno-Yagi
- Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA,USA
| | - Takao Yagi
- Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA,USA
| | - Biju B Thomas
- Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, CA,USA.
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15
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Cui G, Ding H, Xu Y, Li B, Wang DW. Applications of the method of high resolution melting analysis for diagnosis of Leber's disease and the three primary mutation spectrum of LHON in the Han Chinese population. Gene 2012; 512:108-12. [PMID: 23063736 DOI: 10.1016/j.gene.2012.09.110] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2012] [Revised: 09/28/2012] [Accepted: 09/29/2012] [Indexed: 12/28/2022]
Abstract
Current screening methods, such as single strand conformational polymorphism (SSCP), denaturing high performance liquid chromatography (dHPLC) and direct DNA sequencing that are used for detecting mutation in Leber's hereditary optic neuropathy (LHON) subjects are time consuming and costly. Here we tested high-resolution melt (HRM) analysis for mtDNA primary mutations in LHON patients. In this study, we applied the high resolution melting (HRM) technology to screen mtDNA primary mutations in 50 LHON patients from their peripheral blood. In order to evaluate the reliability of this technique, we compared the results obtained by HRM and direct mtDNA sequencing. We also investigated the spectrum of three most common mtDNA mutations implicated in LHON in the Han Chinese population. The results showed HRM analysis differentiated all of the mtDNA primary mutations and identified 4 additional mtDNA mutations from 50 patients in the blind study. The prevalence of three primary mutations were 11778G>A (87.9%), 14484T>C (6.5%) and 3460G>A (1.7%) in the Han Chinese population. In conclusion, HRM analysis is a rapid, reliable, and low-cost tool for detecting mtDNA primary mutations and has practical applications in molecular genetics.
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Affiliation(s)
- Guanglin Cui
- The Institute of Hypertension and Department of Internal Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan People's Republic of China
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Gene delivery to mitochondria by targeting modified adenoassociated virus suppresses Leber's hereditary optic neuropathy in a mouse model. Proc Natl Acad Sci U S A 2012; 109:E1238-47. [PMID: 22523243 DOI: 10.1073/pnas.1119577109] [Citation(s) in RCA: 133] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
To introduce DNA into mitochondria efficiently, we fused adenoassociated virus capsid VP2 with a mitochondrial targeting sequence to carry the mitochondrial gene encoding the human NADH ubiquinone oxidoreductase subunit 4 (ND4). Expression of WT ND4 in cells with the G11778A mutation in ND4 led to restoration of defective ATP synthesis. Furthermore, with injection into the rodent eye, human ND4 DNA levels in mitochondria reached 80% of its mouse homolog. The construct expressed in most inner retinal neurons, and it also suppressed visual loss and optic atrophy induced by a mutant ND4 homolog. The adenoassociated virus cassette accommodates genes of up to ∼5 kb in length, thus providing a platform for introduction of almost any mitochondrial gene and perhaps even allowing insertion of DNA encompassing large deletions of mtDNA, some associated with aging, into the organelle of adults.
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Abu-Amero KK. Leber's Hereditary Optic Neuropathy: The Mitochondrial Connection Revisited. Middle East Afr J Ophthalmol 2011; 18:17-23. [PMID: 21572729 PMCID: PMC3085146 DOI: 10.4103/0974-9233.75880] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Our current understanding of Leber’s hereditary optic neuropathy (LHON)-mitochondrial connection falls short of comprehensive. Twenty years of intensive investigation have yielded a wealth of information about mitochondria, the mitochondrial genome, the metabolism of the optic nerve and other structures, and the phenotypic variability of classic LHON. However, we still cannot completely explain how primary LHON mutations injure the optic nerve or why the optic nerve is particularly at risk. We cannot explain the incomplete penetrance or the male predominance of LHON, the typical onset in young adult life without warning, or the synchronicity of visual loss. Moreover, primary LHON mutations clearly are not present in every family with the LHON phenotype (including multigenerational maternal inheritance), and they are present in only a minority of individuals who have the LHON optic neuropathy phenotype without a family history. All lines of evidence point to abnormalities of the mitochondria as the direct or indirect cause of LHON. Therefore, the mitochondria-LHON connection needs to be revisited and examined closely. This review will attempt to do that and provide an update on various aspects of LHON.
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Affiliation(s)
- Khaled K Abu-Amero
- Department of Ophthalmology, Ophthalmic Genetics Laboratory, College of Medicine, King Saud University, P. O. Box 245, Riyadh 11411, Saudi Arabia
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Abstract
PURPOSE OF REVIEW The use of optical coherence tomography (OCT)-measured retinal nerve fiber layer (RNFL) thickness in neuro-ophthalmic disease has grown since its first use in glaucoma and retinal diseases. OCT-measured RNFL in nonglaucomatous optic neuropathies shows thinning, which may mimic those seen in glaucoma. This article aims to provide insight regarding the use of OCT in nonglaucomatous optic neuropathies and sheds light on common patterns of RNFL loss in different nonglaucomatous optic neuropathies. RECENT FINDINGS RNFL thinning is most likely to occur in the temporal peripapillary quadrant than in other quadrants in nonglaucomatous optic neuropathies. The pattern of RNFL thinning in ischemic optic neuropathy and optic nerve head drusen is more likely to mimic the pattern found in glaucoma due to the superior and inferior quadrant predilection. OCT-measured RNFL thickness in Alzheimer's disease reveals thinning superiorly and inferiorly, whereas superior and temporal thinning is seen in Parkinson's disease. The thinning observed in neurodegenerative diseases is believed to be multifactorial including causes such as axonal degeneration and retrograde degeneration. However, more studies are needed to further study these changes. SUMMARY OCT is a valuable tool in evaluating the peripapillary RNFL in both glaucomatous and nonglaucomatous optic neuropathies. This technology may be used for both research and clinical purposes to assess disease progression in optic neuropathies and diseases that affect the central nervous system. OCT-measured RNFL thickness remains complimentary to the clinical examination skills in the evaluation of nonglaucomatous optic neuropathies.
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Marella M, Seo BB, Thomas BB, Matsuno-Yagi A, Yagi T. Successful amelioration of mitochondrial optic neuropathy using the yeast NDI1 gene in a rat animal model. PLoS One 2010; 5:e11472. [PMID: 20628600 PMCID: PMC2900204 DOI: 10.1371/journal.pone.0011472] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Accepted: 06/15/2010] [Indexed: 01/31/2023] Open
Abstract
Background Leber's hereditary optic neuropathy (LHON) is a maternally inherited disorder with point mutations in mitochondrial DNA which result in loss of vision in young adults. The majority of mutations reported to date are within the genes encoding the subunits of the mitochondrial NADH-quinone oxidoreductase, complex I. Establishment of animal models of LHON should help elucidate mechanism of the disease and could be utilized for possible development of therapeutic strategies. Methodology/Principal Findings We established a rat model which involves injection of rotenone-loaded microspheres into the optic layer of the rat superior colliculus. The animals exhibited the most common features of LHON. Visual loss was observed within 2 weeks of rotenone administration with no apparent effect on retinal ganglion cells. Death of retinal ganglion cells occurred at a later stage. Using our rat model, we investigated the effect of the yeast alternative NADH dehydrogenase, Ndi1. We were able to achieve efficient expression of the Ndi1 protein in the mitochondria of all regions of retinal ganglion cells and axons by delivering the NDI1 gene into the optical layer of the superior colliculus. Remarkably, even after the vision of the rats was severely impaired, treatment of the animals with the NDI1 gene led to a complete restoration of the vision to the normal level. Control groups that received either empty vector or the GFP gene had no effects. Conclusions/Significance The present study reports successful manifestation of LHON-like symptoms in rats and demonstrates the potential of the NDI1 gene therapy on mitochondrial optic neuropathies. Our results indicate a window of opportunity for the gene therapy to be applied successfully after the onset of the disease symptoms.
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Affiliation(s)
- Mathieu Marella
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, United States of America
| | - Byoung Boo Seo
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, United States of America
| | - Biju B. Thomas
- Doheny Eye Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Akemi Matsuno-Yagi
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, United States of America
| | - Takao Yagi
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail:
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Qu J, Zhou X, Zhao F, Liu X, Zhang M, Sun YH, Liang M, Yuan M, Liu Q, Tong Y, Wei QP, Yang L, Guan MX. Low penetrance of Leber's hereditary optic neuropathy in ten Han Chinese families carrying the ND6 T11484C mutation. Biochim Biophys Acta Gen Subj 2009; 1800:305-12. [PMID: 19733221 DOI: 10.1016/j.bbagen.2009.08.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Revised: 08/22/2009] [Accepted: 08/26/2009] [Indexed: 11/27/2022]
Abstract
BACKGROUND Leber's hereditary optic neuropathy (LHON) is a maternally inherited disorder. The purpose of this investigation is to understand the role of mitochondrial haplotypes in the development of LHON associated with ND6 T14484C mutation in Chinese families. METHODS One hundred fourteen subjects from ten Han Chinese families with LHON were studied by the clinical and genetic evaluation as well as molecular and biochemical analyses of mitochondrial DNA (mtDNA). RESULTS Clinical evaluation revealed that ten families exhibited extremely low penetrance of visual impairment, with an average of 10%. In particular, ten (8 males/2 females) of 114 matrilineal relatives in these families exhibited the variable severity and age-at-onset in visual dysfunction. The average age-of-onset of vision loss was 19 years old. Molecular analysis of mitochondrial DNA (mtDNA) identified the homoplasmic T14484C mutation and distinct sets of variants, belonging to the Asian haplogroups B5b, D4, D4g1b, G3a2, R11, R11a and Z3, respectively. However, there was the absence of secondary LHON-associated mtDNA mutations in these ten Chinese families. CONCLUSION The low penetrance of vision loss in these Chinese pedigrees strongly indicated that the T14484C mutation was itself insufficient to produce a clinical phenotype. The absence of secondary LHON mtDNA mutations suggests that these mtDNA haplogroup-specific variants may not play an important role in the phenotypic expression of the T14484C mutation in those Chinese families with low penentrace of vision loss. However, nuclear modifier genes and environmental factors appear to be modifier factors for the phenotypic manifestation of the T14484C mutation in these Chinese families.
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Affiliation(s)
- Jia Qu
- School of Ophthalmology and Optometry, Wenzhou Medical College, Wenzhou, Zhejiang 325003, China.
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Yang J, Zhu Y, Tong Y, Chen L, Liu L, Zhang Z, Wang X, Huang D, Qiu W, Zhuang S, Ma X. Confirmation of the mitochondrial ND1 gene mutation G3635A as a primary LHON mutation. Biochem Biophys Res Commun 2009; 386:50-4. [DOI: 10.1016/j.bbrc.2009.05.127] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Accepted: 05/28/2009] [Indexed: 01/30/2023]
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Yamada K, Oguchi Y, Hotta Y, Nakamura M, Isashiki Y, Mashima Y. Multicenter study on the frequency of three primary mutations of mitochondrial DNA in Japanese pedigrees with Leber’s hereditary optic neuropathy: comparison with American and British counterparts. Neuroophthalmology 2009. [DOI: 10.1076/noph.22.3.187.3724] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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Qu J, Zhou X, Zhang J, Zhao F, Sun YH, Tong Y, Wei QP, Cai W, Yang L, West CE, Guan MX. Extremely low penetrance of Leber's hereditary optic neuropathy in 8 Han Chinese families carrying the ND4 G11778A mutation. Ophthalmology 2009; 116:558-564.e3. [PMID: 19167085 DOI: 10.1016/j.ophtha.2008.10.022] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Revised: 10/18/2008] [Accepted: 10/22/2008] [Indexed: 02/03/2023] Open
Abstract
PURPOSE To investigate the role of mitochondrial haplotypes in the development of Leber's hereditary optic neuropathy (LHON) associated with the ND4 G11778A mutation in Chinese families. DESIGN Eight Han Chinese families with maternally transmitted LHON were studied using clinical, genetic, and molecular evaluations. PARTICIPANTS One hundred sixty-seven subjects from 8 Chinese families with a wide age range and severity of visual impairment. METHODS All subjects underwent the clinical and genetic evaluation, as well as molecular analysis of mitochondrial DNA (mtDNA). MAIN OUTCOME MEASURES The ophthalmologic examinations included visual acuity, visual field examination, visual evoked potentials, and fundus photography. Mitochondrial DNA analysis included the polymerase chain reaction amplification of the entire mtDNA and subsequent sequence determination. RESULTS Eight families exhibited extremely low penetrance of visual impairment, with the average of 13%. In particular, 14 (12 males and 2 females) of 119 matrilineal relatives in these families exhibited the variable severity and age at onset in visual dysfunction. The average age of onset of vision loss was 17 years. Molecular analysis of mtDNA identified the homoplasimic ND4 G11778A mutation and distinct sets of variants belonging to the Asian haplogroups M8a2, D4g2, B4a1c, B5b, N9a1, D4b2b, C, and M7b1. However, there was an absence of secondary LHON-associated mtDNA mutations in these 8 Chinese families. CONCLUSIONS The extremely low penetrance of vision loss in these 8 Chinese pedigrees strongly indicates that the G11778A mutation was itself insufficient to produce a clinical phenotype. The absence of secondary LHON mtDNA mutations suggest that these mtDNA haplogroup-specific variants may not play an important role in the phenotypic expression of the G11778A mutation in those Chinese families with very low penentrace of vision loss. However, nuclear backgrounds and environmental factors seem to be modifying factors for the phenotypic manifestation of the G11778A mutation in these Chinese families.
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Affiliation(s)
- Jia Qu
- School of Ophthalmology and Optometry, Wenzhou Medical College, Wenzhou, Zhejiang, China
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Lee JR, Kim YD, Choi JY, Choi J. Optic Neuropathy from Vitamin B12 Deficiency Associated With Alcoholism and Malnutrition. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2009. [DOI: 10.3341/jkos.2009.50.6.963] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Jong Rak Lee
- Department of Ophthalmology, HanGil Eye Hospital, Incheon, Korea
| | - Yeon-deok Kim
- Department of Ophthalmology, HanGil Eye Hospital, Incheon, Korea
| | - Jin Young Choi
- Department of Ophthalmology, HanGil Eye Hospital, Incheon, Korea
| | - Jaewan Choi
- Department of Ophthalmology, HanGil Eye Hospital, Incheon, Korea
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Hudson G, Yu-Wai-Man P, Chinnery PF. Leber hereditary optic neuropathy. EXPERT OPINION ON MEDICAL DIAGNOSTICS 2008; 2:789-99. [PMID: 23495818 DOI: 10.1517/17530059.2.7.789] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Leber hereditary optic neuropathy (LHON) is a cause of inherited blindness that typically presents with bilateral, painless, subacute visual failure in young adult males. Males are about four times more likely to be affected than females and 95% of LHON carriers become affected before the age of 50. Affected patients may have characteristic ocular fundal appearances and have evidence of optic nerve dysfunction in the form of impaired colour vision (dyschromatopsia), dense visual field defects (central or caecocentral scotoma) and abnormal visual electrophysiology. OBJECTIVES To summarise the current clinical approach to the molecular diagnosis and clinical management of LHON. METHODS To review the literature and present a review of current understanding. RESULTS/CONCLUSIONS The diagnosis of LHON is usually confirmed by molecular genetic analysis for one of three common mitochondrial DNA (mtDNA) mutations that all affect genes coding for complex I subunits of the respiratory chain: m.3460G > A, m.11778G > A and m.14484T > C. Sequencing of the entire mitochondrial genome can reveal the underlying cause in the minority of patients (∼ 5%) who do not harbour one of these three primary mutations, but a molecular diagnosis is not always possible. A minority of LHON patients exhibit a more widespread multi-system involvement with extra neurological features such as dystonia or a multiple sclerosis-like illness. Management is largely supportive, with the provision of low-vision aids, registration with the relevant social services and an important role for genetic counselling.
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Affiliation(s)
- Gavin Hudson
- Newcastle University, Mitochondrial Research Group, M4014, The Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK +44 191 222 8233 ; +44 191 222 8553 ;
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Zhang S, Wang L, Hao Y, Wang P, Hao P, Yin K, Wang QK, Liu M. T14484C and T14502C in the mitochondrial ND6 gene are associated with Leber's hereditary optic neuropathy in a Chinese family. Mitochondrion 2008; 8:205-10. [PMID: 18440284 DOI: 10.1016/j.mito.2008.02.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2007] [Revised: 02/02/2008] [Accepted: 02/26/2008] [Indexed: 11/25/2022]
Abstract
Leber's hereditary optic neuropathy (LHON) is a maternally inherited ocular disease which has been associated with three primary mitochondrial DNA mutations: G3640A, G11778A, and T14484C. In this study, we clinically characterized a Chinese family with complete penetrance of LHON. The patients in the family presented with variable clinical features. By direct DNA sequence analysis, we identified both T14484C mutation and a nearby T to C variant at nucleotide 14502 of mitochondria DNA. The T14502C variant altered I58 to V of the protein ND6, which was present in all patients of the family, but not in four unaffected family members and 200 normal controls. The co-existence of both T14484C mutation and T14502C substitution in all patients from the same LHON family suggests that T14502C may play a synergistic role with the primary mutation T14484C. The two variants together may account for the complete penetrance and absence of marked gender bias and visual recovery in the Chinese LHON family although we cannot exclude the possibility of simultaneous involvement of additional mitochondrial variant(s).
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Affiliation(s)
- Shirong Zhang
- Key Laboratory of Molecular Biophysics of Ministry of Education and Center for Human Genome Research, College of Life Science and Technology, Huazhong University of Science and Technology, 9500 Euclid Avenue, Wuhan 430074, China
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Ramey NA, Park CY, Gehlbach PL, Chuck RS. Imaging Mitochondria in Living Corneal Endothelial Cells Using Autofluorescence Microscopy. Photochem Photobiol 2007; 83:1325-9. [DOI: 10.1111/j.1751-1097.2007.00162.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Wei QP, Zhou X, Yang L, Sun YH, Zhou J, Li G, Jiang R, Lu F, Qu J, Guan MX. The coexistence of mitochondrial ND6 T14484C and 12S rRNA A1555G mutations in a Chinese family with Leber’s hereditary optic neuropathy and hearing loss. Biochem Biophys Res Commun 2007; 357:910-6. [PMID: 17452034 DOI: 10.1016/j.bbrc.2007.04.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2007] [Accepted: 04/04/2007] [Indexed: 10/23/2022]
Abstract
We report here the clinical, genetic and molecular characterization of one three-generation Han Chinese family with Leber's hereditary optic neuropathy (LHON) and hearing loss. Four of 14 matrilineal relatives exhibited the moderate central vision loss at the average age of 12.5 years. Of these, one subject exhibited both LHON and mild hearing impairment. Sequence analysis of the complete mitochondrial genomes in the pedigree showed the presence of homoplasmic LHON-associated ND6 T14484C mutation, deafness-associated 12S rRNA A1555 mutation and 47 other variants belonging to Eastern Asian haplogroup H2. None of other mitochondrial variants was evolutionarily conserved and functional significance. Therefore, the coexistence of the A1555G mutation and T14484C mutations in this Chinese family indicate that the A1555G mutation may play a synergistic role in the phenotypic manifestation of LHON associated ND6 T14484C mutation. However, the incomplete penetrance of vision and hearing loss suggests the involvement of nuclear modifier genes and environmental factors in the phenotypic expression of these mtDNA mutations.
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Affiliation(s)
- Qi-Ping Wei
- Department of Ophthalmology, Dongfang Hospital, Beijing University of Chinese Medicine and Pharmacology, Beijing 100078, China
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Tong Y, Mao Y, Zhou X, Yang L, Zhang J, Cai W, Zhao F, Wang X, Lu F, Qu J, Guan MX. The mitochondrial tRNAGlu A14693G mutation may influence the phenotypic manifestation of ND1 G3460A mutation in a Chinese family with Leber’s hereditary optic neuropathy. Biochem Biophys Res Commun 2007; 357:524-30. [PMID: 17434142 DOI: 10.1016/j.bbrc.2007.03.189] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Accepted: 03/29/2007] [Indexed: 11/17/2022]
Abstract
We report here the clinical, genetic, and molecular characterization of one Han Chinese family with maternally transmitted Leber's hereditary optic neuropathy (LHON). Three of seven matrilineal relatives in this family exhibited the variable degree of central vision loss at the age of 12, 14, and 16 years old, respectively. Sequence analysis of the complete mitochondrial DNA in this pedigree revealed the presence of the ND1 G3460A mutation and 47 other variants, belonging to the Asian haplogroup M7b2. The G3460A mutation is present at homoplasmy in matrilineal relatives of this Chinese family. Of other variants, the homoplasmic A14693G mutation is of special interest as it was implicated to be associated with other mitochondrial disorders. This mutation is located at the TpsiC-loop, at conventional position 54 of tRNA(Glu). The uridine at this position (U54), which is highly conserved from bacteria to human mitochondria, has been implicated to be important for tRNA structure and function. Thus, the A14693G mutation may alter the tertiary structure of this tRNA, cause a failure in this tRNA metabolism, thereby worsening the mitochondrial dysfunction associated with the primary G3460A mutation. Therefore, the tRNA(Glu) A14693G mutation may have a potential modifier role in the phenotypic manifestation of the primary LHON-associated G3460A mutation in this Chinese family.
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Affiliation(s)
- Yi Tong
- School of Ophthalmology and Optometry, Wenzhou Medical College, Wenzhou, Zhejiang 325003, China
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Macarez R, Bazin S, Lagauche D, Soullié B, Giordano P, May F, Guigon B. [Onset of Leber's hereditary optic neuropathy in association with borreliosis]. J Fr Ophtalmol 2007; 28:1095-100. [PMID: 16395203 DOI: 10.1016/s0181-5512(05)81144-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
INTRODUCTION The diagnosis of Lyme disease in the presence of an acute optical neuritis always raises a difficult diagnostic problem. We present a case of Lyme-associated Leber's hereditary optic neuropathy (LHON). OBSERVATION A 17-year-old Eurasian young man presented with left-eye visual impairment for 1 month. This loss of vision acuity in the left eye is related to an optic neuropathy. Mitochondrial DNA testing showed a G to A substitution at position 11778 confirming a diagnosis of LHON. The family history disclosed a case of LHON in a maternal cousin. The mother's family is Asian. Besides, serum examination of anti-Borrelia antibodies was performed and was positive against Borrelia burgdorferi garinii. The patient history indicated that he had been possessing a dog and was living in an endemic area of Lyme disease. But he did not recall receiving a tick bite nor having any erythema chronicum migrans. Initial examination showed bilateral green-red axis colour vision defects which made us fear bilateralisation of the optic neuropathy, which occurred 2 months later (that is 3 months after the onset of symptoms on the left eye). An antibiotic treatment by ceftriaxone was administered for 4 weeks all in all; and a long term ubidecarenone therapy was established. At present, after a 1-year follow up, the eyes' conditions remains unchanged. CONCLUSION To our knowledge, this would be the first case reporting such an association, in which we can discuss the fortuitous character or the role of the infectious factor in the developing of the mitochondrial pathology. This observation also raises the problem of the positive diagnosis of Lyme disease when tick bite and erythema are absent or underestimated.
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Affiliation(s)
- R Macarez
- Service d'Ophtalmologie, HIA Clermont Tonnerre, BP 41, 29240 Brest-Armées
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Park JS, Li YF, Bai Y. Yeast NDI1 improves oxidative phosphorylation capacity and increases protection against oxidative stress and cell death in cells carrying a Leber's hereditary optic neuropathy mutation. Biochim Biophys Acta Mol Basis Dis 2007; 1772:533-42. [PMID: 17320357 PMCID: PMC1905846 DOI: 10.1016/j.bbadis.2007.01.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2006] [Revised: 12/21/2006] [Accepted: 01/16/2007] [Indexed: 12/26/2022]
Abstract
G11778A in the subunit ND4 gene of NADH dehydrogenase complex is the most common primary mutation found in Leber's hereditary optic neuropathy (LHON) patients. The NDI1 gene, which encodes the internal NADH-quinone oxidoreductase in Saccharomyces cerevisiae, was introduced into the nuclear genome of a mitochondrial defective human cell line, Le1.3.1, carrying the G11778A mutation. In transformant cell lines, LeNDI1-1 and -2, total and complex I-dependent respiration were fully restored and largely resistant to complex I inhibitor, rotenone, indicating a dominant role of NDI1 in the transfer of electrons in the host cells. Whereas the original mutant Le1.3.1 cell grows poorly in medium containing galactose, the transformants have a fully restored growth capacity in galactose medium, although the ATP production was not totally recovered. Furthermore, the increased oxidative stress in the cells carrying the G11778A mutation was alleviated in transformants, demonstrated by a decreased reactive oxygen species (ROS) level. Finally, transformants were also shown to be desensitized to induction to apoptosis and also exhibit greater resistance to paraquat-induced cell death. It is concluded that the yeast NDI1 enzyme can improve the oxidative phosphorylation capacity in cells carrying the G11778A mutation and protect the cells from oxidative stress and cell death.
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Affiliation(s)
- Jeong Soon Park
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
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Qu J, Li R, Zhou X, Tong Y, Yang L, Chen J, Zhao F, Lu C, Qian Y, Lu F, Guan MX. Cosegregation of the ND4 G11696A mutation with the LHON-associated ND4 G11778A mutation in a four generation Chinese family. Mitochondrion 2006; 7:140-6. [PMID: 17300996 PMCID: PMC2014724 DOI: 10.1016/j.mito.2006.11.015] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2006] [Accepted: 10/11/2006] [Indexed: 01/09/2023]
Abstract
We report here the characterization of a four-generation Han Chinese family with Leber's hereditary optic neuropathy (LHON). This Chinese family exhibited a variable severity and age-at-onset of visual loss. Notably, the average age-at-onset of vision impairment changed from 26 years (generation III) to 14 years (generation IV), with the average of 18 years in this family. In addition, 30% and 50% of matrilineal relatives in generation III and IV of this family developed visual loss with a variability of severity, ranging from blindness to normal vision. Sequence analysis of the complete mitochondrial DNA in this pedigree revealed the presence of the homoplasmic ND4 G11778A mutation and 33 other variants, belonging to the Asian haplogroup D4. Of other variants, the homoplasmic G11696A mutation in the ND4 gene is of special interest as it was implicated to be associated with LHON in a large Dutch family and five Chinese pedigrees with extremely penetrance of visual loss. In fact, the G11696A mutation caused the substitution of an isoleucine for valine at amino acid position 313, located in a predicted transmembrane region of ND4. These imply that the G11696A mutation may act in synergy with the primary LHON-associated G11778A mutation in this Chinese pedigree.
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Affiliation(s)
- Jia Qu
- School of Ophthalmology and Optometry, Wenzhou Medical College, Wenzhou, Zhejiang 325003, China
- Key Laboratory of Vision Sciences, The Ministry of Heath of China, Wenzhou, Zhejiang 325003, China
- Zhejiang Provincial Key Laboratory of Medical Genetics, School of Life Sciences, Wenzhou Medical College, Wenzhou, Zhejiang 325003, China
| | - Ronghua Li
- Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio 45229, USA
| | - Xiangtian Zhou
- School of Ophthalmology and Optometry, Wenzhou Medical College, Wenzhou, Zhejiang 325003, China
- Key Laboratory of Vision Sciences, The Ministry of Heath of China, Wenzhou, Zhejiang 325003, China
| | - Yi Tong
- School of Ophthalmology and Optometry, Wenzhou Medical College, Wenzhou, Zhejiang 325003, China
- The First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350005, China
| | - Li Yang
- Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio 45229, USA
| | - Jie Chen
- School of Ophthalmology and Optometry, Wenzhou Medical College, Wenzhou, Zhejiang 325003, China
| | - Fuxing Zhao
- School of Ophthalmology and Optometry, Wenzhou Medical College, Wenzhou, Zhejiang 325003, China
- Zhejiang Provincial Key Laboratory of Medical Genetics, School of Life Sciences, Wenzhou Medical College, Wenzhou, Zhejiang 325003, China
| | - Chunjie Lu
- School of Ophthalmology and Optometry, Wenzhou Medical College, Wenzhou, Zhejiang 325003, China
| | - Yaping Qian
- Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio 45229, USA
| | - Fan Lu
- School of Ophthalmology and Optometry, Wenzhou Medical College, Wenzhou, Zhejiang 325003, China
- Key Laboratory of Vision Sciences, The Ministry of Heath of China, Wenzhou, Zhejiang 325003, China
| | - Min-Xin Guan
- Zhejiang Provincial Key Laboratory of Medical Genetics, School of Life Sciences, Wenzhou Medical College, Wenzhou, Zhejiang 325003, China
- Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio 45229, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio 45229, USA
- *Corresponding author: Min-Xin Guan, Ph.D., Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, Ohio 45229, USA, Telephone: (513) 636-3337; Fax: (513) 636-3486; E-mail:
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Sun YH, Wei QP, Zhou X, Qian Y, Zhou J, Lu F, Qu J, Guan MX. Leber’s hereditary optic neuropathy is associated with the mitochondrial ND6 T14484C mutation in three Chinese families. Biochem Biophys Res Commun 2006; 347:221-5. [PMID: 16806060 DOI: 10.1016/j.bbrc.2006.06.075] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2006] [Accepted: 06/13/2006] [Indexed: 11/26/2022]
Abstract
We report here the clinical, genetic, and molecular characterization of three Chinese families with maternally transmitted Leber's hereditary optic neuropathy (LHON). Clinical and genetic evaluations revealed the variable severity and age-of-onset in visual impairment in these families. In the affected matrilineal relatives, the loss of central vision is bilateral, the fellow eye becoming affected either simultaneously (45%) or sequentially (55%). The penetrances of vision loss in these pedigrees were 27%, 50%, and 60%, respectively. The age-at-onset of vision loss in these families was 14, 19, and 24 years, respectively. Furthermore, the ratios between affected male and female matrilineal relatives were 1:1, 1:1.2, and 1:2, respectively. Mutational analysis of mitochondrial DNA revealed the presence of homoplasmic ND6 T14484C mutation, which has been associated with LHON. The incomplete penetrance and phenotypic variability implicate the involvement of nuclear modifier gene(s), environmental factor(s) or mitochondrial haplotype(s) in the phenotypic expression of the LHON-associated T14484C mutation in these Chinese pedigrees.
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Affiliation(s)
- Yan-Hong Sun
- Department of Ophthalmology, Dongfang Hospital, Beijing University of Chinese Medicine and Pharmacology, China
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34
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Li R, Qu J, Zhou X, Tong Y, Hu Y, Qian Y, Lu F, Mo JQ, West CE, Guan MX. The mitochondrial tRNAThr A15951G mutation may influence the phenotypic expression of the LHON-associated ND4 G11778A mutation in a Chinese family. Gene 2006; 376:79-86. [PMID: 16624503 DOI: 10.1016/j.gene.2006.02.014] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2005] [Revised: 02/17/2006] [Accepted: 02/22/2006] [Indexed: 11/16/2022]
Abstract
We report here the characterization of a three-generation Han Chinese family with Leber's hereditary optic neuropathy (LHON). This Chinese family exhibited high penetrance and expressivity of visual impairment. The average age-of-onset was 19 years in this family. All male and 33% female matrilineal relatives in this Chinese family developed visual loss with a wide range of severity, ranging from blindness to normal vision. Sequence analysis of the complete mitochondrial DNA in this pedigree revealed the presence of the ND4 G11778A mutation and 40 other variants, belonging to the Asian haplogroup D4. The G11778A mutation is present at homoplasmy in matrilineal relatives of this Chinese family. Of other variants, the homoplasmic A15951G mutation is of special interest as it is located adjacent to 3' end, at conventional position 71 of tRNA(Thr). The adenine (A71) at this position of tRNA(Thr), highly conserved from bacteria to human mitochondria, has been implicated to be important for tRNA identity and pre-tRNA processing. In fact, the significant reduction of the steady-state levels in tRNA(Thr) was observed in cells carrying both the A15951G and G11778A mutations but not cells carrying only G11778A mutation. Thus, the A15951G mutation most probably leads to a failure in mitochondrial tRNA metabolism, worsening the mitochondrial dysfunction associated with the primary G11778A mutation. These imply that the tRNA(Thr) A15951G mutation may have a potential modifier role in increasing the penetrance and expressivity of the primary LHON-associated G11778A mutation in this Chinese family.
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Affiliation(s)
- Ronghua Li
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
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35
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Zhou X, Wei Q, Yang L, Tong Y, Zhao F, Lu C, Qian Y, Sun Y, Lu F, Qu J, Guan MX. Leber’s hereditary optic neuropathy is associated with the mitochondrial ND4 G11696A mutation in five Chinese families. Biochem Biophys Res Commun 2006; 340:69-75. [PMID: 16364244 DOI: 10.1016/j.bbrc.2005.11.150] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2005] [Accepted: 11/21/2005] [Indexed: 11/18/2022]
Abstract
We report here the clinical, genetic, and molecular characterization of five Chinese families with Leber's hereditary optic neuropathy (LHON). Clinical and genetic evaluations revealed the variable severity and age-of-onset in visual impairment in these families. Strikingly, there were extremely low penetrances of visual impairment in these Chinese families. Sequence analysis of the complete mitochondrial genomes in these pedigrees showed the distinct sets of mtDNA polymorphism, in addition to the identical ND4 G11696A mutation associated with LHON. Indeed, this mutation is present in homoplasmy only in the maternal lineage of those pedigrees but not other members of these families. In fact, the occurrence of the G11696A mutation in these several genetically unrelated subjects affected by visual impairment strongly indicates that this mutation is involved in the pathogenesis of visual impairment. Furthermore, the N405D in the ND5 and G5820A in the tRNA(Cys), showing high evolutional conservation, may contribute to the phenotypic expression of G11696A mutation in the WZ10 pedigree. However, there was the absence of functionally significant mtDNA mutations in other four Chinese pedigrees carrying the G11696A mutation. Therefore, nuclear modifier gene(s) or environmental factor(s) may play a role in the phenotypic expression of the LHON-associated G11696A mutation in these Chinese pedigrees.
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Affiliation(s)
- Xiangtian Zhou
- School of Ophthalmology and Optometry, Wenzhou Medical College, Wenzhou, Zhejiang 325003, China
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36
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Huizing M, Brooks BP, Anikster Y. Optic atrophies in metabolic disorders. Mol Genet Metab 2005; 86:51-60. [PMID: 16194617 PMCID: PMC8336112 DOI: 10.1016/j.ymgme.2005.07.034] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2005] [Revised: 07/24/2005] [Accepted: 07/26/2005] [Indexed: 02/01/2023]
Abstract
Optic nerve involvement in metabolic disorders often results from apoptosis of cells that form or support the optic nerve, the retinal ganglion cell (RGC) axons, the myelin-forming oligodendrocytes, or the supporting vascular system. Given their high energy demands and the long course of their axons, RGCs are particularly sensitive to intracellular metabolic defects. Defects in energy metabolism, formation of reactive oxygen species, and storage of metabolites can all cause apoptosis of RGCs, decreased myelin formation of oligodendrocytes and increased pressure on the optic nerve. Clinically, the loss of RGC axons manifests as pale optic nerves. In general, the ophthalmologist can identify the underlying cause of an optic atrophy by careful examination, neuro-imaging, and family history. In some cases, however, the diagnosis proves elusive. In these instances, and especially when optic atrophy is accompanied by other systemic involvement, a metabolic disorder should be considered. Here, we review the underlying mechanisms of optic atrophy and its significance in metabolic disorders. Early identification of optic atrophy aids the diagnosis and subsequent management of the underlying condition, including anticipation of symptoms, genetic counseling, and possible therapeutic interventions. For many metabolic disorders, molecular testing is available.
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Affiliation(s)
- Marjan Huizing
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA.
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37
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Qian Y, Zhou X, Hu Y, Tong Y, Li R, Lu F, Yang H, Mo JQ, Qu J, Guan MX. Clinical evaluation and mitochondrial DNA sequence analysis in three Chinese families with Leber’s hereditary optic neuropathy. Biochem Biophys Res Commun 2005; 332:614-21. [PMID: 15896721 DOI: 10.1016/j.bbrc.2005.05.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2005] [Accepted: 05/03/2005] [Indexed: 11/22/2022]
Abstract
We report here the clinical, genetic, and molecular characterization of three Chinese families (WZ4, WZ5, and WZ6) with Leber's hereditary optic neuropathy (LHON). Clinical and genetic evaluations revealed the variable severity and age-of-onset in visual impairment in these families. Penetrances of visual impairment in these Chinese families were 33.3%, 35.7%, and 35.5%, respectively, with an average 34.8%. Furthermore, the average age-at-onset in those Chinese families was 17, 20, and 18 years. In addition, the ratios between affected male and female matrilineal relatives in these Chinese families were 3:0, 1:1, and 1.2:1, respectively. Sequence analysis of the complete mitochondrial genomes in these pedigrees showed the distinct sets of mtDNA polymorphism, in addition to the identical G11778A mutation associated with LHON in many families. The fact that mtDNA of those pedigrees belonged to different haplogroups F1, D4, and M10 suggested that the G11778A mutation occurred sporadically and multiplied through evolution of the mtDNA in China. However, there was the absence of functionally significant mutations in tRNA and rRNAs or secondary LHON mutations in these Chinese families. The I187T mutation in the ND1, the S99A mutation in the A6, the V254I in CO3, and I58V in ND6 mutation, showing high evolutional conservation, may contribute to the phenotypic expression of the G11778A mutation in the WZ6 pedigree. By contrast, none of mtDNA variants are evolutionarily conserved and implicated to have significantly functional consequence in WZ4 and WZ5 pedigrees. Apparently, these variants do not have a potential modifying role in the development of visual impairment associated with G11778A mutation in those two families. Thus, nuclear modifier gene(s) or environmental factor(s) seem to account for the penetrance and expressivity of LHON in these three Chinese families carrying the G11778A mutation.
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Affiliation(s)
- Yaping Qian
- Division and Program in Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
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38
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Qu J, Li R, Tong Y, Hu Y, Zhou X, Qian Y, Lu F, Guan MX. Only male matrilineal relatives with Leber’s hereditary optic neuropathy in a large Chinese family carrying the mitochondrial DNA G11778A mutation. Biochem Biophys Res Commun 2005; 328:1139-45. [PMID: 15707996 DOI: 10.1016/j.bbrc.2005.01.062] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2005] [Indexed: 11/29/2022]
Abstract
We report here the characterization of a five-generation large Chinese family with Leber's hereditary optic neuropathy (LHON). Very strikingly, six affected individuals of 38 matrilineal relatives (17 females/21 males) are exclusively males in this Chinese family. These matrilineal relatives in this family exhibited late-onset/progressive visual impairment with a wide range of severity, ranging from blindness to normal vision. The age of onset in visual impairment varies from 17 to 30 years. Sequence analysis of the complete mitochondrial genome in this pedigree revealed the presence of the G11778A mutation in ND4 gene and 29 other variants. This mitochondrial genome belongs to the Southern Chinese haplogroup B5b. We showed that the G11778A mutation is present at near homoplasmy in matrilineal relatives of this Chinese family but not in 164 Chinese controls. Incomplete penetrance of LHON in this family indicates the involvement of modulatory factors in the phenotypic expression of visual dysfunction associated with the G11778A mutation. However, none of other mtDNA variants are evolutionarily conserved and implicated to have significantly functional consequence. Thus, nuclear modifier gene(s) or environmental factor(s) seem to account for the penetrance and phenotypic variability of LHON in this Chinese family carrying the G11778A mutation.
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Affiliation(s)
- Jia Qu
- School of Ophthalmology and Optometry, Wenzhou Medical College, Wenzhou, Zhejiang 325003, China
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Wong LJC, Lin YH, Suwannarat P, Hsu CH, Kwon HY, Mackowiak S. Mitochondrial DNA mutations in a patient with sex reversal and clinical features consistent with Fraser syndrome. Clin Genet 2005; 67:252-7. [PMID: 15691363 DOI: 10.1111/j.1399-0004.2004.00394.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We describe a 20-year-old 46,XY woman, with clinical findings of Fraser syndrome and three mitochondrial DNA (mtDNA) mutations of Leber hereditary optic neuropathy. The patient had microphthalmia, blindness, widely spaced nipples, bifid ureter, syndactyly of the toes, and mental retardation. Sonography showed the presence of a uterus and intra-abdominal gonads. The proband was screened for mtDNA mutations because of chronic gastrointestinal pseudo-obstruction, urinary tract dysmotility, seizures, mental retardation and persistent macrocytosis, as well as the intermittent elevation of methylmalonic acid. Analysis of point mutations by multiplex polymerase chain reaction and allele-specific oligonucleotide dot-blot hybridization revealed three homoplasmic mtDNA mutations, T14484C, T4216C, and T3394C. This represents a unique case with sex reversal, Fraser-like syndrome, and mitochondrial disease.
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Affiliation(s)
- L-J C Wong
- Institute for Molecular and Human Genetics, Georgetown University Medical Center, Washington, DC 20007, USA.
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40
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Mayorov V, Biousse V, Newman NJ, Brown MD. The role of the ND5 gene in LHON: Characterization of a new, heteroplasmic LHON mutation. Ann Neurol 2005; 58:807-11. [PMID: 16240359 DOI: 10.1002/ana.20669] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Leber's hereditary optic neuropathy (LHON) causes central vision loss from bilateral optic neuropathy. Although 13 mitochondrial DNA (mtDNA) mutations are strongly associated with LHON, only three account for roughly 90% of cases and thus are found in multiple independent LHON families. The remaining LHON mutations are rare. Here, we describe the clinical and genetic characterization of a new LHON mtDNA mutation. The 12848T mutation alters a highly conserved amino acid in the ND5 complex I gene, is not found in controls, and is heteroplasmic. Despite ND5 being the largest of the mtDNA complex I genes, ND5 mutations are quite rare in LHON.
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Affiliation(s)
- Vladimir Mayorov
- Division of Basic Medical Sciences, Mercer University School of Medicine, Macon, GA 31207, USA
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Abstract
Metabolic optic neuropathies form a rubric of disease characterized by bilaterally symmetrical visual impairment with loss of central visual acuity, dyschromatopsia, centrocecal visual field defects, temporal optic disc atrophy, and specific loss of the nerve fiber layer in the papillomacular bundle. The three subcategories of metabolic optic neuropathies are heredodegenerative (such as Leber's hereditary optic neuropathy), nutritional deficiencies (such as vitamins B12 or folic acid), or toxicities (such as ethambutol or cyanide). It's interesting to note that the first of these three is a congenital cause of mitochondrial impairment, whereas the latter two are acquired injuries to mitochondria. Hence, most if not all causes of metabolic optic neuropathies are, in fact, related to mitochondrial impairment. At the present time there is no effective treatment for heredodegenerative optic neuropathy. Nutritional deficiency metabolic optic neuropathies are treated by giving supplements of the appropriate nutrient or vitamin, whereas toxic metabolic optic neuropathies are treated by removing or preventing exposure to the toxin in question.
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Affiliation(s)
- Alfredo A Sadun
- Department of Ophthalmology, Doheny Eye Institute, University of Southern California, 1450 San Pablo Street, Los Angeles, CA 90033, USA.
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Abstract
AIM To review the molecular genetic basis of primary inherited optic neuropathies. METHODS Medline and Embase search. RESULTS Inherited optic neuropathies are a genetically diverse group of disorders that present with reduced visual acuity and the clinical appearance of optic atrophy. The inherited optic neuropathies may be sporadic or familial, in which case the mode of inheritance may be Mendelian (autosomal dominant, autosomal recessive, X-linked recessive) or non-Mendelian (mitochondrial). Two genes for dominantly inherited optic atrophy have been mapped (OPA1 and OPA4), of which the gene has been identified in one (OPA1). A gene for recessive optic atrophy (OPA3) has also been identified. X-linked optic atrophy (OPA2) has been mapped but to date no gene has been identified. Mutations in mitochondrial DNA have been identified in Leber's hereditary optic neuropathy. CONCLUSIONS Mutations in genes from both the nuclear and mitochondrial genomes appear to be responsible. Mitochondrial dysfunction, in the broadest sense, is emerging as central to the pathogenesis of this group of conditions.
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Affiliation(s)
- M Votruba
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK.
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43
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Veach J. Functional dichotomy: glutathione and vitamin E in homeostasis relevant to primary open-angle glaucoma. Br J Nutr 2004; 91:809-29. [PMID: 15182385 DOI: 10.1079/bjn20041113] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Primary open-angle glaucoma (POAG) is a complex chronic neurological disease that can result in blindness. The goal of understanding the aetiology of POAG is to be able to target effective treatment to individuals who will eventually go blind without it. Epidemiological studies of POAG have not specifically addressed the possibility that nutrition may play a role in the development of POAG. A handful of papers have considered that nutrition may have an impact on POAG patients. POAG is not believed to be a 'vitamin-deficiency disease'. The concept of 'vitamin-deficiency diseases' and the recommended daily allowances have not kept pace with the growing understanding of the cellular and molecular functions of vitamins and other micronutrients. The aetiology of POAG remains a mystery. Discoveries in cell physiology can be assimilated from the literature and applied to known homeostatic mechanisms of the eye. In this way the possible roles of nutritional components involved in the aetiology of POAG can be described. The mechanisms may be subject to many influences in ways that have yet to be defined. Two distinct changes in the trabecular meshwork can be identified: trabecular meshwork changes that cause intra-ocular pressure to increase and trabecular meshwork changes that are directly correlated to optic nerve atrophy. Compelling evidence suggests that collagen trabecular meshwork extracellular matrix (ECM) remodelling is correlated to increased intraocular pressure in POAG. Elastin trabecular meshwork ECM remodelling is correlated to POAG optic nerve atrophy. There appear to be two different pathways of ECM remodelling and apoptosis induction in POAG. The pathway for collagen remodelling and apoptosis induction seems to be exogenously influenced by water-soluble antioxidants, for example, glutathione. The pathway for elastin remodelling and apoptosis induction seems to be influenced by endogenous lipid-soluble antioxidants, for example, vitamin E. Roles can be defined for antioxidants in the two different pathways of ECM remodelling and apoptosis induction. This suggests that antioxidants are important in maintaining cellular homeostasis relevant to the aetiology of POAG.
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Abstract
Mutations in the mitochondrial DNA (mtDNA) have been shown to be one important cause of deafness. In particular, mutations in the mtDNA have been associated with both syndromic and nonsyndromic forms of sensori-neural hearing loss. The deafness-linked mutations often occur in the mitochondrial 12S rRNA gene and in tRNA genes. Mutations in the 12S rRNA gene account for most of the cases of aminoglycoside ototoxicity. The other hot spot for mutations associated with hearing impairment is the tRNA(Ser(UCN)) gene, as five deafness-linked mutations have been identified in this gene. Nonsyndromic deafness-linked mtDNA mutations are often homoplasmic or at high levels of heteroplasmy, indicating a high threshold for pathogenicity. Phenotypic expression of these mtDNA mutations requires the contribution of other factors such as nuclear modifier gene(s), environmental factor(s), or mitochondrial haplotype(s).
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Affiliation(s)
- Min-Xin Guan
- Cincinnati Children's Hospital Medical Center, and Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio 45229, USA.
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Abstract
Following the discovery in the early 1960s that mitochondria contain their own DNA (mtDNA), there were two major advances, both in the 1980s: the human mtDNA sequence was published in 1981, and in 1988 the first pathogenic mtDNA mutations were identified. The floodgates were opened, and the 1990s became the decade of the mitochondrial genome. There has been a change of emphasis in the first few years of the new millennium, away from the "magic circle" of mtDNA and back to the nuclear genome. Various nuclear genes have been identified that are fundamentally important for mitochondrial homeostasis, and when these genes are disrupted, they cause autosomally inherited mitochondrial disease. Moreover, mitochondrial dysfunction plays an important role in the pathophysiology of several well established nuclear genetic disorders, such as dominant optic atrophy (mutations in OPA1), Friedreich's ataxia (FRDA), hereditary spastic paraplegia (SPG7), and Wilson's disease (ATP7B). The next major challenge is to define the more subtle interactions between nuclear and mitochondrial genes in health and disease.
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Affiliation(s)
- P F Chinnery
- Department of Neurology, The University of Newcastle upon Tyne, Newcastle upon Tyne, UK.
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Howell N, Oostra RJ, Bolhuis PA, Spruijt L, Clarke LA, Mackey DA, Preston G, Herrnstadt C. Sequence analysis of the mitochondrial genomes from Dutch pedigrees with Leber hereditary optic neuropathy. Am J Hum Genet 2003; 72:1460-9. [PMID: 12736867 PMCID: PMC1180306 DOI: 10.1086/375537] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2003] [Accepted: 03/18/2003] [Indexed: 11/03/2022] Open
Abstract
The complete mitochondrial DNA (mtDNA) sequences for 63 Dutch pedigrees with Leber hereditary optic neuropathy (LHON) were determined, 56 of which carried one of the classic LHON mutations at nucleotide (nt) 3460, 11778, or 14484. Analysis of these sequences indicated that there were several instances in which the mtDNAs were either identical or related by descent. The most striking example was a haplogroup J mtDNA that carried the 14484 LHON mutation. Four different but related mitochondrial genotypes were identified in seven of the Dutch pedigrees with LHON, including six of those described by van Senus. The control region of the founder sequence for these Dutch pedigrees with LHON matches the control-region sequence that Macmillan and colleagues identified in the founder mtDNA of French Canadian pedigrees with LHON. In addition, we obtained a perfect match between the Dutch 14484 founder sequence and the complete mtDNA sequences of two Canadian pedigrees with LHON. Those results indicate that these Dutch and French Canadian 14484 pedigrees with LHON share a common ancestor, that the single origin of the 14484 mutation in this megalineage occurred before the year 1600, and that there is a 14484/haplogroup J founder effect. We estimate that this lineage--including the 14484 LHON mutation--arose 900-1,800 years ago. Overall, the phylogenetic analyses of these mtDNA sequences conservatively indicate that a LHON mutation has arisen at least 42 times in the Dutch population. Finally, analysis of the mtDNA sequences from those pedigrees that did not carry classic LHON mutations suggested candidate pathogenic mutations at nts 9804, 13051, and 14325.
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MESH Headings
- Canada/ethnology
- Chromosomes, Human, Pair 10
- DNA Mutational Analysis/methods
- DNA, Mitochondrial/genetics
- Female
- Founder Effect
- Genetic Linkage
- Genotype
- Haplotypes
- Humans
- Mutation
- Netherlands/epidemiology
- Optic Atrophy, Hereditary, Leber/epidemiology
- Optic Atrophy, Hereditary, Leber/etiology
- Optic Atrophy, Hereditary, Leber/genetics
- Optic Atrophy, Hereditary, Leber/physiopathology
- Pedigree
- Phylogeny
- Prevalence
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Howell N, Herrnstadt C, Shults C, Mackey DA. Low penetrance of the 14484 LHON mutation when it arises in a non-haplogroup J mtDNA background. Am J Med Genet A 2003; 119A:147-51. [PMID: 12749053 DOI: 10.1002/ajmg.a.20135] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The penetrance in Leber's hereditary optic neuropathy (LHON) pedigrees is determined primarily by a mutation in the mitochondrial genome (mtDNA), but secondary factors are also necessary for manifestation of the disorder. It has been proposed that mtDNA polymorphisms affect penetrance in LHON pedigrees. In particular, it has been postulated that one or more polymorphisms associated with European haplogroup J mtDNAs substantially increase the penetrance of the primary LHON mutation at nucleotide 14484. We report here a haplogroup H matrilineal pedigree (VIC14) in which the single affected member carries the 14484 LHON mutation, but who manifested a milder and atypical optic nerve disorder. In addition, during a population screen, we identified an individual who carried the 14484 mutation but who had normal vision. Finally, the 14484 mutation is under-represented among haplogroup H mtDNAs that carry a LHON mutation. These results, in conjunction with other studies that are reviewed, indicate that 14484 LHON mutations have a low penetrance when they arise in a haplogroup H mtDNA background.
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Howell N, Miller NR, Mackey DA, Arnold A, Herrnstadt C, Williams IM, Kubacka I. Lightning strikes twice: Leber hereditary optic neuropathy families with two pathogenic mtDNA mutations. J Neuroophthalmol 2002; 22:262-9. [PMID: 12464729 DOI: 10.1097/00041327-200212000-00002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To report the clinical and mitochondrial genetic analyses of two families, each of which carries both the 11778 and 14484 Leber hereditary optic neuropathy (LHON) mutations in mitochondrial DNA. METHODS In addition to detailed clinical histories, the complete sequence of the mitochondrial DNA (mtDNA) from each family was determined. RESULTS A small Australian LHON family (Vic20) and a family from the United States carry the 11778 and 14484 LHON mutations. In addition to the optic neuropathy, one branch of the Baltimore LHON pedigree had a high incidence of a fatal infantile encephalopathy. In both families, the 14484 LHON mutation was homoplasmic, whereas the 11778 LHON mutation was heteroplasmic. CONCLUSIONS There are no additional mtDNA sequence changes that explain the encephalopathy in the Baltimore LHON family, and a nuclear gene involvement is an alternative explanation that is supported by the available data. The ophthalmological characteristics and penetrance in the 11778 and 14484 "two-mutation" LHON families are not markedly more severe than those of classic LHON families who carry a single mtDNA mutation.
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50
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Pang CP, Lam DSC. Differential occurrence of mutations causative of eye diseases in the Chinese population. Hum Mutat 2002; 19:189-208. [PMID: 11857735 DOI: 10.1002/humu.10053] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Ethnic differences and geographic variations affect the frequencies and nature of human mutations. In the literature, descriptions of causative mutations of eye diseases in the Chinese population are few. In this paper we attempt to reveal molecular information on genetic eye diseases involving Chinese patients from published and unpublished works by us and other groups. Our studies on candidate genes of eye diseases in the Chinese population in Hong Kong include MYOC and TISR for primary open angle glaucoma, RHO and RP1 for retinitis pigmentosa, ABCA4 and APOE for age-related macular degeneration, RB1 for retinoblastoma, APC for familial adenomatous polyposis with congenital hypertrophy of retinal pigment epithelium, BIGH3/TGFBI for corneal dystrophies, PAX6 for aniridia and Reiger syndrome, CRYAA and CRYBB2 for cataracts, and mtDNA for Leber hereditary optic neuropathy. We have revealed novel mutations in most of these genes, and in RHO, RP1, RB1, BIGH3, and PAX6 we have reported mutations that contribute to better understanding of the functions and properties of the respective gene products. We showed absence of MYOC does not necessarily cause glaucoma. No disease causative mutations have been identified in MYOC or ABCA4. There are similarities in the patterns of sequence alterations and phenotype-genotype associations in comparison with other ethnic groups, while the MYOC, RB1, APC, and PAX6 genes have more Chinese-specific sequence alterations. Establishment of a mutation database specific for the Chinese is essential for identification of genetic markers with diagnostic, prognostic, or pharmacological values.
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Affiliation(s)
- Chi Pui Pang
- Department of Ophthalmology and Visual Sciences, Chinese University of Hong Kong, Hong Kong, China.
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