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Yang YP, Chang YL, Chiou GY, Lee MS, Wu YR, Chen PW, Lin YY, Lai WY, Liu YH, Hwang DK, Chien Y. Dysregulation of the circRNA_0087207/miR-548c-3p/PLSR1-TGFB2 axis in Leber hereditary optic neuropathy in vitro. J Chin Med Assoc 2024; 87:261-266. [PMID: 38305450 DOI: 10.1097/jcma.0000000000001063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2024] Open
Abstract
BACKGROUND Leber hereditary optic neuropathy (LHON) is mainly the degeneration of retinal ganglion cells (RGCs) associated with high apoptosis and reactive oxygen species (ROS) levels, which is accepted to be caused by the mutations in the subunits of complex I of the mitochondrial electron transport chain. The treatment is still infant while efforts of correcting genes or using antioxidants do not bring good and consistent results. Unaffected carrier carries LHON mutation but shows normal phenotype, suggesting that the disease's pathogenesis is complex, in which secondary factors exist and cooperate with the primary complex I dysfunction. METHODS Using LHON patient-specific induced pluripotent stem cells (iPSCs) as the in vitro disease model, we previously demonstrated that circRNA_0087207 had the most significantly higher expression level in the LHON patient-iPSC-derived RGCs compared with the unaffected carrier-iPSC-derived RGCs. To elaborate the underlying pathologies regulated by circRNA_008720 mechanistically, bioinformatics analysis was conducted and elucidated that circRNA_0087207 could act as a sponge of miR-548c-3p and modulate PLSCR1/TGFB2 levels in ND4 mutation-carrying LHON patient-iPSC-derived RGCs. RESULTS Using LHON iPSC-derived RGCs as the disease-based platform, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis on targeted mRNA of miR-548c-3p showed the connection with apoptosis, suggesting downregulation of miR548c-3p contributes to the apoptosis of LHON patient RGCs. CONCLUSION We showed that the downregulation of miR548c-3p plays a critical role in modulating cellular dysfunction and the apoptotic program of RGCs in LHON.
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Affiliation(s)
- Yi-Ping Yang
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Yuh-Lih Chang
- Department of Pharmacy, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Department of Pharmacy, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
| | - Guang-Yuh Chiou
- Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu, Taiwan, ROC
- Center for Intelligent Drug Systems and Smart Bio-devices, National Yang Ming Chiao Tung University, Hsinchu, Taiwan, ROC
| | - Meng-Shiue Lee
- Institute of Molecular Medicine and Bioengineering, National Yang Ming Chiao Tung University, Hsinchu, Taiwan, ROC
| | - You-Ren Wu
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Institute of Pharmacology, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
| | - Po-Wei Chen
- Department of Pharmacy, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Department of Pharmacy, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
| | - Yi-Ying Lin
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Wei-Yi Lai
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Yu-Hao Liu
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - De-Kuang Hwang
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Yueh Chien
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
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Ma Q, Sun Y, Lei K, Luo W. Progress in diagnosis and treatment of Leber's hereditary optic neuropathy. J Mol Med (Berl) 2024; 102:1-10. [PMID: 37982904 DOI: 10.1007/s00109-023-02389-2] [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: 02/07/2023] [Revised: 10/09/2023] [Accepted: 10/16/2023] [Indexed: 11/21/2023]
Abstract
Leber's hereditary optic neuropathy (LHON) is a mitochondrial genetic disease with central vision loss as the main symptom. It is one of the diseases that cause vision loss and optic atrophy in young and middle-aged people. The mutations of these three primary mitochondrial mutations, m.11778G>A, m.14484T>C, and m.3460G>A, are the main molecular basis, but their pathogenesis is also affected by nuclear genes, mitochondrial genetic background, and environmental factors. This article summarizes the research progress on molecular pathogenesis, clinical symptoms, and treatment of LHON in recent years, aiming to summarize the genetic pathogenesis and clinical treatment points of LHON.
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Affiliation(s)
- Qingyue Ma
- Department of Ophthalmology, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Ying Sun
- The Affiliated Qingdao Central Hospital of Qingdao University, The Second Affiliated Hospital of Medical College of Qingdao University, Qingdao, China
| | - Ke Lei
- Center of Tumor Immunology and Cytotherapy, Medical Research Center, The Affiliated Hospital of Qingdao University, Qingdao, China.
| | - Wenjuan Luo
- Department of Ophthalmology, The Affiliated Hospital of Qingdao University, Qingdao, China.
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Alkhaldi HA, Phan DH, Vik SB. Analysis of Human Clinical Mutations of Mitochondrial ND1 in a Bacterial Model System for Complex I. Life (Basel) 2022; 12:1934. [PMID: 36431069 PMCID: PMC9696053 DOI: 10.3390/life12111934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/13/2022] [Accepted: 11/17/2022] [Indexed: 11/22/2022] Open
Abstract
The most common causes of mitochondrial dysfunction and disease include mutations in subunits and assembly factors of Complex I. Numerous mutations in the mitochondrial gene ND1 have been identified in humans. Currently, a bacterial model system provides the only method for rapid construction and analysis of mutations in homologs of human ND1. In this report, we have identified nine mutations in human ND1 that are reported to be pathogenic and are located at subunit interfaces. Our hypothesis was that these mutations would disrupt Complex I assembly. Seventeen mutations were constructed in the homologous nuoH gene in an E. coli model system. In addition to the clinical mutations, alanine substitutions were constructed in order to distinguish between a deleterious effect from the introduction of the mutant residue and the loss of the original residue. The mutations were moved to an expression vector containing all thirteen genes of the E. coli nuo operon coding for Complex I. Membrane vesicles were prepared and rates of deamino-NADH oxidase activity and proton translocation were measured. Samples were also tested for assembly by native gel electrophoresis and for expression of NuoH by immunoblotting. A range of outcomes was observed: Mutations at four of the sites allow normal assembly with moderate activity (50−76% of wild type). Mutations at the other sites disrupt assembly and/or activity, and in some cases the outcomes depend upon the amino acid introduced. In general, the outcomes are consistent with the proposed pathogenicity in humans.
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Affiliation(s)
| | | | - Steven B. Vik
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275, USA
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Leber’s hereditary optic neuropathy plus dystonia caused by the mitochondrial ND1 gene m.4160 T > C mutation. Neurol Sci 2022; 43:5581-5592. [DOI: 10.1007/s10072-022-06165-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Accepted: 05/17/2022] [Indexed: 10/18/2022]
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Marotta R, Chin J, Chiotis M, Shuey N, Collins SJ. Long-term screening for primary mitochondrial DNA variants associated with Leber hereditary optic neuropathy: incidence, penetrance and clinical features. Mitochondrion 2020; 54:128-132. [PMID: 32861874 DOI: 10.1016/j.mito.2020.08.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 06/22/2020] [Accepted: 08/24/2020] [Indexed: 10/23/2022]
Abstract
Leber hereditary optic neuropathy (LHON) is a neurodegenerative disorder characterised by bilateral, painless, subacute, central vision loss caused by pathogenic sequence variants in mitochondrial DNA (mtDNA). Over the course of 20 years, 734 people were systematically screened by our diagnostic laboratory for suspected LHON or for being at risk of LHON, with 98 found to harbour one of the three primary pathogenic mtDNA variants. Detection incidences were: 0.95% for NC_012920.1(MT-ND1):m.3460G>A; 9.4% for (MT-ND4):m.11778G>A; and 2.9% for (MT-ND6):m.14484T>C. The median age for symptomatic males was 27.3 years and for females 29.5 years, with a male to female ratio of 4.4:1 (62 males; 14 females). Most pathogenic variant carriers were propositi with the other individuals belonging to one of 14 pedigrees with noteworthy intra-family variability of clinical severity of the disease.
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Affiliation(s)
- Rosetta Marotta
- St Vincent's Hospital Melbourne Mitochondrial and Autoimmune Neurological Disorders Laboratory, Department of Clinical Neurosciences and Neurological Research, 5th Floor Daly Wing, St Vincent's Hospital Melbourne, Fitzroy, Victoria, Australia.
| | - Judy Chin
- St Vincent's Hospital Melbourne Mitochondrial and Autoimmune Neurological Disorders Laboratory, Department of Clinical Neurosciences and Neurological Research, 5th Floor Daly Wing, St Vincent's Hospital Melbourne, Fitzroy, Victoria, Australia
| | - Maria Chiotis
- St Vincent's Hospital Melbourne Mitochondrial and Autoimmune Neurological Disorders Laboratory, Department of Clinical Neurosciences and Neurological Research, 5th Floor Daly Wing, St Vincent's Hospital Melbourne, Fitzroy, Victoria, Australia
| | - Neil Shuey
- St Vincent's Hospital Melbourne Mitochondrial and Autoimmune Neurological Disorders Laboratory, Department of Clinical Neurosciences and Neurological Research, 5th Floor Daly Wing, St Vincent's Hospital Melbourne, Fitzroy, Victoria, Australia; Neuro-Ophthalmology Clinic at the Royal Victorian Eye and Ear Hospital, East Melbourne Victoria, Australia
| | - Steven J Collins
- St Vincent's Hospital Melbourne Mitochondrial and Autoimmune Neurological Disorders Laboratory, Department of Clinical Neurosciences and Neurological Research, 5th Floor Daly Wing, St Vincent's Hospital Melbourne, Fitzroy, Victoria, Australia
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Leber's hereditary optic neuropathy following unilateral painful optic neuritis: a case report. BMC Ophthalmol 2020; 20:195. [PMID: 32423393 PMCID: PMC7236174 DOI: 10.1186/s12886-020-01461-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 05/01/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Leber's hereditary optic neuropathy (LHON) is a maternally inherited mitochondrial disease, characterized by acute or subacute, painless, bilateral visual loss. LHON is often misdiagnosed as optic neuritis at an early stage because of the similarity of their clinical presentation. To date, there has been no reported case of actual optic neuritis and LHON in one patient. CASE PRESENTATION A 40-year-old, healthy man was referred to our clinic with acute painful visual loss in the right eye for 2 weeks. In the right eye, visual acuity decreased to 20/40, and the Ishihara colour test score was 8/14 with a relative afferent pupillary defect. Optic disc swelling was found only in the right eye, and magnetic resonance imaging revealed enhancement of the the right optic nerve, consistent with optic neuritis. After receiving 1 g of intravenous methylprednisolone daily for three days, his ocular pain resolved, and visual acuity improved to 20/20 within 2 weeks. Seven months later, the patient developed acute painless visual loss in the right eye. Visual acuity decreased to 20/200 in the right eye. There was no response to the intravenous methylprednisolone therapy at that time. Eight months later, he developed subacute painless visual loss in the left eye. Genetic testing for LHON was performed and revealed the pathologic mtDNA 11778 point mutation. CONCLUSIONS We report a case with painful unilateral optic neuritis preceding the onset of LHON. Even if a typical optic neuritis patient has completely recovered from steroid treatment once in the past, it is advisable to keep in mind the possibility of LHON if acute or subacute loss of vision subsequently or simultaneously occurs in both eyes and does not respond to steroids.
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The Evaluation of Optic Nerves Using 7 Tesla "Silent" Zero Echo Time Imaging in Patients with Leber's Hereditary Optic Neuropathy with or without Idebenone Treatment. J Clin Med 2020; 9:jcm9041112. [PMID: 32295018 PMCID: PMC7230870 DOI: 10.3390/jcm9041112] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 04/08/2020] [Accepted: 04/09/2020] [Indexed: 11/16/2022] Open
Abstract
Magnetic Resonance Imaging (MRI) of the Optic Nerve is difficult due to the fine extended nature of the structure, strong local magnetic field distortions induced by anatomy, and large motion artefacts associated with eye movement. To address these problems we used a Zero Echo Time (ZTE) MRI sequence with an Adiabatic SPectral Inversion Recovery (ASPIR) fat suppression pulse which also imbues the images with Magnetisation Transfer contrast. We investigated an application of the sequence for imaging the optic nerve in subjects with Leber's hereditary optic neuropathy (LHON). Of particular note is the sequence's near-silent operation, which can enhance image quality of the optic nerve by reducing the occurrence of involuntary saccades induced during Magnetic Resonance (MR) scanning.
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Bouquet C, Vignal Clermont C, Galy A, Fitoussi S, Blouin L, Munk MR, Valero S, Meunier S, Katz B, Sahel JA, Thomasson N. Immune Response and Intraocular Inflammation in Patients With Leber Hereditary Optic Neuropathy Treated With Intravitreal Injection of Recombinant Adeno-Associated Virus 2 Carrying the ND4 Gene: A Secondary Analysis of a Phase 1/2 Clinical Trial. JAMA Ophthalmol 2020; 137:399-406. [PMID: 30730541 DOI: 10.1001/jamaophthalmol.2018.6902] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Importance Intravitreal gene therapy is regarded as generally safe with limited mild adverse events, but its systemic effects remain to be investigated. Objective To examine the association between immune response and intraocular inflammation after ocular gene therapy with recombinant adeno-associated virus 2 carrying the ND4 gene (rAAV2/2-ND4). Design, Setting, and Participants This secondary analysis of an open-label, dose-escalation phase 1/2 randomized clinical trial of rAAV2/2-ND4 included data from February 13, 2014 (first patient visit), to March 30, 2017 (last patient visit at week 96), the first 2 years after injection. Patients older than 15 years with diagnosed ND4 Leber hereditary optic neuropathy (LHON) and visual acuity of at least counting fingers were enrolled in 1 of 5 cohorts. Four dose cohorts of 3 patients each were treated sequentially. An extension cohort of 3 patients received the dose of 9 × 1010 viral genomes per eye. Interventions Patients received increasing doses of rAAV2/2-ND4 (9 × 109, 3 × 1010, 9 × 1010, and 1.8 × 1011 viral genomes per eye) as a single unilateral intravitreal injection. Patients were monitored for 96 weeks after injection; ocular examinations were performed regularly, and blood samples were collected for immunologic testing. Main Outcomes and Measures A composite ocular inflammation score (OIS) was calculated based on grades of anterior chamber cells and flare, vitreous cells, and haze according to the Standardization of Uveitis Nomenclature. The systemic immune response was quantified by enzyme-linked immunospot (cellular immune response), enzyme-linked immunosorbent assay (IgG titers), and luciferase assay (neutralizing antibody [NAb] titers). Results The present analysis included 15 patients (mean [SD] age, 47.9 [17.2] years; 13 men and 2 women) enrolled in the 5 cohorts of the clinical trial. Thirteen patients experienced intraocular inflammation after rAAV2/2-ND4 administration. Mild anterior chamber inflammation and vitritis were reported at all doses, and all cases were responsive to treatment. A maximum OIS of 9.5 was observed in a patient with history of idiopathic uveitis. Overall, OIS was not associated with the viral dose administered. No NAbs against AAV2 were detected in aqueous humor before treatment. Two patients tested positive for cellular immune response against AAV2 at baseline and after treatment. Humoral immune response was not apparently associated with the dose administered or with the immune status of patients at baseline. No association was found between OISs and serum NAb titers. Conclusions and Relevance In this study, intravitreal administration of rAAV2/2-ND4 in patients with LHON was safe and well tolerated. Further investigations may shed light into the local immune response to rAAV2/2-ND4 as a potential explanation for the observed intraocular inflammation.
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Affiliation(s)
| | - Catherine Vignal Clermont
- Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France.,Rothschild Ophthalmology Foundation Hospital, Paris, France
| | | | | | | | - Marion R Munk
- Department of Ophthalmology, Bern Photographic Reading Center, Bern, Switzerland.,Inselspital, University Hospital Bern Oberärztin, Bern, Switzerland
| | | | | | | | - José Alain Sahel
- Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France.,Rothschild Ophthalmology Foundation Hospital, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, Paris, France.,Department of Ophthalmology, University of Pittsburgh School of Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
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Berardo A, Emmanuele V, Vargas W, Tanji K, Naini A, Hirano M. Leber hereditary optic neuropathy plus dystonia, and transverse myelitis due to double mutations in MT-ND4 and MT-ND6. J Neurol 2019; 267:823-829. [PMID: 31776719 DOI: 10.1007/s00415-019-09619-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 10/27/2019] [Accepted: 11/02/2019] [Indexed: 11/28/2022]
Abstract
Leber hereditary optic neuropathy (LHON) typically presents as painless central or centrocecal scotoma and is due to maternally inherited mitochondrial DNA (mtDNA) mutations. Over 95% of LHON cases are caused by one of three mtDNA "common" point mutations: m.3460G>A, m.11778G>A, or m.14484T>C, which are all in genes encoding structural subunits of complex I of the respiratory chain. Intriguing features of LHON include: incomplete penetrance, tissue specificity, and male predominance, indicating that additional genetic or environmental factors are modulating the phenotypic expression of the pathogenic mtDNA mutations. However, since its original description as a purely ophthalmological disorder, LHON has also been linked to multisystemic conditions with variable neurological, cardiac, and skeletal abnormalities. Although double "common" mutations have been reported to cause LHON and LHON-plus, they are extremely rare. Here, we present a patient with an unusual double point mutation (m.11778 G>A and m.14484T>C) with a multisystemic LHON-plus phenotype characterized by: optic neuropathy, ptosis, ataxia, dystonia, dysarthria, and recurrent extensive transverse myelitis.
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Affiliation(s)
- Andres Berardo
- Department of Neurology, H. Houston Merritt Neuromuscular Research Center, Columbia University Medical Center, 630 West 168th Street, P&S 4-423, New York, NY, 10032, USA
| | - Valentina Emmanuele
- Department of Neurology, H. Houston Merritt Neuromuscular Research Center, Columbia University Medical Center, 630 West 168th Street, P&S 4-423, New York, NY, 10032, USA
| | - Wendy Vargas
- Department of Neurology, H. Houston Merritt Neuromuscular Research Center, Columbia University Medical Center, 630 West 168th Street, P&S 4-423, New York, NY, 10032, USA
| | - Kurenai Tanji
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Ali Naini
- Department of Neurology, H. Houston Merritt Neuromuscular Research Center, Columbia University Medical Center, 630 West 168th Street, P&S 4-423, New York, NY, 10032, USA.,Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Michio Hirano
- Department of Neurology, H. Houston Merritt Neuromuscular Research Center, Columbia University Medical Center, 630 West 168th Street, P&S 4-423, New York, NY, 10032, USA.
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Lin YH, Wang NK, Yeung L, Lai CC, Chuang LH. Juvenile open-angle Glaucoma associated with Leber's hereditary optic neuropathy: a case report and literature review. BMC Ophthalmol 2018; 18:323. [PMID: 30558558 PMCID: PMC6296145 DOI: 10.1186/s12886-018-0980-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 11/29/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Leber's hereditary optic neuropathy (LHON) is a maternally inherited recessive disease rarely complicated with glaucoma. We conducted a clinical and genetic retrospective case series to describe three cases of juvenile open-angle glaucoma (JOAG) and an ND4 m11778G > A mitochondrial DNA (mtDNA) mutation, which is pathognomonic for LHON. CASE PRESENTATION Patient 1 was a 16-year-old boy diagnosed with bilateral JOAG and high myopia. His intraocular pressure (IOP) was poorly controlled with the use of full topical anti-glaucoma medications. His best-corrected visual acuity (BCVA) decreased gradually over 5 years. Fundoscopic examination revealed bilateral enlarged disc cupping of the optic nerves with sectorial excavation and reduction of the neural rim in the left eye. His visual field (VF) was characterized by bilateral progressive central scotoma. Pattern visual evoked potentials (VEPs) and pattern electroretinograms (ERGs) showed extinguished responses in both eyes. Because of the non-specific visual field findings and the optic neuropathy disclosed by the pattern VEPs and pattern ERGs, we arranged a genetic test for the patient, which revealed an m11778G > A mtDNA mutation. Patient 2, the younger brother of Patient 1, was a 15-year-old boy who had been diagnosed with bilateral JOAG in 2010. The BCVA of both eyes remained at 1.0 during the follow-up period. Fundoscopic examination revealed bilateral mildly paled optic disc with enlarged cupping and reduction of the neural rim. The pattern ERG revealed a decreased N95 amplitude bilaterally. The genetic test revealed an m11778G > A mtDNA mutation. Patient 3 was a 35-year-old man with bilateral JOAG. His BCVA decreased gradually over 10 years. Fundoscopic examination revealed paled optic disc with enlarged disc cupping and reduction of the neural rim in both eyes. The pattern ERG revealed a decreased N95 amplitude bilaterally. The genetic test revealed an m11778G > A mtDNA mutation. CONCLUSIONS This case series describes three patients with concomitant occurrence of JOAG and LHON. These two diseases may have a cumulative effect on oxidative stress and retinal ganglion cell death with the rapid deterioration of vision, which may occur during adolescence.
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Affiliation(s)
- Yun-Hsuan Lin
- Department of Ophthalmology, Chang-Gung Memorial Hospital, 222 Mai-Chin Rd, Keelung, 204, Taiwan (Republic of China)
| | - Nan-Kai Wang
- Department of Ophthalmology, Chang-Gung Memorial Hospital, Linkou, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Ling Yeung
- Department of Ophthalmology, Chang-Gung Memorial Hospital, 222 Mai-Chin Rd, Keelung, 204, Taiwan (Republic of China).,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chi-Chun Lai
- Department of Ophthalmology, Chang-Gung Memorial Hospital, Linkou, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Lan-Hsin Chuang
- Department of Ophthalmology, Chang-Gung Memorial Hospital, 222 Mai-Chin Rd, Keelung, 204, Taiwan (Republic of China). .,College of Medicine, Chang Gung University, Taoyuan, Taiwan.
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Kogachi K, Ter-Zakarian A, Asanad S, Sadun A, Karanjia R. Toxic medications in Leber's hereditary optic neuropathy. Mitochondrion 2018; 46:270-277. [PMID: 30081212 DOI: 10.1016/j.mito.2018.07.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 05/23/2018] [Accepted: 07/31/2018] [Indexed: 12/18/2022]
Abstract
Leber's hereditary optic neuropathy (LHON) is a maternally inherited mitochondrial disorder characterized by acute bilateral vision loss. The pathophysiology involves reactive oxygen species (ROS), which can be affected by medications. This article reviews the evidence for medications with demonstrated and theoretical effects on mitochondrial function, specifically in relation to increased ROS production. The data reviewed provides guidance when selecting medications for individuals with LHON mutations (carriers) and are susceptible to conversion to affected. However, as with all medications, the proven benefits of these therapies must be weighed against, in some cases, purely theoretical risks for this unique patient population.
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Affiliation(s)
- Kaitlin Kogachi
- Doheny Eye Institute, 1355 San Pablo Street, Los Angeles, CA 90033, USA.
| | - Anna Ter-Zakarian
- Doheny Eye Institute, 1355 San Pablo Street, Los Angeles, CA 90033, USA
| | - Samuel Asanad
- Doheny Eye Institute, 1355 San Pablo Street, Los Angeles, CA 90033, USA; Doheny Eye Center, Department of Ophthalmology, David Geffen School of Medicine at UCLA, 800 South Fairmount Avenue, Suite 215, Pasadena, CA 91105, USA
| | - Alfredo Sadun
- Doheny Eye Institute, 1355 San Pablo Street, Los Angeles, CA 90033, USA; Doheny Eye Center, Department of Ophthalmology, David Geffen School of Medicine at UCLA, 800 South Fairmount Avenue, Suite 215, Pasadena, CA 91105, USA
| | - Rustum Karanjia
- Doheny Eye Institute, 1355 San Pablo Street, Los Angeles, CA 90033, USA; Doheny Eye Center, Department of Ophthalmology, David Geffen School of Medicine at UCLA, 800 South Fairmount Avenue, Suite 215, Pasadena, CA 91105, USA; The Ottawa Eye Institute, University of Ottawa, 501 Smyth Rd, Ottawa, ON K1H 8M2, Canada; Ottawa Hospital Research Institute, 1053 Carling Avenue, Ottawa, ON K1Y 4E9, Canada
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Analysis of Visual Field Defects Obtained with Semiautomated Kinetic Perimetry in Patients with Leber Hereditary Optic Neuropathy. J Ophthalmol 2018; 2018:5985702. [PMID: 29750122 PMCID: PMC5884167 DOI: 10.1155/2018/5985702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 01/18/2018] [Accepted: 02/06/2018] [Indexed: 11/18/2022] Open
Abstract
Purpose To analyse visual field (VF) defects obtained using semiautomated kinetic perimetry (SKP) in patients suffering from Leber hereditary optic neuropathy (LHON). Methods Twenty-two eyes of eleven consecutive LHON male patients with confirmed mitochondrial 11778G>A DNA mutation were prospectively examined with the V4e stimulus of SKP in both eyes. The mean time after the onset of LHON was one year. The area of obtained isopters was measured in square degrees (deg2). Additionally, static automated perimetry (SAP) within 30° was performed. Results Visual acuity ranged from counting fingers to 50 cm to 0.4. VFs obtained with SKP showed central scotomas in 18 eyes (82%); the periphery of the VF in these eyes remained intact. The mean area of central scotoma was 408.8 deg2, and the mean area of the peripheral VF was 12291.1 deg2; SAP also revealed central scotoma in these patients. In four eyes (18%) with the worst visual acuity, only the residual central island of VF was found using SKP (mean area 898.4 deg2). SAP was difficult to obtain in these patients. Conclusions SKP provides additional clinical information in regard to the visual function of LHON patients. SKP enables the quantification of the area of central scotoma, preserved peripheral VF, and residual central island of vision. Using V4 stimulus is especially useful in LHON patients with poor visual acuity, when SAP is difficult to obtain.
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Bursle C, Riney K, Stringer J, Moore D, Gole G, Kearns LS, Mackey DA, Coman D. Leber Hereditary Optic Neuropathy and Longitudinally Extensive Transverse Myelitis. JIMD Rep 2017; 42:53-60. [PMID: 29249004 PMCID: PMC6226398 DOI: 10.1007/8904_2017_79] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 11/02/2017] [Accepted: 11/27/2017] [Indexed: 12/23/2022] Open
Abstract
Leber Hereditary Optic Neuropathy is an inherited optic neuropathy caused by mitochondrial DNA point mutations leading to sudden, painless loss of vision. We report a case of an 8-year-old boy presenting with a radiological phenotype of longitudinally extensive transverse myelitis on a background of severe visual impairment secondary to Leber Hereditary Optic Neuropathy (LHON). He was found to have dual mitochondrial DNA mutations at 14484 (MTND6 gene) and 4160 (MTND1 gene) in a family with a severe form of LHON characterised by not only an unusually high penetrance of optic neuropathy, but also severe extra-ocular neurological complications. The m.14484T>C mutation is a common LHON mutation, but the m.4160T>C mutation is to our knowledge not reported outside this family and appears to drive the neurological manifestations. To our knowledge there have been no previous reports of spinal cord lesions in children with LHON.
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Affiliation(s)
- C Bursle
- Neurosciences Unit, The Lady Cilento Children's Hospital, Brisbane, QLD, Australia
- School of Medicine, The University of Queensland, Brisbane, QLD, Australia
| | - K Riney
- Neurosciences Unit, The Lady Cilento Children's Hospital, Brisbane, QLD, Australia
- School of Medicine, The University of Queensland, Brisbane, QLD, Australia
| | - J Stringer
- Neurosciences Unit, The Lady Cilento Children's Hospital, Brisbane, QLD, Australia
| | - D Moore
- Department of Paediatrics, The Wesley Hospital, Brisbane, QLD, Australia
| | - G Gole
- Department of Ophthalmology, The Lady Cilento Children's Hospital, Brisbane, QLD, Australia
| | - L S Kearns
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, Parkville, VIC, Australia
| | - D A Mackey
- Lions Eye Institute, Centre for Ophthalmology and Visual Science, University of Western Australia, Perth, WA, Australia
- School of Medicine, Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
| | - D Coman
- Neurosciences Unit, The Lady Cilento Children's Hospital, Brisbane, QLD, Australia.
- UnitingCare Clinical School, The Wesley Hospital, Brisbane, QLD, Australia.
- School of Medicine, The University of Queensland, Brisbane, QLD, Australia.
- Department of Paediatrics, The Wesley Hospital, Brisbane, QLD, Australia.
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Mother's curse neutralizes natural selection against a human genetic disease over three centuries. Nat Ecol Evol 2017; 1:1400-1406. [PMID: 29046555 DOI: 10.1038/s41559-017-0276-6] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Accepted: 06/06/2017] [Indexed: 12/30/2022]
Abstract
According to evolutionary theory, mitochondria could be poisoned gifts that mothers transmit to their sons. This is because mutations harmful to males are expected to accumulate in the mitochondrial genome, the so-called 'mother's curse'. However, the contribution of the mother's curse to the mutation load in nature remains largely unknown and hard to predict, because compensatory mechanisms could impede the spread of deleterious mitochondria. Here we provide evidence for the mother's curse in action over 290 years in a human population. We studied a mutation causing Leber's hereditary optical neuropathy, a disease with male-biased prevalence and which has long been suspected to be maintained in populations by the mother's curse. Male carriers showed a low fitness relative to non-carriers and to females, mostly explained by their high rate of infant mortality. Despite poor male fitness, selection analysis predicted a slight (albeit non-significant) increase in frequency, which sharply contrasts with the 35.5% per-generation decrease predicted if mitochondrial DNA transmission had been through males instead of females. Our results are therefore even suggestive of positive selection through the female line that may exacerbate effects of the mother's curse. This study supports a contribution of the mother's curse to the reduction of male lifespan, uncovering a large fitness effect associated with a single mitochondrial variant.
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Abstract
Mitochondrial diseases are a clinically heterogeneous group of disorders that ultimately result from dysfunction of the mitochondrial respiratory chain. There is some evidence to suggest that mitochondrial dysfunction plays a role in neuropsychiatric illness; however, the data are inconclusive. This article summarizes the available literature published in the area of neuropsychiatric manifestations in both children and adults with primary mitochondrial disease, with a focus on autism spectrum disorder in children and mood disorders and schizophrenia in adults.
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Affiliation(s)
- Samantha E Marin
- Department of Neurosciences, University of California, San Diego (UCSD), 9500 Gilman Drive #0935, La Jolla, CA 92093-0935, USA
| | - Russell P Saneto
- Department of Neurology, Seattle Children's Hospital, University of Washington, 4800 Sand Point Way Northeast, Seattle, WA 98105, USA; Department of Pediatrics, Seattle Children's Hospital, University of Washington, 4800 Sand Point Way Northeast, Seattle, WA 98105, USA.
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16
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Kim SH, Kim JS. Leber's 'Plus' in a Korean Patient with 14484/ND6 Mutation. J Clin Neurol 2016; 12:512-514. [PMID: 27486939 PMCID: PMC5063883 DOI: 10.3988/jcn.2016.12.4.512] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 03/14/2016] [Accepted: 03/15/2016] [Indexed: 11/17/2022] Open
Affiliation(s)
- Sung Hee Kim
- Department of Neurology, Kyungpook National University School of Medicine, Daegu, Korea
| | - Ji Soo Kim
- Department of Neurology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
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17
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Kolarova H, Liskova P, Tesarova M, Kucerova Vidrova V, Forgac M, Zamecnik J, Hansikova H, Honzik T. Unique presentation of LHON/MELAS overlap syndrome caused by m.13046T>C in MTND5. Ophthalmic Genet 2016; 37:419-423. [PMID: 26894521 DOI: 10.3109/13816810.2015.1092045] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Leber hereditary optic neuropathy (LHON) and mitochondrial encephalopathy, myopathy, lactic acidosis and stroke-like episodes (MELAS) syndromes are mitochondrially inherited disorders characterized by acute visual failure and variable multiorgan system presentation, respectively. MATERIALS AND METHODS A 12-year-old girl with otherwise unremarkable medical history presented with abrupt, painless loss of vision. Over the next few months, she developed moderate sensorineural hearing loss, vertigo, migraines, anhedonia and thyroiditis. Ocular examination confirmed bilateral optic nerve atrophy. Metabolic workup documented elevated cerebrospinal fluid lactate. Initial genetic analyses excluded the three most common LHON mutations. Subsequently, Sanger sequencing of the entire mitochondrial DNA (mtDNA) genome was performed. RESULTS Whole mtDNA sequencing revealed a pathogenic heteroplasmic mutation m.13046T>C in MTND5 encoding the ND5 subunit of complex I. This particular variant has previously been described in a single case report of MELAS/Leigh syndrome (subacute necrotizing encephalopathy). Based on the constellation of clinical symptoms in our patient, we diagnose the condition as LHON/MELAS overlap syndrome. CONCLUSIONS We describe a unique presentation of LHON/MELAS overlap syndrome resulting from a m.13046T>C mutation in a 12-year-old girl. In patients with sudden vision loss in which three of the most prevalent LHON mitochondrial mutations have been ruled out, molecular genetic examination should be extended to other mtDNA-encoded subunits of MTND5 complex I. Furthermore, atypical clinical presentations must be considered, even in well-described phenotypes.
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Affiliation(s)
- Hana Kolarova
- a Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine , Charles University in Prague and General University Hospital in Prague , Czech Republic
| | - Petra Liskova
- b Laboratory of the Biology and Pathology of the Eye, Institute of Inherited Metabolic Disorders, First Faculty of Medicine , Charles University in Prague and General University Hospital in Prague , Czech Republic.,c Department of Ophthalmology, First Faculty of Medicine , Charles University in Prague and General University Hospital in Prague , Czech Republic
| | - Marketa Tesarova
- a Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine , Charles University in Prague and General University Hospital in Prague , Czech Republic
| | - Vendula Kucerova Vidrova
- a Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine , Charles University in Prague and General University Hospital in Prague , Czech Republic
| | - Martin Forgac
- d Department of Neurology and Centre of Clinical Neuroscience, First Faculty of Medicine , Charles University in Prague and General University Hospital in Prague , Czech Republic
| | - Josef Zamecnik
- e Department of Pathology and Molecular Medicine , Second Faculty of Medicine, Charles University in Prague and University Hospital Motol in Prague , Czech Republic
| | - Hana Hansikova
- a Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine , Charles University in Prague and General University Hospital in Prague , Czech Republic
| | - Tomas Honzik
- a Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine , Charles University in Prague and General University Hospital in Prague , Czech Republic
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Meyerson C, Van Stavern G, McClelland C. Leber hereditary optic neuropathy: current perspectives. Clin Ophthalmol 2015; 9:1165-76. [PMID: 26170609 PMCID: PMC4492634 DOI: 10.2147/opth.s62021] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Leber hereditary optic neuropathy (LHON) is one of the most common inherited optic neuropathies causing bilateral central vision loss. The disorder results from point mutations in mitochondrial DNA and subsequent mitochondrial dysfunction. The primary cell type that is lost in LHON is the retinal ganglion cell, which is highly susceptible to disrupted ATP production and oxidative stress. Inheritance of LHON follows that of mitochondrial genetics, and it has a highly variable clinical phenotype, as other genetic and environmental factors also play a role. Although LHON usually presents with isolated vision loss, some patients suffer other neurological sequelae. For ill-defined reasons, male LHON mutation carriers are more affected than females. Most LHON patients remain legally blind, but a small proportion can experience spontaneous partial recovery, often within the first year of symptom onset. Unfortunately, at this time there are no established curative interventions and treatment is largely supportive. Patients should be offered low vision services and counseled on mitigating risk factors for additional vision loss, such as smoking and consuming alcohol. Encouraging treatments currently undergoing investigation includes ubiquinone analogs, such as idebenone, as well as gene therapy and stem cells to restore ATP synthesis and provide neuroprotection to surviving retinal ganglion cells.
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Affiliation(s)
- Cherise Meyerson
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St Louis, MO, USA
| | - Greg Van Stavern
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St Louis, MO, USA
| | - Collin McClelland
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St Louis, MO, USA
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Piotrowska A, Korwin M, Bartnik E, Tońska K. Leber hereditary optic neuropathy — Historical report in comparison with the current knowledge. Gene 2015; 555:41-9. [DOI: 10.1016/j.gene.2014.09.048] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 09/19/2014] [Accepted: 09/22/2014] [Indexed: 12/22/2022]
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Hirano M. Weighing in on Leber hereditary optic neuropathy: effects of mitochondrial mass. ACTA ACUST UNITED AC 2014; 137:308-9. [PMID: 24501072 DOI: 10.1093/brain/awu005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Michio Hirano
- Columbia University Medical Centre New York, NY USA E-mail:
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21
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Maresca A, la Morgia C, Caporali L, Valentino ML, Carelli V. The optic nerve: a "mito-window" on mitochondrial neurodegeneration. Mol Cell Neurosci 2013; 55:62-76. [PMID: 22960139 PMCID: PMC3629569 DOI: 10.1016/j.mcn.2012.08.004] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Revised: 07/27/2012] [Accepted: 08/06/2012] [Indexed: 01/16/2023] Open
Abstract
Retinal ganglion cells (RGCs) project their long axons, composing the optic nerve, to the brain, transmitting the visual information gathered by the retina, ultimately leading to formed vision in the visual cortex. The RGC cellular system, representing the anterior part of the visual pathway, is vulnerable to mitochondrial dysfunction and optic atrophy is a very frequent feature of mitochondrial and neurodegenerative diseases. The start of the molecular era of mitochondrial medicine, the year 1988, was marked by the identification of a maternally inherited form of optic atrophy, Leber's hereditary optic neuropathy, as the first disease due to mitochondrial DNA point mutations. The field of mitochondrial medicine has expanded enormously over the last two decades and many neurodegenerative diseases are now known to have a primary mitochondrial etiology or mitochondrial dysfunction plays a relevant role in their pathogenic mechanism. Recent technical advancements in neuro-ophthalmology, such as optical coherence tomography, prompted a still ongoing systematic re-investigation of retinal and optic nerve involvement in neurodegenerative disorders. In addition to inherited optic neuropathies, such as Leber's hereditary optic neuropathy and dominant optic atrophy, and in addition to the syndromic mitochondrial encephalomyopathies or mitochondrial neurodegenerative disorders such as some spinocerebellar ataxias or familial spastic paraparesis and other disorders, we draw attention to the involvement of the optic nerve in classic age-related neurodegenerative disorders such as Parkinson and Alzheimer disease. We here provide an overview of optic nerve pathology in these different clinical settings, and we review the possible mechanisms involved in the pathogenesis of optic atrophy. This may be a model of general value for the field of neurodegeneration. This article is part of a Special Issue entitled 'Mitochondrial function and dysfunction in neurodegeneration'.
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Affiliation(s)
| | | | | | | | - Valerio Carelli
- Corresponding author at: IRCCS Institute of Neurological Sciences of Bologna, Department of Neurological Sciences, University of Bologna, Via Ugo Foscolo 7, 40123 Bologna, Italy. Fax: + 39 051 2092751.
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23
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Leber's Hereditary Optic Neuropathy-Gene Therapy: From Benchtop to Bedside. J Ophthalmol 2010; 2011:179412. [PMID: 21253496 PMCID: PMC3021870 DOI: 10.1155/2011/179412] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 10/07/2010] [Accepted: 11/12/2010] [Indexed: 02/06/2023] Open
Abstract
Leber's hereditary optic neuropathy (LHON) is a maternally transmitted disorder caused by point mutations in mitochondrial DNA (mtDNA). Most cases are due to mutations in genes encoding subunits of the NADH-ubiquinone oxidoreductase that is Complex I of the electron transport chain (ETC). These mutations are located at nucleotide positions 3460, 11778, or 14484 in the mitochondrial genome. The disease is characterized by apoplectic, bilateral, and severe visual loss. While the mutated mtDNA impairs generation of ATP by all mitochondria, there is only a selective loss of retinal ganglion cells and degeneration of optic nerve axons. Thus, blindness is typically permanent. Half of the men and 10% of females who harbor the pathogenic mtDNA mutation actually develop the phenotype. This incomplete penetrance and gender bias is not fully understood. Additional mitochondrial and/or nuclear genetic factors may modulate the phenotypic expression of LHON. In a population-based study, the mtDNA background of haplogroup J was associated with an inverse relationship of low-ATP generation and increased production of reactive oxygen species (ROS). Effective therapy for LHON has been elusive. In this paper, we describe the findings of pertinent published studies and discuss the controversies of potential strategies to ameliorate the disease.
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Fraser JA, Biousse V, Newman NJ. The neuro-ophthalmology of mitochondrial disease. Surv Ophthalmol 2010; 55:299-334. [PMID: 20471050 PMCID: PMC2989385 DOI: 10.1016/j.survophthal.2009.10.002] [Citation(s) in RCA: 177] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 09/21/2009] [Accepted: 10/01/2009] [Indexed: 01/16/2023]
Abstract
Mitochondrial diseases frequently manifest neuro-ophthalmologic symptoms and signs. Because of the predilection of mitochondrial disorders to involve the optic nerves, extraocular muscles, retina, and even the retrochiasmal visual pathways, the ophthalmologist is often the first physician to be consulted. Disorders caused by mitochondrial dysfunction can result from abnormalities in either the mitochondrial DNA or in nuclear genes which encode mitochondrial proteins. Inheritance of these mutations will follow patterns specific to their somatic or mitochondrial genetics. Genotype-phenotype correlations are inconstant, and considerable overlap may occur among these syndromes. The diagnostic approach to the patient with suspected mitochondrial disease entails a detailed personal and family history, careful ophthalmic, neurologic, and systemic examination, directed investigations, and attention to potentially life-threatening sequelae. Although curative treatments for mitochondrial disorders are currently lacking, exciting research advances are being made, particularly in the area of gene therapy. Leber hereditary optic neuropathy, with its window of opportunity for timely intervention and its accessibility to directed therapy, offers a unique model to study future therapeutic interventions. Most patients and their relatives benefit from informed genetic counseling.
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Affiliation(s)
- J. Alexander Fraser
- Departments of Ophthalmology (J.A.F., V.B., N.J.N.), Neurology (V.B., N.J.N.), and Neurological Surgery (N.J.N.), Emory University School of Medicine, Atlanta, GA
| | - Valérie Biousse
- Departments of Ophthalmology (J.A.F., V.B., N.J.N.), Neurology (V.B., N.J.N.), and Neurological Surgery (N.J.N.), Emory University School of Medicine, Atlanta, GA
| | - Nancy J. Newman
- Departments of Ophthalmology (J.A.F., V.B., N.J.N.), Neurology (V.B., N.J.N.), and Neurological Surgery (N.J.N.), Emory University School of Medicine, Atlanta, GA
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25
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Nikoskelainen E, Riekkinen P. Optic neuritis--a sign of multiple sclerosis or other diseases of the central nervous system. Acta Neurol Scand 2009; 50:690-718. [PMID: 4440449 DOI: 10.1111/j.1600-0404.1974.tb02815.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Abstract
AIMS To provide a clinical update on the hereditary optic neuropathies. METHODS Review of the literature. RESULTS The hereditary optic neuropathies comprise a group of disorders in which the cause of optic nerve dysfunction appears to be hereditable, based on familial expression or genetic analysis. In some hereditary optic neuropathies, optic nerve dysfunction is typically the only manifestation of the disease. In others, various neurologic and systemic abnormalities are regularly observed. CONCLUSION The most common hereditary optic neuropathies are autosomal dominant optic atrophy (Kjer's disease) and maternally inherited Leber's hereditary optic neuropathy. We review the clinical phenotypes of these and other inherited disorders with optic nerve involvement.
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MESH Headings
- Dysautonomia, Familial/complications
- Dysautonomia, Familial/genetics
- Female
- Friedreich Ataxia/complications
- Friedreich Ataxia/genetics
- Humans
- Male
- Muscular Dystrophies/complications
- Muscular Dystrophies/genetics
- Optic Atrophies, Hereditary/complications
- Optic Atrophies, Hereditary/genetics
- Optic Atrophies, Hereditary/physiopathology
- Optic Atrophy, Autosomal Dominant/complications
- Optic Atrophy, Autosomal Dominant/genetics
- Optic Atrophy, Autosomal Dominant/physiopathology
- Optic Atrophy, Hereditary, Leber/complications
- Optic Atrophy, Hereditary, Leber/genetics
- Optic Atrophy, Hereditary, Leber/physiopathology
- Pedigree
- Spinocerebellar Ataxias/complications
- Spinocerebellar Ataxias/genetics
- Vision Disorders/etiology
- Vision Disorders/genetics
- Vision Disorders/physiopathology
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Affiliation(s)
- N J Newman
- Department of Ophthalmology, Emory University School of Medicine, Atlanta, GA 30022, USA.
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Abstract
Mitochondria are increasingly recognized as central players in the life and death of cells and especially of neurons. The energy-dependence of retinal ganglion cells (RGC) and their axons, which form the optic nerve, is singularly skewed. In fact, while mitochondria are very abundant in the initial, unmyelinated part of the axons anterior to the lamina cribrosa, their number suddenly decreases as the myelin sheath begins more posteriorly. The vascular system also presents different blood-brain barrier properties anterior and posterior to the lamina, possibly reflecting the different metabolic needs of the optic nerve head (unmyelinated) and of the retrobulbar optic nerve (myelinated). Mitochondrial biogenesis occurs within the cellular somata of RGC in the retina. It needs the coordinated interaction of nuclear and mitochondrial genomes. Mitochondria are then transported down the axons and distributed where they are needed. These locations are along the unmyelinated portion of the nerve, under the nodes of Ranvier in the retrobulbar nerve, and at the synaptic terminals. Efficient transportation of mitochondria depends on multiple factors, including their own energy production, the integrity of the cytoskeleton and its protein components (tubulin, etc.), and adequate myelination of the axons. Any dysfunction of these systems may be of pathological relevance for optic neuropathies with primary or secondary involvement of mitochondria. Leber's hereditary optic neuropathy (LHON) is the paradigm of mitochondrial optic neuropathies where a primary role for mitochondrial dysfunction is certified by maternal inheritance and association with specific mutations in the mitochondrial DNA (mtDNA). Clinical phenocopies of this pathology are represented by the wide array of optic neuropathies associated with vitamin depletion, toxic exposures, alcohol and tobacco abuse, and use of certain drugs. Moreover, the recent identification of mutations in the nuclear gene OPA1 as the causative factor in dominant optic atrophy (DOA, Kjer's type) brought the unexpected finding that this gene encodes for a mitochondrial protein, suggesting that DOA and LHON may be linked by similar pathogenesis. Polymorphisms in this very same gene may be associated with normal tension glaucoma (NTG), which might be considered a genetically determined optic neuropathy that again shows similarities with both LHON and DOA. Exciting new developments come from first examples of mitochondrial optic neuropathies in animal models that are genetically determined or are the result of ingenious engineering of mitochondrial gene expression, or from biochemical manipulations of the respiratory complexes. Even more exciting is the first successful attempt to correct the LHON-related complex I dysfunction by the allotopic nuclear expression of the recoded mitochondrial gene. There is hope that the genetic complexities, biochemical dysfunctions, and integrated anatomical-physiological cellular relationships will soon be precisely delineated and that promising therapeutic and prophylactic strategies will be proposed.
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Affiliation(s)
- Valerio Carelli
- Doheny Eye Institute and Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA.
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Vinkler C, Lev D, Kalish H, Watemberg N, Yanoov-Sharav M, Leshinsky-Silver E, Lerman-Sagie T. Familial optic atrophy with white matter changes. Am J Med Genet A 2003; 121A:263-5. [PMID: 12923868 DOI: 10.1002/ajmg.a.20238] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We report two brothers who suffer from infantile onset optic atrophy and blindness. MRI of the brain demonstrated periventricular white matter changes in both children. Neurological and developmental examination are normal. Extensive laboratory investigations rule out metabolic disorders that can be associated with optic atrophy. No mutations associated with Leber hereditary optic neuropathy (LHON) were found and sequencing of the mitochondrially encoded complex 1 subunits was normal. We suggest that this family represents either an atypical variant of LHON with a yet undescribed mtDNA mutation or a new syndrome.
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Affiliation(s)
- Chana Vinkler
- Institute of Clinical Genetics, Metabolic-Neurogenetic Clinic, Wolfson Medical Center, Holon, Israel
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29
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Sun F, Cui J, Gavras H, Schwartz F. A novel class of tests for the detection of mitochondrial DNA-mutation involvement in diseases. Am J Hum Genet 2003; 72:1515-26. [PMID: 12730827 PMCID: PMC1180311 DOI: 10.1086/375656] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2003] [Accepted: 03/27/2003] [Indexed: 11/04/2022] Open
Abstract
We develop a novel class of tests to detect mitochondrial DNA (mtDNA)-mutation involvement in complex diseases by the study of affected pedigree members. For a pedigree, affected individuals are first considered and are then connected through their relatives. We construct a reduced pedigree from an original pedigree. Each configuration of a reduced pedigree is given a score, with high scores given to configurations that are consistent with mtDNA-mutation involvement and low scores given to configurations that are not consistent with mtDNA-mutation involvement. For many pedigrees, the weighted sum of scores of the pedigrees is calculated. The tests are formed by comparing the observed score with the expected score under the null hypothesis that only nuclear autosomal mutations are involved. We study the optimality of score functions and weights under the heterogeneity model without phenocopies. We also develop a method to estimate the contribution that mtDNA mutations make if they are involved under a heterogeneity model. Finally, we apply our methods to three data sets: Leber hereditary optic neuropathy, a disease that has been proved to be caused by mtDNA mutations; non-insulin-dependent diabetes mellitus (NIDDM); and hypertension (HTN). We find evidence of mtDNA-mutation involvement in all three diseases. The estimated fraction of patients with NIDDM due to mtDNA-mutation involvement is 22% (95% confidence interval [CI] 6%-38%). The fraction of patients with HTN potentially due to mtDNA-mutation involvement is estimated at 55% (95% CI 45%-65%).
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Affiliation(s)
- Fengzhu Sun
- Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA.
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Howell N, Smejkal CB, Mackey DA, Chinnery PF, Turnbull DM, Herrnstadt C. The pedigree rate of sequence divergence in the human mitochondrial genome: there is a difference between phylogenetic and pedigree rates. Am J Hum Genet 2003; 72:659-70. [PMID: 12571803 PMCID: PMC1180241 DOI: 10.1086/368264] [Citation(s) in RCA: 157] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2002] [Accepted: 12/13/2002] [Indexed: 11/03/2022] Open
Abstract
We have extended our previous analysis of the pedigree rate of control-region divergence in the human mitochondrial genome. One new germline mutation in the mitochondrial DNA (mtDNA) control region was detected among 185 transmission events (generations) from five Leber hereditary optic neuropathy (LHON) pedigrees. Pooling the LHON pedigree analyses yields a control-region divergence rate of 1.0 mutation/bp/10(6) years (Myr). When the results from eight published studies that used a similar approach were pooled with the LHON pedigree studies, totaling >2,600 transmission events, a pedigree divergence rate of 0.95 mutations/bp/Myr for the control region was obtained with a 99.5% confidence interval of 0.53-1.57. Taken together, the cumulative results support the original conclusion that the pedigree divergence rate for the control region is approximately 10-fold higher than that obtained with phylogenetic analyses. There is no evidence that any one factor explains this discrepancy, and the possible roles of mutational hotspots (rate heterogeneity), selection, and random genetic drift and the limitations of phylogenetic approaches to deal with high levels of homoplasy are discussed. In addition, we have extended our pedigree analysis of divergence in the mtDNA coding region. Finally, divergence of complete mtDNA sequences was analyzed in two tissues, white blood cells and skeletal muscle, from each of 17 individuals. In three of these individuals, there were four instances in which an mtDNA mutation was found in one tissue but not in the other. These results are discussed in terms of the occurrence of somatic mtDNA mutations.
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Abstract
In this era of "the gene and the genome", communication of complex genetic information to individuals and their families is becoming an increasingly common but difficult task for the clinician. This problem is particularly evident in the rapidly evolving field of mitochondrial disease: the clinician is faced with a diversity of clinical presentations and myriad mutations with, for many, only a loose relation between genotype and phenotype. The aim of this review is to familiarise the clinician with the main clinical syndromes encountered in practice, and to provide an overview of current concepts of mitochondrial genetics, including recent advances in molecular aetiology. In addition, we have included clinical guidance on the investigation and management of patients with suspected or proven mitochondrial disease based on our own experience over the past decade.
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Affiliation(s)
- Robert McFarland
- Department of Neurology, Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne, UK
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Swerdlow RH. Mitochondrial DNA--related mitochondrial dysfunction in neurodegenerative diseases. Arch Pathol Lab Med 2002; 126:271-80. [PMID: 11860299 DOI: 10.5858/2002-126-0271-mdrmdi] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Mitochondrial dysfunction occurs in several late-onset neurodegenerative diseases. Determining its origin and significance may provide insight into the pathogeneses of these disorders. Regarding origin, one hypothesis proposes mitochondrial dysfunction is driven by mitochondrial DNA (mtDNA) aberration. This hypothesis is primarily supported by data from studies of cytoplasmic hybrid (cybrid) cell lines, which facilitate the study of mitochondrial genotype-phenotype relationships. In cybrid cell lines in which mtDNA from persons with certain neurodegenerative diseases is assessed, mitochondrial physiology is altered in ways that are potentially relevant to programmed cell death pathways. Connecting mtDNA-related mitochondrial dysfunction with programmed cell death underscores the crucial if not central role for these organelles in neurodegenerative pathophysiology. This review discusses the cybrid technique and summarizes cybrid data implicating mtDNA-related mitochondrial dysfunction in certain neurodegenerative diseases.
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Affiliation(s)
- Russell H Swerdlow
- Center for the Study of Neurodegenerative Diseases and the Department of Neurology, University of Virginia Health System, Charlottesville 22908, USA.
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Carelli V. Chapter 4 Leber's Hereditary Optic Neuropathy. MITOCHONDRIAL DISORDERS IN NEUROLOGY 2 2002. [DOI: 10.1016/s1877-3419(09)70063-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Kato T. The other, forgotten genome: mitochondrial DNA and mental disorders. Mol Psychiatry 2001; 6:625-33. [PMID: 11673790 DOI: 10.1038/sj.mp.4000926] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2000] [Revised: 03/20/2001] [Accepted: 03/23/2001] [Indexed: 01/08/2023]
Abstract
This paper summarizes recent research on mitochondrial DNA (mtDNA)--which might be described as the "other, forgotten genome". Recent studies suggest the possible pathophysiological significance of mtDNA in schizophrenia and neurodegenerative and mood disorders. Decreased activity of the mitochondrial electron transport chain has been implicated in both Parkinson's and Alzheimer's disease and while age-related accumulation of mtDNA deletions has been suggested as a possible cause, there is no concrete evidence that particular mtDNA polymorphisms are responsible. In schizophrenia, the activity and/or mRNA expression of complex IV are involved, but the direction of the alteration is not the same and there is no evidence linking schizophrenia with mtDNA. In bipolar disorder, there is some evidence of parent-of-origin effects and association with mtDNA polymorphisms but further investigation is needed to elucidate the role of mtDNA in mental disorders.
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Affiliation(s)
- T Kato
- Laboratory for Molecular Dynamics of Mental Disorders, Brain Science Institute, RIKEN, Hirosawa 2-1, Wako, Saitama, 351-0198, Japan.
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Abstract
BACKGROUND Previous studies suggested mitochondrial abnormality in bipolar disorder: (1) possible contribution of parent-of-origin effect in transmission of bipolar disorder; (2) abnormal brain phosphorus metabolism detected by phosphorus-31 magnetic resonance spectroscopy; (3) comorbidity of affective disorders in patients with mitochondrial encephalopathy; (4) increased levels of the 4977bp deletion of mitochondrial DNA (mtDNA) in the postmortem brains. We investigated mtDNA polymorphisms in association with bipolar disorder. METHODS Twelve PCR fragments including all tRNA genes were examined by the single-strand conformation polymorphism method in 43 bipolar patients. All observed polymorphisms were sequenced. Association of these polymorphisms with bipolar disorder was examined by restriction fragment length polymorphism method in 135 bipolar patients and 187 controls. RESULTS In total, we found 28 polymorphisms including 14 polymorphisms that have not been reported previously. The A10398G polymorphism was significantly associated with bipolar disorder (10398A genotype: 33.1% in bipolar, 22.2% in the control, P<0.05). Although this difference was not significant after Bonferroni correction, the CA haplotype of the 5178 and 10398 polymorphisms was still significantly associated with bipolar disorder (CA haplotype: 33.6% in bipolar, 16.8% in control, P<0.001). Three rare mutations substituting evolutionary conserved bases; A5539G in tRNA(Trp) gene, A5747G in the origin of L-strand replication, and A8537G in ATPase subunit-6 and -8 genes, were found in patients with family history in which maternal transmission was suspected. DISCUSSION The 5178C/10398A haplotype in mtDNA may be a risk factor of bipolar disorder (odds ratio, 2.4). Pathophysiological significance of rare mtDNA mutations needs to be verified in the future. This finding may imply the pathophysiological significance of mtDNA in bipolar disorder.
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Affiliation(s)
- T Kato
- Department of Neuropsychiatry, Faculty of Medicine, University of Tokyo, Hongo 7-3-1, Bunkyo, Tokyo 113-8655, Japan.
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Abstract
Mitochondrial dysfunction is implicated in bipolar disorder based on the following lines of evidence: 1) Abnormal brain energy metabolism measured by 31P-magnetic resonance spectroscopy, that is, decreased intracellular pH, decreased phosphocreatine (PCr), and enhanced response of PCr to photic stimulation. 2) Possible role of maternal inheritance in the transmission of bipolar disorder. 3) Increased levels of the 4977-bp deletion in mitochondrial DNA (mtDNA) in autopsied brains. 4) Comorbidity of affective disorders in certain types of mitochondrial disorders, such as autosomal inherited chronic progressive external ophthalmoplegia and mitochondrial diabetes mellitus with the 3243 mutation. Based on these findings, we searched for mtDNA mutations/ polymorphisms associated with bipolar disorder and found that 5178C and 10398A polymorphisms in mtDNA were risk factors for bipolar disorder. The 5178C genotype was associated with lower brain intracellular pH. mtDNA variations may play a part in the pathophysiology of bipolar disorder through alteration of intracellular calcium signaling systems. The mitochondrial dysfunction hypothesis, which comprehensively accounts for the pathophysiology of bipolar disorder, is proposed.
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Affiliation(s)
- T Kato
- Department of Neuropsychiatry, Faculty of Medicine, University of Tokyo, Japan.
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Abstract
Defects of mitochondrial metabolism result in a wide variety of human disorders, which can present at any time from infancy to late adulthood and involve virtually any tissue either alone or in combination. Abnormalities of the electron transport and oxidative phosphorylation (OXPHOS) system are probably the most common cause of mitochondrial diseases. Thirteen of the protein subunits of OXPHOS are encoded by mitochondrial DNA (mtDNA) and mutations of this genome are important causes of OXPHOS deficiency. The link between genotype and phenotype with respect to mtDNA mutations is not clear: the same mutation may result in a variety of phenotypes, and the same phenotype may be seen with a variety of different mtDNA mutations. The pathogenesis of mtDNA mutations is unclear although OXPHOS and ATP deficiency, and free radical generation, are thought to contribute to tissue dysfunction. There is now strong evidence for mitochondrial dysfunction in neurodegenerative disorders. In some cases, e.g. Friedreich's ataxia, hereditary spastic paraplegia, this is a result of a mutation of a nuclear gene encoding a mitochondrial protein, whilst in others, e.g. Huntington's disease, amyotrophic lateral sclerosis, the OXPHOS defect is secondary to events induced by a mutation in a nuclear gene encoding a non-mitochondrial protein. In yet a third group, e.g. Parkinson's disease, Alzheimer's disease, the relationship of the mitochondrial defect to aetiology and pathogenesis is unclear.
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Affiliation(s)
- A H Schapira
- University Department of Clinical Neurosciences, Royal Free and University College Medical School; London, UK
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Parker Jr WD. The Other Genome. Clin Chem 1999. [DOI: 10.1093/clinchem/45.8.1129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Chalmers RM, Schapira AH. Clinical, biochemical and molecular genetic features of Leber's hereditary optic neuropathy. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1410:147-58. [PMID: 10076023 DOI: 10.1016/s0005-2728(98)00163-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Leber's hereditary optic neuropathy (LHON) has traditionally been considered a disease causing severe and permanent visual loss in young adult males. In nearly all families with LHON it is associated with one of three pathogenic mitochondrial DNA (mtDNA) mutations, at bp 11778, 3460 or 14484. The availability of mtDNA confirmation of a diagnosis of LHON has demonstrated that LHON occurs with a wider range of age at onset and more commonly in females than previously recognised. In addition, analysis of patients grouped according to mtDNA mutation has demonstrated differences both in the clinical features of visual failure and in recurrence risks to relatives associated with each of the pathogenic mtDNA mutations. Whilst pathogenic mtDNA mutations are required for the development of LHON, other factors must be reponsible for the variable penetrance and male predominance of this condition. Available data on a number of hypotheses including the role of an additional X-linked visual loss susceptibility locus, impaired mitochondrial respiratory chain activity, mtDNA heteroplasmy, environmental factors and autoimmunity are discussed. Subacute visual failure is seen in association with all three pathogenic LHON mutations. However, the clinical and experimental data reviewed suggest differences in the phenotype associated with each of the three mutations which may reflect variation in the disease mechanisms resulting in this common end-point.
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Affiliation(s)
- R M Chalmers
- University Department of Clinical Neurosciences, Royal Free Hospital and University College Medical School of University College London, London NW3 2PF, UK
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41
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Howell N. Human mitochondrial diseases: answering questions and questioning answers. INTERNATIONAL REVIEW OF CYTOLOGY 1998; 186:49-116. [PMID: 9770297 DOI: 10.1016/s0074-7696(08)61051-7] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Since the first identification in 1988 of pathogenic mitochondrial DNA (mtDNA) mutations, the mitochondrial diseases have emerged as a major clinical entity. The most striking feature of these disorders is their marked heterogeneity, which extends to their clinical, biochemical, and genetic characteristics. The major mitochondrial encephalomyopathies include MELAS (mitochondrial encephalopathy with lactic acidosis and stroke-like episodes), MERRF (myoclonic epilepsy with ragged red fibers), KSS/CPEO (Kearns-Sayre syndrome/chronic progressive external ophthalmoplegia), and NARP/MILS (neuropathy, ataxia, and retinitis pigmentosum/maternally inherited Leigh syndrome) and they typically present highly variable multisystem defects that usually involve abnormalities of skeletal muscle and/or the CNS. The primary emphasis here is to review recent investigations of these mitochondrial diseases from the standpoint of how the complexities of mitochondrial genetics and biogenesis might determine their varied features. In addition, the mitochondrial encephalomyopathies are compared and contrasted to Leber hereditary optic neuropathy, a mitochondrial disease in which the pathogenic mtDNA mutations produce a more uniform and focal neuropathology. All of these disorders involve, at some level, a mitochondrial respiratory chain dysfunction. Because mitochondrial genetics differs so strikingly from the Mendelian inheritance of chromosomes, recent research on the origin and subsequent segregation and transmission of mtDNA mutations is reviewed.
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Affiliation(s)
- N Howell
- Department of Radiation Oncology, University of Texas Medical Branch, Galveston 77555, USA.
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Kato T, Winokur G, Coryell W, Rice J, Endicott J, Keller MB, Akiskal HS. Failure to demonstrate parent-of-origin effect in transmission of bipolar II disorder. J Affect Disord 1998; 50:135-41. [PMID: 9858073 DOI: 10.1016/s0165-0327(97)00102-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
BACKGROUND Parent-of-origin effect (POE) is suggested in transmission of bipolar disorder. Bipolar II disorder (BPII) should be considered separately. METHODS The gender difference of transmitting parents, prevalence rate in children, and age at onset of patients in relation to the sex of the transmitting parent, were examined in 220 BPII patients. RESULTS No evidence suggesting involvement of POE was found. CONCLUSION POE is not involved in transmission of BPII. LIMITATION Number of subjects is not sufficient. Rate of interviewed subjects differs between mothers and fathers. CLINICAL RELEVANCE Female BPII patients do not transmit the disease more often than male patients.
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Affiliation(s)
- T Kato
- Department of Psychiatry, University of Iowa College of Medicine, Iowa City 52242-1000, USA
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43
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Howell N. Leber hereditary optic neuropathy: respiratory chain dysfunction and degeneration of the optic nerve. Vision Res 1998; 38:1495-504. [PMID: 9667014 DOI: 10.1016/s0042-6989(97)00444-6] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Leber hereditary optic neuropathy (LHON) is an inherited form of bilateral optic atrophy in which the primary etiological event is a mutation in the mitochondrial genome. The optic neuropathy involves a loss of central vision due to degeneration of the retinal ganglion cells and optic nerve axons that subserve central vision. The primary mitochondrial mutation is necessary, but not sufficient, for manifestation of the optic neuropathy and secondary genetic and/or epigenetic risk factors are also involved, although they are poorly defined at the present time. There is broad agreement that mutations at nucleotides 3460, 11,778 and 14,484 are primary LHON mutations, but there may also be other rare primary mutations. It appears that the three primary LHON mutations are associated with respiratory chain dysfunction, but the derangement may be relatively subtle. There is also debate on whether there are mitochondrial mutations that have a secondary etiological or pathogenic role in LHON. The specific pattern of neurodegeneration in LHON may arise from a 'chokepoint' in the optic nerve in the region of the nerve head and lamina cribosa and which may be more severe in those LHON family members who become visually affected. It is hypothesized that the respiratory chain dysfunction leads to axoplasmic stasis and swelling, thereby blocking ganglion cell function and causing loss of vision. In some LHON patients, this loss of function is reversible in a substantial number of ganglion cells, but in others, a cell death pathway (probably apoptotic) is activated with subsequent extensive degeneration of the retinal ganglion cell layer and optic nerve.
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Affiliation(s)
- N Howell
- Department of Radiation Oncology, Department of Human Biological Chemistry and Genetics, University of Texas Medical Branch, Galveston 77555-0656, USA.
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44
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Abstract
A patient with Fuch's corneal dystrophy, sensorineural hearing loss, diabetes, cardiac conduction defects, ataxia, and hyperreflexia is described. Analysis of lymphocyte mitochondrial DNA showed missense mutations usually associated with Leber's hereditary optic neuropathy. The occurrence of Fuch's dystrophy in this patient and the biology of corneal endothelial cells suggest that mitochondrial defects could be the cause of Fuch's endothelial dystrophy.
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Affiliation(s)
- R L Albin
- Department of Neurology, University of Michigan Medical Center, Ann Arbor, USA
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45
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Howell N. Leber hereditary optic neuropathy: mitochondrial mutations and degeneration of the optic nerve. Vision Res 1997; 37:3495-507. [PMID: 9425526 DOI: 10.1016/s0042-6989(96)00167-8] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The predominant manifestation of Leber hereditary optic neuropathy (LHON) is a sudden and usually severe bilateral loss of central vision, most often in the mid-20s, that is due to a degeneration of the ganglion cell layer and optic nerve. LHON is an inherited form of blindness in which a mutation in the mitochondrial genome (mtDNA) is the primary etiological event. More than 95% of the LHON pedigrees in peoples of Northern European descent harbor one of the three mitochondrial mutations at nucleotides 3460, 11,778 and 14,484, although there are other rare primary mutations. In addition, there may be mtDNA mutations that have a secondary etiological role. The penetrance of the optic neuropathy is incomplete in LHON families, and males are affected much more often then females. The incomplete penetrance indicates that secondary etiological factors are necessary for the development of the optic neuropathy, although they are poorly understood at the present time. Several types of studies suggest that optic nerve function in LHON patients is impaired in the presymptomatic phase, probably as a result of a mitochondrial respiratory chain abnormality, although visual acuity is not compromised. In some family members, the presence of secondary etiological factors triggers a wave of optic nerve dysfunction in which vision is lost (the acute phase). Depending upon the particular primary LHON mutation that the patient carries, a variable proportion of the dysfunctional ganglion cells and optic nerve axons die during the atrophic phase, probably through an apoptotic pathway. In 11,778 LHON patients, retinal ganglion cell degeneration occurs almost without exception, and recovery of vision is extremely rare. In contrast, activation of the cell death pathway is less frequent, or less extensive, in 14,484 LHON patients and there is often a substantial recovery of vision.
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Affiliation(s)
- N Howell
- Department of Radiation Therapy, University of Texas Medical Branch, Galveston 77555-0656, USA
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46
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Kato T, Stine OC, McMahon FJ, Crowe RR. Increased levels of a mitochondrial DNA deletion in the brain of patients with bipolar disorder. Biol Psychiatry 1997; 42:871-5. [PMID: 9359971 DOI: 10.1016/s0006-3223(97)00012-7] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Mutations in mitochondrial DNA (mtDNA) have been implicated in the pathophysiology of affective disorders. To examine possible pathophysiological significance of mtDNA deletions in bipolar disorder, the concentration of the 4977-base-pair deletion in mtDNA in the autopsied brains of 7 patients with bipolar disorder, 9 suicide victims, and 9 controls was examined using a quantitative polymerase chain reaction method. The ratio of deleted to wild-type mtDNA in cerebral cortex was significantly higher in patients with bipolar disorder [0.23 +/- 0.18 (mean +/- SD)%] compared with that in age-matched controls (0.06 +/- 0.07%, p < 0.05). This result supports a hypothesis that mtDNA deletions may play a role in the pathophysiology of bipolar disorder.
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Affiliation(s)
- T Kato
- Department of Psychiatry, Shiga University of Medical Science, Otsu, Japan
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47
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Kato T, Winokur G, McMahon FJ, DePaulo JR, Crowe RR. Quantitative analysis of leukocyte mitochondrial DNA deletion in affective disorders. Biol Psychiatry 1997; 42:311-6. [PMID: 9276070 DOI: 10.1016/s0006-3223(96)00377-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Mutations in mitochondrial DNA (mtDNA) are implicated in the pathophysiology of affective disorders. To determine whether the 4977-base-pair deletion in mtDNA is more frequent in affective disorders, we quantitated the concentration of this deletion in leukocyte mtDNA in 34 probands with affective disorders (20 bipolar and 14 unipolar) and 20 controls. We found no significant difference in the quantitative ratio of deletion to wild-type mtDNA between patients and controls. One patient with unipolar depression and 1 of 2 patients previously reported as having a large quantity of the deleted mtDNA did have a markedly high ratio; however, the deletion did not segregate with the disease in these two families. These results do not support a hypothesis that the 4977-base-pair deletion plays an important role in the pathophysiology of affective disorders.
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Affiliation(s)
- T Kato
- Department of Psychiatry, Shiga University of Medical Science, Otsu, Japan
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Howell N. Leber hereditary optic neuropathy: how do mitochondrial DNA mutations cause degeneration of the optic nerve? J Bioenerg Biomembr 1997; 29:165-73. [PMID: 9239541 DOI: 10.1023/a:1022690030664] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Leber hereditary optic neuropathy (LHON) is an inherited form of bilateral optic atrophy in which the primary etiological event is a mutation in the mitochondrial genome. The optic neuropathy involves a loss of central vision due to degeneration of the retinal ganglion cells and optic nerve axons that subserve central vision. The primary mitochondrial mutation is necessary--but not sufficient--for development of the optic neuropathy, and secondary genetic and/or epigenetic risk factors must also be present although they are poorly defined at the present time. There is broad agreement that mutations at nucleotides 3460, 11778, and 14484 are primary LHON mutations, but there may also be other rare primary mutations. It appears that the three primary LHON mutations are associated with respiratory chain dysfunction, but the derangements may be relatively subtle. There is also debate on whether there are mitochondrial mutations that have a secondary etiological or pathogenic role in LHON. The specific pattern of the optic neuropathy may arise from a "chokepoint" in the optic nerve in the region of the nerve head and lamina cribosa, and which may be more severe in those LHON family members who become visually affected. It is hypothesized that the respiratory chain dysfunction leads to axoplasmic stasis and swelling, thereby blocking ganglion cell function and causing loss of vision. In some LHON patients, this loss of function is reversible in a substantial number of ganglion cells, but in others, a cell death pathway (probably apoptotic) is activated with subsequent extensive degeneration of the retinal ganglion cell layer and optic nerve.
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Affiliation(s)
- N Howell
- Department of Radiation Oncology, University of Texas Medical Branch, Galveston 77555, USA
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Kato T, Winokur G, Coryell W, Keller MB, Endicott J, Rice J. Parent-of-origin effect in transmission of bipolar disorder. AMERICAN JOURNAL OF MEDICAL GENETICS 1996; 67:546-50. [PMID: 8950412 DOI: 10.1002/(sici)1096-8628(19961122)67:6<546::aid-ajmg6>3.0.co;2-f] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Recently, possible involvement of a parent-of-origin effect in the transmission of bipolar disorder has been suggested. We examined the possible contribution of parent-of-origin effect by using data from a large family and family history study of bipolar patients in the Collaborative Depression Study. In 276 probands with bipolar I disorder, family histories were examined using three diagnostic criteria: 1) bipolar I disorder, 2) bipolar I or bipolar II disorder, and 3) bipolar disorders or recurrent unipolar depression for parents and siblings. An excess of affected mothers was not observed when unipolar depression was excluded. Age-at-onset was significantly lower in probands having a father with bipolar disorders or recurrent unipolar depression than in probands with an affected mother. This difference was not observed when unipolar depression was excluded. There was no significant difference of prevalence rate in children of affected mothers and those with affected fathers. These data do not support the contribution of parent-of-origin effect in the transmission of bipolar disorder.
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Affiliation(s)
- T Kato
- Department of Psychiatry, University of Iowa College of Medicine, Iowa City, USA
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Jun AS, Trounce IA, Brown MD, Shoffner JM, Wallace DC. Use of transmitochondrial cybrids to assign a complex I defect to the mitochondrial DNA-encoded NADH dehydrogenase subunit 6 gene mutation at nucleotide pair 14459 that causes Leber hereditary optic neuropathy and dystonia. Mol Cell Biol 1996; 16:771-7. [PMID: 8622678 PMCID: PMC231057 DOI: 10.1128/mcb.16.3.771] [Citation(s) in RCA: 128] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
A heteroplasmic G-to-A transition at nucleotide pair (np) 14459 within the mitochondrial DNA (mtDNA)-encoded NADH dehydrogenase subunit 6 (ND6) gene has been identified as the cause of Leber hereditary optic neuropathy (LHON) and/or pediatric-onset dystonia in three unrelated families. This ND6 np 14459 mutation changes a moderately conserved alanine to a valine at amino acid position 72 of the ND6 protein. Enzymologic analysis of mitochondrial NADH dehydrogenase (complex I) with submitochondrial particles isolated from Epstein-Barr virus-transformed lymphoblasts revealed a 60% reduction (P < 0.005) of complex I-specific activity in patient cell lines compared with controls, with no differences in enzymatic activity for complexes II plus III, III and IV. This biochemical defect was assigned to the ND6 np 14459 mutation by using transmitochondrial cybrids in which patient Epstein-Barr virus-transformed lymphoblast cell lines were enucleated and the cytoplasts were fused to a mtDNA-deficient (p 0) lymphoblastoid recipient cell line. Cybrids harboring the np 14459 mutation exhibited a 39% reduction (p < 0.02) in complex I-specific activity relative to wild-type cybrid lines but normal activity for the other complexes. Kinetic analysis of the np 14459 mutant complex I revealed that the Vmax of the enzyme was reduced while the Km remained the same as that of wild type. Furthermore, specific activity was inhibited by increasing concentrations of the reduced coenzyme Q analog decylubiquinol. These observations suggest that the np 14459 mutation may alter the coenzyme Q-binding site of complex I.
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Affiliation(s)
- A S Jun
- Department of Genetics and Molecular Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
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