1
|
Handzic A, Xie JS, Margolin EA. Diagnostic Yield of Investigations in Symmetric Optic Neuropathy. J Neuroophthalmol 2024; 44:365-370. [PMID: 37616072 DOI: 10.1097/wno.0000000000001947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
BACKGROUND Symmetric optic neuropathy (SON) is commonly seen in neuro-ophthalmic practice and is often discovered incidentally. Although multiple investigations might be performed to discover the underlying cause, they are not always indicated. The aim of this study was to report a clinically reasonable and cost-effective approach to investigating patients with SON. METHODS SON was defined as bilateral optic neuropathy with normal and/or symmetrically decreased central visual acuity, absence of relative afferent pupillary defect, presence of symmetric optic disc pallor, symmetric thinning of peripapillary retinal nerve fiber layer on optical coherence tomography, and absence of other identifiable causes of optic neuropathy. Records of all patients diagnosed with SON seen at a tertiary university-affiliated neuro-ophthalmology practice from 2016 to 2022 were reviewed to identify the yield of various investigations. Clinical data from the initial and last follow-up visit were obtained. Subgroup analysis was performed to ascertain whether diagnostic yield is higher in patients with severe visual loss (central acuity worse than 20/40) compared with those with mild visual loss (acuity 20/40 or better). RESULTS One hundred thirty-six patients met inclusion criteria. Testing for OPA1 and OPA2 mutations had the highest diagnostic yield (16.0%), followed by mitochondrial genome sequencing (13.6%), serum vitamin B12 (6.1%), and serum folate (1.6%). MRI brain was performed in 54.4% of patients and had a diagnostic yield of only 5%. Both patients who had abnormal MRI had symptoms of demyelination at presentation. Patients were followed for a mean of 15.0 (SD 21.3) months. The most frequently identified etiologies of SON were Leber hereditary optic neuropathy (8.1%), alcohol/tobacco amblyopia (7.4%), vitamin B12 deficiency (5.9%), and dominant optic atrophy (2.9%). Patients with severe visual impairment were more likely to have a final diagnosis compared with those with milder visual impairment (63.9% vs 12.0%, P < 0.001). CONCLUSIONS The diagnostic yield of investigating SON in patients with preserved visual function, normal diet, and absence of other neurological symptoms is very low. It is reasonable to observe patients with SON with mild visual impairment, reserving costly investigations for those with the visual acuity worse than 20/40 or progressive course.
Collapse
Affiliation(s)
- Armin Handzic
- Department of Ophthalmology and Vision Sciences (AH, EAM), Faculty of Medicine, University of Toronto, Toronto, Canada; Michael G. DeGroote School of Medicine (JSX), McMaster University, Hamilton, Canada; and Division of Neurology (EAM), Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Canada
| | | | | |
Collapse
|
2
|
Pohl KA, Zhang X, Pham AH, Chan JW, Sadun AA, Yang XJ. Establishing induced pluripotent stem cell lines from two dominant optic atrophy patients with distinct OPA1 mutations and clinical pathologies. Front Genet 2023; 14:1251216. [PMID: 37745862 PMCID: PMC10513078 DOI: 10.3389/fgene.2023.1251216] [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: 07/01/2023] [Accepted: 08/17/2023] [Indexed: 09/26/2023] Open
Abstract
Dominant optic atrophy (DOA) is an inherited disease that leads to the loss of retinal ganglion cells (RGCs), the projection neurons that relay visual information from the retina to the brain through the optic nerve. The majority of DOA cases can be attributed to mutations in optic atrophy 1 (OPA1), a nuclear gene encoding a mitochondrial-targeted protein that plays important roles in maintaining mitochondrial structure, dynamics, and bioenergetics. Although OPA1 is ubiquitously expressed in all human tissues, RGCs appear to be the primary cell type affected by OPA1 mutations. DOA has not been extensively studied in human RGCs due to the general unavailability of retinal tissues. However, recent advances in stem cell biology have made it possible to produce human RGCs from pluripotent stem cells (PSCs). To aid in establishing DOA disease models based on human PSC-derived RGCs, we have generated iPSC lines from two DOA patients who carry distinct OPA1 mutations and present very different disease symptoms. Studies using these OPA1 mutant RGCs can be correlated with clinical features in the patients to provide insights into DOA disease mechanisms.
Collapse
Affiliation(s)
- Katherine A. Pohl
- Department of Ophthalmology, Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA, United States
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Xiangmei Zhang
- Department of Ophthalmology, Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Anh H. Pham
- Department of Ophthalmology, Doheny Eye Institute, University of California, Los Angeles, Pasadena, CA, United States
| | - Jane W. Chan
- Department of Ophthalmology, Doheny Eye Institute, University of California, Los Angeles, Pasadena, CA, United States
| | - Alfredo A. Sadun
- Department of Ophthalmology, Doheny Eye Institute, University of California, Los Angeles, Pasadena, CA, United States
| | - Xian-Jie Yang
- Department of Ophthalmology, Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA, United States
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, United States
| |
Collapse
|
3
|
Brodsky MC, Olson RJ, Asumda FZ, Lopour MQ, Schimmenti LA, Klee EW. Identification of AFG3L2 dominant optic atrophy following reanalysis of clinical exome sequencing. Am J Ophthalmol Case Rep 2023; 30:101825. [PMID: 36974169 PMCID: PMC10038781 DOI: 10.1016/j.ajoc.2023.101825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Revised: 02/09/2023] [Accepted: 02/24/2023] [Indexed: 03/11/2023] Open
Abstract
Purpose To highlight the importance of the utility of clinical exome sequencing, and show how it led to the diagnosis of nonsyndromic autosomal dominant optic atrophy arising from an autosomal dominant variant in AFG3L2. Observations A healthy father and daughter of East African heritage experienced the onset of vision loss in the first decade of life due to optic atrophy. No additional neurologic or neuroimaging abnormalities were detected. Clinical exome sequencing was initially performed and provided a negative result. Reanalysis of the sequencing data revealed an autosomal dominant pathogenic variant in AFG3L2, c.1064C>T (p.Thr355Met), a gene that was recently identified to be associated with non-syndromic optic atrophy. This variant has previously been reported in a patient with optic atrophy, motor disturbances, and an abnormal brain MRI. Conclusions As the causes of dominant optic atrophy continue to expand, accurate genetic diagnosis is aided by an iterative reanalysis process for individuals and families when initial exome and genome testing does not provide an answer.
Collapse
Affiliation(s)
- Michael C. Brodsky
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, United States
- Department of Neurology, Mayo Clinic, Rochester, MN, United States
- Corresponding author. Mayo Clinic, Department of Ophthalmology, 200 First St SW, Rochester, MN, 55905, United States.
| | - Rory J. Olson
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, United States
| | - Faizal Z. Asumda
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, United States
- Department of Pediatrics, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | | | - Lisa A. Schimmenti
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, United States
- Department of Otorhinolaryngology, Mayo Clinic, Rochester, MN, United States
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, United States
| | - Eric W. Klee
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, United States
| |
Collapse
|
4
|
Eliseeva DD, Kalashnikova AK, Bryukhov VV, Andreeva NA, Zhorzholadze NV, Murakhovskaya YK, Krilova TD, Tsygankova PG, Zakharova MN, Sheremet NL. [Hereditary optic neuropathy associated with demyelinating diseases of the central nervous system]. Zh Nevrol Psikhiatr Im S S Korsakova 2023; 123:122-132. [PMID: 37560844 DOI: 10.17116/jnevro2023123072122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/11/2023]
Abstract
Demyelinating optic neuritis and hereditary optic neuropathy (HON) take a leading place among the diseases, the leading clinical syndrome of which is bilateral optic neuropathy with a simultaneous or sequential significant decrease in visual acuity. Optic neuritis can occur at the onset or be one of the syndromes within multiple sclerosis (MS), neuromyelitis optica spectrum disorders (NMOSD), and myelin oligodendrocyte glycoprotein (MOG) antibody disease (MOGAD). HON are a group of neurodegenerative diseases, among which the most common variants are Leber's hereditary optic neuropathy (LHON), associated with mitochondrial DNA (mtDNA) mutations, and autosomal recessive optic neuropathy (ARON), caused by nuclear DNA (nDNA) mutations in DNAJC30. There are phenotypes of LHON «plus», one of which is the association of HON and CNS demyelination in the same patient. In such cases, the diagnosis of each of these diseases causes significant difficulties, due to the fact that in some cases there are clinical and radiological coincidences between demyelinating and hereditary mitochondrial diseases.
Collapse
Affiliation(s)
| | - A K Kalashnikova
- Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | | | - N A Andreeva
- Research Institute of Eye Diseases, Moscow, Russia
| | | | | | - T D Krilova
- Research Centre for Medical Genetics, Moscow, Russia
| | | | | | - N L Sheremet
- Research Institute of Eye Diseases, Moscow, Russia
| |
Collapse
|
5
|
Chekuri A, Logan EM, Krauson AJ, Salani M, Ackerman S, Kirchner EG, Bolduc JM, Wang X, Dietrich P, Dragatsis I, Vandenberghe LH, Slaugenhaupt SA, Morini E. Selective retinal ganglion cell loss and optic neuropathy in a humanized mouse model of familial dysautonomia. Hum Mol Genet 2022; 31:1776-1787. [PMID: 34908112 PMCID: PMC9169455 DOI: 10.1093/hmg/ddab359] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 12/09/2021] [Accepted: 12/10/2021] [Indexed: 11/21/2022] Open
Abstract
Familial dysautonomia (FD) is an autosomal recessive neurodegenerative disease caused by a splicing mutation in the gene encoding Elongator complex protein 1 (ELP1, also known as IKBKAP). This mutation results in tissue-specific skipping of exon 20 with a corresponding reduction of ELP1 protein, predominantly in the central and peripheral nervous system. Although FD patients have a complex neurological phenotype caused by continuous depletion of sensory and autonomic neurons, progressive visual decline leading to blindness is one of the most problematic aspects of the disease, as it severely affects their quality of life. To better understand the disease mechanism as well as to test the in vivo efficacy of targeted therapies for FD, we have recently generated a novel phenotypic mouse model, TgFD9; IkbkapΔ20/flox. This mouse exhibits most of the clinical features of the disease and accurately recapitulates the tissue-specific splicing defect observed in FD patients. Driven by the dire need to develop therapies targeting retinal degeneration in FD, herein, we comprehensively characterized the progression of the retinal phenotype in this mouse, and we demonstrated that it is possible to correct ELP1 splicing defect in the retina using the splicing modulator compound (SMC) BPN-15477.
Collapse
Affiliation(s)
- Anil Chekuri
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
- Department of Neurology, Massachusetts General Hospital Research Institute and Harvard Medical School, Boston, MA, USA
- Grousbeck Gene Therapy Center, Schepens Eye Research Institute and Massachusetts Eye and Ear Infirmary, Boston, MA, USA
| | - Emily M Logan
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Aram J Krauson
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Monica Salani
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Sophie Ackerman
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Emily G Kirchner
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Jessica M Bolduc
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Xia Wang
- Grousbeck Gene Therapy Center, Schepens Eye Research Institute and Massachusetts Eye and Ear Infirmary, Boston, MA, USA
| | - Paula Dietrich
- Department of Physiology, The University of Tennessee, Health Science Center, Memphis, TN, USA
| | - Ioannis Dragatsis
- Department of Physiology, The University of Tennessee, Health Science Center, Memphis, TN, USA
| | - Luk H Vandenberghe
- Grousbeck Gene Therapy Center, Schepens Eye Research Institute and Massachusetts Eye and Ear Infirmary, Boston, MA, USA
| | - Susan A Slaugenhaupt
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
- Department of Neurology, Massachusetts General Hospital Research Institute and Harvard Medical School, Boston, MA, USA
| | - Elisabetta Morini
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
- Department of Neurology, Massachusetts General Hospital Research Institute and Harvard Medical School, Boston, MA, USA
| |
Collapse
|
6
|
First Description of Inheritance of a Postzygotic OPA1 Mosaic Variant. Genes (Basel) 2022; 13:genes13030478. [PMID: 35328032 PMCID: PMC8948733 DOI: 10.3390/genes13030478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 02/08/2022] [Accepted: 03/04/2022] [Indexed: 12/02/2022] Open
Abstract
Optic atrophy 1 (MIM #165500) is caused by pathogenic variants in the gene OPA1 (OPA1 MITOCHONDRIAL DYNAMIN-LIKE GTPase, MIM *605290) and is inherited in an autosomal dominant manner. We describe a 6-year-old male patient with severe early onset manifestation of optic atrophy, whose parents are subjectively asymptomatic. OPA1-sequence analysis revealed the heterozygous missense variant NM_015560.3:c.806C>T, p.(Ser269Phe) in the patient. Segregation analysis of the parents showed that the mother carried a low-grade postzygotic mosaic of this variant, which apparently also involves germline cells. In line with this, ophthalmological investigation of the mother showed subclinical manifestation of optic atrophy 1. This is the first report of an OPA1 postzygotic mosaic that was inherited to offspring.
Collapse
|
7
|
Milanowski P, Kosior-Jarecka E, Łukasik U, Wróbel-Dudzińska D, Milanowska J, Khor CC, Aung T, Kocki J, Żarnowski T. Associations between OPA1, MFN1, and MFN2 polymorphisms and primary open angle glaucoma in Polish participants of European ancestry. Ophthalmic Genet 2021; 43:42-47. [PMID: 34425738 DOI: 10.1080/13816810.2021.1970197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
BACKGROUND Glaucomatous optic nerve damage is caused by selective death of retinal ganglion cells (RGCs). Another condition with underlying loss of RGCs is autosomal dominant optic atrophy (ADOA). Majority of ADOA patients have mutations in OPA1, gene responsible for mitochondrial fusion final steps. Clinical resemblance between the two diseases make genes involved in mitochondrial fusion good candidates as glaucoma genes. In this study, we investigated if selected polymorphisms of OPA1, MFN1, and MFN2 were associated with glaucoma in Polish population. METHODS Four OPA1 (rs166850, rs10451941, rs7624750, rs9851685), one MFN1 (rs2111534), and two MFN2 (rs873458, rs2295281) single nucleotide polymorphisms were investigated in 304 primary open angle glaucoma patients (204 with normal tension glaucoma, 100 with high-tension glaucoma) and 258 control subjects using RT-PCR method. RESULTS There was a significant difference in genotype frequencies of rs9851685 and rs2111534 polymorphisms between glaucoma patients and control subjects. Several genotype combinations comprising SNPs at OPA1 and MFN1 were significantly differently distributed in a three-way comparison between controls, patients with NTG and patients with HTG. None of the studied MFN2 polymorphisms was significantly associated with HTG or NTG. CONCLUSIONS In studied population, genotype CC and allele C of rs9851685 OPA1 polymorphism are NTG risk factors, whereas TT genotype and T allele of this polymorphism are protective factors against NTG. Genotype GA of rs2111534 MFN1 polymorphism is an HTG risk factor and AA genotype of this polymorphism is a protective factor against HTG. Several OPA1 and MFN2 genotype combinations are significantly associated with either increased or decreased risk of glaucoma in this population.
Collapse
Affiliation(s)
- Piotr Milanowski
- Department of Diagnostics and Microsurgery of Glaucoma, Medical University of Lublin, Lublin, Poland
| | - Ewa Kosior-Jarecka
- Department of Diagnostics and Microsurgery of Glaucoma, Medical University of Lublin, Lublin, Poland
| | - Urszula Łukasik
- Department of Diagnostics and Microsurgery of Glaucoma, Medical University of Lublin, Lublin, Poland
| | - Dominika Wróbel-Dudzińska
- Department of Diagnostics and Microsurgery of Glaucoma, Medical University of Lublin, Lublin, Poland
| | - Joanna Milanowska
- Department of Applied Psychology, Medical University of Lublin, Lublin, Poland
| | - Chiea Chuen Khor
- Laboratory of Complex Disease Genetics, Genome Institute of Singapore, Singapore
| | - Tin Aung
- Singapore Eye Research Institute, Singapore National Eye Center, Singapore
| | - Janusz Kocki
- Department of Clinical Genetics, Medical University of Lublin, Lublin, Poland
| | - Tomasz Żarnowski
- Department of Diagnostics and Microsurgery of Glaucoma, Medical University of Lublin, Lublin, Poland
| |
Collapse
|
8
|
Kim GN, Kim JA, Kim MJ, Lee EJ, Hwang JM, Kim TW. Comparison of Lamina Cribrosa Morphology in Normal Tension Glaucoma and Autosomal-Dominant Optic Atrophy. Invest Ophthalmol Vis Sci 2020; 61:9. [PMID: 32392317 PMCID: PMC7405716 DOI: 10.1167/iovs.61.5.9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Purpose To compare lamina cribrosa (LC) morphology in patients with normal tension glaucoma (NTG) and autosomal-dominant optic atrophy (ADOA). Methods This cross-sectional study matched 24 patients diagnosed with ADOA (24 eyes) by age and retinal nerve fiber layer thickness with 48 patients diagnosed with NTG (48 eyes) by age with 48 healthy controls (48 eyes). Optic nerve heads were scanned by enhanced-depth imaging (EDI) optical coherence tomography (OCT). The LC curvature index (LCCI) and LC depth (LCD) on B-scan images obtained using EDI-OCT were measured at seven locations spaced equidistantly across the vertical optic disc diameter and compared among the NTG, ADOA, and control groups. Results Mean LCCI and LCD were significantly greater in NTG than in ADOA and healthy eyes (P < 0.001 each) but did not differ significantly in ADOA and healthy eyes. Conclusions NTG eyes have a more posteriorly curved and deeper LC than ADOA and healthy eyes. This finding provides insight into the role of LC morphology in NTG and provides a clinical clue to distinguish between NTG and ADOA.
Collapse
|
9
|
Du R, Wang X, He S. BDNF improves axon transportation and rescues visual function in a rodent model of acute elevation of intraocular pressure. SCIENCE CHINA-LIFE SCIENCES 2020; 63:1337-1346. [PMID: 32201927 DOI: 10.1007/s11427-019-1567-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 09/28/2019] [Indexed: 12/12/2022]
Abstract
Optic neuropathies lead to blindness; the common pathology is the degeneration of axons of the retinal ganglion cells. In this study, we used a rat model of retinal ischemia-reperfusion and a one-time intravitreal brain-derived neurotrophic factor (BDNF) injection; then we examined axon transportation function, continuity, physical presence of axons in different part of the optic nerve, and the expression level of proteins involved in axon transportation. We found that in the disease model, axon transportation was the most severely affected, followed by axon continuity, then the number of axons in the distal and proximal optic nerve. BDNF treatment relieved all reductions and significantly restored function. The molecular changes were more minor, probably due to massive gliosis of the optic nerve, so interpretation of protein expression data should be done with some caution. The process in this acute model resembles a fast-forward of changes in the chronic model of glaucoma. Therefore, impairment in axon transportation appears to be a common early process underlying different optic neuropathies. This research on effective intervention can be used to develop interventions for all optic neuropathies targeting axon transportation.
Collapse
Affiliation(s)
- Rui Du
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xu Wang
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Shigang He
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China. .,Institute of Natural Sciences, Shanghai Jiao Tong University, Shanghai, 200240, China. .,Bio-X Institute, Shanghai Jiao Tong University, Shanghai, 200240, China.
| |
Collapse
|
10
|
Le Roux B, Lenaers G, Zanlonghi X, Amati-Bonneau P, Chabrun F, Foulonneau T, Caignard A, Leruez S, Gohier P, Procaccio V, Milea D, den Dunnen JT, Reynier P, Ferré M. OPA1: 516 unique variants and 831 patients registered in an updated centralized Variome database. Orphanet J Rare Dis 2019; 14:214. [PMID: 31500643 PMCID: PMC6734442 DOI: 10.1186/s13023-019-1187-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 08/30/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The dysfunction of OPA1, a dynamin GTPase involved in mitochondrial fusion, is responsible for a large spectrum of neurological disorders, each of which includes optic neuropathy. The database dedicated to OPA1 ( https://www.lovd.nl/OPA1 ), created in 2005, has now evolved towards a centralized and more reliable database using the Global Variome shared Leiden Open-source Variation Database (LOVD) installation. RESULTS The updated OPA1 database, which registers all the patients from our center as well as those reported in the literature, now covers a total of 831 patients: 697 with isolated dominant optic atrophy (DOA), 47 with DOA "plus", and 83 with asymptomatic or unclassified DOA. It comprises 516 unique OPA1 variants, of which more than 80% (414) are considered pathogenic. Full clinical data for 118 patients are documented using the Human Phenotype Ontology, a standard vocabulary for referencing phenotypic abnormalities. Contributors may now make online submissions of phenotypes related to OPA1 mutations, giving clinical and molecular descriptions together with detailed ophthalmological and neurological data, according to an international thesaurus. CONCLUSIONS The evolution of the OPA1 database towards the LOVD, using unified nomenclature, should ensure its interoperability with other databases and prove useful for molecular diagnoses based on gene-panel sequencing, large-scale mutation statistics, and genotype-phenotype correlations.
Collapse
Affiliation(s)
- Bastien Le Roux
- Département d'Ophtalmologie, Centre Hospitalier Universitaire d'Angers, Angers, France
| | - Guy Lenaers
- Unité Mixte de Recherche MITOVASC, CNRS 6015/INSERM 1083, Université d'Angers, Angers, France
| | - Xavier Zanlonghi
- Centre de Compétence Maladie Rare, Clinique Jules Verne, Nantes, France
| | - Patrizia Amati-Bonneau
- Unité Mixte de Recherche MITOVASC, CNRS 6015/INSERM 1083, Université d'Angers, Angers, France.,Département de Biochimie et Génétique, Centre Hospitalier Universitaire d'Angers, Angers, France
| | - Floris Chabrun
- Unité Mixte de Recherche MITOVASC, CNRS 6015/INSERM 1083, Université d'Angers, Angers, France.,Département de Biochimie et Génétique, Centre Hospitalier Universitaire d'Angers, Angers, France
| | - Thomas Foulonneau
- Unité Mixte de Recherche MITOVASC, CNRS 6015/INSERM 1083, Université d'Angers, Angers, France
| | - Angélique Caignard
- Département d'Ophtalmologie, Centre Hospitalier Universitaire d'Angers, Angers, France
| | - Stéphanie Leruez
- Département d'Ophtalmologie, Centre Hospitalier Universitaire d'Angers, Angers, France
| | - Philippe Gohier
- Département d'Ophtalmologie, Centre Hospitalier Universitaire d'Angers, Angers, France
| | - Vincent Procaccio
- Unité Mixte de Recherche MITOVASC, CNRS 6015/INSERM 1083, Université d'Angers, Angers, France.,Département de Biochimie et Génétique, Centre Hospitalier Universitaire d'Angers, Angers, France
| | - Dan Milea
- Singapore National Eye Center, Singapore Eye Research Institute, Duke-NUS, Singapore, Singapore
| | - Johan T den Dunnen
- Human Genetics and Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Pascal Reynier
- Unité Mixte de Recherche MITOVASC, CNRS 6015/INSERM 1083, Université d'Angers, Angers, France.,Département de Biochimie et Génétique, Centre Hospitalier Universitaire d'Angers, Angers, France
| | - Marc Ferré
- Unité Mixte de Recherche MITOVASC, CNRS 6015/INSERM 1083, Université d'Angers, Angers, France.
| |
Collapse
|
11
|
|
12
|
Li H, Jones EM, Li H, Yang L, Sun Z, Yuan Z, Chen R, Dong F, Sui R. Clinical and genetic features of eight Chinese autosomal-dominant optic atrophy pedigrees with six novel OPA1 pathogenic variants. Ophthalmic Genet 2018; 39:569-576. [PMID: 29952689 DOI: 10.1080/13816810.2018.1466337] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
BACKGROUND Autosomal-dominant optic atrophy (ADOA) is one of the most common types of inherited optic atrophy. We identify OPA1 pathogenic variants and assess the clinical features of a cohort of Chinese ADOA patients Materials and Methods: Detailed clinical evaluations were performed and genomic DNA was extracted from peripheral blood for all the participants. Sanger sequencing was used to analyze all exons and exon/intron junctions of OPA1 for eight pedigrees. Target exome capture plus next-generation sequencing (NGS) were applied for one atypical family with photophobia. Reverse transcription polymerase chain reaction was carried out to further characterize the mRNA change of selected splicing alteration. RESULTS All 17 patients had impaired vision and optic-disk pallor; however, the clinical severity varied markedly. Two patients complicated with hearing loss. Six novel and two reported pathogenic variants in OPA1 (GenBank Accession No. NM_130837.2) were identified including four nonsynonymous variants (c.2400T > G, c.1468T > C, c.1567A > G and c.1466T > C), two splicing variants (c.2984-1_2986delGAGA and c.2983 + 5G > A), one small deletion (c.2960_2968delGCGTTCAAC), and one small insertion (c.3009_3010insA). RNA analysis revealed the splicing variant c.2984-1_2986delGAGA caused small deletion of mRNA (r.2983_2988del). CONCLUSIONS ADOA patients presented variable clinical manifestations. Novel OPA1 pathogenic variants are the main genetic defect for Chinese ADOA cases. NGS may be a useful molecular testing tool for atypical ADOA.
Collapse
Affiliation(s)
- Huajin Li
- a Department of Ophthalmology , Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences , Beijing , China
| | - Evan M Jones
- b Department of Molecular and Human Genetics , Baylor College of Medicine , Houston , TX , USA
| | - Hui Li
- a Department of Ophthalmology , Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences , Beijing , China
| | - Lizhu Yang
- a Department of Ophthalmology , Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences , Beijing , China
| | - Zixi Sun
- a Department of Ophthalmology , Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences , Beijing , China
| | - Zhisheng Yuan
- a Department of Ophthalmology , Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences , Beijing , China
| | - Rui Chen
- b Department of Molecular and Human Genetics , Baylor College of Medicine , Houston , TX , USA
| | - Fangtian Dong
- a Department of Ophthalmology , Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences , Beijing , China
| | - Ruifang Sui
- a Department of Ophthalmology , Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences , Beijing , China
| |
Collapse
|
13
|
Zorzano A, Claret M. Implications of mitochondrial dynamics on neurodegeneration and on hypothalamic dysfunction. Front Aging Neurosci 2015; 7:101. [PMID: 26113818 PMCID: PMC4461829 DOI: 10.3389/fnagi.2015.00101] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 05/11/2015] [Indexed: 01/10/2023] Open
Abstract
Mitochondrial dynamics is a term that encompasses the movement of mitochondria along the cytoskeleton, regulation of their architecture, and connectivity mediated by tethering and fusion/fission. The importance of these events in cell physiology and pathology has been partially unraveled with the identification of the genes responsible for the catalysis of mitochondrial fusion and fission. Mutations in two mitochondrial fusion genes (MFN2 and OPA1) cause neurodegenerative diseases, namely Charcot-Marie Tooth type 2A and autosomal dominant optic atrophy (ADOA). Alterations in mitochondrial dynamics may be involved in the pathophysiology of prevalent neurodegenerative conditions. Moreover, impairment of the activity of mitochondrial fusion proteins dysregulates the function of hypothalamic neurons, leading to alterations in food intake and in energy homeostasis. Here we review selected findings in the field of mitochondrial dynamics and their relevance for neurodegeneration and hypothalamic dysfunction.
Collapse
Affiliation(s)
- Antonio Zorzano
- Molecular Medicine Program, Institute of Research in Biomedicine (IRB Barcelona) Barcelona, Spain ; Departament de Bioquímica i Biologia Molecular, Facultat de Biologia, Universitat de Barcelona Barcelona, Spain ; CIBER de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III Barcelona, Spain
| | - Marc Claret
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III Barcelona, Spain ; Diabetes and Obesity Research Laboratory, Institut d'Investigacions Biomèdiques August Pi i Sunyer Barcelona, Spain
| |
Collapse
|
14
|
Roubertie A, Leboucq N, Picot MC, Nogue E, Brunel H, Le Bars E, Manes G, Angebault Prouteau C, Blanchet C, Mondain M, Chevassus H, Amati-Bonneau P, Sarzi E, Pagès M, Villain M, Meunier I, Lenaers G, Hamel CP. Neuroradiological findings expand the phenotype of OPA1-related mitochondrial dysfunction. J Neurol Sci 2015; 349:154-60. [PMID: 25641387 DOI: 10.1016/j.jns.2015.01.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 12/31/2014] [Accepted: 01/05/2015] [Indexed: 11/26/2022]
Abstract
OBJECTIVE OPA1 mutations are responsible for more than half of autosomal dominant optic atrophy (ADOA), a blinding disease affecting the retinal ganglion neurons. In most patients the clinical presentation is restricted to the optic nerve degeneration, albeit in 20% of them, additional neuro-sensorial symptoms might be associated to the loss of vision, as frequently encountered in mitochondrial diseases. This study describes clinical and neuroradiological features of OPA1 patients. METHODS Twenty two patients from 17 families with decreased visual acuity related to optic atrophy and carrying an OPA1 mutation were enrolled. Patients underwent neuro-ophthalmological examinations. Brain magnetic resonance imaging (T1, T2 and flair sequences) was performed on a 1.5-Tesla MR Unit. Twenty patients underwent 2-D proton spectroscopic imaging. RESULTS Brain imaging disclosed abnormalities in 12 patients. Cerebellar atrophy mainly involving the vermis was observed in almost a quarter of the patients; other abnormalities included unspecific white matter hypersignal, hemispheric cortical atrophy, and lactate peak. Neurological examination disclosed one patient with a transient right hand motor deficit and ENT examination revealed hearing impairment in 6 patients. Patients with abnormal MRI were characterized by: (i) an older age (ii) more severe visual impairment with chronic visual acuity deterioration, and (iii) more frequent associated deafness. CONCLUSIONS Our results demonstrate that brain imaging abnormalities are common in OPA1 patients, even in those with normal neurological examination. Lactate peak, cerebellar and cortical atrophies are consistent with the mitochondrial dysfunction related to OPA1 mutations and might result from widespread neuronal degeneration.
Collapse
Affiliation(s)
- Agathe Roubertie
- CHU Montpellier, Department of Pediatric Neurology, Gui de Chauliac Hospital, Montpellier, France; INSERM, U-1051, Institut des Neurosciences, Montpellier, France.
| | - Nicolas Leboucq
- CHU Montpellier, Department of Neuroradiology, Montpellier, France; CHU Montpellier, Institut d'Imagerie Fonctionnelle Humaine, Montpellier, France
| | - Marie Christine Picot
- CHU Montpellier, Centre d'Investigation Clinique, Montpellier, France INSERM, CIC 1411, Montpellier, France
| | - Erika Nogue
- CHU Montpellier, Centre d'Investigation Clinique, Montpellier, France INSERM, CIC 1411, Montpellier, France
| | - Hervé Brunel
- CHU Montpellier, Department of Neuroradiology, Montpellier, France
| | - Emmanuelle Le Bars
- CHU Montpellier, Department of Neuroradiology, Montpellier, France; CHU Montpellier, Institut d'Imagerie Fonctionnelle Humaine, Montpellier, France
| | - Gael Manes
- INSERM, U-1051, Institut des Neurosciences, Montpellier, France
| | | | | | | | - Hugues Chevassus
- CHU Montpellier, Centre d'Investigation Clinique, Montpellier, France INSERM, CIC 1411, Montpellier, France
| | | | | | - Michel Pagès
- CHU Montpellier, Department of Neurology, Montpellier, France
| | - Max Villain
- CHU Montpellier, Centre of Reference for Genetic Sensory Diseases, Montpellier, France
| | - Isabelle Meunier
- INSERM, U-1051, Institut des Neurosciences, Montpellier, France; CHU Montpellier, Centre of Reference for Genetic Sensory Diseases, Montpellier, France
| | - Guy Lenaers
- INSERM, U-1051, Institut des Neurosciences, Montpellier, France
| | - Christian P Hamel
- INSERM, U-1051, Institut des Neurosciences, Montpellier, France; CHU Montpellier, Centre of Reference for Genetic Sensory Diseases, Montpellier, France
| |
Collapse
|
15
|
Ferré M, Caignard A, Milea D, Leruez S, Cassereau J, Chevrollier A, Amati-Bonneau P, Verny C, Bonneau D, Procaccio V, Reynier P. Improved Locus-Specific Database forOPA1Mutations Allows Inclusion of Advanced Clinical Data. Hum Mutat 2014; 36:20-5. [DOI: 10.1002/humu.22703] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 09/12/2014] [Indexed: 11/09/2022]
Affiliation(s)
- Marc Ferré
- CNRS 6214/INSERM 1083; Angers University; Angers France
- Department of Biochemistry and Genetics; University Hospital; Angers France
| | - Angélique Caignard
- CNRS 6214/INSERM 1083; Angers University; Angers France
- Department of Ophthalmology; University Hospital; Angers France
| | - Dan Milea
- CNRS 6214/INSERM 1083; Angers University; Angers France
- Department of Ophthalmology; University Hospital; Angers France
- Singapore National Eye Centre, Singapore Eye Research Institute; Duke-NUS Singapore
| | - Stéphanie Leruez
- CNRS 6214/INSERM 1083; Angers University; Angers France
- Department of Ophthalmology; University Hospital; Angers France
| | - Julien Cassereau
- CNRS 6214/INSERM 1083; Angers University; Angers France
- Department of Neurology; University Hospital; Angers France
| | | | - Patrizia Amati-Bonneau
- CNRS 6214/INSERM 1083; Angers University; Angers France
- Department of Biochemistry and Genetics; University Hospital; Angers France
| | - Christophe Verny
- CNRS 6214/INSERM 1083; Angers University; Angers France
- Department of Neurology; University Hospital; Angers France
| | - Dominique Bonneau
- CNRS 6214/INSERM 1083; Angers University; Angers France
- Department of Biochemistry and Genetics; University Hospital; Angers France
| | - Vincent Procaccio
- CNRS 6214/INSERM 1083; Angers University; Angers France
- Department of Biochemistry and Genetics; University Hospital; Angers France
| | - Pascal Reynier
- CNRS 6214/INSERM 1083; Angers University; Angers France
- Department of Biochemistry and Genetics; University Hospital; Angers France
| |
Collapse
|
16
|
Hereditäre Optikusatrophien. MED GENET-BERLIN 2014. [DOI: 10.1007/s11825-014-0435-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Zusammenfassung
Bei hereditären Optikusatrophien werden 2 Untergruppen differenziert: isolierte hereditäre Optikusatrophien und hereditäre Optikusatrophien als Teil von syndromalen Erkrankungen. In der 1. Gruppe ist die Beeinträchtigung des N. opticus typischerweise die einzige Manifestation. Diese Gruppe umfasst insbesondere autosomal-dominante und autosomal-rezessive Optikusatrophien, darüber hinaus auch die mitochondrial vererbte hereditäre Leber-Optikusneuropathie (LHON).
In der 2. Gruppe, die die syndromalen Erkrankungen umfasst, wird eine Vielzahl neurologischer und anderer systemischer Auffälligkeiten beobachtet. Am häufigsten sind hier Veränderungen der mitochondrialen DNA (mtDNA) ursächlich. Weiterhin ist eine Optikusatrophie Symptom von einigen erblichen peripheren Neuropathien bzw. Charcot-Marie-Tooth-Erkrankungen (CMT2A2, CMTX5), hereditären sensorischen Neuropathie Typ 3 (HSAN3), Friedreich-Ataxie, Leukodystrophien, Sphingolipidosen, Zeroidlipofuszinosen und Eisenspeichererkrankungen („neurodegeneration with brain iron accumulation“, NBIA). Im vorliegenden Beitrag werden die zugrundeliegenden genetischen Prädispositionen und die klinischen Phänotypen erläutert.
Collapse
|
17
|
High-resolution en face images of microcystic macular edema in patients with autosomal dominant optic atrophy. BIOMED RESEARCH INTERNATIONAL 2013; 2013:676803. [PMID: 24369534 PMCID: PMC3863472 DOI: 10.1155/2013/676803] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 10/21/2013] [Accepted: 11/04/2013] [Indexed: 11/24/2022]
Abstract
The purpose of this study was to investigate the characteristics of microcystic macular edema (MME) determined from the en face images obtained by an adaptive optics (AO) fundus camera in patients with autosomal dominant optic atrophy (ADOA) and to try to determine the mechanisms underlying the degeneration of the inner retinal cells and RNFL by using the advantage of AO. Six patients from 4 families with ADOA underwent detailed ophthalmic examinations including spectral domain optical coherence tomography (SD-OCT). Mutational screening of all coding and flanking intron sequences of the OPA1 gene was performed by DNA sequencing. SD-OCT showed a severe reduction in the retinal nerve fiber layer (RNFL) thickness in all patients. A new splicing defect and two new frameshift mutations with premature termination of the Opa1 protein were identified in three families. A reported nonsense mutation was identified in one family. SD-OCT of one patient showed MME in the inner nuclear layer (INL) of the retina. AO images showed microcysts in the en face images of the INL. Our data indicate that AO is a useful method to identify MME in neurodegenerative diseases and may also help determine the mechanisms underlying the degeneration of the inner retinal cells and RNFL.
Collapse
|
18
|
Meunier I, Lenaers G, Hamel C, Defoort-Dhellemmes S. [Hereditary optic neuropathies: from clinical signs to diagnosis]. J Fr Ophtalmol 2013; 36:886-900. [PMID: 24161764 DOI: 10.1016/j.jfo.2013.05.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 04/17/2013] [Accepted: 05/17/2013] [Indexed: 10/26/2022]
Abstract
Inherited optic atrophy must be considered when working up any optic nerve involvement and any systemic disease with signs of optic atrophy, even with a negative family history. There are two classical forms: dominant optic atrophy, characterized by insidious, bilateral, slowly progressive visual loss and temporal disc pallor, and Leber's optic atrophy, characterized by acute loss of central vision followed by the same event in the fellow eye within a few weeks to months, with disc hyperemia in the acute phase. Family history is critical for diagnosis. In the absence of family history, the clinician must rule out an identifiable acquired cause, i.e. toxic, inflammatory, perinatal injury, traumatic or tumoral, with orbital and brain imaging (MRI). Recessive optic atrophies are more rare and more severe and occur as part of multisystemic disorders, particularly Wolfram syndrome (diabetes mellitus, diabetes insipidus, and hearing loss). Effective treatments are limited; alcohol and smoking should be avoided. A cyclosporine trial (taken immediately upon visual loss in the first eye) is in progress in Leber's optic atrophy to prevent involvement of the fellow eye.
Collapse
Affiliation(s)
- I Meunier
- Centre national de référence maladies rares, affections sensorielles génétiques, service d'ophtalmologie, hôpital Gui-de-Chauliac, 80, avenue Augustin-Fliche, 34295 Montpellier cedex 5, France.
| | | | | | | |
Collapse
|
19
|
Skidd PM, Lessell S, Cestari DM. Autosomal Dominant Hereditary Optic Neuropathy (ADOA): A Review of the Genetics and Clinical Manifestations of ADOA and ADOA+. Semin Ophthalmol 2013; 28:422-6. [DOI: 10.3109/08820538.2013.825296] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
20
|
Alavi MV, Fuhrmann N. Dominant optic atrophy, OPA1, and mitochondrial quality control: understanding mitochondrial network dynamics. Mol Neurodegener 2013; 8:32. [PMID: 24067127 PMCID: PMC3856479 DOI: 10.1186/1750-1326-8-32] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 09/16/2013] [Indexed: 12/13/2022] Open
Abstract
Mitochondrial quality control is fundamental to all neurodegenerative diseases, including the most prominent ones, Alzheimer’s Disease and Parkinsonism. It is accomplished by mitochondrial network dynamics – continuous fission and fusion of mitochondria. Mitochondrial fission is facilitated by DRP1, while MFN1 and MFN2 on the mitochondrial outer membrane and OPA1 on the mitochondrial inner membrane are essential for mitochondrial fusion. Mitochondrial network dynamics are regulated in highly sophisticated ways by various different posttranslational modifications, such as phosphorylation, ubiquitination, and proteolytic processing of their key-proteins. By this, mitochondria process a wide range of different intracellular and extracellular parameters in order to adapt mitochondrial function to actual energetic and metabolic demands of the host cell, attenuate mitochondrial damage, recycle dysfunctional mitochondria via the mitochondrial autophagy pathway, or arrange for the recycling of the complete host cell by apoptosis. Most of the genes coding for proteins involved in this process have been associated with neurodegenerative diseases. Mutations in one of these genes are associated with a neurodegenerative disease that originally was described to affect retinal ganglion cells only. Since more and more evidence shows that other cell types are affected as well, we would like to discuss the pathology of dominant optic atrophy, which is caused by heterozygous sequence variants in OPA1, in the light of the current view on OPA1 protein function in mitochondrial quality control, in particular on its function in mitochondrial fusion and cytochrome C release. We think OPA1 is a good example to understand the molecular basis for mitochondrial network dynamics.
Collapse
Affiliation(s)
- Marcel V Alavi
- Department of Ophthalmology, University of California, San Francisco, 10 Koret Way, 94143-0730 San Francisco, CA, USA.
| | | |
Collapse
|
21
|
First cases of dominant optic atrophy in Saudi Arabia: report of two novel OPA1 mutations. J Neuroophthalmol 2013; 33:349-53. [PMID: 24051421 DOI: 10.1097/wno.0b013e31829ffb9a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Fifty to 60% of patients with dominant optic atrophy (DOA) have mutations of the OPA1 gene, which encodes dynamin-related GTPase, a protein of the internal mitochondrial membrane. To date, more than 200 OPA1 mutations in the OPA1 gene have been described. However, DOA is genetically heterogeneous with certain families linked to other chromosomal loci, that is, OPA3, OPA4, OPA5, and OPA7. METHODS This study describes a clinical series of 40 patients from Saudi Arabia with a positive DOA phenotype (i.e., decreased visual acuity during the first 2 decades of life, temporal or global optic disc pallor, and absence of other neurological or ophthalmological diseases that could explain the optic neuropathy) who underwent molecular genetic testing for OPA1 (and, in some cases, for OPA3). RESULTS This study describes for the first time 4 OPA1 mutations in DOA patients from Saudi Arabia, including 2 novel OPA1 mutations in 2 different patients. CONCLUSION The question remains whether certain patients in Saudi Arabia with a clearly defined DOA phenotype may be due to mutations in chromosomal loci other than OPA1 and OPA3. It is likely that genetic alterations associated with different loci will be discovered in the future.
Collapse
|
22
|
Neuhann T, Rautenstrauss B. Genetic and phenotypic variability of optic neuropathies. Expert Rev Neurother 2013; 13:357-67. [PMID: 23545052 DOI: 10.1586/ern.13.19] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Hereditary optic neuropathies comprise a group of clinically and genetically heterogeneous disorders. Two subgroups can be formed: isolated hereditary optic atrophies and optic neuropathy as part of complex disorders. In group 1 of hereditary optic neuropathies, optic nerve dysfunction is typically the only manifestation of the disease. This group comprises autosomal dominant, autosomal recessive and X-linked recessive optic atrophy and the maternally inherited Leber's hereditary optic neuropathy. Among the autosomal-dominant forms of optic atrophy, Kjer's disease is most frequently observed. In the second group of complex disorders, various neurologic and other systemic abnormalities are regularly observed. Most frequent in this group are mtDNA mutations, inherited peripheral neuropathies, Charcot-Marie-Tooth disorders (CMT2A2, CMTX5), hereditary sensory neuropathy type 3 (HSAN3), Friedreich's ataxia, leukodystrophies, sphingolipidoses, ceroid-lipofuscinoses and neurodegeneration with brain iron accumulation. We review current knowledge about the underlying genetic predispositions, the most urgent open questions and how this may affect our management of this heterogeneous group of disorders in the future.
Collapse
Affiliation(s)
- Teresa Neuhann
- Medizinisch Genetisches Zentrum, Munich, Bayerstrasse 3-5, Munich 80335, Germany.
| | | |
Collapse
|
23
|
|
24
|
Abstract
The hereditary optic neuropathies are inherited disorders in which optic nerve dysfunction is a prominent feature in the phenotypic expression of disease. Optic neuropathy may be primarily an isolated finding, such as in Leber hereditary optic neuropathy and dominant optic atrophy, or part of a multisystem disorder. The pathophysiological mechanisms underlying the hereditary optic neuropathies involve mitochondrial dysfunction owing to mutations in mitochondrial or nuclear DNA that encodes proteins essential to mitochondrial function. Effective treatments are limited, and current management includes therapies directed at enhancing mitochondrial function and preventing oxidative damage, as well as genetic counselling, and supportive and symptomatic measures. New therapies, including gene therapy, are emerging via animal models and human clinical trials. Leber hereditary optic neuropathy, in particular, provides a unique model for testing promising treatments owing to its characteristic sequential bilateral involvement and the accessibility of target tissue within the eye. Lessons learned from treatment of the hereditary optic neuropathies may have therapeutic implications for other disorders of presumed mitochondrial dysfunction. In this Review, the natural history of the common inherited optic neuropathies, the presumed pathogenesis of several of these disorders, and the literature to date regarding potential therapies are summarized.
Collapse
Affiliation(s)
- Nancy J Newman
- Neuro-ophthalmology Unit, Department of Ophthalmology, Neurology and Neurological Surgery, Emory University School of Medicine, 1365-B Clifton Road NE, Atlanta, GA 30322, USA
| |
Collapse
|
25
|
Zhang J, Yuan Y, Lin B, Feng H, Li Y, Dai X, Zhou H, Dong X, Liu XL, Guan MX. A novel OPA1 mutation in a Chinese family with autosomal dominant optic atrophy. Biochem Biophys Res Commun 2012; 419:670-5. [PMID: 22382025 DOI: 10.1016/j.bbrc.2012.02.073] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2012] [Accepted: 02/13/2012] [Indexed: 12/01/2022]
Abstract
A large four-generation Chinese family with autosomal dominant optic atrophy (ADOA) was investigated in the present study. Eight of the family members were affected in this pedigree. The affected family members exhibited early-onset and progressive visual impairment, resulting in mild to profound loss of visual acuity. The average age-at-onset was 15.9years. A new heterozygous mutation c.C1198G was identified by sequence analysis of the 12th exon of the OPA1 gene. This mutation resulted in a proline to alanine substitution at codon 400, which was located in an evolutionarily conserved region. This missense mutation in the GTPase domain was supposed to result in a loss of function for the encoded protein and act through a dominant negative effect. No other mutations associated with optic atrophy were found in our present study. The c.C1198G heterozygous mutation in the OPA1 gene may be a novel key pathogenic mutation in this pedigree with ADOA. Furthermore, additional nuclear modifier genes, environmental factors, and psychological factors may also contribute to the phenotypic variability of ADOA in this pedigree.
Collapse
Affiliation(s)
- Juanjuan Zhang
- School of Ophthalmology and Optometry, Wenzhou Medical College, Wenzhou 325027, Zhejiang, China
| | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Hamahata T, Fujimaki T, Fujiki K, Miyazaki A, Mizota A, Murakami A. OPA1 mutations in Japanese patients suspected to have autosomal dominant optic atrophy. Jpn J Ophthalmol 2011; 56:91-7. [PMID: 22042570 DOI: 10.1007/s10384-011-0096-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 07/25/2011] [Indexed: 11/29/2022]
Abstract
PURPOSE To report three types of heterozygous mutations in the OPA1 gene in five patients from three families with autosomal dominant optic atrophy (ADOA, MIM#165500). METHODS DNA was extracted from the leukocytes of the peripheral blood. For mtDNA, mutations were examined at positions 11778, 3460 and 14484. For the OPA1 gene, the exons were amplified by PCR and mutations were detected by restriction enzymes or the dye terminator method. RESULTS We detected three types of OPA1 mutation but no mtDNA mutations. In the OPA1 gene, heterozygous frameshift mutations from codon 903 due to a four-base pair deletion in exon 27 were detected in three patients from one family (c.2708_2711delTTAG, p.V903GfsX905). A heterozygous mutation due to a three-base pair deletion in exon 17, leading to a one-amino acid deletion (c.1618_1620delACT, p.T540del), and a heterozygous mutation due to a one-base substitution in exon 11, leading to a stop codon (c.1084G>T, p.E362X), were detected in sporadic cases. CONCLUSION OPA1 mutations existed in three Japanese families with ADOA. After a detailed clinical assessment of the proband, the screening of the OPA1 gene may be helpful for precise diagnosis of ADOA, provided the relevant information of the family members is limited.
Collapse
Affiliation(s)
- Tetsuya Hamahata
- Department of Ophthalmology, Juntendo University School of Medicine, 3-1-3 Hongo, Bunkyo-ku, Tokyo 113-8431, Japan.
| | | | | | | | | | | |
Collapse
|
27
|
Auditory and optic neuropathy in Kjer's disease: case report. The Journal of Laryngology & Otology 2011; 126:309-12. [PMID: 22017926 DOI: 10.1017/s0022215111002696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE Description of a female patient with diagnosed Kjer's disease and sensorineural hearing loss, who specifically complained of a progressive inability to understand speech in noisy situations. DESIGN Case report. SUBJECT A 30-year-old, Caucasian woman with Kjer's disease. RESULTS Audiological assessment showed low-frequency sensorineural hearing loss and a disproportionate deterioration in speech discrimination. This inconsistency gave rise to suspicion of possible aggravation. Follow-up testing showed that brainstem responses were absent, while clear otoacoustic emissions and cochlear microphonics were present. Hearing aids were fitted but no improvement was shown. CONCLUSION This case shows a combination of auditory neuropathy and Kjer's optic neuropathy. It also illustrates that the combination of unexplained hearing loss and apparently inconsistent audiometric outcomes may be associated with auditory neuropathy. Such unexpected hearing evaluation outcomes may be due to other neurological conditions, such as Kjer's disease.
Collapse
|
28
|
Yu-Wai-Man P, Griffiths PG, Chinnery PF. Mitochondrial optic neuropathies - disease mechanisms and therapeutic strategies. Prog Retin Eye Res 2011; 30:81-114. [PMID: 21112411 PMCID: PMC3081075 DOI: 10.1016/j.preteyeres.2010.11.002] [Citation(s) in RCA: 440] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Leber hereditary optic neuropathy (LHON) and autosomal-dominant optic atrophy (DOA) are the two most common inherited optic neuropathies in the general population. Both disorders share striking pathological similarities, marked by the selective loss of retinal ganglion cells (RGCs) and the early involvement of the papillomacular bundle. Three mitochondrial DNA (mtDNA) point mutations; m.3460G>A, m.11778G>A, and m.14484T>C account for over 90% of LHON cases, and in DOA, the majority of affected families harbour mutations in the OPA1 gene, which codes for a mitochondrial inner membrane protein. Optic nerve degeneration in LHON and DOA is therefore due to disturbed mitochondrial function and a predominantly complex I respiratory chain defect has been identified using both in vitro and in vivo biochemical assays. However, the trigger for RGC loss is much more complex than a simple bioenergetic crisis and other important disease mechanisms have emerged relating to mitochondrial network dynamics, mtDNA maintenance, axonal transport, and the involvement of the cytoskeleton in maintaining a differential mitochondrial gradient at sites such as the lamina cribosa. The downstream consequences of these mitochondrial disturbances are likely to be influenced by the local cellular milieu. The vulnerability of RGCs in LHON and DOA could derive not only from tissue-specific, genetically-determined biological factors, but also from an increased susceptibility to exogenous influences such as light exposure, smoking, and pharmacological agents with putative mitochondrial toxic effects. Our concept of inherited mitochondrial optic neuropathies has evolved over the past decade, with the observation that patients with LHON and DOA can manifest a much broader phenotypic spectrum than pure optic nerve involvement. Interestingly, these phenotypes are sometimes clinically indistinguishable from other neurodegenerative disorders such as Charcot-Marie-Tooth disease, hereditary spastic paraplegia, and multiple sclerosis, where mitochondrial dysfunction is also thought to be an important pathophysiological player. A number of vertebrate and invertebrate disease models has recently been established to circumvent the lack of human tissues, and these have already provided considerable insight by allowing direct RGC experimentation. The ultimate goal is to translate these research advances into clinical practice and new treatment strategies are currently being investigated to improve the visual prognosis for patients with mitochondrial optic neuropathies.
Collapse
MESH Headings
- Animals
- DNA, Mitochondrial/genetics
- Disease Models, Animal
- Humans
- Optic Atrophy, Autosomal Dominant/pathology
- Optic Atrophy, Autosomal Dominant/physiopathology
- Optic Atrophy, Autosomal Dominant/therapy
- Optic Atrophy, Hereditary, Leber/pathology
- Optic Atrophy, Hereditary, Leber/physiopathology
- Optic Atrophy, Hereditary, Leber/therapy
- Optic Nerve/pathology
- Phenotype
- Point Mutation
- Retinal Ganglion Cells/pathology
Collapse
Affiliation(s)
- Patrick Yu-Wai-Man
- Mitochondrial Research Group, Institute for Ageing and Health, The Medical School, Newcastle University, UK.
| | | | | |
Collapse
|
29
|
Scherer C, Procaccio V, Ferre M, Guillet V, Reynier P, Amati-Bonneau P, Dubas F, Bonneau D, Verny C. [Hereditary optic atrophies]. Rev Neurol (Paris) 2010; 166:959-65. [PMID: 21056443 DOI: 10.1016/j.neurol.2010.07.033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Revised: 04/20/2010] [Accepted: 07/20/2010] [Indexed: 10/18/2022]
Abstract
INTRODUCTION Hereditary optic neuropathies, resulting from retinal ganglion cell degeneration, are a heterogeneous group of diseases ranging from asymptomatic forms to legal blindness. STATE OF KNOWLEDGE Two most frequent phenotypes are Kjer's disease, an autosomal dominant optic atrophy caused by OPA1 gene mutations, and Leber's disease due to maternally inherited mitochondrial DNA mutations. PROSPECTS AND CONCLUSION Both optic neuropathies usually isolated are sometimes associated with extraocular symptoms, especially neurological symptoms, thus justifying a systematic neurological evaluation and brain imaging.
Collapse
Affiliation(s)
- C Scherer
- Département de neurologie, CHU d'Angers, Angers, France
| | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Lee S, Van Bergen NJ, Kong GY, Chrysostomou V, Waugh HS, O'Neill EC, Crowston JG, Trounce IA. Mitochondrial dysfunction in glaucoma and emerging bioenergetic therapies. Exp Eye Res 2010; 93:204-12. [PMID: 20691180 DOI: 10.1016/j.exer.2010.07.015] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Revised: 07/16/2010] [Accepted: 07/27/2010] [Indexed: 12/22/2022]
Abstract
The similarities between glaucoma and mitochondrial optic neuropathies have driven a growing interest in exploring mitochondrial function in glaucoma. The specific loss of retinal ganglion cells is a common feature of mitochondrial diseases - not only the classic mitochondrial optic neuropathies of Leber's Hereditary Optic Neuropathy and Autosomal Dominant Optic Atrophy - but also occurring together with more severe central nervous system involvement in many other syndromic mitochondrial diseases. The retinal ganglion cell, due to peculiar structural and energetic constraints, appears acutely susceptible to mitochondrial dysfunction. Mitochondrial function is also well known to decline with aging in post-mitotic tissues including neurons. Because age is a risk factor for glaucoma this adds another impetus to investigating mitochondria in this common and heterogeneous neurodegenerative disease. Mitochondrial function may be impaired by either nuclear gene or mitochondrial DNA genetic risk factors, by mechanical stress or chronic hypoperfusion consequent to the commonly raised intraocular pressure in glaucomatous eyes, or by toxic xenobiotic or even light-induced oxidative stress. If primary or secondary mitochondrial dysfunction is further established as contributing to glaucoma pathogenesis, emerging therapies aimed at optimizing mitochondrial function represent potentially exciting new clinical treatments that may slow retinal ganglion cell and vision loss in glaucoma.
Collapse
Affiliation(s)
- Shanjean Lee
- Centre for Eye Research Australia, University of Melbourne, Department of Ophthalmology, Royal Victorian Eye and Ear Hospital, 32 Gisborne Street East, Melbourne, Victoria 3002, Australia
| | | | | | | | | | | | | | | |
Collapse
|
31
|
The prevalence and natural history of dominant optic atrophy due to OPA1 mutations. Ophthalmology 2010; 117:1538-46, 1546.e1. [PMID: 20417570 DOI: 10.1016/j.ophtha.2009.12.038] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Revised: 12/17/2009] [Accepted: 12/22/2009] [Indexed: 11/22/2022] Open
Abstract
PURPOSE Autosomal dominant optic atrophy (DOA) is a major cause of visual impairment in young adults that is characterized by selective retinal ganglion cell loss. To define the prevalence and natural history of this optic nerve disorder, we performed a population-based epidemiologic and molecular study of presumed DOA cases in the north of England. DESIGN Case series. PARTICIPANTS Seventy-six affected probands with a clinical diagnosis of DOA were identified from our neuro-ophthalmology and neurogenetics database. METHODS OPA1 genetic testing was performed using a polymerase chain reaction-based sequencing strategy. OPA1-negative cases were then screened for large-scale OPA1 rearrangements and OPA3 mutations. Additional affected family members identified through contact tracing were examined, and longitudinal visual data were analyzed. MAIN OUTCOME MEASURES The prevalence and molecular characteristics of DOA in the north of England. Visual function and disease progression among patients with OPA1-positive mutations. RESULTS The detection rate of OPA1 mutations was 57.6% among probands with a positive family history of optic atrophy (19/33) and 14.0% among singleton cases (6/43). Approximately two thirds of our families with DOA harbored OPA1 mutations (14/22, 63.6%), and 5 novel OPA1 mutations were identified. Only 1 family carried a large-scale OPA1 rearrangement, and no OPA3 mutations were found in our optic atrophy cohort. The minimum point prevalence of DOA in the north of England was 2.87 per 100,000 (95% confidence interval [CI], 2.54-3.20), or 2.09 per 100,000 (95% CI, 1.95-2.23) when only OPA1-positive cases were considered. Snellen visual acuity varied markedly between OPA1-positive cases with a mean of 20/173 (range 20/20 to hand movements), and visual function worsened in 67.4% of patients during follow-up. The mean rate of visual loss was 0.032 logarithm of the minimum angle of resolution per year, but some patients experienced faster visual decline (range = 0-0.171 logarithm of the minimum angle of resolution/year). OPA1 missense mutations were associated with a significantly worse visual outcome compared with other mutational subtypes (P=0.0001). CONCLUSIONS Dominant optic atrophy causes significant visual morbidity and affects at least 1 in 35,000 of the general population.
Collapse
|
32
|
Yu-Wai-Man P, Griffiths PG, Gorman GS, Lourenco CM, Wright AF, Auer-Grumbach M, Toscano A, Musumeci O, Valentino ML, Caporali L, Lamperti C, Tallaksen CM, Duffey P, Miller J, Whittaker RG, Baker MR, Jackson MJ, Clarke MP, Dhillon B, Czermin B, Stewart JD, Hudson G, Reynier P, Bonneau D, Marques W, Lenaers G, McFarland R, Taylor RW, Turnbull DM, Votruba M, Zeviani M, Carelli V, Bindoff LA, Horvath R, Amati-Bonneau P, Chinnery PF. Multi-system neurological disease is common in patients with OPA1 mutations. ACTA ACUST UNITED AC 2010; 133:771-86. [PMID: 20157015 PMCID: PMC2842512 DOI: 10.1093/brain/awq007] [Citation(s) in RCA: 325] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Additional neurological features have recently been described in seven families transmitting pathogenic mutations in OPA1, the most common cause of autosomal dominant optic atrophy. However, the frequency of these syndromal 'dominant optic atrophy plus' variants and the extent of neurological involvement have not been established. In this large multi-centre study of 104 patients from 45 independent families, including 60 new cases, we show that extra-ocular neurological complications are common in OPA1 disease, and affect up to 20% of all mutational carriers. Bilateral sensorineural deafness beginning in late childhood and early adulthood was a prominent manifestation, followed by a combination of ataxia, myopathy, peripheral neuropathy and progressive external ophthalmoplegia from the third decade of life onwards. We also identified novel clinical presentations with spastic paraparesis mimicking hereditary spastic paraplegia, and a multiple sclerosis-like illness. In contrast to initial reports, multi-system neurological disease was associated with all mutational subtypes, although there was an increased risk with missense mutations [odds ratio = 3.06, 95% confidence interval = 1.44-6.49; P = 0.0027], and mutations located within the guanosine triphosphate-ase region (odds ratio = 2.29, 95% confidence interval = 1.08-4.82; P = 0.0271). Histochemical and molecular characterization of skeletal muscle biopsies revealed the presence of cytochrome c oxidase-deficient fibres and multiple mitochondrial DNA deletions in the majority of patients harbouring OPA1 mutations, even in those with isolated optic nerve involvement. However, the cytochrome c oxidase-deficient load was over four times higher in the dominant optic atrophy + group compared to the pure optic neuropathy group, implicating a causal role for these secondary mitochondrial DNA defects in disease pathophysiology. Individuals with dominant optic atrophy plus phenotypes also had significantly worse visual outcomes, and careful surveillance is therefore mandatory to optimize the detection and management of neurological disability in a group of patients who already have significant visual impairment.
Collapse
Affiliation(s)
- P Yu-Wai-Man
- Mitochondrial Research Group, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Amati-Bonneau P, Milea D, Bonneau D, Chevrollier A, Ferré M, Guillet V, Gueguen N, Loiseau D, Crescenzo MAPD, Verny C, Procaccio V, Lenaers G, Reynier P. OPA1-associated disorders: Phenotypes and pathophysiology. Int J Biochem Cell Biol 2009; 41:1855-65. [DOI: 10.1016/j.biocel.2009.04.012] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Revised: 04/09/2009] [Accepted: 04/14/2009] [Indexed: 10/20/2022]
|
34
|
Abstract
Hereditary optic neuropathies are caused by mutations either in the nuclear or mitochondrial genome and lead to retinal ganglion cell death mediated by reduced oxidative phosphorylation, fragmentation of the mitochondrial network, and increased sensitivity to apoptosis. Nuclear mutations result in autosomal dominant optic atrophy, autosomal recessive optic atrophy, or X-linked recessive optic atrophy, whereas mitochondrial mutations result in Leber's hereditary optic neuropathy, which is maternally inherited. A tentative diagnosis of a hereditary optic neuropathy can usually be made on the grounds of a thorough patient and family history, visual field and color vision tests, and a detailed assessment of the optic nerve head. The rarity of hereditary optic neuropathies makes it difficult to include these disorders in the differential diagnosis. Molecular genetic testing of a blood DNA sample should be performed on every patient, with implications for future genetic counseling and prediction of the disease course.
Collapse
|
35
|
Liesa M, Palacín M, Zorzano A. Mitochondrial dynamics in mammalian health and disease. Physiol Rev 2009; 89:799-845. [PMID: 19584314 DOI: 10.1152/physrev.00030.2008] [Citation(s) in RCA: 686] [Impact Index Per Article: 45.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The meaning of the word mitochondrion (from the Greek mitos, meaning thread, and chondros, grain) illustrates that the heterogeneity of mitochondrial morphology has been known since the first descriptions of this organelle. Such a heterogeneous morphology is explained by the dynamic nature of mitochondria. Mitochondrial dynamics is a concept that includes the movement of mitochondria along the cytoskeleton, the regulation of mitochondrial architecture (morphology and distribution), and connectivity mediated by tethering and fusion/fission events. The relevance of these events in mitochondrial and cell physiology has been partially unraveled after the identification of the genes responsible for mitochondrial fusion and fission. Furthermore, during the last decade, it has been identified that mutations in two mitochondrial fusion genes (MFN2 and OPA1) cause prevalent neurodegenerative diseases (Charcot-Marie Tooth type 2A and Kjer disease/autosomal dominant optic atrophy). In addition, other diseases such as type 2 diabetes or vascular proliferative disorders show impaired MFN2 expression. Altogether, these findings have established mitochondrial dynamics as a consolidated area in cellular physiology. Here we review the most significant findings in the field of mitochondrial dynamics in mammalian cells and their implication in human pathologies.
Collapse
Affiliation(s)
- Marc Liesa
- Institute for Research in Biomedicine (IRB Barcelona), CIBER de Diabetes y Enfermedades Metabólicas Asociadas, and Departament de Bioquímica i Biologia Molecular, Universitat de Barcelona, Barcelona 08028, Spain
| | | | | |
Collapse
|
36
|
Yu-Wai-Man P, Griffiths PG, Hudson G, Chinnery PF. Inherited mitochondrial optic neuropathies. J Med Genet 2009; 46:145-58. [PMID: 19001017 PMCID: PMC2643051 DOI: 10.1136/jmg.2007.054270] [Citation(s) in RCA: 287] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 09/08/2008] [Accepted: 10/07/2008] [Indexed: 02/02/2023]
Abstract
Leber hereditary optic neuropathy (LHON) and autosomal dominant optic atrophy (DOA) are the two most common inherited optic neuropathies and they result in significant visual morbidity among young adults. Both disorders are the result of mitochondrial dysfunction: LHON from primary mitochondrial DNA (mtDNA) mutations affecting the respiratory chain complexes; and the majority of DOA families have mutations in the OPA1 gene, which codes for an inner mitochondrial membrane protein critical for mtDNA maintenance and oxidative phosphorylation. Additional genetic and environmental factors modulate the penetrance of LHON, and the same is likely to be the case for DOA which has a markedly variable clinical phenotype. The selective vulnerability of retinal ganglion cells (RGCs) is a key pathological feature and understanding the fundamental mechanisms that underlie RGC loss in these disorders is a prerequisite for the development of effective therapeutic strategies which are currently limited.
Collapse
MESH Headings
- DNA, Mitochondrial
- Female
- GTP Phosphohydrolases/genetics
- Humans
- Male
- Optic Atrophy, Autosomal Dominant/diagnosis
- Optic Atrophy, Autosomal Dominant/epidemiology
- Optic Atrophy, Autosomal Dominant/genetics
- Optic Atrophy, Autosomal Dominant/pathology
- Optic Atrophy, Hereditary, Leber/diagnosis
- Optic Atrophy, Hereditary, Leber/epidemiology
- Optic Atrophy, Hereditary, Leber/genetics
- Optic Atrophy, Hereditary, Leber/pathology
- Point Mutation
Collapse
Affiliation(s)
- P Yu-Wai-Man
- Mitochondrial Research Group, The Medical School, Newcastle University, Newcastle upon Tyne, UK
- Department of Ophthalmology, Royal Victoria Infirmary, Newcastle upon Tyne, UK
| | - P G Griffiths
- Department of Ophthalmology, Royal Victoria Infirmary, Newcastle upon Tyne, UK
| | - G Hudson
- Mitochondrial Research Group, The Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - P F Chinnery
- Mitochondrial Research Group, The Medical School, Newcastle University, Newcastle upon Tyne, UK
- Institute of Human Genetics, Newcastle University, Newcastle upon Tyne, NE1 3BZ, UK
| |
Collapse
|
37
|
Li C, Kosmorsky G, Zhang K, Katz BJ, Ge J, Traboulsi EI. Optic atrophy and sensorineural hearing loss in a family caused by an R445H OPA1 mutation. Am J Med Genet A 2008; 138A:208-11. [PMID: 16158427 DOI: 10.1002/ajmg.a.30794] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Autosomal dominant optic atrophy (ADOA) is the most common form of inherited optic atrophy. Four genetic loci have been associated with ADOA: OPA1, OPA2, OPA3, and OPA4. Out of these four loci, only one gene has been identified, OPA1. We previously described a unique syndrome of optic atrophy, sensorineural hearing loss, ptosis, and ophthalmoplegia in two unrelated families associated with an R445H mutation in OPA1. The R445H mutation is the only OPA1 mutation that has been associated with this syndrome. In this manuscript, we clinically characterize an unrelated family with four members affected by optic atrophy and hearing loss without extraocular motility abnormalities or ptosis. This family also harbors the R445H mutation. These cases help illustrate the intra- and inter-family variability in phenotype associated with this mutation. As we continue to learn more about OPA1 and the function of its protein product, we will begin to understand the pathophysiology of optic atrophy. This understanding will ultimately lead to novel treatments directed toward preventing the visual loss and disability associated with this inherited disease.
Collapse
Affiliation(s)
- Chunmei Li
- Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences Center, Salt Lake City, UT 84132, USA
| | | | | | | | | | | |
Collapse
|
38
|
Abstract
PURPOSE To describe the Stratus optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) thickness profile of dominant optic atrophy (DOA), to differentiate it from that of glaucoma. METHODS RNFL thickness was measured using Stratus OCT in 32 eyes of 16 DOA patients. RESULTS The temporal-most clock hour measurement was outside the 95% normal limit in 29 of the 32 DOA eyes (90.6%). The pattern of RNFL damage was bilaterally symmetrical in location and severity in all subjects. CONCLUSION Stratus OCT shows characteristic findings differentiating DOA from glaucoma.
Collapse
|
39
|
Bette S, Zimmermann U, Wissinger B, Knipper M. OPA1, the disease gene for optic atrophy type Kjer, is expressed in the inner ear. Histochem Cell Biol 2007; 128:421-30. [PMID: 17828551 DOI: 10.1007/s00418-007-0321-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/19/2007] [Indexed: 11/26/2022]
Abstract
Autosomal dominant optic atrophy (adOA) is the most common form of hereditary optic neuropathy. The majority of cases are associated with mutations in the OPA1 gene. A few cases of adOA are known to be associated with moderate progressive hearing loss. To gain insight into the pathogenesis of this hearing loss, we performed expression analyses of OPA1 in the rat auditory and vestibular organ. In cochlear tissue, several splice variants of OPA1 were detected, which are also expressed in retinal tissue. OPA1 mRNA and protein was found in the hair cells and ganglion cells of the cochlea and vestibular organ. In ganglion cells, OPA1 mRNA and protein was already detectable at birth, whereas in the organ of Corti OPA1 mRNA and protein was up-regulated after birth and reached mature-like expression level during the onset of hearing. Comparison of an antibody directed to the mitochondrial marker protein HSP60 with antibodies directed to different amino acid stretches of OPA1 revealed a sub-cellular distribution of OPA1 in areas of significant density of mitochondria. The data suggest that defects in OPA1 cause hearing disorders due to a progressing metabolic disturbance of hair and ganglion cells in the inner ear.
Collapse
Affiliation(s)
- Stefanie Bette
- Molecular Genetics Laboratory, University Eye Hospital, Röntgenweg 11, 72076, Tübingen, Germany
| | | | | | | |
Collapse
|
40
|
Moslemi AR, Darin N. Molecular genetic and clinical aspects of mitochondrial disorders in childhood. Mitochondrion 2007; 7:241-52. [PMID: 17376748 DOI: 10.1016/j.mito.2007.02.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2006] [Revised: 01/17/2007] [Accepted: 02/02/2007] [Indexed: 12/21/2022]
Abstract
Mitochondrial OXPHOS disorders are caused by mutations in mitochondrial or nuclear genes, which directly or indirectly affect mitochondrial oxidative phosphorylation (OXPHOS). Primary mtDNA abnormalities in children are due to rearrangements (deletions or duplications) and point mutations or insertions. Mutations in the nuclear-encoded polypeptide subunits of OXPHOS result in complex I and II deficiency, whereas mutations in the nuclear proteins involved in the assembly of OXPHOS subunits cause defects in complexes I, III, IV, and V. Here, we review recent progress in the identification of mitochondrial and nuclear gene defects and the associated clinical manifestations of these disorders in childhood.
Collapse
Affiliation(s)
- Ali-Reza Moslemi
- Department of Pathology, Göteborg University, Sahlgrenska University Hospital, SE-413 45 Göteborg, Sweden.
| | | |
Collapse
|
41
|
Hayashi T, Takeuchi T, Gekka T, Kitahara K. Dominant optic atrophy in a Japanese family with OPA1 frameshift mutation (V942fsX966). Eur J Ophthalmol 2007; 17:253-8. [PMID: 17415700 DOI: 10.1177/112067210701700216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PURPOSE The authors report the ophthalmic characteristics of a male proband in a Japanese family with autosomal dominant optic atrophy (DOA) harboring a frameshift mutation in the OPA1 gene. METHODS Conventional ophthalmologic examinations including static automated perimetry were performed, as well as assessment of the three-generation family history. The peripapillary retinal nerve fiber layer (RNFL) was evaluated using scanning laser polarimetry. Mutation screening of the OPA1 gene was performed with polymerase chain reaction amplification and direct sequencing. RESULTS A frameshift mutation (p.V942fsX966) was identified in the proband and his mother. In comparison with the adolescent onset of visual loss in the proband and his maternal grandfather, the mother presented with only subtle temporal disc pallor and has never been aware of any visual disturbances. Symmetric thinned peripapillary RNFL was detected in the proband, whose visual field abnormalities were limited to central scotomas and were without mean deviation worsening between 11 to 17 years of age in both eyes. The proband's logMAR visual acuity (0.52 to 0.7) has remained almost unchanged for more than 10 years since initial evaluation at age 10. CONCLUSIONS The OPA1 mutation may be correlated with slow progression of DOA, and with phenotypic variations within the family. Further study is necessary to determine whether symmetric thinned peripapillary RNFL represents a feature of DOA.
Collapse
Affiliation(s)
- T Hayashi
- Department of Ophthalmology, Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan.
| | | | | | | |
Collapse
|
42
|
Cohn AC, Toomes C, Potter C, Towns KV, Hewitt AW, Inglehearn CF, Craig JE, Mackey DA. Autosomal dominant optic atrophy: penetrance and expressivity in patients with OPA1 mutations. Am J Ophthalmol 2007; 143:656-62. [PMID: 17306754 DOI: 10.1016/j.ajo.2006.12.038] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2006] [Revised: 12/12/2006] [Accepted: 12/17/2006] [Indexed: 10/23/2022]
Abstract
PURPOSE We identified families with autosomal dominant optic atrophy (ADOA), determined the number and type of OPA1 mutations, and investigated the phenotypic variation and penetrance in ADOA Australian pedigrees. DESIGN Cross-sectional genetics study. METHODS Probands were identified on the basis of characteristic clinical features of ADOA. We screened the OPA1 gene using single-strand conformational polymorphism, heteroduplex analysis (SSCP/HA), or by direct sequencing. Penetrance for pedigrees in which a mutation of OPA1 had been identified was calculated initially using all recruited individuals, and subanalysis was performed using only those families for which there was total recruitment of siblings. RESULTS A total of 406 patients from 17 pedigrees were recruited, and OPA1 mutations were identified in 11/17 (65%) of these. The mean age at clinical examination was 38.2 +/- 19.9 years (median age, 35 years; range, four to 83 years). The median best-corrected visual acuity in OPA1-mutation carriers was 20/70 (range, 20/16 to hand movements [HM]). The penetrance in Australian ADOA pedigrees in the families with complete sibling recruitment was 82.5%. On the other hand, overall penetrance for all individuals harboring an OPA1 mutation was 88%. CONCLUSIONS OPA1 mutations were identified in 11/17 (65%) of the ADOA pedigrees in this study. The penetrance in our cohort was lower than originally described (82.5% vs 98%) but higher than some recent studies since the availability of genotyping. It is anticipated that this figure would be even lower as more asymptomatic individuals are identified. There are likely to be other genetic and environmental modifiers influencing disease penetrance.
Collapse
Affiliation(s)
- Amy C Cohn
- Ocular Diagnostic Clinic, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
| | | | | | | | | | | | | | | |
Collapse
|
43
|
|
44
|
Mabuchi F, Tang S, Kashiwagi K, Yamagata Z, Iijima H, Tsukahara S. The OPA1 gene polymorphism is associated with normal tension and high tension glaucoma. Am J Ophthalmol 2007; 143:125-130. [PMID: 17188046 DOI: 10.1016/j.ajo.2006.09.028] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2006] [Revised: 08/26/2006] [Accepted: 09/12/2006] [Indexed: 10/24/2022]
Abstract
PURPOSE To assess whether genetic polymorphisms of optic atrophy 1 (OPA1) are associated with primary open-angle glaucoma (POAG). DESIGN Prospective case control association study. METHODS Japanese patients with normal tension glaucoma (NTG, n = 194), and high tension glaucoma (HTG, n = 191), and 185 control subjects were analyzed for the OPA1 intervening sequence (IVS) 8+4 cystosine thymine (C/T) and IVS 8+32 thymine cystosine (T/C) polymorphisms using pyrosequencing technique. RESULTS There was a significant difference in the OPA1 IVS 8 +32 T/C genotype frequencies between the NTG patients and control subjects (P = .0074), and the frequency of the cystosine (C) allele was significantly higher in the NTG patients compared with the control subjects (19.3% vs 11.6%, P = .0036). Adjusted for age, gender, refractive error, and intraocular pressure, an almost two-fold increased risk of NTG (P = .004, odds ratio 2.27, 95% confidence interval 1.30 to 3.97) was found with the OPA1 IVS 8 +32 C allele. Although there was no significant difference in the OPA1 IVS 8 +32 T/C genotype frequencies between the HTG patients and control subjects (P = .24), the age at the time of diagnosis (53 +/- 11.0 years, median value +/- median absolute deviation) in the HTG patients with the OPA1 IVS 8 +32 C allele was significantly younger than that (57 +/- 12.0 years) in the HTG patients without C allele (P = .048). CONCLUSIONS The OPA1 IVS 8 +32 T/C polymorphism is associated with NTG, and may be used as a marker for this disease association. This polymorphism also influences the phenotypic feature in patients with HTG and should be considered to be a genetic risk factor not only for NTG, but also for HTG.
Collapse
Affiliation(s)
- Fumihiko Mabuchi
- Department of Ophthalmology, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo-shi, Yamanashi 409-3898, Japan.
| | | | | | | | | | | |
Collapse
|
45
|
Olichon A, Landes T, Arnauné-Pelloquin L, Emorine LJ, Mils V, Guichet A, Delettre C, Hamel C, Amati-Bonneau P, Bonneau D, Reynier P, Lenaers G, Belenguer P. Effects of OPA1 mutations on mitochondrial morphology and apoptosis: Relevance to ADOA pathogenesis. J Cell Physiol 2007; 211:423-30. [PMID: 17167772 DOI: 10.1002/jcp.20950] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
To characterize the molecular links between type-1 autosomal dominant optic atrophy (ADOA) and OPA1 dysfunctions, the effects of pathogenic alleles of this dynamin on mitochondrial morphology and apoptosis were analyzed, either in fibroblasts from affected individuals, or in HeLa cells transfected with similar mutants. The alleles were missense substitutions in the GTPase domain (OPA1(G300E) and OPA1(R290Q)) or deletion of the GTPase effector domain (OPA1(Delta58)). Fragmentation of mitochondria and apoptosis increased in OPA1(R290Q) fibroblasts and in OPA1(G300E) transfected HeLa cells. OPA1(Delta58) did not influence mitochondrial morphology, but increased the sensitivity to staurosporine of fibroblasts. In these cells, the amount of OPA1 protein was half of that in control fibroblasts. We conclude that GTPase mutants exert a dominant negative effect by competing with wild-type alleles to integrate into fusion-competent complexes, whereas C-terminal truncated alleles act by haplo-insufficiency. We present a model where antagonistic fusion and fission forces maintain the mitochondrial network, within morphological limits that are compatible with cellular functions. In the retinal ganglion cells (RGCs) of patients suffering from type-1 ADOA, OPA1-driven fusion cannot adequately oppose fission, thereby rendering them more sensitive to apoptotic stimuli and eventually leading to optic nerve degeneration.
Collapse
Affiliation(s)
- Aurélien Olichon
- Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération, Université Paul Sabatier, Toulouse, France
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
46
|
Eiberg H, Hansen L, Kjer B, Hansen T, Pedersen O, Bille M, Rosenberg T, Tranebjaerg L. Autosomal dominant optic atrophy associated with hearing impairment and impaired glucose regulation caused by a missense mutation in the WFS1 gene. J Med Genet 2006; 43:435-40. [PMID: 16648378 PMCID: PMC2649014 DOI: 10.1136/jmg.2005.034892] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Autosomal dominant optic atrophy (ADOA) is genetically heterogeneous, with OPA1 on 3q28 being the most prevalently mutated gene. Additional loci are OPA3, OPA4, and OPA5, located at 19q13.2, 18q12.2, and 22q12.1-q13.1, respectively. Mutations in the WFS1 gene, at 4p16.3, are associated with either optic atrophy (OA) as part of the autosomal recessive Wolfram syndrome or with autosomal dominant progressive low frequency sensorineural hearing loss (LFSNHL) without any ophthalmological abnormalities. Linkage and sequence mutation analyses of the ADOA candidate genes OPA1, OPA3, OPA4, and OPA5, including the genes WFS1, GJB2, and GJB6 associated with recessive inherited OA or dominant LFSNHL, were performed. We identified one novel WFS1 missense mutation E864K, c.2590G-->A in exon 8 that co-segregates with ADOA combined with hearing impairment and impaired glucose regulation. This is the first example of autosomal dominant optic atrophy and hearing loss associated with a WFS1 mutation, supporting the notion that mutations in WFS1 as well as in OPA1 may lead to ADOA combined with impaired hearing.
Collapse
Affiliation(s)
- H Eiberg
- Department of Medical Biochemistry and Genetics, Panum Institute, University of Copenhagen, DK-2200 Copenhagen N, Denmark.
| | | | | | | | | | | | | | | |
Collapse
|
47
|
Olichon A, Guillou E, Delettre C, Landes T, Arnauné-Pelloquin L, Emorine LJ, Mils V, Daloyau M, Hamel C, Amati-Bonneau P, Bonneau D, Reynier P, Lenaers G, Belenguer P. Mitochondrial dynamics and disease, OPA1. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1763:500-9. [PMID: 16737747 DOI: 10.1016/j.bbamcr.2006.04.003] [Citation(s) in RCA: 175] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2006] [Revised: 04/07/2006] [Accepted: 04/10/2006] [Indexed: 11/26/2022]
Abstract
The mitochondria are dynamic organelles that constantly fuse and divide. An equilibrium between fusion and fission controls the morphology of the mitochondria, which appear as dots or elongated tubules depending the prevailing force. Characterization of the components of the fission and fusion machineries has progressed considerably, and the emerging question now is what role mitochondrial dynamics play in mitochondrial and cellular functions. Its importance has been highlighted by the discovery that two human diseases are caused by mutations in the two mitochondrial pro-fusion genes, MFN2 and OPA1. This review will focus on data concerning the function of OPA1, mutations in which cause optic atrophy, with respect to the underlying pathophysiological processes.
Collapse
Affiliation(s)
- Aurélien Olichon
- Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération, Université Paul Sabatier, 118 route de Narbonne, 31062 Toulouse, France
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Nakamura M, Lin J, Ueno S, Asaoka R, Hirai T, Hotta Y, Miyake Y, Terasaki H. Novel mutations in the OPA1 gene and associated clinical features in Japanese patients with optic atrophy. Ophthalmology 2006; 113:483-488.e1. [PMID: 16513463 DOI: 10.1016/j.ophtha.2005.10.054] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Revised: 08/15/2005] [Accepted: 10/24/2005] [Indexed: 11/17/2022] Open
Abstract
PURPOSE Autosomal dominant optic atrophy (ADOA) is characterized by symmetrical bilateral optic atrophy associated with reduced corrected visual acuity (VA), central or centrocecal scotoma, and color vision disturbances. The disease is genetically heterogeneous, and the OPA1 gene has been identified as the only causative gene. The aims of this study were to identify and report mutations in the OPA1 gene in Japanese patients with ADOA and to describe the clinical features associated with the mutations. DESIGN Molecular genetic study and observational case reports. PARTICIPANTS Nine unrelated Japanese families with optic atrophy and 8 isolated cases of optic atrophy. METHODS Genomic DNA was extracted from peripheral leukocytes, and all exons containing the open reading frame of the OPA1 gene and the flanking intron splice sites were sequenced directly. Complete ophthalmologic examinations were performed. MAIN OUTCOME MEASURES Direct sequencing of the OPA1 gene and clinical evaluations including VA, visual field, color vision, and disc appearance. RESULTS Ten different heterozygous mutations, including 6 novel mutations, were detected in the OPA1 gene. The identified mutations included 5 deletions/insertions (c.2061delA, c.2098_2103delCTTAAA, c.2538insT, c.2591insC, and c.2708_2711delTTAG), 4 nonsense mutations (c.112C>T [p.R38X], c.181C>T [p.Q61X], c.946A>T [p.R316X], and c.2713C>T [p.R905X]), and 1 missense mutation (c.1635C>A [p.S545R]). The most common mutation in Caucasians (c.2708_2711delTTAG) was found in 3 unrelated families, suggesting that it is a mutational hot spot. We detected an OPA1 mutation in 8 of 9 familial cases of optic atrophy and in 4 of 8 cases that were initially considered to be sporadic from the patients' family histories. Examinations of family members of 2 sporadic probands revealed the existence of other family members with the OPA1 mutations whose phenotype was very mild or within normal limits. This indicates that patients with ADOA sometimes seem to be sporadic because of the extensive variation in the phenotype or, alternatively, a low penetrance of ADOA. CONCLUSIONS OPA1 gene mutations are causative in most familial cases of ADOA in Japanese. Sporadic cases of optic atrophy frequently may be caused by OPA1 mutations in the Japanese population. Molecular genetic examinations are useful in determining the hereditary patterns in some cases of optic atrophy.
Collapse
Affiliation(s)
- Makoto Nakamura
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
49
|
Katz BJ, Zhao Y, Warner JEA, Tong Z, Yang Z, Zhang K. A family with X-linked optic atrophy linked to the OPA2 locus Xp11.4-Xp11.2. Am J Med Genet A 2006; 140:2207-11. [PMID: 16969871 DOI: 10.1002/ajmg.a.31455] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Autosomal dominant optic atrophy (ADOA) is the most common inherited optic atrophy. Clinical features of ADOA include a slowly progressive bilateral loss of visual acuity, constriction of peripheral visual fields, central scotomas, and color vision abnormalities. Although ADOA is the most commonly inherited optic atrophy, autosomal recessive, X-linked, mitochondrial, and sporadic forms have also been reported. Four families with X-linked optic atrophy (XLOA) were previously described. One family was subsequently linked to Xp11.4-Xp11.2 (OPA2). This investigation studied one multi-generation family with an apparently X-linked form of optic atrophy and compared their clinical characteristics with those of the previously described families, and determined whether this family was linked to the same genetic locus. Fifteen individuals in a three-generation Idaho family underwent complete eye examination, color vision testing, automated perimetry, and fundus photography. Polymorphic markers were used to genotype each individual and to determine linkage. Visual acuities ranged from 20/30 to 20/100. All affected subjects had significant optic nerve pallor. Obligate female carriers were clinically unaffected. Preliminary linkage analysis (LOD score = 1.8) revealed that the disease gene localized to the OPA2 locus on Xp11.4-Xp11.2. Four forms of inherited optic neuropathy, ADOA, autosomal recessive optic atrophy (Costeff Syndrome), Leber hereditary optic neuropathy, and Charcot-Marie-Tooth disease with optic atrophy, are associated with mitochondrial dysfunction. Future identification of the XLOA gene will reveal whether this form of optic atrophy is also associated with a mitochondrial defect. Identification of the XLOA gene will advance our understanding of the inherited optic neuropathies and perhaps suggest treatments for these diseases. An improved understanding of inherited optic neuropathies may in turn advance our understanding of acquired optic nerve diseases, such as glaucoma and ischemic optic neuropathy.
Collapse
Affiliation(s)
- Bradley J Katz
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah Health Sciences Center, Salt Lake City, Utah 84132, USA.
| | | | | | | | | | | |
Collapse
|
50
|
JU WONKYU, MISAKA TAKUMI, KUSHNAREVA YULIA, NAKAGOMI SAYA, AGARWAL NEERAJ, KUBO YOSHIHIRO, LIPTON STUARTA, BOSSY-WETZEL ELLA. OPA1 expression in the normal rat retina and optic nerve. J Comp Neurol 2005; 488:1-10. [PMID: 15912498 PMCID: PMC1350956 DOI: 10.1002/cne.20586] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Autosomal dominant optic atrophy (DOA) is the most common form of hereditary optic neuropathy. DOA presents in the first decade of life and manifests as progressive vision loss. In DOA retinal ganglion cells and the optic nerve degenerate by an unknown mechanism. The gene mutated in DOA, Optic Atrophy Type 1 (OPA1), encodes a dynamin-related GTPase implicated in mitochondrial fusion and maintenance of the mitochondrial network and genome. Here, we determine which cell types in the normal retina and the optic nerve express OPA1. In the normal rat retina, OPA1 is expressed in the ganglion cell layer as well as in the outer plexiform layer, the inner nuclear layer, and the inner plexiform layer. In the ganglion cell layer, OPA1 is expressed predominantly in retinal ganglion cells. By contrast, OPA1 protein is low or undetectable in astrocytes and oligodendrocytes of the optic nerve. Additionally, OPA1 protein is present in axonal mitochondria. Last, OPA1 expression is present in mitochondria of processes and cell bodies of purified retinal ganglion cells and of the RGC-5 cell line. Thus, OPA1 is predominantly expressed in retinal ganglion cells of the normal rat retina and axons of the optic nerve. These findings may explain the selective vulnerability of retinal ganglion cells to OPA1 loss of function.
Collapse
Affiliation(s)
- WON-KYU JU
- Center for Neuroscience and Aging, The Burnham Institute, La Jolla, California 92037
| | - TAKUMI MISAKA
- Division of Biophysics and Neurobiology, Department of Molecular Physiology, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
| | - YULIA KUSHNAREVA
- Center for Neuroscience and Aging, The Burnham Institute, La Jolla, California 92037
| | - SAYA NAKAGOMI
- Center for Neuroscience and Aging, The Burnham Institute, La Jolla, California 92037
| | - NEERAJ AGARWAL
- Department of Cell Biology and Genetics, University of North Texas Health Science Center, Fort Worth, Texas 76107
| | - YOSHIHIRO KUBO
- Division of Biophysics and Neurobiology, Department of Molecular Physiology, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
| | - STUART A. LIPTON
- Center for Neuroscience and Aging, The Burnham Institute, La Jolla, California 92037
| | - ELLA BOSSY-WETZEL
- Center for Neuroscience and Aging, The Burnham Institute, La Jolla, California 92037
- *Correspondence to: Ella Bossy-Wetzel, Center for Neuroscience and Aging, The Burnham Institute, La Jolla, CA 92037., E-mail:
| |
Collapse
|