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Other Hereditary Optic Neuropathy. Neuroophthalmology 2022. [DOI: 10.1007/978-981-19-4668-4_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Zhang XH, Xie Y, Xu QG, Cao K, Xu K, Jin ZB, Li Y, Wei SH. Mitochondrial Mutations in Ethambutol-Induced Optic Neuropathy. Front Cell Dev Biol 2021; 9:754676. [PMID: 34676220 PMCID: PMC8525703 DOI: 10.3389/fcell.2021.754676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 09/15/2021] [Indexed: 11/13/2022] Open
Abstract
Background: Ethambutol-induced optic neuropathy (EON) is a well-recognized ocular complication in patients who take ethambutol as a tuberculosis treatment. The aim of the current study was to investigate the presence of mitochondrial mutations, including OPA1 and Leber's hereditary optic neuropathy (LHON)-mitochondrial DNA (mtDNA), in patients with EON and to determine their effect on clinical features of these patients. Methods: All 47 patients underwent clinical evaluations, including best-corrected visual acuity, fundus examination, and color fundus photography; 37 patients were then followed up over time. Molecular screening methods, including PCR-based sequencing of the OPA1 gene and LHON-mtDNA mutations, together with targeted exome sequencing, were used to detect mutations. Results: We detected 15 OPA1 mutations in 18 patients and two LHON-mtDNA mutations in four patients, for an overall mutation detection rate of 46.8%. The mean presentation age was significantly younger in the patients with the mitochondrial mutations (27.5 years) than in those without mutations (48 years). Fundus examination revealed a greater prevalence of optic disc hyperemia in the patients with mutations (70.5%) than without mutations (48%). Half of the patients with mutations and 91% of the patients without mutations had improved vision. After adjusting for confounders, the logistic regression revealed that the patients with optic disc pallor on the first visit (p = 0.004) or the patients with the mitochondrial mutations (p < 0.001) had a poorer vision prognosis. Conclusion: Our results indicated that carriers with OPA1 mutations might be more vulnerable for the toxicity of EMB to develop EON.
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Affiliation(s)
- Xiao-Hui Zhang
- Department of Ophthalmology, The Chinese People's Liberation Army General Hospital, The Chinese People's Liberation Army Medical School, Beijing, China.,Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Yue Xie
- Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Quan-Gang Xu
- Department of Ophthalmology, The Chinese People's Liberation Army General Hospital, The Chinese People's Liberation Army Medical School, Beijing, China
| | - Kai Cao
- Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Ke Xu
- Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Zi-Bing Jin
- Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Yang Li
- Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Shi-Hui Wei
- Department of Ophthalmology, The Chinese People's Liberation Army General Hospital, The Chinese People's Liberation Army Medical School, Beijing, China
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Sanz-Morello B, Ahmadi H, Vohra R, Saruhanian S, Freude KK, Hamann S, Kolko M. Oxidative Stress in Optic Neuropathies. Antioxidants (Basel) 2021; 10:1538. [PMID: 34679672 PMCID: PMC8532958 DOI: 10.3390/antiox10101538] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/07/2021] [Accepted: 09/12/2021] [Indexed: 01/23/2023] Open
Abstract
Increasing evidence indicates that changes in the redox system may contribute to the pathogenesis of multiple optic neuropathies. Optic neuropathies are characterized by the neurodegeneration of the inner-most retinal neurons, the retinal ganglion cells (RGCs), and their axons, which form the optic nerve. Often, optic neuropathies are asymptomatic until advanced stages, when visual impairment or blindness is unavoidable despite existing treatments. In this review, we describe systemic and, whenever possible, ocular redox dysregulations observed in patients with glaucoma, ischemic optic neuropathy, optic neuritis, hereditary optic neuropathies (i.e., Leber's hereditary optic neuropathy and autosomal dominant optic atrophy), nutritional and toxic optic neuropathies, and optic disc drusen. We discuss aspects related to anti/oxidative stress biomarkers that need further investigation and features related to study design that should be optimized to generate more valuable and comparable results. Understanding the role of oxidative stress in optic neuropathies can serve to develop therapeutic strategies directed at the redox system to arrest the neurodegenerative processes in the retina and RGCs and ultimately prevent vision loss.
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Affiliation(s)
- Berta Sanz-Morello
- Eye Translational Research Unit, Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark; (B.S.-M.); (H.A.); (R.V.)
| | - Hamid Ahmadi
- Eye Translational Research Unit, Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark; (B.S.-M.); (H.A.); (R.V.)
- Department of Ophthalmology, Rigshospitalet, 2600 Glostrup, Denmark;
| | - Rupali Vohra
- Eye Translational Research Unit, Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark; (B.S.-M.); (H.A.); (R.V.)
- Group of Stem Cell Models for Studies of Neurodegenerative Diseases, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870 Frederiksberg, Denmark; (S.S.); (K.K.F.)
| | - Sarkis Saruhanian
- Group of Stem Cell Models for Studies of Neurodegenerative Diseases, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870 Frederiksberg, Denmark; (S.S.); (K.K.F.)
| | - Kristine Karla Freude
- Group of Stem Cell Models for Studies of Neurodegenerative Diseases, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870 Frederiksberg, Denmark; (S.S.); (K.K.F.)
| | - Steffen Hamann
- Department of Ophthalmology, Rigshospitalet, 2600 Glostrup, Denmark;
| | - Miriam Kolko
- Eye Translational Research Unit, Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark; (B.S.-M.); (H.A.); (R.V.)
- Department of Ophthalmology, Rigshospitalet, 2600 Glostrup, Denmark;
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Xu X, Wang P, Jia X, Sun W, Li S, Xiao X, Hejtmancik JF, Zhang Q. Pathogenicity evaluation and the genotype-phenotype analysis of OPA1 variants. Mol Genet Genomics 2021; 296:845-862. [PMID: 33884488 DOI: 10.1007/s00438-021-01783-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 04/02/2021] [Indexed: 12/21/2022]
Abstract
Autosomal dominant optic atrophy (ADOA) is an important cause of irreversible visual impairment in children and adolescents. About 60-90% of ADOA is caused by the pathogenic variants of OPA1 gene. By evaluating the pathogenicity of OPA1 variants and summarizing the relationship between the genotype and phenotype, this study aimed to provide a reference for clinical genetic test involving OPA1. Variants in OPA1 were selected from the exome sequencing results in 7092 cases of hereditary eye diseases and control groups from our in-house data. At the same time, the urine cells of some optic atrophy patients with OPA1 variants as well as their family members were collected and oxygen consumption rates (OCR) were measured in these cells to evaluate the pathogenicity of variants. As a result, 97 variants were detected, including 94 rare variants and 3 polymorphisms. And the 94 rare variants were classified into three groups: pathogenic (33), variants of uncertain significance (19), and likely benign (42). Our results indicated that the frameshift variants at the 3' terminus might be pathogenic, while the variants in exon 7 and intron 4 might be benign. The penetrance of the missense variants was higher than that of truncation variants. The OCR of cells with pathogenic OPA1 variants were significantly lower than those without pathogenic variants. In conclusion, some variants might be benign although predicted pathogenic in previous studies while some might have unknown pathogenesis. Measuring the OCR in urine cells could be used as a method to evaluate the pathogenicity of some OPA1 variants.
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Affiliation(s)
- Xingyu Xu
- State Key Laboratory of Ophthalmology, Pediatric and Genetic Eye Clinic, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlie Road, Guangzhou, 510060, China
| | - Panfeng Wang
- State Key Laboratory of Ophthalmology, Pediatric and Genetic Eye Clinic, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlie Road, Guangzhou, 510060, China
| | - Xiaoyun Jia
- State Key Laboratory of Ophthalmology, Pediatric and Genetic Eye Clinic, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlie Road, Guangzhou, 510060, China
| | - Wenmin Sun
- State Key Laboratory of Ophthalmology, Pediatric and Genetic Eye Clinic, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlie Road, Guangzhou, 510060, China
| | - Shiqiang Li
- State Key Laboratory of Ophthalmology, Pediatric and Genetic Eye Clinic, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlie Road, Guangzhou, 510060, China
| | - Xueshan Xiao
- State Key Laboratory of Ophthalmology, Pediatric and Genetic Eye Clinic, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlie Road, Guangzhou, 510060, China
| | - J Fielding Hejtmancik
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Qingjiong Zhang
- State Key Laboratory of Ophthalmology, Pediatric and Genetic Eye Clinic, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlie Road, Guangzhou, 510060, China.
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Holody C, Anfray A, Mast H, Lessard M, Han WH, Carpenter R, Bourque S, Sauvé Y, Lemieux H. Differences in relative capacities of oxidative phosphorylation pathways may explain sex- and tissue-specific susceptibility to vision defects due to mitochondrial dysfunction. Mitochondrion 2020; 56:102-110. [PMID: 33271347 DOI: 10.1016/j.mito.2020.11.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 10/09/2020] [Accepted: 11/18/2020] [Indexed: 01/03/2023]
Abstract
Mitochondrial dysfunction is a major cause and/or contributor to the development and progression of vision defects in many ophthalmologic and mitochondrial diseases. Despite their mechanistic commonality, these diseases exhibit an impressive variety in sex- and tissue-specific penetrance, incidence, and severity. Currently, there is no functional explanation for these differences. We measured the function, relative capacities, and patterns of control of various oxidative phosphorylation pathways in the retina, the eyecup, the extraocular muscles, the optic nerve, and the sciatic nerve of adult male and female rats. We show that the control of mitochondrial respiratory pathways in the visual system is sex- and tissue-specific and that this may be an important factor in determining susceptibility to mitochondrial dysfunction between these groups. The optic nerve showed a low relative capacity of the NADH pathway, depending on complex I, compared to other tissues relying mainly on mitochondria for energy production. Furthermore, NADH pathway capacity is higher in females compared to males, and this sexual dimorphism occurs only in the optic nerve. Our results propose an explanation for Leber's hereditary optic neuropathy, a mitochondrial disease more prevalent in males where the principal tissue affected is the optic nerve. To our knowledge, this is the first study to identify and provide functional explanations for differences in the occurrence and severity of visual defects between tissues and between sexes. Our results highlight the importance of considering sex- and tissue-specific mitochondrial function in elucidating pathophysiological mechanisms of visual defects.
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Affiliation(s)
- Claudia Holody
- Faculty Saint-Jean, University of Alberta, Edmonton, Alberta, Canada; Dept. of Pediatrics, University of Alberta, Edmonton, Alberta, Canada; Women and Children Research Health Institute, University of Alberta, Edmonton, Alberta, Canada; Dept. of Anesthesiology & Pain Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Anaïs Anfray
- Faculty Saint-Jean, University of Alberta, Edmonton, Alberta, Canada
| | - Heather Mast
- Faculty Saint-Jean, University of Alberta, Edmonton, Alberta, Canada
| | - Martin Lessard
- Faculty Saint-Jean, University of Alberta, Edmonton, Alberta, Canada
| | - Woo Hyun Han
- Faculty Saint-Jean, University of Alberta, Edmonton, Alberta, Canada
| | - Rowan Carpenter
- Faculty Saint-Jean, University of Alberta, Edmonton, Alberta, Canada
| | - Stephane Bourque
- Dept. of Pediatrics, University of Alberta, Edmonton, Alberta, Canada; Women and Children Research Health Institute, University of Alberta, Edmonton, Alberta, Canada; Dept. of Anesthesiology & Pain Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Yves Sauvé
- Dept. of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Hélène Lemieux
- Faculty Saint-Jean, University of Alberta, Edmonton, Alberta, Canada; Women and Children Research Health Institute, University of Alberta, Edmonton, Alberta, Canada; Dept. of Medicine, University of Alberta, Edmonton, Alberta, Canada.
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Tetramethylpyrazine Analogue T-006 Exerts Neuroprotective Effects against 6-Hydroxydopamine-Induced Parkinson's Disease In Vitro and In Vivo. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:8169125. [PMID: 31827703 PMCID: PMC6885178 DOI: 10.1155/2019/8169125] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 06/17/2019] [Accepted: 07/18/2019] [Indexed: 11/25/2022]
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc), and there is no cure for it at present. We have previously reported that the tetramethylpyrazine (TMP) derivative T-006 exhibited beneficial effects in Alzheimer's disease (AD) models. However, its effect on PD remains unclear. In the present study, we investigated the neuroprotective effects and underlying mechanisms of T-006 against 6-hydroxydopamine- (6-OHDA-) induced lesions in in vivo and in vitro PD models. Our results demonstrated that T-006 alleviated mitochondrial membrane potential loss and restored the energy metabolism and mitochondrial biogenesis that were induced by 6-OHDA in PC12 cells. In addition, animal experiments showed that administration of T-006 significantly attenuated the 6-OHDA-induced loss of tyrosine hydroxylase- (TH-) positive neurons in the SNpc, as well as dopaminergic nerve fibers in the striatum, and also increased the concentration of dopamine and its metabolites (DOPAC, HVA) in the striatum. Functional deficits were restored following T-006 treatment in 6-OHDA-lesioned mice, as demonstrated by improved motor coordination and rotational behavior. In addition, we found that the neuroprotective effects of T-006 were mediated, at least in part, by the activation of both the PKA/Akt/GSK-3β and CREB/PGC-1α/NRF-1/TFAM pathways. In summary, our findings demonstrate that T-006 could be developed as a novel neuroprotective agent for PD, and the two pathways might be promising therapeutic targets for PD.
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Guo H, Li S, Dai L, Huang X, Yu T, Yin Z, Bai Y. Genetic analysis in a cohort of patients with hereditary optic neuropathies in Southwest of China. Mitochondrion 2018; 46:327-333. [PMID: 30201499 DOI: 10.1016/j.mito.2018.09.002] [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] [Received: 07/03/2017] [Revised: 02/25/2018] [Accepted: 09/04/2018] [Indexed: 11/16/2022]
Abstract
We report the results of molecular screening in 121 patients with suspected hereditary optic neuropathies. The 34 primary and 9 secondary LHON mutations were screened in all the patients. In the familial cases, OPA1 was also tested when negative finding for the mtDNA mutations screening. Molecular defects were identified in 35 patients (28.9% of screened patients). Among these, 33 patients (94.3%) had an mtDNA mutation, including m.11778G > A (69.7%), m.14484 T > C, m.3460G > A, m.3635G > A, m.14502 T > C and three secondary mutations m.3316G > A, m.3394 T > C, m.3497C > T. Two novel OPA1 mutations, c.1301 T > G (p.Leu434Arg) and c.985-1G > A (IVS9-1G > A), were also detected in families with the evidence of father-to-son transmission. In conclusion, we reported the results of the molecular screening of 121 patients with hereditary optic neuropathies from southwest of China. Our results highlight the importance of investigating LHON-causing mtDNA mutations and OPA1 mutations in cases of suspected hereditary optic neuropathy.
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Affiliation(s)
- Hong Guo
- Department of Medical Genetics, Army Medical University, 30#, Gaotanyan St., Shapingba District, Chongqing 400038, PR China
| | - Shiying Li
- Southwest Eye Hospital, Southwest Hospital, Army Medical University, 30#, Gaotanyan St., Shapingba District 400038, Chongqing, PR China
| | - Limeng Dai
- Department of Medical Genetics, Army Medical University, 30#, Gaotanyan St., Shapingba District, Chongqing 400038, PR China
| | - Xiaoyong Huang
- Southwest Eye Hospital, Southwest Hospital, Army Medical University, 30#, Gaotanyan St., Shapingba District 400038, Chongqing, PR China
| | - Tao Yu
- Southwest Eye Hospital, Southwest Hospital, Army Medical University, 30#, Gaotanyan St., Shapingba District 400038, Chongqing, PR China
| | - Zhengqin Yin
- Southwest Eye Hospital, Southwest Hospital, Army Medical University, 30#, Gaotanyan St., Shapingba District 400038, Chongqing, PR China.
| | - Yun Bai
- Department of Medical Genetics, Army Medical University, 30#, Gaotanyan St., Shapingba District, Chongqing 400038, PR China.
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Finsterer J, Mancuso M, Pareyson D, Burgunder JM, Klopstock T. Mitochondrial disorders of the retinal ganglion cells and the optic nerve. Mitochondrion 2017; 42:1-10. [PMID: 29054473 DOI: 10.1016/j.mito.2017.10.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 10/02/2017] [Accepted: 10/06/2017] [Indexed: 12/13/2022]
Abstract
OBJECTIVES To summarise and discuss recent findings and future perspectives concerning mitochondrial disorders (MIDs) affecting the retinal ganglion cells and the optic nerve (mitochondrial optic neuropathy. MON). METHOD Literature review. RESULTS MON in MIDs is more frequent than usually anticipated. MON may occur in specific as well as non-specific MIDs. In specific and non-specific MIDs, MON may be a prominent or non-prominent phenotypic feature and due to mutations in genes located either in the mitochondrial DNA (mtDNA) or the nuclear DNA (nDNA). Clinically, MON manifests with painless, bilateral or unilateral, slowly or rapidly progressive visual impairment and visual field defects. In some cases, visual impairment may spontaneously recover. The most frequent MIDs with MON include LHON due to mutations in mtDNA-located genes and autosomal dominant optic atrophy (ADOA) or autosomal recessive optic atrophy (AROA) due to mutations in nuclear genes. Instrumental investigations for diagnosing MON include fundoscopy, measurement of visual acuity, visual fields, and color vision, visually-evoked potentials, optical coherence tomography, fluorescein angiography, electroretinography, and MRI of the orbita and cerebrum. In non-prominent MON, work-up of the muscle biopsy with transmission electron microscopy may indicate mitochondrial destruction. Treatment is mostly supportive but idebenone has been approved for LHON and experimental approaches are promising. CONCLUSIONS MON needs to be appreciated, requires extensive diagnostic work-up, and supportive treatment should be applied although loss of vision, as the most severe outcome, can often not be prevented.
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Affiliation(s)
| | - Michelangelo Mancuso
- Department of Clinical and Experimental Medicine, Neurological Clinic, University of Pisa, Italy
| | - Davide Pareyson
- Department of Clinical Neurosciences, C. Besta Neurological Institute, IRCCS Foundation, Milan, Italy.
| | - Jean-Marc Burgunder
- Department of Neurology, University of Bern, Switzerland; Department of Neurology, Sun Yat Sen University, Guangzhou, China; Department of Neurology, Sichuan University, Chendgu, China.
| | - Thomas Klopstock
- Department of Neurology, Friedrich-Baur Institute, Ludwig-Maximilians-Universität München, Munich, Germany; German Center for Neurodegenerative Diseases (DZNE), Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.
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Genetic and Clinical Analyses of DOA and LHON in 304 Chinese Patients with Suspected Childhood-Onset Hereditary Optic Neuropathy. PLoS One 2017; 12:e0170090. [PMID: 28081242 PMCID: PMC5230780 DOI: 10.1371/journal.pone.0170090] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 12/28/2016] [Indexed: 02/08/2023] Open
Abstract
Leber hereditary optic neuropathy (LHON) and dominant optic atrophy (DOA), the most common forms of hereditary optic neuropathy, are easily confused, and it is difficult to distinguish one from the other in the clinic, especially in young children. The present study was designed to survey the mutation spectrum of common pathogenic genes (OPA1, OPA3 and mtDNA genes) and to analyze the genotype-phenotype characteristics of Chinese patients with suspected childhood-onset hereditary optic neuropathy. Genomic DNA and clinical data were collected from 304 unrelated Chinese probands with suspected hereditary optic neuropathy with an age of onset below 14 years. Sanger sequencing was used to screen variants in the coding and adjacent regions of OPA1, OPA3 and the three primary LHON-related mutation sites in mitochondrial DNA (mtDNA) (m.3460G>A, m.11778G>A and m.14484T>C). All patients underwent a complete ophthalmic examination and were compared with age-matched controls. We identified 89/304 (29.3%) primary mtDNA mutations related to LHON in 304 probands, including 76 mutations at m.11778 (76/89, 85.4% of all mtDNA mutations), four at m.3460 (4/89, 4.5%) and nine at m.14484 (9/89, 10.1%). This result was similar to the mutation frequency among Chinese patients with LHON of any age. Screening of OPA1 revealed 23 pathogenic variants, including 11 novel and 12 known pathogenic mutations. This study expanded the OPA1 mutation spectrum, and our results showed that OPA1 mutation is another common cause of childhood-onset hereditary optic neuropathy in Chinese pediatric patients, especially those with disease onset during preschool age.
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Multiethnic involvement in autosomal-dominant optic atrophy in Singapore. Eye (Lond) 2016; 31:475-480. [PMID: 27858935 DOI: 10.1038/eye.2016.255] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 09/30/2016] [Indexed: 11/08/2022] Open
Abstract
PurposeAutosomal-dominant optic atrophy (ADOA), often associated with mutations in the OPA1 gene (chromosome 3q28-q29) is rarely reported in Asia. Our aim was to identify and describe this condition in an Asian population in Singapore.Patients and methodsPreliminary cross-sectional study at the Singapore National Eye Centre, including patients with clinical suspicion of ADOA, who subsequently underwent genetic testing by direct sequencing of the OPA1 gene.ResultsAmong 12 patients (10 families) with clinically suspected ADOA, 7 patients (5 families) from 3 different ethnic origins (Chinese, Indian, and Malay) carried a heterozygous pathogenic variant in the OPA1 gene. The OPA1 mutations were located on exons 8, 9, 11, and 17: c.869G>A (p.Arg290Glu), c.892A>G (p.Ser298Gly), c.1140G>A (splicing mutation), and c.1669C>T (p.Arg557*), respectively. One splicing mutation (c.871-1G>A) was identified in intron 8. We also identified a novel mutation causing optic atrophy and deafness (c.892A>G (p.Ser298Gly)). Among the phenotypic features, colour pupillometry disclosed a dissociation between low vision and preserved pupillary light reflex in ADOA.ConclusionWe report the first cases of genetically confirmed OPA1-related ADOA from Singapore, including a novel mutation causing 'ADOA plus' syndrome. Further epidemiological studies are needed in order to determine the prevalence of ADOA in South-East Asia.
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