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Martins S, Santos MJ, Teixeira M, Diogo L, do Carmo Macário M, Marques JP, Fonseca P, Grazina M. GenEye24: Novel rapid screening test for the top-3 Leber's Hereditary Optic Neuropathy pathogenic sequence variants. Mitochondrion 2023; 69:64-70. [PMID: 36716943 DOI: 10.1016/j.mito.2023.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 01/19/2023] [Accepted: 01/22/2023] [Indexed: 01/29/2023]
Abstract
Leber's Hereditary Optic Neuropathy (LHON) has been mainly (90-95 %) associated to one of three variants: m.3460G>A, m.11778G>A, m.14484T>C. Herein, a screening method was developed for its detection, supporting clinical/therapeutics decision. It relies on real-time PCR with High-Resolution Melting (HRM) analysis. Variant classification is made using HRM Software and quality controls. A total of 101 samples were analyzed. All samples were correctly assigned: 58 wild-type, 35 positive for m.11778G>A, 6 positive for m.14484T>C, 2 positive for m.3460G>A. Results presented sensitivity = 1, specificity = 1, Positive Predictive Value = 1 and Negative Predictive Value = 1. A new Real-Time PCR/HRM screening method cost-efficient, simple, robust and quick, detecting LHON's top-3 is described.
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Affiliation(s)
- Sara Martins
- CIBB - Center for Innovative Biomedicine and Biotechnology (www.cibb.uc.pt/), Coimbra, Portugal; Laboratory of Mitochondrial Biomedicine and Theranostics, CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal; Biology Department, University of Aveiro, Aveiro, Portugal
| | - Maria João Santos
- CIBB - Center for Innovative Biomedicine and Biotechnology (www.cibb.uc.pt/), Coimbra, Portugal; Laboratory of Mitochondrial Biomedicine and Theranostics, CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal; FMUC - Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Márcia Teixeira
- CIBB - Center for Innovative Biomedicine and Biotechnology (www.cibb.uc.pt/), Coimbra, Portugal; Laboratory of Mitochondrial Biomedicine and Theranostics, CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Luísa Diogo
- CIBB - Center for Innovative Biomedicine and Biotechnology (www.cibb.uc.pt/), Coimbra, Portugal; FMUC - Faculty of Medicine, University of Coimbra, Coimbra, Portugal; Reference Centre of Inherited Metabolic Diseases - CHUC- Centro Hospitalar e Universitário de Coimbra, EPE, Coimbra, Portugal; CHUC - Centro Hospitalar e Universitário de Coimbra, EPE, Coimbra, Portugal
| | - Maria do Carmo Macário
- CIBB - Center for Innovative Biomedicine and Biotechnology (www.cibb.uc.pt/), Coimbra, Portugal; FMUC - Faculty of Medicine, University of Coimbra, Coimbra, Portugal; Reference Centre of Inherited Metabolic Diseases - CHUC- Centro Hospitalar e Universitário de Coimbra, EPE, Coimbra, Portugal; CHUC - Centro Hospitalar e Universitário de Coimbra, EPE, Coimbra, Portugal
| | - João Pedro Marques
- FMUC - Faculty of Medicine, University of Coimbra, Coimbra, Portugal; CHUC - Centro Hospitalar e Universitário de Coimbra, EPE, Coimbra, Portugal
| | - Pedro Fonseca
- CIBB - Center for Innovative Biomedicine and Biotechnology (www.cibb.uc.pt/), Coimbra, Portugal; FMUC - Faculty of Medicine, University of Coimbra, Coimbra, Portugal; CHUC - Centro Hospitalar e Universitário de Coimbra, EPE, Coimbra, Portugal
| | - Manuela Grazina
- CIBB - Center for Innovative Biomedicine and Biotechnology (www.cibb.uc.pt/), Coimbra, Portugal; Laboratory of Mitochondrial Biomedicine and Theranostics, CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal; FMUC - Faculty of Medicine, University of Coimbra, Coimbra, Portugal.
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Gene therapy restores mitochondrial function and protects retinal ganglion cells in optic neuropathy induced by a mito-targeted mutant ND1 gene. Gene Ther 2022; 29:368-378. [PMID: 35383288 PMCID: PMC9233058 DOI: 10.1038/s41434-022-00333-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 03/19/2022] [Accepted: 03/24/2022] [Indexed: 11/21/2022]
Abstract
Therapies for genetic disorders caused by mutated mitochondrial DNA are an unmet need, in large part due barriers in delivering DNA to the organelle and the absence of relevant animal models. We injected into mouse eyes a mitochondrially targeted Adeno-Associated-Virus (MTS-AAV) to deliver the mutant human NADH ubiquinone oxidoreductase subunit I (hND1/m.3460G>A) responsible for Leber’s hereditary optic neuropathy, the most common primary mitochondrial genetic disease. We show that the expression of the mutant hND1 delivered to retinal ganglion cells (RGC) layer colocalizes with the mitochondrial marker PORIN and the assembly of the expressed hND1 protein into host respiration complex I. The hND1 injected eyes exhibit hallmarks of the human disease with progressive loss of RGC function and number, as well as optic nerve degeneration. We also show that gene therapy in the hND1 eyes by means of an injection of a second MTS-AAV vector carrying wild type human ND1 restores mitochondrial respiratory complex I activity, the rate of ATP synthesis and protects RGCs and their axons from dysfunction and degeneration. These results prove that MTS-AAV is a highly efficient gene delivery approach with the ability to create mito-animal models and has the therapeutic potential to treat mitochondrial genetic diseases.
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Shuai J, Shi J, Liang Y, Ji F, Gu L, Yuan Z. Mutational analysis of mitochondrial tRNA genes in 138 patients with Leber's hereditary optic neuropathy. Ir J Med Sci 2021; 191:865-876. [PMID: 34053002 DOI: 10.1007/s11845-021-02656-6] [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: 04/29/2021] [Accepted: 05/19/2021] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Mutations in mitochondrial DNA (mtDNA) are the most important causes for Leber's hereditary optic neuropathy (LHON). Of these, three primary mtDNA mutations account for more than 90% cases of this disease. However, to date, little is known regarding the relationship between mitochondrial tRNA (mt-tRNA) variants and LHON. AIM In this study, we aimed to investigate the association between mt-tRNA variants and LHON. METHODOLOGY One hundred thirty-eight LHON patients lacking three primary mutations (ND1 3460G > A, ND4 11778Gxs > A, and ND6 14484 T > C), as well as 266 controls were enrolled in this study. PCR-Sanger sequencing was performed to screen the mt-tRNA variants. Moreover, the phylogenetic analysis, pathogenicity scoring system, as well as mitochondrial functions were performed. RESULTS We identified 8 possible pathogenic variants: tRNAPhe 593 T > C, tRNALeu(UUR) 3275C > T, tRNAGln 4363 T > C, tRNAMet 4435A > G, tRNAAla 5587 T > C, tRNAGlu 14693A > G, tRNAThr 15927G > A, and 15951A > G, which may change the structural and functional impact on the corresponding tRNAs, and subsequently lead to a failure in tRNA metabolism. Furthermore, significant reductions in mitochondrial ATP and MMP levels and an overproduction of ROS were observed in cybrid cells containing these mt-tRNA variants, suggesting that these variants may lead to mitochondrial dysfunction which was responsible for LHON. CONCLUSION Our study indicated that mt-tRNA variants were associated with LHON, and screening for mt-tRNA variants were recommended for early detection, diagnosis, and prevention of maternally inherited LHON.
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Affiliation(s)
- Jie Shuai
- Department of Ophthalmology, the Affiliated Hospital of Nantong University, Nantong, China
| | - Jian Shi
- Department of Ophthalmology, the Affiliated Hospital of Nantong University, Nantong, China
| | - Ya Liang
- Department of Ophthalmology, the First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing, Jiangsu Province, China
| | - Fangfang Ji
- Department of Ophthalmology, the First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing, Jiangsu Province, China
| | - Luo Gu
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Zhilan Yuan
- Department of Ophthalmology, the First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing, Jiangsu Province, China.
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Sun CB, Bai HX, Xu DN, Xiao Q, Liu Z. Mitochondrial 13513G>A Mutation With Low Mutant Load Presenting as Isolated Leber's Hereditary Optic Neuropathy Assessed by Next Generation Sequencing. Front Neurol 2021; 12:601307. [PMID: 33746872 PMCID: PMC7970004 DOI: 10.3389/fneur.2021.601307] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 02/10/2021] [Indexed: 11/13/2022] Open
Abstract
Objective: Mitochondrial 13513G>A mutation presenting as isolated Leber's hereditary optic neuropathy (LHON) without any extraocular pathology has not been reported in literature. We herein evaluate the clinical characteristics and heteroplasmy of m.13513G>A mutation manifesting as isolated LHON. Methods: Seven members of a Chinese family were enrolled in this study. All subjects underwent detailed systemic and ophthalmic examinations. Mitochondrial DNA in their blood was assessed by targeted PCR amplifications, next generation sequencing (NGS), and pyrosequencing. One hundred of blood samples from ethnic-matched healthy volunteers were tested by NGS and pyrosequencing as normal controls. Results: Isolated LHON without any other ocular or extraocular pathology was identified in a 16 year old patient in this family. Heteroplasmic m.13513G>A mutation was detected by NGS of the full mtDNA genome in the patient with mutant load of 33.56%, and of 26% 3 months and 3 years after the onset of LHON, respectively. No m.13513G>A mutation was detected in all his relatives by NGS. Pyrosequencing revealed the mutant load of m.13513G>A mutation of the LHON patient, his mother, father and sister were 22.4, 1.9, 0, and 0%, respectively. None of 100 healthy control subjects was detected to harbor m.13513G>A mutation either by NGS or by pyrosequencing of the full mt DNA genome. Conclusions: We first report m.13513G>A mutation with low mutant load presenting as isolated LHON. NGS of the full mitochondrial DNA genome is highly recommended for LHON suspects when targeted PCR amplification for main primary point mutations of LHON was negative.
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Affiliation(s)
- Chuan-Bin Sun
- Eye Center, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Hai-Xia Bai
- Eye Center, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Dan-Ni Xu
- Eye Center, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Qing Xiao
- Eye Center, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Zhe Liu
- Department of Ophthalmology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, China
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Ramlogan-Steel CA, Murali A, Andrzejewski S, Dhungel B, Steel JC, Layton CJ. Gene therapy and the adeno-associated virus in the treatment of genetic and acquired ophthalmic diseases in humans: Trials, future directions and safety considerations. Clin Exp Ophthalmol 2019; 47:521-536. [PMID: 30345694 DOI: 10.1111/ceo.13416] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Revised: 10/04/2018] [Accepted: 10/15/2018] [Indexed: 12/27/2022]
Abstract
Voretigene neparvovec-rzyl was recently approved for the treatment of Leber congenital amaurosis, and the use of gene therapy for eye disease is attracting even greater interest. The eye has immune privileged status, is easily accessible, requires a reduced dosage of therapy due to its size and is highly compartmentalized, significantly reducing systemic spread. Adeno-associated virus (AAV), with its low pathogenicity, prolonged expression profile and ability to transduce multiple cell types, has become the leading gene therapy vector. Target diseases have moved beyond currently untreatable inherited dystrophies to common, partially treatable acquired conditions such as exudative age-related macular degeneration and glaucoma, but use of the technology in these conditions imposes added obligations for caution in vector design. This review discusses the current status of AAV gene therapy trials in genetic and acquired ocular diseases, and explores new scientific developments, which could help ensure effective and safe use of the therapy in the future.
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Affiliation(s)
- Charmaine A Ramlogan-Steel
- LVF Ophthalmology Research Centre, Translational Research Institute, Brisbane, Australia.,Greenslopes Clinical School, Faculty of Medicine, University of Queensland, Greenslopes Hospital, Brisbane, Australia.,Medical and Applied Science, Central Queensland University, School of Health, Rockhampton, Australia
| | - Aparna Murali
- LVF Ophthalmology Research Centre, Translational Research Institute, Brisbane, Australia.,Greenslopes Clinical School, Faculty of Medicine, University of Queensland, Greenslopes Hospital, Brisbane, Australia
| | - Slawomir Andrzejewski
- LVF Ophthalmology Research Centre, Translational Research Institute, Brisbane, Australia.,Greenslopes Clinical School, Faculty of Medicine, University of Queensland, Greenslopes Hospital, Brisbane, Australia
| | - Bijay Dhungel
- Greenslopes Clinical School, Faculty of Medicine, University of Queensland, Greenslopes Hospital, Brisbane, Australia
| | - Jason C Steel
- Medical and Applied Science, Central Queensland University, School of Health, Rockhampton, Australia
| | - Christopher J Layton
- LVF Ophthalmology Research Centre, Translational Research Institute, Brisbane, Australia.,Greenslopes Clinical School, Faculty of Medicine, University of Queensland, Greenslopes Hospital, Brisbane, Australia
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Vignal C, Uretsky S, Fitoussi S, Galy A, Blouin L, Girmens JF, Bidot S, Thomasson N, Bouquet C, Valero S, Meunier S, Combal JP, Gilly B, Katz B, Sahel JA. Safety of rAAV2/2- ND4 Gene Therapy for Leber Hereditary Optic Neuropathy. Ophthalmology 2018; 125:945-947. [DOI: 10.1016/j.ophtha.2017.12.036] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 12/27/2017] [Accepted: 12/28/2017] [Indexed: 12/16/2022] Open
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Finsterer J, Zarrouk-Mahjoub S. Biomarkers for Detecting Mitochondrial Disorders. J Clin Med 2018; 7:E16. [PMID: 29385732 PMCID: PMC5852432 DOI: 10.3390/jcm7020016] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Revised: 12/28/2017] [Accepted: 01/19/2018] [Indexed: 01/22/2023] Open
Abstract
(1) Objectives: Mitochondrial disorders (MIDs) are a genetically and phenotypically heterogeneous group of slowly or rapidly progressive disorders with onset from birth to senescence. Because of their variegated clinical presentation, MIDs are difficult to diagnose and are frequently missed in their early and late stages. This is why there is a need to provide biomarkers, which can be easily obtained in the case of suspecting a MID to initiate the further diagnostic work-up. (2) Methods: Literature review. (3) Results: Biomarkers for diagnostic purposes are used to confirm a suspected diagnosis and to facilitate and speed up the diagnostic work-up. For diagnosing MIDs, a number of dry and wet biomarkers have been proposed. Dry biomarkers for MIDs include the history and clinical neurological exam and structural and functional imaging studies of the brain, muscle, or myocardium by ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), MR-spectroscopy (MRS), positron emission tomography (PET), or functional MRI. Wet biomarkers from blood, urine, saliva, or cerebrospinal fluid (CSF) for diagnosing MIDs include lactate, creatine-kinase, pyruvate, organic acids, amino acids, carnitines, oxidative stress markers, and circulating cytokines. The role of microRNAs, cutaneous respirometry, biopsy, exercise tests, and small molecule reporters as possible biomarkers is unsolved. (4) Conclusions: The disadvantages of most putative biomarkers for MIDs are that they hardly meet the criteria for being acceptable as a biomarker (missing longitudinal studies, not validated, not easily feasible, not cheap, not ubiquitously available) and that not all MIDs manifest in the brain, muscle, or myocardium. There is currently a lack of validated biomarkers for diagnosing MIDs.
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Affiliation(s)
- Josef Finsterer
- Krankenanstalt Rudolfstiftung, Postfach 20, 1180 Vienna, Austria.
| | - Sinda Zarrouk-Mahjoub
- El Manar and Genomics Platform, Pasteur Institute of Tunis, University of Tunis, Tunis 1068, Tunisia.
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Ji Y, Qiao L, Liang X, Zhu L, Gao Y, Zhang J, Jia Z, Wei QP, Liu X, Jiang P, Guan MX. Leber's hereditary optic neuropathy is potentially associated with a novel m.5587T>C mutation in two pedigrees. Mol Med Rep 2017; 16:8997-9004. [PMID: 28990081 DOI: 10.3892/mmr.2017.7734] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 07/21/2017] [Indexed: 12/17/2022] Open
Abstract
Mitochondrial (mt)DNA mutations have been revealed to be associated with Leber's hereditary optic neuropathy (LHON). The present study conducted clinical, genetic and molecular evaluations of two Han Chinese families. A total of 4 (3 men and 1 female) out of 14 matrilineal relatives in the families exhibited visual impairment with variable severity and age of onset. The average age of onset of visual loss was 20.5 years old. Molecular analysis of the complete mitochondrial genome in these pedigrees demonstrated that the three primary mutations associated with LHON were not detected; however, the homoplasmic m.5587T>C mutation was identified, which was localized at the end of the mitochondrially encoded transfer (t)RNA alanine gene and may alter the tertiary structure of this tRNA. Subsequently, this structural alteration may result in tRNA metabolism failure. In addition, distinct sets of mtDNA polymorphisms belonging to haplogroup F1 were detected in both families tested. The findings of the present study suggested that the m.5587T>C mutation may be involved in the pathogenesis of visual impairment. In addition, the mtDNA variant m.15024G>A(p.C93H) in the mitochondrially encoded cytochrome B gene was detected in both families, which exhibited evolutionary conservation, indicating it may serve a potential modifying role in the development of visual impairment associated with m.5587T>C mutation in these families. Furthermore, other modifying factors, including nuclear modifier genes, and environmental and personal factors may also contribute to the development of LHON in subjects carrying this mutation.
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Affiliation(s)
- Yanchun Ji
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
| | - Lihua Qiao
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
| | - Xiaoyang Liang
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
| | - Ling Zhu
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
| | - Yinglong Gao
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
| | - Juanjuan Zhang
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang 325025, P.R. China
| | - Zidong Jia
- Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
| | - Qi-Ping Wei
- Department of Ophthalmology, Beijing University of Chinese Medicine, Beijing 100029, P.R. China
| | - Xiaoling Liu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang 325025, P.R. China
| | - Pingping Jiang
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
| | - Min-Xin Guan
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
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Heimer G, Kerätär J, Riley L, Balasubramaniam S, Eyal E, Pietikäinen L, Hiltunen JK, Marek-Yagel D, Hamada J, Gregory A, Rogers C, Hogarth P, Nance MA, Shalva N, Veber A, Tzadok M, Nissenkorn A, Tonduti D, Renaldo F, Kraoua I, Panteghini C, Valletta L, Garavaglia B, Cowley MJ, Gayevskiy V, Roscioli T, Silberstein JM, Hoffmann C, Raas-Rothschild A, Tiranti V, Anikster Y, Christodoulou J, Kastaniotis AJ, Ben-Zeev B, Hayflick SJ, Bamshad M, Leal S, Nickerson D, Anderson P, Annable M, Blue E, Buckingham K, Chin J, Chong J, Cornejo R, Davis C, Frazar C, He Z, Jarvik G, Jimenez G, Johanson E, Kolar T, Krauter S, Luksic D, Marvin C, McGee S, McGoldrick D, Patterson K, Perez M, Phillips S, Pijoan J, Robertson P, Santos-Cortez R, Shankar A, Slattery K, Shively K, Siegel D, Smith J, Tackett M, Wang G, Wegener M, Weiss J, Wernick R, Wheeler M, Yi Q. MECR Mutations Cause Childhood-Onset Dystonia and Optic Atrophy, a Mitochondrial Fatty Acid Synthesis Disorder. Am J Hum Genet 2016; 99:1229-1244. [PMID: 27817865 DOI: 10.1016/j.ajhg.2016.09.021] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 09/26/2016] [Indexed: 11/24/2022] Open
Abstract
Mitochondrial fatty acid synthesis (mtFAS) is an evolutionarily conserved pathway essential for the function of the respiratory chain and several mitochondrial enzyme complexes. We report here a unique neurometabolic human disorder caused by defective mtFAS. Seven individuals from five unrelated families presented with childhood-onset dystonia, optic atrophy, and basal ganglia signal abnormalities on MRI. All affected individuals were found to harbor recessive mutations in MECR encoding the mitochondrial trans-2-enoyl-coenzyme A-reductase involved in human mtFAS. All six mutations are extremely rare in the general population, segregate with the disease in the families, and are predicted to be deleterious. The nonsense c.855T>G (p.Tyr285∗), c.247_250del (p.Asn83Hisfs∗4), and splice site c.830+2_830+3insT mutations lead to C-terminal truncation variants of MECR. The missense c.695G>A (p.Gly232Glu), c.854A>G (p.Tyr285Cys), and c.772C>T (p.Arg258Trp) mutations involve conserved amino acid residues, are located within the cofactor binding domain, and are predicted by structural analysis to have a destabilizing effect. Yeast modeling and complementation studies validated the pathogenicity of the MECR mutations. Fibroblast cell lines from affected individuals displayed reduced levels of both MECR and lipoylated proteins as well as defective respiration. These results suggest that mutations in MECR cause a distinct human disorder of the mtFAS pathway. The observation of decreased lipoylation raises the possibility of a potential therapeutic strategy.
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Holmøy T, Beiske AG, Zarnovicky S, Myro AZ, Røsjø E, Kerty E. Severe inflammatory disease activity 14 months after cessation of Natalizumab in a patient with Leber's optic neuropathy and multiple sclerosis - a case report. BMC Neurol 2016; 16:197. [PMID: 27756254 PMCID: PMC5070176 DOI: 10.1186/s12883-016-0720-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Accepted: 10/14/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Leber's hereditary optic neuropathy (LHON) co-occuring with multiple sclerosis-like disease (LHON-MS) is suggested to be a separate disease entity denoted Harding's disease. Little is known about the response to initiation and discontinuation of potent immunomodulatory treatment in LHON-MS. CASE PRESENTATION We describe a LHON-MS patient with 27 years disease duration who developed severe disease activity peaking 14 months after discontinuation of natalizumab, with extensive new inflammatory lesions throughout the brain and in the spinal cord resembling immune inflammatory reconstitution syndrome. She had previously been clinically and radiologically stable on natalizumab treatment for 6 years, and before that only experienced subtle clinical activity during 9 years on interferon beta1a. CONCLUSION This is the first report on severe exacerbation of inflammatory disease activity after discontinuation of natalizumab in LHON-MS, and suggests that late rebound activity can occur in these patients.
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Affiliation(s)
- Trygve Holmøy
- Department of Neurology, Akershus University Hospital, Lørenskog, Norway. .,Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
| | | | | | - Aija Zuleron Myro
- Department of Neurology, Akershus University Hospital, Lørenskog, Norway
| | - Egil Røsjø
- Department of Neurology, Akershus University Hospital, Lørenskog, Norway.,Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Emilia Kerty
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway.,Department of Neurology, Oslo University Hospital Rikshospitalet, Oslo, Norway
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