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Emperador S, Habbane M, López-Gallardo E, Del Rio A, Llobet L, Mateo J, Sanz-López AM, Fernández-García MJ, Sánchez-Tocino H, Benbunan-Ferreiro S, Calabuig-Goena M, Narvaez-Palazón C, Fernández-Vega B, González-Iglesias H, Urreizti R, Artuch R, Pacheu-Grau D, Bayona-Bafaluy P, Montoya J, Ruiz-Pesini E. Identification and characterization of a new pathologic mutation in a large Leber hereditary optic neuropathy pedigree. Orphanet J Rare Dis 2024; 19:148. [PMID: 38582886 PMCID: PMC10999093 DOI: 10.1186/s13023-024-03165-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Accepted: 03/30/2024] [Indexed: 04/08/2024] Open
Abstract
BACKGROUND Most patients suffering from Leber hereditary optic neuropathy carry one of the three classic pathologic mutations, but not all individuals with these genetic alterations develop the disease. There are different risk factors that modify the penetrance of these mutations. The remaining patients carry one of a set of very rare genetic variants and, it appears that, some of the risk factors that modify the penetrance of the classical pathologic mutations may also affect the phenotype of these other rare mutations. RESULTS We describe a large family including 95 maternally related individuals, showing 30 patients with Leber hereditary optic neuropathy. The mutation responsible for the phenotype is a novel transition, m.3734A > G, in the mitochondrial gene encoding the ND1 subunit of respiratory complex I. Molecular-genetic, biochemical and cellular studies corroborate the pathogenicity of this genetic change. CONCLUSIONS With the study of this family, we confirm that, also for this very rare mutation, sex and age are important factors modifying penetrance. Moreover, this pedigree offers an excellent opportunity to search for other genetic or environmental factors that additionally contribute to modify penetrance.
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Affiliation(s)
- Sonia Emperador
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50009- and 50013, Zaragoza, Spain
- Instituto de Investigación Sanitaria (IIS) de Aragón, 50009, Zaragoza, Spain
- Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain
| | - Mouna Habbane
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50009- and 50013, Zaragoza, Spain
- Laboratoire Biologie Et Santé, Faculté Des Sciences Ben M'Sick, Hassan II University of Casablanca, 20670, Casablanca, Morocco
| | - Ester López-Gallardo
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50009- and 50013, Zaragoza, Spain
- Instituto de Investigación Sanitaria (IIS) de Aragón, 50009, Zaragoza, Spain
- Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain
| | - Alejandro Del Rio
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50009- and 50013, Zaragoza, Spain
| | - Laura Llobet
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50009- and 50013, Zaragoza, Spain
- Instituto de Investigación Sanitaria (IIS) de Aragón, 50009, Zaragoza, Spain
- Certest Biotec, 50840-San Mateo de Gállego, Zaragoza, Spain
| | - Javier Mateo
- Servicio de Oftalmología, Hospital Clínico Universitario Lozano Blesa, 50009, Zaragoza, Spain
| | - Ana María Sanz-López
- Servicio de Oftalmología, Hospital Universitario de Toledo, 45004, Toledo, Spain
| | | | | | - Sol Benbunan-Ferreiro
- Servicio de Oftalmología. Hospital Universitario Río Hortega, 47012, Valladolid, Spain
| | - María Calabuig-Goena
- Servicio de Oftalmología. Hospital Universitario Río Hortega, 47012, Valladolid, Spain
| | | | | | - Hector González-Iglesias
- Instituto de Productos Lácteos de Asturias, Consejo Superior de Investigaciones Científicas (IPLA-CSIC), 33300-Villaviciosa, Asturias, Spain
| | - Roser Urreizti
- Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain
- Departament de Bioquímica Clínica, Institut de Recerca Sant Joan de Déu, 08950, Barcelona, Spain
| | - Rafael Artuch
- Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain
- Departament de Bioquímica Clínica, Institut de Recerca Sant Joan de Déu, 08950, Barcelona, Spain
| | - David Pacheu-Grau
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50009- and 50013, Zaragoza, Spain
- Instituto de Investigación Sanitaria (IIS) de Aragón, 50009, Zaragoza, Spain
- Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain
| | - Pilar Bayona-Bafaluy
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50009- and 50013, Zaragoza, Spain
- Instituto de Investigación Sanitaria (IIS) de Aragón, 50009, Zaragoza, Spain
- Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain
- Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Universidad de Zaragoza, 50018, Zaragoza, Spain
| | - Julio Montoya
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50009- and 50013, Zaragoza, Spain.
- Instituto de Investigación Sanitaria (IIS) de Aragón, 50009, Zaragoza, Spain.
- Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain.
| | - Eduardo Ruiz-Pesini
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50009- and 50013, Zaragoza, Spain.
- Instituto de Investigación Sanitaria (IIS) de Aragón, 50009, Zaragoza, Spain.
- Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain.
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Vikramdeo KS, Sudan SK, Singh AP, Singh S, Dasgupta S. Mitochondrial respiratory complexes: Significance in human mitochondrial disorders and cancers. J Cell Physiol 2022; 237:4049-4078. [PMID: 36074903 DOI: 10.1002/jcp.30869] [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: 11/17/2021] [Revised: 07/18/2022] [Accepted: 08/23/2022] [Indexed: 11/07/2022]
Abstract
Mitochondria are pivotal organelles that govern cellular energy production through the oxidative phosphorylation system utilizing five respiratory complexes. In addition, mitochondria also contribute to various critical signaling pathways including apoptosis, damage-associated molecular patterns, calcium homeostasis, lipid, and amino acid biosynthesis. Among these diverse functions, the energy generation program oversee by mitochondria represents an immaculate orchestration and functional coordination between the mitochondria and nuclear encoded molecules. Perturbation in this program through respiratory complexes' alteration results in the manifestation of various mitochondrial disorders and malignancy, which is alarmingly becoming evident in the recent literature. Considering the clinical relevance and importance of this emerging medical problem, this review sheds light on the timing and nature of molecular alterations in various respiratory complexes and their functional consequences observed in various mitochondrial disorders and human cancers. Finally, we discussed how this wealth of information could be exploited and tailored to develop respiratory complex targeted personalized therapeutics and biomarkers for better management of various incurable human mitochondrial disorders and cancers.
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Affiliation(s)
- Kunwar Somesh Vikramdeo
- Department of Pathology, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama, USA.,Department of Pathology, College of Medicine, University of South Alabama, Mobile, Alabama, USA
| | - Sarabjeet Kour Sudan
- Department of Pathology, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama, USA.,Department of Pathology, College of Medicine, University of South Alabama, Mobile, Alabama, USA
| | - Ajay P Singh
- Department of Pathology, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama, USA.,Department of Pathology, College of Medicine, University of South Alabama, Mobile, Alabama, USA.,Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA
| | - Seema Singh
- Department of Pathology, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama, USA.,Department of Pathology, College of Medicine, University of South Alabama, Mobile, Alabama, USA.,Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA
| | - Santanu Dasgupta
- Department of Pathology, Mitchell Cancer Institute, University of South Alabama, Mobile, Alabama, USA.,Department of Pathology, College of Medicine, University of South Alabama, Mobile, Alabama, USA.,Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA
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Mitochondrial Mutations in Multiple Sclerosis Patients with Atypical Optic Neuropathy. Mult Scler Relat Disord 2021; 55:103166. [PMID: 34333271 DOI: 10.1016/j.msard.2021.103166] [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: 02/20/2021] [Revised: 05/03/2021] [Accepted: 07/22/2021] [Indexed: 11/23/2022]
Abstract
BACKGROUND Multiple sclerosis-related optic neuritis is mostly associated with good recovery. The aim of this study was to investigate the causes of progressive visual worsening in multiple sclerosis patients despite treatment. METHODS We retrospectively reviewed the medical records of multiple sclerosis patients with optic neuritis admitted to the ward of our Neurology Department between 2001 and 2020. The patients with unilateral/bilateral progressive visual loss or non-substantial recovery of visual acuity were screened for genetic testing for Leber's hereditary optic neuropathy. RESULTS Of 1014 multiple sclerosis patients, 411 (39%) reported having optic neuritis. During follow-up, 11 patients manifested atypical characteristics of multiple sclerosis-related optic neuritis (presence of one of the following clinical findings: bilateral simultaneous or sequential eye involvement, progressive visual loss, or no response to corticosteroids during hospitalization), while others presented with typical multiple sclerosis-related optic neuritis. Those multiple sclerosis patients with atypical characteristics of optic neuritis were screened for other possible etiologies of optic neuropathy. We found pathogenic mitochondrial mutations in 5 patients with multiple sclerosis in our study group. CONCLUSION In our study group, the prevalence of mitochondrial mutations among all multiple sclerosis patients with optic neuritis was 0.12%. We strongly recommend investigating Leber's hereditary optic neuropathy mutations in MS patients if they suffer from severe or bilateral visual loss without recovery during follow-up. Because Leber's hereditary optic neuropathy mitochondrial mutations indicate relatively poor visual prognosis and have important implications for genetic counseling.
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Cui S, Yang L, Jiang H, Peng J, Shang J, Wang J, Zhang X. Clinical Features of Chinese Sporadic Leber Hereditary Optic Neuropathy Caused by Rare Primary mtDNA Mutations. J Neuroophthalmol 2020; 40:30-36. [PMID: 32045392 DOI: 10.1097/wno.0000000000000799] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OBJECTIVE The primary aim of this study was to describe clinical features of Chinese sporadic Leber hereditary optic neuropathy (LHON) caused by rare primary mitochondrial DNA (mtDNA) mutations. METHODS We characterized a Chinese patient cohort with rare primary mtDNA mutations at Beijing Tongren Hospital between 2015 and 2018. The clinical features of these patients were retrospectively recorded and analyzed. RESULTS Sixteen patients with LHON who had the selected rare primary mutations, including m.4171C>A (3 patients), m.10197G>A (1 patient), m.14459G>A (4 patients), and m.14502T>C (8 patients), were evaluated. The mean age at disease onset was 15 ± 6 years, and the male to female ratio was 15:1. Of 32 eyes of all patients, 75% (24/32) had a worst Snellen best-corrected visual acuity ≤0.1 (worse than 20/200), while 67% (2/3) who were carrying the m.4171C>A mutation experienced significant visual improvement. In addition, 40% (2/5) of patients with LHON carrying only m.14502T>C mutation had only mild visual impairment. Isolated manifestations of LHON was present in 94% (15/16) of all patients; 1 patient with the m.14459G>A mutation had LHON plus dystonia. Brain MRI T2 short tau inversion recovery sequences demonstrated optic atrophy in 62.5% (10/16); increased T2 signal in the optic nerve was found in 38% (6/16) of patients. The patient with LHON plus dystonia demonstrated optic atrophy and increased T2 signal in basal ganglia. CONCLUSION Patients with LHON and rare primary mutations have diverse clinical phenotypes. Those with the m.4171C>A mutation are more likely to have a good visual prognosis, while the m.14502T>C mutation may play a synergistic role in disease onset. Increased signal in the optic nerve on MRI is not rare, and this feature should not exclude LHON as the potential cause for optic neuropathy.
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Affiliation(s)
- Shilei Cui
- Department of Neurology (SC, HJ, JP, JW, XZ), Beijing Tongren Hospital, Capital Medical University, Beijing, China; and Medical Research Center (LY, JS), Beijing Tongren Hospital, Capital Medical University, Beijing, China
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5
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Clinical syndromes associated with mtDNA mutations: where we stand after 30 years. Essays Biochem 2018; 62:235-254. [DOI: 10.1042/ebc20170097] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 05/29/2018] [Accepted: 05/30/2018] [Indexed: 01/16/2023]
Abstract
The landmark year 1988 can be considered as the birthdate of mitochondrial medicine, when the first pathogenic mutations affecting mtDNA were associated with human diseases. Three decades later, the field still expands and we are not ‘scraping the bottom of the barrel’ yet. Despite the tremendous progress in terms of molecular characterization and genotype/phenotype correlations, for the vast majority of cases we still lack a deep understanding of the pathogenesis, good models to study, and effective therapeutic options. However, recent technological advances including somatic cell reprogramming to induced pluripotent stem cells (iPSCs), organoid technology, and tailored endonucleases provide unprecedented opportunities to fill these gaps, casting hope to soon cure the major primary mitochondrial phenotypes reviewed here. This group of rare diseases represents a key model for tackling the pathogenic mechanisms involving mitochondrial biology relevant to much more common disorders that affect our currently ageing population, such as diabetes and metabolic syndrome, neurodegenerative and inflammatory disorders, and cancer.
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Manickam AH, Michael MJ, Ramasamy S. Mitochondrial genetics and therapeutic overview of Leber's hereditary optic neuropathy. Indian J Ophthalmol 2017; 65:1087-1092. [PMID: 29133631 PMCID: PMC5700573 DOI: 10.4103/ijo.ijo_358_17] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 09/09/2017] [Indexed: 12/22/2022] Open
Abstract
Leber's hereditary optic neuropathy (LHON) is a common inherited mitochondrial disorder that is characterized by the degeneration of the optic nerves, leading to vision loss. The major mutations in the mitochondrial genes ND1, ND4, and ND6 of LHON subjects are found to increase the oxidative stress experienced by the optic nerve cell, thereby leading to nerve cell damage. Accurate treatments are not available and drugs that are commercially available like Idebenone, EPI-743, and Bendavia with their antioxidant role help in reducing the oxidative stress experienced by the cell thereby preventing the progression of the disease. Genetic counseling plays an effective role in making the family members aware of the inheritance pattern of the disease. Gene therapy is an alternative for curing the disease but is still under study. This review focuses on the role of mitochondrial genes in causing LHON and therapeutics available for treating the disease. A systematic search has been adopted in various databases using the keywords "LHON," "mitochondria," "ND1," "ND4," "ND6," and "therapy" and the following review on mitochondrial genetics and therapeutics of LHON has been developed with obtained articles from 1988 to 2017.
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Affiliation(s)
- Agaath Hedina Manickam
- Molecular Genetics and Cancer Biology Laboratory, Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore, Tami Nadu, India
| | - Minu Jenifer Michael
- Molecular Genetics and Cancer Biology Laboratory, Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore, Tami Nadu, India
| | - Sivasamy Ramasamy
- Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore, Tami Nadu, India
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Nesti C, Meschini MC, Meunier B, Sacchini M, Doccini S, Romano A, Petrillo S, Pezzini I, Seddiki N, Rubegni A, Piemonte F, Donati MA, Brasseur G, Santorelli FM. Additive effect of nuclear and mitochondrial mutations in a patient with mitochondrial encephalomyopathy. Hum Mol Genet 2015; 24:3248-56. [PMID: 25736212 DOI: 10.1093/hmg/ddv078] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 02/26/2015] [Indexed: 12/12/2022] Open
Abstract
We describe the case of a woman in whom combination of a mitochondrial (MT-CYB) and a nuclear (SDHB) mutation was associated with clinical and metabolic features suggestive of a mitochondrial disorder. The mutations impaired overall energy metabolism in the patient's muscle and fibroblasts and increased cellular susceptibility to oxidative stress. To clarify the contribution of each mutation to the phenotype, mutant yeast strains were generated. A significant defect in strains carrying the Sdh2 mutation, either alone or in combination with the cytb variant, was observed. Our data suggest that the SDHB mutation was causative of the mitochondrial disorder in our patient with a possible cumulative contribution of the MT-CYB variant. To our knowledge, this is the first association of bi-genomic variants in the mtDNA and in a nuclear gene encoding a subunit of complex II.
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Affiliation(s)
| | | | - Brigitte Meunier
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, 1 Avenue de la Terrasse, 91198 Gif-sur-Yvette, France
| | - Michele Sacchini
- Metabolic and Neuromuscular Unit, AOU Meyer Hospital, Florence, Italy
| | | | - Alessandro Romano
- Neuropathology Unit, Institute of Experimental Neurology and Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Sara Petrillo
- Unit for Neuromuscular and Neurodegenerative Diseases, "Bambino Gesù" Children's Hospital, Rome, Italy and
| | | | - Nadir Seddiki
- Laboratoire de Chimie Bactérienne, CNRS, 31 ch. J. Aiguier, 13402 Marseilles, France
| | - Anna Rubegni
- Molecular Medicine, IRCCS Stella Maris, Pisa, Italy
| | - Fiorella Piemonte
- Unit for Neuromuscular and Neurodegenerative Diseases, "Bambino Gesù" Children's Hospital, Rome, Italy and
| | - M Alice Donati
- Metabolic and Neuromuscular Unit, AOU Meyer Hospital, Florence, Italy
| | - Gael Brasseur
- Laboratoire de Chimie Bactérienne, CNRS, 31 ch. J. Aiguier, 13402 Marseilles, France
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Martínez-Romero Í, Herrero-Martín MD, Llobet L, Emperador S, Martín-Navarro A, Narberhaus B, Ascaso FJ, López-Gallardo E, Montoya J, Ruiz-Pesini E. New MT-ND1 pathologic mutation for Leber hereditary optic neuropathy. Clin Exp Ophthalmol 2014; 42:856-64. [PMID: 24800637 DOI: 10.1111/ceo.12355] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 04/21/2014] [Indexed: 11/30/2022]
Abstract
BACKGROUND Mutations causing Leber hereditary optic neuropathy are usually homoplasmic, show incomplete penetrance, and many of the affected positions are not well conserved through evolution. A large percentage of patients harbouring these mutations have no family history of disease. Moreover, the transfer of the mutation in the cybrid model is frequently not accompanied by the transfer of the cellular, biochemical and molecular phenotype. All these features make difficult their classification as the etiologic factors for this disease. We report a patient who exhibits typical clinical features of Leber hereditary optic neuropathy but lacks all three of the most common mitochondrial DNA mutations. METHODS The diagnosis was made based on clinical studies. The mitochondrial DNA was completely sequenced, and the candidate mutation was analysed in more than 18 000 individuals around the world, its conservation index was estimated in more than 3100 species from protists to mammals, its position was modelled in the crystal structure of a bacteria ortholog subunit, and its functional consequences were studied in a cybrid model. RESULTS Genetic analysis revealed an m.3472T>C transition in the MT-ND1 gene that changes a phenylalanine to leucine at position 56. Bioinformatics, molecular-genetic analysis and functional studies suggest that this transition is the etiological factor for the disorder. CONCLUSIONS This mutation expands the spectrum of deleterious changes in mitochondrial DNA-encoded complex I polypeptides associated with this pathology and highlights the difficulties in assigning pathogenicity to new homoplasmic mutations that show incomplete penetrance in sporadic Leber hereditary optic neuropathy patients.
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Affiliation(s)
- Íñigo Martínez-Romero
- Departamento de Bioquímica, Biología Molecular y Celular and Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Zaragoza, Spain
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La Morgia C, Caporali L, Gandini F, Olivieri A, Toni F, Nassetti S, Brunetto D, Stipa C, Scaduto C, Parmeggiani A, Tonon C, Lodi R, Torroni A, Carelli V. Association of the mtDNA m.4171C>A/MT-ND1 mutation with both optic neuropathy and bilateral brainstem lesions. BMC Neurol 2014; 14:116. [PMID: 24884847 PMCID: PMC4047257 DOI: 10.1186/1471-2377-14-116] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 04/01/2014] [Indexed: 11/18/2022] Open
Abstract
Background An increasing number of mitochondrial DNA (mtDNA) mutations, mainly in complex I genes, have been associated with variably overlapping phenotypes of Leber’s hereditary optic neuropathy (LHON), mitochondrial encephalomyopathy with stroke-like episodes (MELAS) and Leigh syndrome (LS). We here describe the first case in which the m.4171C>A/MT-ND1 mutation, previously reported only in association with LHON, leads also to a Leigh-like phenotype. Case presentation A 16-year-old male suffered subacute visual loss and recurrent vomiting and vertigo associated with bilateral brainstem lesions affecting the vestibular nuclei. His mother and one sister also presented subacute visual loss compatible with LHON. Sequencing of the entire mtDNA revealed the homoplasmic m.4171C>A/MT-ND1 mutation, previously associated with pure LHON, on a haplogroup H background. Three additional non-synonymous homoplasmic transitions affecting ND2 (m.4705T>C/MT-ND2 and m.5263C>T/MT-ND2) and ND6 (m.14180T>C/MT-ND6) subunits, well recognized as polymorphisms in other mtDNA haplogroups but never found on the haplogroup H background, were also present. Conclusion This case widens the phenotypic expression of the rare m.4171C>A/MT-ND1 LHON mutation, which may also lead to Leigh-like brainstem lesions, and indicates that the co-occurrence of other ND non-synonymous variants, found outside of their usual mtDNA backgrounds, may have increased the pathogenic potential of the primary LHON mutation.
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Affiliation(s)
- Chiara La Morgia
- UOC Clinica Neurologica, IRCCS Istituto delle Scienze Neurologiche di Bologna, Ospedale Bellaria, Bologna, Italy.
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Soini HK, Moilanen JS, Vilmi-Kerälä T, Finnilä S, Majamaa K. Mitochondrial DNA variant m.15218A > G in Finnish epilepsy patients who have maternal relatives with epilepsy, sensorineural hearing impairment or diabetes mellitus. BMC MEDICAL GENETICS 2013; 14:73. [PMID: 23870133 PMCID: PMC3726289 DOI: 10.1186/1471-2350-14-73] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 07/17/2013] [Indexed: 01/04/2023]
Abstract
BACKGROUND Mitochondrial diseases caused by mutations in mitochondrial DNA (mtDNA) affect tissues with high energy demand. Epilepsy is one of the manifestations of mitochondrial dysfunction when the brain is affected. We have studied here 79 Finnish patients with epilepsy and who have maternal first- or second-degree relatives with epilepsy, sensorineural hearing impairment or diabetes mellitus. METHODS The entire mtDNA was studied by using conformation sensitive gel electrophoresis and PCR fragments that differed in mobility were directly sequenced. RESULTS We found a common nonsynonymous variant m.15218A > G (p.T158A, MTCYB) that occurs in haplogroup U5a1 to be more frequent in patients with epilepsy. The m.15218A > G variant was present in five patients with epilepsy and in four out of 403 population controls (p = 0.0077). This variant was present in two branches in the phylogenetic network constructed on the basis of mtDNA variation among the patients. Three algorithms predicted that m.15218A > G is damaging in effect. CONCLUSIONS We suggest that the m.15218A > G variant is mildly deleterious and that mtDNA involvement should be considered in patients with epilepsy and who have a maternal history of epilepsy, sensorineural hearing impairment or diabetes mellitus.
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Affiliation(s)
- Heidi K Soini
- Department of Neurology, Oulu University Hospital, P.O. Box 20, Oulu FI-90029, OYS, Finland
- Department of Clinical Medicine, Neurology, University of Oulu, P.O. Box 5000, FI-90014, Oulu, Finland
- Clinical Research Center, Oulu University Hospital, P.O. Box 5000, FI-90014, Oulu, Finland
| | - Jukka S Moilanen
- Department of Clinical Genetics, Oulu University Hospital and University of Oulu P.O. Box 23, FI-90029, OYS, Oulu, Finland
| | - Tiina Vilmi-Kerälä
- Department of Neurology, Oulu University Hospital, P.O. Box 20, Oulu FI-90029, OYS, Finland
- Department of Clinical Medicine, Neurology, University of Oulu, P.O. Box 5000, FI-90014, Oulu, Finland
- Clinical Research Center, Oulu University Hospital, P.O. Box 5000, FI-90014, Oulu, Finland
| | - Saara Finnilä
- Department of Neurology, Oulu University Hospital, P.O. Box 20, Oulu FI-90029, OYS, Finland
- Department of Clinical Medicine, Neurology, University of Oulu, P.O. Box 5000, FI-90014, Oulu, Finland
- Clinical Research Center, Oulu University Hospital, P.O. Box 5000, FI-90014, Oulu, Finland
| | - Kari Majamaa
- Department of Neurology, Oulu University Hospital, P.O. Box 20, Oulu FI-90029, OYS, Finland
- Department of Clinical Medicine, Neurology, University of Oulu, P.O. Box 5000, FI-90014, Oulu, Finland
- Clinical Research Center, Oulu University Hospital, P.O. Box 5000, FI-90014, Oulu, Finland
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Lloyd RE, McGeehan JE. Structural analysis of mitochondrial mutations reveals a role for bigenomic protein interactions in human disease. PLoS One 2013; 8:e69003. [PMID: 23874847 PMCID: PMC3706435 DOI: 10.1371/journal.pone.0069003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2013] [Accepted: 06/05/2013] [Indexed: 12/25/2022] Open
Abstract
Mitochondria are the energy producing organelles of the cell, and mutations within their genome can cause numerous and often severe human diseases. At the heart of every mitochondrion is a set of five large multi-protein machines collectively known as the mitochondrial respiratory chain (MRC). This cellular machinery is central to several processes important for maintaining homeostasis within cells, including the production of ATP. The MRC is unique due to the bigenomic origin of its interacting proteins, which are encoded in the nucleus and mitochondria. It is this, in combination with the sheer number of protein-protein interactions that occur both within and between the MRC complexes, which makes the prediction of function and pathological outcome from primary sequence mutation data extremely challenging. Here we demonstrate how 3D structural analysis can be employed to predict the functional importance of mutations in mtDNA protein-coding genes. We mined the MITOMAP database and, utilizing the latest structural data, classified mutation sites based on their location within the MRC complexes III and IV. Using this approach, four structural classes of mutation were identified, including one underexplored class that interferes with nuclear-mitochondrial protein interactions. We demonstrate that this class currently eludes existing predictive approaches that do not take into account the quaternary structural organization inherent within and between the MRC complexes. The systematic and detailed structural analysis of disease-associated mutations in the mitochondrial Complex III and IV genes significantly enhances the predictive power of existing approaches and our understanding of how such mutations contribute to various pathologies. Given the general lack of any successful therapeutic approaches for disorders of the MRC, these findings may inform the development of new diagnostic and prognostic biomarkers, as well as new drugs and targets for gene therapy.
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Affiliation(s)
- Rhiannon E. Lloyd
- Cellular and Molecular Neuro-Oncology Group, Institute of Biomedical and Biomolecular Sciences, School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, United Kingdom
| | - John E. McGeehan
- Biophysics Laboratories, Institute of Biomedical and Biomolecular Science, School of Biological Sciences, University of Portsmouth, Portsmouth, United Kingdom
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MitoLSDB: a comprehensive resource to study genotype to phenotype correlations in human mitochondrial DNA variations. PLoS One 2013; 8:e60066. [PMID: 23585830 PMCID: PMC3621970 DOI: 10.1371/journal.pone.0060066] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 02/20/2013] [Indexed: 01/16/2023] Open
Abstract
Human mitochondrial DNA (mtDNA) encodes a set of 37 genes which are essential structural and functional components of the electron transport chain. Variations in these genes have been implicated in a broad spectrum of diseases and are extensively reported in literature and various databases. In this study, we describe MitoLSDB, an integrated platform to catalogue disease association studies on mtDNA (http://mitolsdb.igib.res.in). The main goal of MitoLSDB is to provide a central platform for direct submissions of novel variants that can be curated by the Mitochondrial Research Community. MitoLSDB provides access to standardized and annotated data from literature and databases encompassing information from 5231 individuals, 675 populations and 27 phenotypes. This platform is developed using the Leiden Open (source) Variation Database (LOVD) software. MitoLSDB houses information on all 37 genes in each population amounting to 132397 variants, 5147 unique variants. For each variant its genomic location as per the Revised Cambridge Reference Sequence, codon and amino acid change for variations in protein-coding regions, frequency, disease/phenotype, population, reference and remarks are also listed. MitoLSDB curators have also reported errors documented in literature which includes 94 phantom mutations, 10 NUMTs, six documentation errors and one artefactual recombination. MitoLSDB is the largest repository of mtDNA variants systematically standardized and presented using the LOVD platform. We believe that this is a good starting resource to curate mtDNA variants and will facilitate direct submissions enhancing data coverage, annotation in context of pathogenesis and quality control by ensuring non-redundancy in reporting novel disease associated variants.
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Iommarini L, Calvaruso MA, Kurelac I, Gasparre G, Porcelli AM. Complex I impairment in mitochondrial diseases and cancer: Parallel roads leading to different outcomes. Int J Biochem Cell Biol 2013; 45:47-63. [DOI: 10.1016/j.biocel.2012.05.016] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 05/03/2012] [Accepted: 05/24/2012] [Indexed: 02/06/2023]
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Meunier B, Fisher N, Ransac S, Mazat JP, Brasseur G. Respiratory complex III dysfunction in humans and the use of yeast as a model organism to study mitochondrial myopathy and associated diseases. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1827:1346-61. [PMID: 23220121 DOI: 10.1016/j.bbabio.2012.11.015] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 11/21/2012] [Accepted: 11/28/2012] [Indexed: 11/25/2022]
Abstract
The bc1 complex or complex III is a central component of the aerobic respiratory chain in prokaryotic and eukaryotic organisms. It catalyzes the oxidation of quinols and the reduction of cytochrome c, establishing a proton motive force used to synthesize adenosine triphosphate (ATP) by the F1Fo ATP synthase. In eukaryotes, the complex III is located in the inner mitochondrial membrane. The genes coding for the complex III have a dual origin. While cytochrome b is encoded by the mitochondrial genome, all the other subunits are encoded by the nuclear genome. In this review, we compile an exhaustive list of the known human mutations and associated pathologies found in the mitochondrially-encoded cytochrome b gene as well as the fewer mutations in the nuclear genes coding for the complex III structural subunits and accessory proteins such as BCS1L involved in the assembly of the complex III. Due to the inherent difficulties of studying human biopsy material associated with complex III dysfunction, we also review the work that has been conducted to study the pathologies with the easy to handle eukaryotic microorganism, the yeast Saccharomyces cerevisiae. Phenotypes, biochemical data and possible effects due to the mutations are also discussed in the context of the known three-dimensional structure of the eukaryotic complex III. This article is part of a Special Issue entitled: Respiratory complex III and related bc complexes.
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Affiliation(s)
- B Meunier
- CNRS, Centre de Génétique Moléculaire, UPR 3404, Gif-sur-Yvette, F-91198, France
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15
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Achilli A, Iommarini L, Olivieri A, Pala M, Hooshiar Kashani B, Reynier P, La Morgia C, Valentino ML, Liguori R, Pizza F, Barboni P, Sadun F, De Negri AM, Zeviani M, Dollfus H, Moulignier A, Ducos G, Orssaud C, Bonneau D, Procaccio V, Leo-Kottler B, Fauser S, Wissinger B, Amati-Bonneau P, Torroni A, Carelli V. Rare primary mitochondrial DNA mutations and probable synergistic variants in Leber's hereditary optic neuropathy. PLoS One 2012; 7:e42242. [PMID: 22879922 PMCID: PMC3411744 DOI: 10.1371/journal.pone.0042242] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Accepted: 07/02/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Leber's hereditary optic neuropathy (LHON) is a maternally inherited blinding disorder, which in over 90% of cases is due to one of three primary mitochondrial DNA (mtDNA) point mutations (m.11778G>A, m.3460G>A and m.14484T>C, respectively in MT-ND4, MT-ND1 and MT-ND6 genes). However, the spectrum of mtDNA mutations causing the remaining 10% of cases is only partially and often poorly defined. METHODOLOGY/PRINCIPAL FINDINGS In order to improve such a list of pathological variants, we completely sequenced the mitochondrial genomes of suspected LHON patients from Italy, France and Germany, lacking the three primary common mutations. Phylogenetic and conservation analyses were performed. Sixteen mitochondrial genomes were found to harbor at least one of the following nine rare LHON pathogenic mutations in genes MT-ND1 (m.3700G>A/p.A132T, m.3733G>A-C/p.E143K-Q, m.4171C>A/p.L289M), MT-ND4L (m.10663T>C/p.V65A) and MT-ND6 (m.14459G>A/p.A72V, m.14495A>G/p.M64I, m.14482C>A/p.L60S, and m.14568C>T/p.G36S). Phylogenetic analyses revealed that these substitutions were due to independent events on different haplogroups, whereas interspecies comparisons showed that they affected conserved amino acid residues or domains in the ND subunit genes of complex I. CONCLUSIONS/SIGNIFICANCE Our findings indicate that these nine substitutions are all primary LHON mutations. Therefore, despite their relative low frequency, they should be routinely tested for in all LHON patients lacking the three common mutations. Moreover, our sequence analysis confirms the major role of haplogroups J1c and J2b (over 35% in our probands versus 6% in the general population of Western Europe) and other putative synergistic mtDNA variants in LHON expression.
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Affiliation(s)
- Alessandro Achilli
- Dipartimento di Biologia Cellulare e Ambientale, Università di Perugia, Perugia, Italy
| | - Luisa Iommarini
- IRCCS Istituto delle Scienze Neurologiche di Bologna and Dipartimento di Scienze Neurologiche, Università di Bologna, Bologna, Italy
| | - Anna Olivieri
- Dipartimento di Biologia e Biotecnologie, Università di Pavia, Pavia, Italy
| | - Maria Pala
- Dipartimento di Biologia e Biotecnologie, Università di Pavia, Pavia, Italy
| | | | - Pascal Reynier
- UMR INSERM, U1083-CNRS6214, Angers, France
- University of Angers, School of Medicine, Angers, France
- University Hospital of Angers, Department of Biochemistry and Genetics, Angers, France
| | - Chiara La Morgia
- IRCCS Istituto delle Scienze Neurologiche di Bologna and Dipartimento di Scienze Neurologiche, Università di Bologna, Bologna, Italy
| | - Maria Lucia Valentino
- IRCCS Istituto delle Scienze Neurologiche di Bologna and Dipartimento di Scienze Neurologiche, Università di Bologna, Bologna, Italy
| | - Rocco Liguori
- IRCCS Istituto delle Scienze Neurologiche di Bologna and Dipartimento di Scienze Neurologiche, Università di Bologna, Bologna, Italy
| | - Fabio Pizza
- IRCCS Istituto delle Scienze Neurologiche di Bologna and Dipartimento di Scienze Neurologiche, Università di Bologna, Bologna, Italy
| | - Piero Barboni
- IRCCS Istituto delle Scienze Neurologiche di Bologna and Dipartimento di Scienze Neurologiche, Università di Bologna, Bologna, Italy
- Studio Oculistico D’Azeglio, Bologna, Italy
| | | | | | - Massimo Zeviani
- Unit of Molecular Neurogenetics, Pierfranco and Luisa Mariani Center for the Study of Children’s Mitochondrial Disorders, Foundation “C. Besta” Neurological Institute-IRCCS, Milan, Italy
| | - Helene Dollfus
- Centre de référence pour les Affections Rares en Génétique Ophtalmologique, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Antoine Moulignier
- Service de Neurologie, Fondation Ophtalmologique Adolphe de Rothschild, Paris, France
| | - Ghislaine Ducos
- Department of Ophthalmology, Saint Jean Languedoc Clinic, Toulouse, France
| | - Christophe Orssaud
- Centre de Référence des Maladies Rares en Ophtalmologie, Consultationd ‘Ophtalmologie, HEGP, Assistance Publique – Hôpitaux de Paris, Paris, France
| | - Dominique Bonneau
- UMR INSERM, U1083-CNRS6214, Angers, France
- University of Angers, School of Medicine, Angers, France
- University Hospital of Angers, Department of Biochemistry and Genetics, Angers, France
| | - Vincent Procaccio
- UMR INSERM, U1083-CNRS6214, Angers, France
- University of Angers, School of Medicine, Angers, France
- University Hospital of Angers, Department of Biochemistry and Genetics, Angers, France
| | - Beate Leo-Kottler
- Centre for Ophthalmology, University Clinics Tuebingen, Tubingen, Germany
| | - Sascha Fauser
- Department of Vitreo-Retinal Surgery, Center of Ophthalmology, University of Cologne, Cologne, Germany
| | - Bernd Wissinger
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Centre for Ophthalmology, University Clinics Tuebingen, Tuebingen, Germany
| | - Patrizia Amati-Bonneau
- UMR INSERM, U1083-CNRS6214, Angers, France
- University Hospital of Angers, Department of Biochemistry and Genetics, Angers, France
| | - Antonio Torroni
- Dipartimento di Biologia e Biotecnologie, Università di Pavia, Pavia, Italy
| | - Valerio Carelli
- IRCCS Istituto delle Scienze Neurologiche di Bologna and Dipartimento di Scienze Neurologiche, Università di Bologna, Bologna, Italy
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Kim MJ, Park SS, Hwang JM. Visual Prognosis of Leber's Hereditary Optic Neuropathy with T14484C Mitochondrial DNA Mutation in Koreans. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2012. [DOI: 10.3341/jkos.2012.53.1.151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Mi Jeung Kim
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea
| | - Sung Sup Park
- Department of Clinical Pathology, Seoul National University College of Medicine, Seoul, Korea
| | - Jeong-Min Hwang
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea
- Department of Ophthalmology, Seoul National University Bundang Hospital, Seongnam, Korea
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