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Buonfiglio PI, Menazzi S, Francipane L, Lotersztein V, Ferreiro V, Elgoyhen AB, Dalamón V. Mitochondrial DNA variants in a cohort from Argentina with suspected Leber's hereditary optic neuropathy (LHON). PLoS One 2023; 18:e0275703. [PMID: 36827238 PMCID: PMC9956067 DOI: 10.1371/journal.pone.0275703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 01/31/2023] [Indexed: 02/25/2023] Open
Abstract
The present study investigates the spectrum and analysis of mitochondrial DNA (mtDNA) variants associated with Leber hereditary optic neuropathy (LHON) in an Argentinean cohort, analyzing 3 LHON-associated mitochondrial genes. In 32% of the cases, molecular confirmation of the diagnosis could be established, due to the identification of disease-causing variants. A total of 54 variants were observed in a cohort of 100 patients tested with direct sequencing analysis. The frequent causative mutations m.11778G>A in MT-ND4, m.3460G>A in MT-ND1, and m.14484T>C in MT-ND6 were identified in 28% of the cases of our cohort. Secondary mutations in this Argentinean LHON cohort were m.11253T>C p.Ile165Thr in MT-ND4, identified in three patients (3/100, 3%) and m.3395A>G p.Tyr30Cys in MT-ND1, in one of the patients studied (1%). This study shows, for the first time, the analysis of mtDNA variants in patients with a probable diagnosis of LHON in Argentina. Standard molecular methods are an effective first approach in order to achieve genetic diagnosis of the disease, leaving NGS tests for those patients with negative results.
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Affiliation(s)
- Paula I. Buonfiglio
- Laboratorio de Fisiología y Genética de la Audición, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular “Dr. Héctor N. Torres”, Consejo Nacional de Investigaciones Científicas y Técnicas - INGEBI / CONICET, Ciudad Autónoma de Buenos Aires, Argentina
| | - Sebastián Menazzi
- División Genética, Hospital de Clínicas “José de San Martín”, Ciudad Autónoma de Buenos Aires, Argentina
| | - Liliana Francipane
- División Genética, Hospital de Clínicas “José de San Martín”, Ciudad Autónoma de Buenos Aires, Argentina
| | - Vanesa Lotersztein
- Servicio de Genética, Hospital Militar Central “Dr. Cosme Argerich”, Ciudad Autónoma de Buenos Aires, Argentina
| | | | - Ana Belén Elgoyhen
- Laboratorio de Fisiología y Genética de la Audición, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular “Dr. Héctor N. Torres”, Consejo Nacional de Investigaciones Científicas y Técnicas - INGEBI / CONICET, Ciudad Autónoma de Buenos Aires, Argentina
- División Genética, Hospital de Clínicas “José de San Martín”, Ciudad Autónoma de Buenos Aires, Argentina
- Servicio de Genética, Hospital Militar Central “Dr. Cosme Argerich”, Ciudad Autónoma de Buenos Aires, Argentina
- Laboratorio Genos, Ciudad Autónoma de Buenos Aires, Argentina
- Departamento de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, C1121ABG, Ciudad Autónoma de Buenos Aires, Argentina
| | - Viviana Dalamón
- Laboratorio de Fisiología y Genética de la Audición, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular “Dr. Héctor N. Torres”, Consejo Nacional de Investigaciones Científicas y Técnicas - INGEBI / CONICET, Ciudad Autónoma de Buenos Aires, Argentina
- * E-mail:
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Alkhaldi HA, Phan DH, Vik SB. Analysis of Human Clinical Mutations of Mitochondrial ND1 in a Bacterial Model System for Complex I. Life (Basel) 2022; 12:1934. [PMID: 36431069 PMCID: PMC9696053 DOI: 10.3390/life12111934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/13/2022] [Accepted: 11/17/2022] [Indexed: 11/22/2022] Open
Abstract
The most common causes of mitochondrial dysfunction and disease include mutations in subunits and assembly factors of Complex I. Numerous mutations in the mitochondrial gene ND1 have been identified in humans. Currently, a bacterial model system provides the only method for rapid construction and analysis of mutations in homologs of human ND1. In this report, we have identified nine mutations in human ND1 that are reported to be pathogenic and are located at subunit interfaces. Our hypothesis was that these mutations would disrupt Complex I assembly. Seventeen mutations were constructed in the homologous nuoH gene in an E. coli model system. In addition to the clinical mutations, alanine substitutions were constructed in order to distinguish between a deleterious effect from the introduction of the mutant residue and the loss of the original residue. The mutations were moved to an expression vector containing all thirteen genes of the E. coli nuo operon coding for Complex I. Membrane vesicles were prepared and rates of deamino-NADH oxidase activity and proton translocation were measured. Samples were also tested for assembly by native gel electrophoresis and for expression of NuoH by immunoblotting. A range of outcomes was observed: Mutations at four of the sites allow normal assembly with moderate activity (50−76% of wild type). Mutations at the other sites disrupt assembly and/or activity, and in some cases the outcomes depend upon the amino acid introduced. In general, the outcomes are consistent with the proposed pathogenicity in humans.
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Affiliation(s)
| | | | - Steven B. Vik
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275, USA
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Muacevic A, Adler JR. A Case of a 23-Year-Old Male With Leber Hereditary Optic Neuropathy With a Rare Mutation. Cureus 2022; 14:e30198. [PMID: 36381806 PMCID: PMC9650921 DOI: 10.7759/cureus.30198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2022] [Indexed: 01/25/2023] Open
Abstract
Mitochondrial DNA (mtDNA) is responsible for encoding 13 subunits of the respiratory chain. These subunits are crucial in providing reducing equivalents for the energy-intensive intracellular processes. Leber hereditary optic neuropathy (LHON) is a mitochondrial illness that causes carcinogenesis due to oxidative stress and painless loss of central vision as a result of selective degradation of retinal ganglion cells as well as their axons. We present a case of a 23-year-old male patient who was diagnosed with subacute LHON. The mutation in our patient was found in a less commonly mutated exon sequence of MT-NDL4, which codes for NADH (nicotinamide adenine dinucleotide hydrogen, reduced) dehydrogenase subunit 4L. The MT-ND4L exon is located immediately upstream of the MTD4 exon on the human mtDNA. The take-home message is to always perform a comprehensive mitochondrial genome analysis for identifying rare mutations when LHON is suspected.
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Gutiérrez Cortés N, Pertuiset C, Dumon E, Börlin M, Da Costa B, Le Guédard M, Stojkovic T, Loundon N, Rouillon I, Nadjar Y, Letellier T, Jonard L, Marlin S, Rocher C. Mutation m.3395A > G in MT-ND1 leads to variable pathologic manifestations. Hum Mol Genet 2021; 29:980-989. [PMID: 32011699 DOI: 10.1093/hmg/ddaa020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 01/27/2020] [Accepted: 01/31/2020] [Indexed: 11/12/2022] Open
Abstract
A non-synonymous mtDNA mutation, m.3395A > G, which changes tyrosine in position 30 to cysteine in p.MT-ND1, was found in several patients with a wide range of clinical phenotypes such as deafness, diabetes and cerebellar syndrome but no Leber's hereditary optic neuropathy. Although this mutation has already been described, its pathogenicity has not been demonstrated. Here, it was found isolated for the first time, allowing a study to investigate its pathogenicity. To do so, we constructed cybrid cell lines and carried out a functional study to assess the possible consequences of the mutation on mitochondrial bioenergetics. Results obtained demonstrated that this mutation causes an important dysfunction of the mitochondrial respiratory chain with a decrease in both activity and quantity of complex I due to a diminution of p.MT-ND1 quantity. However, no subcomplexes were found in cybrids carrying the mutation, indicating that the quality of the complex I assembly is not affected. Moreover, based on the crystal structure of p.MT-ND1 and the data found in the literature, we propose a hypothesis for the mechanism of the degradation of p.MT-ND1. Our study provides new insights into the pathophysiology of mitochondrial diseases and in particular of MT-ND1 mutations.
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Affiliation(s)
- Nicolás Gutiérrez Cortés
- INSERM-U688 Physiopathologie Mitochondriale, Université Bordeaux Segalen, 146 rue Léo Saignat, 33076 Bordeaux, France
| | - Claire Pertuiset
- INSERM-U688 Physiopathologie Mitochondriale, Université Bordeaux Segalen, 146 rue Léo Saignat, 33076 Bordeaux, France
| | - Elodie Dumon
- INSERM-U688 Physiopathologie Mitochondriale, Université Bordeaux Segalen, 146 rue Léo Saignat, 33076 Bordeaux, France
| | - Marine Börlin
- INSERM-U688 Physiopathologie Mitochondriale, Université Bordeaux Segalen, 146 rue Léo Saignat, 33076 Bordeaux, France
| | - Barbara Da Costa
- INSERM-U688 Physiopathologie Mitochondriale, Université Bordeaux Segalen, 146 rue Léo Saignat, 33076 Bordeaux, France
| | - Marina Le Guédard
- Laboratoire de Biogenèse Membranaire, CNRS UMR 5200, Université de Bordeaux, INRA Bordeaux Aquitaine, Villenave d'Ornon, France.,LEB Aquitaine Transfert-ADERA, FR-33883 Villenave d'Ornon, Cedex, France
| | - Tanya Stojkovic
- APHP, Centre de Référence des Maladies Neuromusculaires Ile de France Nord Est, G-H Pitié-Salpêtrière, 75013 Paris, France
| | - Natalie Loundon
- Otorhinolaryngologie Pédiatrique, Centre de Référence des Surdités Génétiques, Hôpital Necker, AP-HP, Paris, France
| | - Isabelle Rouillon
- Otorhinolaryngologie Pédiatrique, Centre de Référence des Surdités Génétiques, Hôpital Necker, AP-HP, Paris, France
| | - Yann Nadjar
- Neurologie, GH Pitié Salpêtrière, 75013 Paris, France
| | - Thierry Letellier
- Equipe de Médecine Evolutive, AMIS, UMR 5288 CNRS/Université Paul Sabatier, 31073 Toulouse, France
| | - Laurence Jonard
- Service de Génétique Moléculaire, Hôpital Necker-Enfants Malades, Assistance Publique-Hôpitaux de Paris, 75015 Paris, France
| | - Sandrine Marlin
- Service de Génétique Moléculaire, Hôpital Necker-Enfants Malades, Assistance Publique-Hôpitaux de Paris, 75015 Paris, France.,Centre de Référence des Surdités Génétiques, Service de Génétique Médicale, Hôpital Necker-Enfants Malades, Assistance Publique-Hôpitaux de Paris, 75015 Paris, France.,UMR 1163, Université Paris Descartes, Sorbonne Paris Cité, Institut IMAGINE, 24 Boulevard du Montparnasse, 75015 Paris, France
| | - Christophe Rocher
- INSERM-U688 Physiopathologie Mitochondriale, Université Bordeaux Segalen, 146 rue Léo Saignat, 33076 Bordeaux, France
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Liu XT, Shen MX, Chen C, Huang SH, Zhuang XR, Ma QK, Chen Q, Lu F, Yuan YM. Foveal pit morphological changes in asymptomatic carriers of the G11778A mutation with Leber's hereditary optic neuropathy. Int J Ophthalmol 2020; 13:766-772. [PMID: 32420224 DOI: 10.18240/ijo.2020.05.11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 03/12/2020] [Indexed: 12/31/2022] Open
Abstract
AIM To investigate the foveal pit morphology changes in unaffected carriers and affected Leber's hereditary optic neuropathy (LHON) patients with the G11778A mutation from one family. METHODS This study was a prospective cross-sectional study. Both eyes from 16 family members (age from 9 to 47y) with the G11778A mutation were analyzed and compared with 1 eye from 20 normal control subjects. Eleven family members with the G11778A mutation but without optic neuropathy were classified as unaffected carriers (n=22 eyes). Five family members (n=10 eyes) expressed the LHON phenotype and were classified as affected patients. Retinal images of all the subjects were taken by optical coherence tomography (OCT), and an automatic algorithm was used to segment the retina to eight layers. Horizontal and vertical OCT images centered on the fovea were used to measure intra-retinal layer thicknesses and foveal morphometry. RESULTS Thicker foveal thickness, thinner foveal pit depth, and flatter foveal slopes were observed in unaffected carriers and affected LHON patients (all P<0.001). Further, the slopes of all four sectors in the LHON were flatter than those in the unaffected carriers (all P<0.001). Compared with the control group, affected LHON patients had a thinner retinal nerve fiber layer (RNFL), ganglion cell layer and inner plexiform layer (GCL+IPL), and total retina (all P<0.01). The retinal nerve fiber layer (RNFL) of affected patients was 38.0% thinner than that of controls while the GCL+IPL was 40.1% thinner. CONCLUSION The foveal pit morphology shows changes in both unaffected carriers and affects patients. RNFL and GCL+IPL are thinner in affected LHON patients but not in unaffected carriers.
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Affiliation(s)
- Xin-Ting Liu
- School of Ophthalmology and Optometry, the Eye Hospital, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China
| | - Mei-Xiao Shen
- School of Ophthalmology and Optometry, the Eye Hospital, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China
| | - Chong Chen
- School of Ophthalmology and Optometry, the Eye Hospital, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China
| | - Sheng-Hai Huang
- School of Ophthalmology and Optometry, the Eye Hospital, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China
| | - Xi-Ran Zhuang
- School of Ophthalmology and Optometry, the Eye Hospital, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China
| | - Qing-Kai Ma
- School of Ophthalmology and Optometry, the Eye Hospital, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China
| | - Qi Chen
- School of Ophthalmology and Optometry, the Eye Hospital, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China
| | - Fan Lu
- School of Ophthalmology and Optometry, the Eye Hospital, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China
| | - Yi-Min Yuan
- School of Ophthalmology and Optometry, the Eye Hospital, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China
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