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Vila-Sanjurjo A, Mallo N, Elson JL, Smith PM, Blakely EL, Taylor RW. Structural analysis of mitochondrial rRNA gene variants identified in patients with deafness. Front Physiol 2023; 14:1163496. [PMID: 37362424 PMCID: PMC10285412 DOI: 10.3389/fphys.2023.1163496] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 04/18/2023] [Indexed: 06/28/2023] Open
Abstract
The last few years have witnessed dramatic advances in our understanding of the structure and function of the mammalian mito-ribosome. At the same time, the first attempts to elucidate the effects of mito-ribosomal fidelity (decoding accuracy) in disease have been made. Hence, the time is right to push an important frontier in our understanding of mitochondrial genetics, that is, the elucidation of the phenotypic effects of mtDNA variants affecting the functioning of the mito-ribosome. Here, we have assessed the structural and functional role of 93 mitochondrial (mt-) rRNA variants thought to be associated with deafness, including those located at non-conserved positions. Our analysis has used the structural description of the human mito-ribosome of the highest quality currently available, together with a new understanding of the phenotypic manifestation of mito-ribosomal-associated variants. Basically, any base change capable of inducing a fidelity phenotype may be considered non-silent. Under this light, out of 92 previously reported mt-rRNA variants thought to be associated with deafness, we found that 49 were potentially non-silent. We also dismissed a large number of reportedly pathogenic mtDNA variants, 41, as polymorphisms. These results drastically update our view on the implication of the primary sequence of mt-rRNA in the etiology of deafness and mitochondrial disease in general. Our data sheds much-needed light on the question of how mt-rRNA variants located at non-conserved positions may lead to mitochondrial disease and, most notably, provide evidence of the effect of haplotype context in the manifestation of some mt-rRNA variants.
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Affiliation(s)
- Antón Vila-Sanjurjo
- Grupo GIBE. Departamento de Bioloxía e Centro Interdisciplinar de Química e Bioloxía (CICA), Universidade da Coruña (UDC), A Coruña, Spain
| | - Natalia Mallo
- Grupo GIBE. Departamento de Bioloxía e Centro Interdisciplinar de Química e Bioloxía (CICA), Universidade da Coruña (UDC), A Coruña, Spain
| | - Joanna L. Elson
- The Bioscience Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
- Human Metabolomics, North-West University, Potchefstroom, South Africa
| | - Paul M. Smith
- Department of Paediatrics, Raigmore Hospital, Inverness, United Kingdom
| | - Emma L. Blakely
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Robert W. Taylor
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
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Adadey SM, Wonkam-Tingang E, Aboagye ET, Quaye O, Awandare GA, Wonkam A. Hearing loss in Africa: current genetic profile. Hum Genet 2021; 141:505-517. [PMID: 34609590 PMCID: PMC9034983 DOI: 10.1007/s00439-021-02376-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 09/21/2021] [Indexed: 01/03/2023]
Abstract
Hearing impairment (HI) is highly heterogeneous with over 123 associated genes reported to date, mostly from studies among Europeans and Asians. Here, we performed a systematic review of literature on the genetic profile of HI in Africa. The study protocol was registered on PROSPERO, International Prospective Register of Systematic Reviews with the registration number “CRD42021240852”. Literature search was conducted on PubMed, Scopus, Africa-Wide Information, and Web of Science databases. A total of 89 full-text records was selected and retrieved for data extraction and analyses. We found reports from only 17/54 (31.5%) African countries. The majority (61/89; 68.5%) of articles were from North Africa, with few reports found from sub-Saharan Africa. The most common method used in these publications was targeted gene sequencing (n = 66/111; 59.5%), and only 13.5% (n = 15/111) used whole-exome sequencing. More than half of the studies were performed in families segregating HI (n = 51/89). GJB2 was the most investigated gene, with GJB2: p.(R143W) founder variant only reported in Ghana, while GJB2: c.35delG was common in North African countries. Variants in MYO15A were the second frequently reported in both North and Central Africa, followed by ATP6V1B1 only reported from North Africa. Usher syndrome was the main syndromic HI molecularly investigated, with variants in five genes reported: USH2A, USH1G, USH1C, MYO7A, and PCDH15. MYO7A: p.(P1780S) founder variant was reported as the common Usher syndrome variant among Black South Africans. This review provides the most comprehensive data on HI gene variants in the largely under-investigated African populations. Future exomes studies particularly in multiplex families will likely provide opportunities for the discovery of the next sets of novel HI genes, and well as unreported variants in known genes to further our understanding of HI pathobiology, globally.
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Affiliation(s)
- Samuel Mawuli Adadey
- Department of Biochemistry, Cell and Molecular Biology, West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, P.O. Box LG 54, Legon, Accra, Ghana.,Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory, Cape Town, 7925, South Africa
| | - Edmond Wonkam-Tingang
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory, Cape Town, 7925, South Africa
| | - Elvis Twumasi Aboagye
- Department of Biochemistry, Cell and Molecular Biology, West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, P.O. Box LG 54, Legon, Accra, Ghana
| | - Osbourne Quaye
- Department of Biochemistry, Cell and Molecular Biology, West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, P.O. Box LG 54, Legon, Accra, Ghana
| | - Gordon A Awandare
- Department of Biochemistry, Cell and Molecular Biology, West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, P.O. Box LG 54, Legon, Accra, Ghana
| | - Ambroise Wonkam
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory, Cape Town, 7925, South Africa.
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Human Mitoribosome Biogenesis and Its Emerging Links to Disease. Int J Mol Sci 2021; 22:ijms22083827. [PMID: 33917098 PMCID: PMC8067846 DOI: 10.3390/ijms22083827] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 03/23/2021] [Accepted: 03/24/2021] [Indexed: 12/20/2022] Open
Abstract
Mammalian mitochondrial ribosomes (mitoribosomes) synthesize a small subset of proteins, which are essential components of the oxidative phosphorylation machinery. Therefore, their function is of fundamental importance to cellular metabolism. The assembly of mitoribosomes is a complex process that progresses through numerous maturation and protein-binding events coordinated by the actions of several assembly factors. Dysregulation of mitoribosome production is increasingly recognized as a contributor to metabolic and neurodegenerative diseases. In recent years, mutations in multiple components of the mitoribosome assembly machinery have been associated with a range of human pathologies, highlighting their importance to cell function and health. Here, we provide a review of our current understanding of mitoribosome biogenesis, highlighting the key factors involved in this process and the growing number of mutations in genes encoding mitoribosomal RNAs, proteins, and assembly factors that lead to human disease.
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Screening for deafness-associated mitochondrial 12S rRNA mutations by using a multiplex allele-specific PCR method. Biosci Rep 2020; 40:224124. [PMID: 32400865 PMCID: PMC7263198 DOI: 10.1042/bsr20200778] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 04/30/2020] [Accepted: 05/12/2020] [Indexed: 11/17/2022] Open
Abstract
Mitochondrial 12S rRNA A1555G and C1494T mutations are the major contributors to hearing loss. As patients with these mutations are sensitive to aminoglycosides, mutational screening for 12S rRNA is therefore recommended before the use of aminoglycosides. Most recently, we developed a novel multiplex allele-specific PCR (MAS-PCR) that can be used for detecting A1555G and C1494T mutations. In the present study, we employed this MAS-PCR to screen the 12S rRNA mutations in 500 deaf patients and 300 controls from 5 community hospitals. After PCR and electrophoresis, two patients with A1555G and one patient with C1494T were identified, this was consistent with Sanger sequence results. We further traced the origin of three Chinese pedigrees. Clinical evaluation revealed variable phenotypes of hearing loss including severity, age at onset and audiometric configuration in these patients. Sequence analysis of the mitochondrial genomes from matrilineal relatives suggested the presence of three evolutionarily conserved mutations: tRNACys T5802C, tRNALys A8343G and tRNAThr G15930A, which may result the failure in tRNAs metabolism and lead to mitochondrial dysfunction that was responsible for deafness. However, the lack of any functional variants in GJB2, GJB3, GJB6 and TRMU suggested that nuclear genes may not play active roles in deafness expression. Hence, aminoglycosides and mitochondrial genetic background may contribute to the clinical expression of A1555G/C1494T-induced deafness. Our data indicated that the MAS-PCR was a fast, convenience method for screening the 12S rRNA mutations, which was useful for early detection and prevention of mitochondrial deafness.
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Ibrahim I, Dominguez-Valentin M, Segal B, Zeitouni A, da Silva SD. Mitochondrial mutations associated with hearing and balance disorders. Mutat Res 2018; 810:39-44. [PMID: 29615272 DOI: 10.1016/j.mrfmmm.2018.03.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 12/20/2017] [Accepted: 03/09/2018] [Indexed: 06/08/2023]
Abstract
Hearing and balance disorders are related to the inner ear and are among the major cause of falls in older adults. Hearing loss that commonly occurs with aging (aka presbyacusis) can result from noise exposure, smoking, ototoxic drugs and genetic factors such as mutations in nuclear and mitochondrial genes. Mutations in mitochondrial DNA (mtDNA) have been reported to play an important role in cell function by providing energy, as well as, cell death (apoptosis). This study aims to systematically review mitochondrial mutations associated with presbyacusis and suggests preventive measurements to improve the quality of life in older adults.
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Affiliation(s)
- Iman Ibrahim
- Department of Otolaryngology-Head and Neck Surgery, McGill University, Canada.
| | - Mev Dominguez-Valentin
- Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway.
| | - Bernard Segal
- Department of Otolaryngology-Head and Neck Surgery, McGill University, Canada.
| | - Anthony Zeitouni
- Department of Otolaryngology-Head and Neck Surgery, McGill University, Canada.
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Mkaouar-Rebai E, Chamkha I, Mezghani N, Ben Ayed I, Fakhfakh F. Screening of mitochondrial mutations in Tunisian patients with mitochondrial disorders: an overview study. ACTA ACUST UNITED AC 2013; 24:163-78. [PMID: 23301511 DOI: 10.3109/19401736.2012.748045] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
To investigate the spectrum of common mitochondrial mutations in Tunisia during the years of 2002-2012, 226 patients with mitochondrial disorders were clinically diagnosed with hearing loss, Leigh syndrome (LS), diabetes, cardiomyopathy, Kearns-Sayre syndrome (KSS), Pearson syndrome (PS), myopathy, mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes syndrome (MELAS) and Wolfram syndrome. Restriction fragment length polymorphism (PCR-RFLP), radioactive PCR, single specific primer-PCR (SSP-PCR) analysis and PCR-sequencing methods were used to identify the mutations. Two cases with m.1555A>G mutation and two families with the novel 12S rRNA m.735A>G transition were detected in patients with hearing loss. Three cases with m.8993T>G mutation, two patients with the novel m.5523T>G and m.5559A>G mutations in the tRNA(Trp) gene, and two individuals with the undescribed m.9478T>C mutation in the cytochrome c oxidase subunit III (COXIII) gene were found with LS. In addition, one case with hypertrophic cardiomyopathy and deafness presented the ND1 m.3395A>G mutation and the tRNA(Ile) m.4316A>G variation. Besides, multiple mitochondrial deletions were detected in patients with KSS, PS, and Wolfram syndrome. The m.14709T>C mutation in the tRNA(Glu) was reported in four maternally inherited diabetes and deafness patients and a novel tRNA(Val) m.1640A>G mutation was detected in a MELAS patient.
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Affiliation(s)
- Emna Mkaouar-Rebai
- Human Molecular Genetic Laboratory, Faculty of Medicine of Sfax, Avenue Magida Boulila, 3029 Sfax, Tunisia.
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Nogueira C, Coutinho M, Pereira C, Tessa A, Santorelli FM, Vilarinho L. Molecular investigation of pediatric portuguese patients with sensorineural hearing loss. GENETICS RESEARCH INTERNATIONAL 2011; 2011:587602. [PMID: 22567359 PMCID: PMC3335713 DOI: 10.4061/2011/587602] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Accepted: 07/27/2011] [Indexed: 12/02/2022]
Abstract
The understanding of the molecular genetics in sensorineural hearing loss (SNHL) has advanced rapidly during the last decade, but the molecular etiology of hearing impairment in the Portuguese population has not been investigated thoroughly. To provide appropriate genetic testing and counseling to families, we analyzed the whole mitochondrial genome in 95 unrelated children with SNHL (53 nonsyndromic and 42 syndromic) and searched for variations in two frequent genes, GJB2 and GJB6, in the non-syndromic patients. Mutations in mtDNA were detected in 4.2% of the cases, including a hitherto undescribed change in the mtDNA-tRNATrp gene (namely, m.5558A>G). We also identified mono- or biallelic GJB2 mutations in 20 of 53 non-syndromic cases and also detected two novel mutations (p.P70R and p.R127QfsX84). Our data further reinforce the notion that genetic heterogeneity is paramount in children with SNHL.
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Affiliation(s)
- Célia Nogueira
- Genetics Department, Medical Genetics Center, National Institute of Health (INSA), Praça Pedro Nunes 88, 4099-028 Porto, Portugal
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