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Zhang D, Wu J, Yuan Y, Li X, Gao X, Kang D, Zhang X, Huang SS, Dai P. Mitochondrial tRNA Ser(UCN) mutations associated non-syndromic sensorineural hearing loss in Chinese families. Heliyon 2024; 10:e27041. [PMID: 38501023 PMCID: PMC10945119 DOI: 10.1016/j.heliyon.2024.e27041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 12/29/2023] [Accepted: 02/22/2024] [Indexed: 03/20/2024] Open
Abstract
Mitochondrial transfer RNA mutation is one of the most important causes of hereditary hearing loss in humans. Mitochondrial transfer RNASer (UCN) gene is another hot spot for mutations associated with non-syndromic hearing loss, besides the 12S ribosomal RNA gene. In this study, we assessed the clinical phenotype and the molecular characteristics of two Chinese families with non-syndromic hearing loss. Mutational analysis revealed that 7445A > G and 7510T > C mutations in the mitochondrial transfer RNASer (UCN) gene were the molecular etiology of Family 1 and Family 2, respectively. However, the clinical and genetic characteristics of the two families carrying the above mutations in the transfer RNASer (UCN) gene exhibited a variable expression of hearing loss and an incomplete penetrance. Sequencing analysis of the complete mitochondrial genome showed the presence of transfer RNATrp 5568A > G and NADH-ubiquinone oxidoreductase chain 4 11696G > A mutations in Family 1. The mitochondrial haplotype analysis showed that the two families belonged to Asian D4 and M80'D haplotypes, respectively, and no pathogenic variations were found in the nuclear genes. To our knowledge, our study is the first to report 7445A > G and 7510T > C mutations in the mitochondrial transfer RNASer (UCN) gene, in multi-generation non-syndromic hearing loss pedigrees from China. Our study suggests that 5568A > G and 11696G > A mutations may enhance the penetrance of hearing loss in Chinese Family 1, while mitochondrial haplotypes and known nuclear genes may not be modifiers for the phenotypic expression of 7445A > G and 7510T > C mutations in these Chinese families.
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Affiliation(s)
- Dejun Zhang
- Department of Otolaryngology Head and Neck Surgery, The Second Hospital of Jilin University, Changchun, China
- ColIege of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Beijing, China
- State Key Lab of Hearing Science, Ministry of Education, National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Beijing Key Lab of Hearing Impairment for Prevention and Treatment, Beijing, China
| | - Jie Wu
- ColIege of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Beijing, China
- State Key Lab of Hearing Science, Ministry of Education, National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Beijing Key Lab of Hearing Impairment for Prevention and Treatment, Beijing, China
| | - Yongyi Yuan
- ColIege of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Beijing, China
- State Key Lab of Hearing Science, Ministry of Education, National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Beijing Key Lab of Hearing Impairment for Prevention and Treatment, Beijing, China
| | - Xiaohong Li
- Department of Otolaryngology, Head and Neck Surgery, National Children's Medical Center/Beijing Children's Hospital, Capital Medical University, Beijing, China
| | - Xue Gao
- Department of Otolaryngology, PLA Rocket Force Characteristic Medical Center, Beijing, China
| | - Dongyang Kang
- ColIege of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Beijing, China
- State Key Lab of Hearing Science, Ministry of Education, National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Beijing Key Lab of Hearing Impairment for Prevention and Treatment, Beijing, China
| | - Xin Zhang
- ColIege of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Beijing, China
- State Key Lab of Hearing Science, Ministry of Education, National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Beijing Key Lab of Hearing Impairment for Prevention and Treatment, Beijing, China
| | - Sha-sha Huang
- ColIege of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Beijing, China
- State Key Lab of Hearing Science, Ministry of Education, National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Beijing Key Lab of Hearing Impairment for Prevention and Treatment, Beijing, China
| | - Pu Dai
- ColIege of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Beijing, China
- State Key Lab of Hearing Science, Ministry of Education, National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Beijing Key Lab of Hearing Impairment for Prevention and Treatment, Beijing, China
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Joo SY, Jang SH, Kim JA, Kim SJ, Kim B, Kim HY, Choi JY, Gee HY, Jung J. Prevalence and Clinical Characteristics of Mitochondrial DNA Mutations in Korean Patients With Sensorineural Hearing Loss. J Korean Med Sci 2023; 38:e355. [PMID: 38084023 PMCID: PMC10713439 DOI: 10.3346/jkms.2023.38.e355] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 09/12/2023] [Indexed: 12/18/2023] Open
Abstract
BACKGROUND Mutations in mitochondrial DNA (mtDNA) are associated with several genetic disorders, including sensorineural hearing loss. However, the prevalence of mtDNA mutations in a large cohort of Korean patients with hearing loss has not yet been investigated. Thus, this study aimed to investigate the frequency of mtDNA mutations in a cohort of with pre- or post-lingual hearing loss of varying severity. METHODS A total of 711 Korean families involving 1,099 individuals were evaluated. Six mitochondrial variants associated with deafness (MTRNR1 m.1555A>G, MTTL1 m.3243A>G, MTCO1 m.7444G>A and m.7445A>G, and MTTS1 m.7471dupC and m.7511T>C) were screened using restriction fragment length polymorphism. The prevalence of the six variants was also analyzed in a large control dataset using whole-genome sequencing data from 4,534 Korean individuals with unknown hearing phenotype. RESULTS Overall, 12 of the 711 (1.7%) patients with hearing loss had mtDNA variants, with 10 patients from independent families positive for the MTRNR1 m.1555A>G mutation and 2 patients positive for the MTCO1 m.7444G>A mutation. The clinical characteristics of patients with the mtDNA variants were characterized by post-lingual progressive hearing loss due to the m.1555A>G variant (9 of 472; 1.9%). In addition, 18/4,534 (0.4%) of the Korean population have mitochondrial variants associated with hearing loss, predominantly the m.1555A>G variant. CONCLUSION A significant proportion of Korean patients with hearing loss is affected by the mtDNA variants, with the m.1555A>G variant being the most prevalent. These results clarify the genetic basis of hearing loss in the Korean population and emphasize the need for genetic testing for mtDNA variants.
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Affiliation(s)
- Sun Young Joo
- Department of Pharmacology, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, Korea
- Won-Sang Lee Institute for Hearing Loss, Seoul, Korea
| | - Seung Hyun Jang
- Department of Pharmacology, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, Korea
- Won-Sang Lee Institute for Hearing Loss, Seoul, Korea
| | - Jung Ah Kim
- Department of Pharmacology, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, Korea
- Won-Sang Lee Institute for Hearing Loss, Seoul, Korea
| | - Se Jin Kim
- Department of Pharmacology, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, Korea
- Won-Sang Lee Institute for Hearing Loss, Seoul, Korea
| | - Bonggi Kim
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Korea
| | - Hye-Youn Kim
- Department of Pharmacology, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, Korea
- Won-Sang Lee Institute for Hearing Loss, Seoul, Korea
| | - Jae Young Choi
- Won-Sang Lee Institute for Hearing Loss, Seoul, Korea
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Korea
| | - Heon Yung Gee
- Department of Pharmacology, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, Korea
- Won-Sang Lee Institute for Hearing Loss, Seoul, Korea.
| | - Jinsei Jung
- Won-Sang Lee Institute for Hearing Loss, Seoul, Korea
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Korea.
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Yu X, Li S, Ding Y. Maternally transmitted nonsyndromic hearing impairment may be associated with mitochondrial tRNA Ala 5601C>T and tRNA Leu(CUN) 12311T>C mutations. J Clin Lab Anal 2022; 36:e24298. [PMID: 35218233 PMCID: PMC8993639 DOI: 10.1002/jcla.24298] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/31/2022] [Accepted: 02/08/2022] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Sequence alternations in mitochondrial genomes, especially in genes encoding mitochondrial tRNA (mt-tRNA), were the important contributors to nonsyndromic hearing loss (NSHL); however, the molecular mechanisms remained largely undetermined. METHODS A maternally transmitted Chinese pedigree with NSHL underwent clinical, genetic, and biochemical assessment. PCR and direct sequence analyses were performed to detect mitochondrial DNA (mtDNA), GJB2, and SLC26A4 gene mutations from matrilineal relatives of this family. Mitochondrial functions including mitochondrial membrane potential (MMP), ATP, and ROS were evaluated in polymononuclear leukocytes (PMNs) derived from three deaf patients and three controls from this pedigree. RESULTS Four of nine matrilineal relatives developed hearing loss at the variable age of onset. Two putative pathogenic mutations, m.5601C>T in tRNAAla and m.12311T>C in tRNALeu(CUN) , were identified via PCR-Sanger sequencing, as well as 34 variants that belonged to mtDNA haplogroup G2b2. Intriguingly, m.5601C>T mutation resided at very conserved nucleotide in the TψC loop of tRNAAla (position 59), while the T-to-C substitution at position 12311 located at position 48 in the variable stem of tRNALeu(CUN) and was believed to alter the aminoacylation and the steady-state level of tRNA. Biochemical analysis revealed the impairment of mitochondrial functions including the significant reductions of ATP and MMP, whereas markedly increased ROS levels were found in PMNs derived from NSHL patients with m.5601C>T and m.12311T>C mutations. However, we did not detect any mutations in GJB2 and SLC26A4 genes. CONCLUSION Our data indicated that mt-tRNAAla m.5601C>T and tRNALeu(CUN) 12311T>C mutations were associated with NSHL.
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Affiliation(s)
- Xuejiao Yu
- Department of Clinical LaboratoryQuzhou People's Hospitalthe Quzhou Affiliated Hospital of Wenzhou Medical UniversityQuzhouChina
| | - Sheng Li
- Department of OtolaryngologyQuzhou People's Hospitalthe Quzhou Affiliated Hospital of Wenzhou Medical UniversityQuzhouChina
| | - Yu Ding
- Central LaboratoryHangzhou First People’s HospitalZhejiang University School of MedicineHangzhouChina
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Govindaraj P, Rani B, Sundaravadivel P, Vanniarajan A, Indumathi KP, Khan NA, Dhandapany PS, Rani DS, Tamang R, Bahl A, Narasimhan C, Rakshak D, Rathinavel A, Premkumar K, Khullar M, Thangaraj K. Mitochondrial genome variations in idiopathic dilated cardiomyopathy. Mitochondrion 2019; 48:51-59. [PMID: 30910572 DOI: 10.1016/j.mito.2019.03.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 03/19/2019] [Indexed: 12/22/2022]
Abstract
Idiopathic dilated cardiomyopathy (DCM) is a structural heart disease with strong genetic background. The aim of this study was to assess the role of mitochondrial DNA (mtDNA) variations and haplogroups in Indian DCM patients. Whole mtDNA analysis of 221 DCM patients revealed 48 novel, 42 disease-associated and 97 private variations. The frequency of reported variations associated with hearing impairment, DEAF, SNHL and LHON are significantly high in DCM patients than controls. Haplogroups H and HV were over represented in DCM than controls. Functional analysis of two private variations (m.8812A>G & m.10320G>A) showed decrease in mitochondrial functions, suggesting the role of mtDNA variations in DCM.
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Affiliation(s)
- Periyasamy Govindaraj
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India; Department of Biomedical Science, School of Basic Medical Sciences, Bharathidasan University, Tiruchirappalli, India
| | - Bindu Rani
- Department of Experimental Medicine and Biotechnology, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | | | | | - K P Indumathi
- Department of Biochemistry, Kongu Arts and Science College, Erode, India
| | | | - Perundurai S Dhandapany
- Centre for Cardiovascular Biology and disease, Institute of Stem Cell Biology and Regenerative Medicine(inStem), Bengaluru, India; The Knight Cardiovascular Institute, Departments of Medicine, Molecular and Medical Genetics, Oregon Health and Science University, Portland, USA
| | - Deepa Selvi Rani
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Rakesh Tamang
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Ajay Bahl
- Department of Cardiology, PGIMER, Chandigarh, India
| | | | | | - Andiappan Rathinavel
- Department of Cardio-Thoracic Surgery, Madurai Medical College & Government Rajaji hospital, Madurai, India
| | - Kumpati Premkumar
- Department of Biomedical Science, School of Basic Medical Sciences, Bharathidasan University, Tiruchirappalli, India
| | - Madhu Khullar
- Department of Experimental Medicine and Biotechnology, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
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Matsushima K, Nakano A, Arimoto Y, Mutai H, Yamazawa K, Murayama K, Matsunaga T. High-level heteroplasmy for the m.7445A>G mitochondrial DNA mutation can cause progressive sensorineural hearing loss in infancy. Int J Pediatr Otorhinolaryngol 2018; 108:125-131. [PMID: 29605341 DOI: 10.1016/j.ijporl.2018.02.037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 01/11/2018] [Accepted: 02/23/2018] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Hearing loss caused by mutation of mitochondrial DNA typically develops in late childhood or early adulthood, but rarely in infancy. We report the investigation of a patient to determine the cause of his early onset hearing loss. MATERIALS AND METHODS The proband was a boy aged 1 year and 2 months at presentation. Newborn hearing screening test by automated auditory brainstem response generated "pass" results for both ears. His reaction to sound deteriorated by 9 months. Average pure tone threshold at 0.5, 1, and 2 kHz was 55 dB by conditioned orientation response audiometry. His father had congenital hearing loss, and his mother had progressive hearing loss since childhood. Invader assays and Sanger sequencing were performed to investigate genetic causes of the hearing loss in the proband, and heteroplasmy was assessed by PCR-restriction fragment length polymorphism, Sanger sequencing, and pyrosequencing. Additionally, mitochondrial function was evaluated by measurement of the oxygen consumption rate of patient skin fibroblasts. RESULTS An m.7445A > G mitochondrial DNA mutation and a heterozygous c.235delC (p.L79Cfs*3) mutation of GJB2 were detected in the proband. His mother carried the m.7445A > G mitochondrial DNA mutation, and his father was a compound heterozygote for GJB2 mutations (c.[235delC]; [134G > A; 408C > A]). Tissue samples from both the proband and his mother exhibited a high degree of heteroplasmy. Fibroblasts from the proband exhibited markedly reduced oxygen consumption rates. These data indicate that the proband had impaired mitochondrial function, resulting in hearing loss. CONCLUSION This research demonstrates that hearing loss in a proband who presented in infancy and that of his mother resulted from a high level of heteroplasmy for the m.7445A > G mitochondrial DNA mutation, indicating that this alteration can cause hearing loss in infancy.
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Affiliation(s)
- Kana Matsushima
- Division of Otorhinolaryngology, Chiba Children's Hospital, 579-1 Hetacho, Midori-ku, Chiba, Chiba 266-0007, Japan.
| | - Atsuko Nakano
- Division of Otorhinolaryngology, Chiba Children's Hospital, 579-1 Hetacho, Midori-ku, Chiba, Chiba 266-0007, Japan.
| | - Yukiko Arimoto
- Division of Otorhinolaryngology, Chiba Children's Hospital, 579-1 Hetacho, Midori-ku, Chiba, Chiba 266-0007, Japan.
| | - Hideki Mutai
- Division of Hearing and Balance Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, 2-5-1 Higashigaoka, Meguro, Tokyo 152-8902, Japan.
| | - Kazuki Yamazawa
- Medical Genetics Center, National Hospital Organization Tokyo Medical Center, 2-5-1 Higashigaoka, Meguro, Tokyo 152-8902, Japan.
| | - Kei Murayama
- Division of Metabolism, Chiba Children's Hospital, 579-1 Hetacho, Midori-ku, Chiba, Chiba 266-0007, Japan.
| | - Tatsuo Matsunaga
- Division of Hearing and Balance Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, 2-5-1 Higashigaoka, Meguro, Tokyo 152-8902, Japan; Medical Genetics Center, National Hospital Organization Tokyo Medical Center, 2-5-1 Higashigaoka, Meguro, Tokyo 152-8902, Japan.
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Lechowicz U, Pollak A, Frączak A, Rydzanicz M, Stawiński P, Lorens A, Skarżyński PH, Skarżyński H, Płoski R, Ołdak M. Application of next‑generation sequencing to identify mitochondrial mutations: Study on m.7511T>C in patients with hearing loss. Mol Med Rep 2017; 17:1782-1790. [PMID: 29257206 PMCID: PMC5780123 DOI: 10.3892/mmr.2017.8064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 10/24/2017] [Indexed: 11/23/2022] Open
Abstract
Interruptions in the activity of mitochondria induced by mutations in the mitochondrial genome (mtDNA) can be the source of numerous diseases including hearing loss (HL). One of the mitochondrial variants responsible for HL is the m.7511T>C mutation located in the mitochondrially encoded tRNA serine 1 (UCN) gene. Next-generation sequencing was used to search for the HL mutations in the whole mtDNA of 2 patients with maternal inheritance and real time-polymerase chain reaction was applied for population screening of the m.7511T>C mutation in a group of 1,644 patients with HL. Sequencing of the whole mtDNA in 2 probands revealed a homoplasmic m.7511T>C mutation. Inheritance of the m.7511T>C mutation has been confirmed in examined matrilineal relatives in both families. The mean age of HL onset was 14.1 years old with the mean degree of HL equaling 74.8 dB. A large-scale search for the m.7511T>C mutation among the patients with HL established the frequency of the m.7511T>C mutation at 0.12% among Polish patients with HL. In conclusion, this first report on central European patients harboring the m.7511T>C mutation reveals that the m.7511T>C may be important when diagnosing patients with maternally inherited HL.
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Affiliation(s)
- Urszula Lechowicz
- Department of Genetics, World Hearing Center, Institute of Physiology and Pathology of Hearing, 02‑042 Warsaw, Poland
| | - Agnieszka Pollak
- Department of Genetics, World Hearing Center, Institute of Physiology and Pathology of Hearing, 02‑042 Warsaw, Poland
| | - Agnieszka Frączak
- Department of Genetics, World Hearing Center, Institute of Physiology and Pathology of Hearing, 02‑042 Warsaw, Poland
| | - Małgorzata Rydzanicz
- Department of Medical Genetics, Center for Biostructure, Medical University of Warsaw, 02‑106 Warsaw, Poland
| | - Piotr Stawiński
- Department of Genetics, World Hearing Center, Institute of Physiology and Pathology of Hearing, 02‑042 Warsaw, Poland
| | - Artur Lorens
- Department of Implants and Auditory Perception, Institute of Physiology and Pathology of Hearing, 02‑042 Warsaw, Poland
| | - Piotr H Skarżyński
- World Hearing Center, Institute of Physiology and Pathology of Hearing, 02‑042 Warsaw, Poland
| | - Henryk Skarżyński
- Oto‑Rhino‑Laryngology Surgery Clinic, Institute of Physiology and Pathology of Hearing, 02‑042 Warsaw, Poland
| | - Rafał Płoski
- Department of Medical Genetics, Center for Biostructure, Medical University of Warsaw, 02‑106 Warsaw, Poland
| | - Monika Ołdak
- Department of Genetics, World Hearing Center, Institute of Physiology and Pathology of Hearing, 02‑042 Warsaw, Poland
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Subathra M, Ramesh A, Selvakumari M, Karthikeyen NP, Srisailapathy CRS. Genetic Epidemiology of Mitochondrial Pathogenic Variants Causing Nonsyndromic Hearing Loss in a Large Cohort of South Indian Hearing Impaired Individuals. Ann Hum Genet 2017; 80:257-73. [PMID: 27530448 DOI: 10.1111/ahg.12161] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 05/16/2016] [Indexed: 01/28/2023]
Abstract
Mitochondria play a critical role in the generation of metabolic energy in the form of ATP. Tissues and organs that are highly dependent on aerobic metabolism are involved in mitochondrial disorders including nonsyndromic hearing loss (NSHL). Seven pathogenic variants leading to NSHL have so far been reported on two mitochondrial genes: MT-RNR1 encoding 12SrRNA and MT-TS1 encoding tRNA for Ser((UCN)) . We screened 729 prelingual NSHL subjects to determine the prevalence of MT-RNR1 variants at position m.961, m.1555A>G and m.1494C>T, and MT-TS1 m.7445A>G, m.7472insC m.7510T>C and m.7511T>C variants. Mitochondrial pathogenic variants were found in eight probands (1.1%). Five of them were found to have the m.1555A>G variant, two others had m.7472insC and one proband had m.7444G>A. The extended relatives of these probands showed variable degrees of hearing loss and age at onset. This study shows that mitochondrial pathogenic alleles contribute to about 1% prelingual hearing loss. This study will henceforth provide the reference for the prevalence of mitochondrial pathogenic alleles in the South Indian population, which to date has not been estimated. The m.1555A>G variant is a primary predisposing genetic factor for the development of hearing loss. Our study strongly suggests that mitochondrial genotyping should be considered for all hearing impaired individuals and particularly in families where transmission is compatible with maternal inheritance, after ruling out the most common variants.
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Affiliation(s)
- Mahalingam Subathra
- Department of Genetics, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
| | - Arabandi Ramesh
- Department of Genetics, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
| | - Mathiyalagan Selvakumari
- Department of Genetics, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
| | - N P Karthikeyen
- DOAST (Doctrine Oriented Art of Symbiotic Treatment) Hearing Care Center and Integrated Therapy Center for Autism, Anna Nagar West, Chennai, India
| | - C R Srikumari Srisailapathy
- Department of Genetics, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
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Postlingual hearing loss as a mitochondrial 3243A>G mutation phenotype. PLoS One 2012; 7:e44054. [PMID: 23133508 PMCID: PMC3485002 DOI: 10.1371/journal.pone.0044054] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Accepted: 07/30/2012] [Indexed: 11/19/2022] Open
Abstract
Background The prevalence of isolated hearing loss (HL) associated with the m.3243A>G mutation is unknown. The aim of this study was to assess the frequency and heteroplasmy level of the m.3243A>G mutation in a large group of Polish patients with postlingual bilateral sensorineural HL of unidentified cause. Methodology/Principal Findings A molecular search was undertaken in the archival blood DNA of 1482 unrelated patients with isolated HL that had begun at ages between 5 and 40 years. Maternal relatives of the probands were subsequently investigated and all carriers underwent audiological tests. The m.3243A>G mutation was found in 16 of 1482 probands (an incidence of 1.08%) and 18 family members. Of these 34 individuals, hearing impairment was detected in 29 patients and the mean onset of HL was at 26 years. Some 42% of the identified m.3243A>G carriers did not develop multisystem symptomatology over the following 10 years. Mean heteroplasmy level of m.3243A>G was lowest in blood at a level of 14% and highest in urine at 58%. These values were independent of the manifested clinical severity of the disease. Conclusions A single m.3243A>G carrier can usually be found among each 100 individuals who have postlingual hearing loss of unknown cause. Urine samples are best for detecting the m.3243A>G mutation and diagnosing mitochondrially inherited hearing loss.
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Identyfikacja mutacji w mitochondrialnym genie 12S rRNA u osób z niedosłuchem po leczeniu antybiotykami aminoglikozydowymi. Otolaryngol Pol 2011; 65:297-9. [DOI: 10.1016/s0030-6657(11)70695-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 05/29/2011] [Indexed: 11/20/2022]
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