Detection of Deafness-Causing Mutations in the Greek Mitochondrial Genome

Kokotas, Haris; Grigoriadou, Maria; Korres, George; Ferekidou, Elisabeth; Kandiloros, Dimitrios; Korres, Stavros; Petersen, Michael B.

doi:10.1155/2011/350987

Cited by 12 publications

(3 citation statements)

References 44 publications

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“…Two patients with hearing loss possess this mitochondrial mutation (0.53%). Surprisingly, this rate is similar to that found among 513 Greek children with hearing loss (0.4%) [32] but is much less than the 3.6% found among SNHL patients of neighboring Poland [33].…”

Section: Resultssupporting

confidence: 78%

Spectrum of Genetic Changes in Patients with Non-Syndromic Hearing Impairment and Extremely High Carrier Frequency of 35delG GJB2 Mutation in Belarus

et al. 2012

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The genetic nature of sensorineural hearing loss (SNHL) has so far been studied for many ethnic groups in various parts of the world. The single-nucleotide guanine deletion (35delG) of the GJB2 gene coding for connexin 26 was shown to be the main genetic cause of autosomal recessive deafness among Europeans. Here we present the results of the first study of GJB2 and three mitochondrial mutations among two groups of Belarusian inhabitants: native people with normal hearing (757 persons) and 391 young patients with non-syndromic SNHL. We have found an extremely high carrier frequency of 35delG GJB2 mutation in Belarus −5.7%. This point deletion has also been detected in 53% of the patients with SNHL. The 312del14 GJB2 was the second most common mutation in the Belarus patient cohort. Mitochondrial A1555G mt-RNR1 substitution was found in two SNHL patients (0.55%) but none were found in the population cohort. No individuals carried the A7445G mutation of mitochondrial mt-TS1. G7444A as well as T961G substitutions were detected in mitochondrial mt-RNR1 at a rate of about 1% both in the patient and population cohorts. A possible reason for Belarusians having the highest mutation carrier frequency in Europe 35delG is discussed.

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Section: Resultssupporting

confidence: 78%

Spectrum of Genetic Changes in Patients with Non-Syndromic Hearing Impairment and Extremely High Carrier Frequency of 35delG GJB2 Mutation in Belarus

et al. 2012

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“…In Europe, the lowest frequency was observed in Belgium and the highest frequency was observed in the Spanish population. The prevalence of this allele varied between 0.3% and 20.8% (Lehtonen et al., ; Lopez‐Bigas et al., ; Gallo‐Teran et al., 2002; Kupka et al., ; del Castillo et al., ; Jacobs et al., ; Bravo et al., ; Berrettini et al., ; Konings et al., 2008; Rydzanicz et al., ; Angulo et al., ; Kokotas et al., ). In New Zealand, the frequency of the m.1555A>G variant was observed to be less than 0.5% (Scrimshaw et al.…”

Section: Discussionmentioning

confidence: 99%

Genetic Epidemiology of Mitochondrial Pathogenic Variants Causing Nonsyndromic Hearing Loss in a Large Cohort of South Indian Hearing Impaired Individuals

Subathra

Ramesh

Selvakumari

et al. 2016

Annals of Human Genetics

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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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“…Finally, 2% agarose gel electrophoresis was performed to determine whether the tested samples were positive for the variants. 22 Mutation analyses of GJB2 , TRMU p.A10S, MTND1 m.3308T>C, and MTND6 m.14484T>C were performed using the primers listed in Supplementary Table 2 . The PCR products were analyzed using Sanger sequencing.…”

Section: Methodsmentioning

confidence: 99%

Prevalence and Clinical Characteristics of Mitochondrial DNA Mutations in Korean Patients With Sensorineural Hearing Loss

Joo,

Jang,

Kim

et al. 2023

J Korean Med Sci

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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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Detection of Deafness-Causing Mutations in the Greek Mitochondrial Genome

Cited by 12 publications

References 44 publications

Spectrum of Genetic Changes in Patients with Non-Syndromic Hearing Impairment and Extremely High Carrier Frequency of 35delG GJB2 Mutation in Belarus

Spectrum of Genetic Changes in Patients with Non-Syndromic Hearing Impairment and Extremely High Carrier Frequency of 35delG GJB2 Mutation in Belarus

Genetic Epidemiology of Mitochondrial Pathogenic Variants Causing Nonsyndromic Hearing Loss in a Large Cohort of South Indian Hearing Impaired Individuals

Prevalence and Clinical Characteristics of Mitochondrial DNA Mutations in Korean Patients With Sensorineural Hearing Loss

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