C1494T mitochondrial dna mutation, hearing loss, and aminoglycosides antibiotics

Mariana Postal,Bruna Palodeto,Edi Lúcia Sartorato,Camila Andréa De Oliveira

doi:10.1016/s1808-8694(15)30554-1

Abstract

SummaryIn view of the complex mechanism of hearing, it is not difficult to understand that hearing impairment may result from a wide variety of genetically determined anomalies and various environmental factors. Specific mutations in the mitochondrial DNA 12S rRNA gene are responsible for maternally inherited non-syndromic hearing loss, and for increased susceptibility to the ototoxicity of aminoglycoside antibiotics.AimTo asses the presence of C1494T mutation among individuals with normal hearing and hearing impairment who used aminoglycosides and those who had not had contact with the antibiotic.Material and MethodThe study was composed of 20 patients with ***nonsyndromic sensorineural hearing loss without prior use of aminoglycosides and 40 premature and high-risk newborns who used ototoxic drugs, of whom 20 had good hearing and 20 had hearing loss. The samples were analyzed by PCR-RFLP with the restriction enzyme Hph I.Study DesignExperimental.ResultsThe mitochondrial 12S rRNA C1494T mutation was not detected in any of the samples analyzed.ConclusionOur data suggest that the hearing loss of the individuals we analyzed was not related to the ototoxicity of mutation C1494T, showing that this mutation is not frequent in our population.

Highlights

In recent years, there has been a major progress in our understanding of hearing mechanisms; numerous genes involved in this process have been discovered and the ways by which they interact has been broadly investigated
Many of the mitochondrial DNA (mtDNA) mutations described in the literature are associated with syndromic and non-syndromic forms of hearing impairment[3,4]
We investigated the presence of mitochondrial mutation C1494T among the patients with hearing impairment and with normal hearing exposed to aminoglycosides and the patients with hearing impairment who did not have contact with the antibiotic

Summary

Introduction

There has been a major progress in our understanding of hearing mechanisms; numerous genes involved in this process have been discovered and the ways by which they interact has been broadly investigated. Mutations in mitochondrial DNA (mtDNA) are responsible for a variety of disorders which affect numerous organs and tissues[2]. Many of the mtDNA mutations described in the literature are associated with syndromic and non-syndromic forms of hearing impairment[3,4]. The organs which require more energy are the ones that present functional alterations in cases of mitochondrial DNA mutations, such as nerve, muscle, endocrine, optical and auditory cells. As the cochlea consumes large amounts of energy, alterations in the mitochondrial DNA in the hair cells cause hearing impairment in a ratio of 0.5% to 1% of all the genetic hearing impairment[5]

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