Tracking of the genetic deafness associated to the aging in Brazilian patients

Abstract

Introduction Presbyacusis is the most common cause of auditory dysfunction that is generally associated with aging in industrialized societies. Objective To assess the presence of the mitochondrial 4977-bp deletion in Brazilian patients with presbyacusis. Materials and methods One hundred unrelated patients of both genders were clinically examined to exclude syndromic forms of deafness. Specific oligonucleotide primers were designed to amplify the cytochrome b gene and the 4977-bp deletion of the mtDNA using the polymerase chain reaction. Results The mtDNA 4977 deletion was not identified in any of the samples analyzed. A region of the cytochrome b gene has been previously amplified and the presence of the mtDNA and the non-deleted mtDNA was confirmed in all of the samples. Conclusions These molecular findings disagree with reports describing the mtDNA 4977 deletion associated with aging, but do not discard the possibility of the existence of mutations in other genes in the patients and, highlight the importance of identifying the underlying genetic causes of presbyacusis, in the Brazilian population, to provide a better understanding of the internal ear diseases.