Estudo de mutações no gene GJB3 como causa de deficiencia auditiva neurossensorial não-sindromica

AUTOR(ES)

Fabiana Alexandrino

DATA DE PUBLICAÇÃO

2003

RESUMO

Deafness is one of the most common sensory defects in the general population and its prevalence increases with age. In developed countries about 60% of hearing loss cases are due to genetic factors. In Brazil the majority of cases of hearing loss are due to environmental factors. However, the proportion of genetic causes tends to increase as a result of improvement in health care, and thus modify daily medical practice in the etiologic investigation of deafuess. Recent years have seen tremendous progress localizing and cloning genes associated with inherited hearing loss. Most of cases inherited are nonsyndromic, and approximately 80% of these genes are autosomal recessive, 18% autosomal dominant, and 2% X-linked or mitochondrial inherited. Several connexin genes have been found mutated in patients with non-syndromic and syndromic deafness indicating an important role these proteins in the auditory system. Mutations in the connexin 26 (GJB2) lead to hearing impairment in most ofpopulations alI over the countries. This gene is responsible for approximateIy 80% ofthe non-syndromic recessive deafness. The GJB3 gene (Cx31) has recently been found as deafuess gene. Mutations in the connexin 31 have been detected either in erythrokeratodermia variabilis and non-syndromic autosomal recessive or dominant deafness. To determine the contribution of connexin 31 to sporadic deafness, we ana1ysed the entire gene of connexin 31 in 67 families with non-syndromic hearing impairment. We reported three amino acid changes, YI77D, 49deIK and R32W, and two nuc1eotides variants, which represents a silent mutation. The R32W substitution has been previously described, and its invo lvement in hearing impairment remains uncertain.We presume that mutations in connexin 31 gene are an infrequent cause of non syndromic deafness

ASSUNTO(S)

surdez mutação (biologia) disturbios da audição

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