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TNC Gene Mutation: A Rare Cause for Early-Onset Sensorineural Hearing Loss

Pedro Carneiro de Sousa*, Ines Gamboa, Delfim Duarte and Nuno Trigueiros-Cunha

The authors aim to emphasize the important of a complete and exhaustive framework in order to find the cause of isolated hearing loss in an young patients, even if there is no familial history. Case Report: 20- year-old woman presented with isolated progressive bilateral hearing loss since the last six months. In the physical examination, otoscopy, acumetry and vestibular examination were normal. Audiometry confirmed bilateral hearing loss with a flat curve, but brainstem evoked response audiometry wave latencies and amplitudes and brain magnetic resonance imaging (MRI) were normal. Genetic study showed a mutation in the TNC gene. Discussion: TNC gene encodes tenascin-C, an extracellular matrix glycoprotein present in the human cochlea. This protein may have a role in the neosynaptogenesis after cochlear injury and in ionic homeostasis. In fact, TNC gene mutation causes a post-lingual autosomal dominant hearing loss."