The precise diagnosis of hearing loss can be clarified by genetic investigation. Non-syndromic hearing loss is responsible for 70% of all genetic causes of hearing loss. More than 100 genes are potentially involved in non-syndromic hearing loss. A specific mutation (35delG) on the GJB2 gene that codifies Conexin 26 protein is the most common finding in non-syndromic hereditary hearing loss. AIM: In this study the presence of mutations 35delG, A1555G/12SeRNA and A7445G/tRNASer (UCN) where investigated for patients with hearing loss of unknown cause. STUDY DESIGN: Clinical study with transversal cohort. MATERIAL AND METHOD: 75 outpatients from the Department of Otolaryngology and Head and Neck Surgery of the University of Campinas-UNICAMP were evaluated from July to December of 2000. A total of six mutations were found, four 35delG/GJB2, one A7445G/tRNASer (UCN) and W172X/GJB2, a mutation not yet described in previous literature. CONCLUSION: The investigation of mutations associated with hearing loss can be carried out easily, elucidates the etiology and allows genetic counseling of the family.
hereditary hearing loss; genetic; conexin26
