Prevalence of the 35delG mutation in deaf South Brazilian infants submitted to cochlear implantation

ObjectiveDetermine the prevalence of 35delG mutation in GJB2 gene in patients with prelingual deafness of no defined etiology whose underwent cochlear implant in the Otolaryngology Department at the Hospital de Clínicas de Porto Alegre and compare the speech recognition index using an open-set of sentences according to the presence or absence of the 35delG mutation.MethodsCross-sectional study nested in a cohort. Were analyzed 37 patients with indeterminate etiology for deafness that underwent to cochlear implant. DNA was extracted and the mutations were studied using Polymerase Chain Reaction followed by gene sequencing.ResultsThe prevalence of 35delG mutation was 11%. The speech recognition index was 72% in the group with 35delG mutation, and 30% in the group without this mutation (p > 0.05).ConclusionsPrevalence of 35delG mutation in this study confirmed findings in the Brazilian literature. There was a clinically significant difference in hearing performance in patients with 35delG. Absence of statistical significance in this result might be attributed to the small number of patients with 35delG in our sample.