Analysis of genetic mutation in patients with nonsyndromic hearing loss received cochlear implant

Abstract

To investigate the prevalence of mutations of the gap junction protein (GJB) 2 and mitochondria 12SrRNA in patients with nonsyndromic hearing loss who received cochlear implant. Genomic DNA was extracted from the peripheral blood samples obtained from 100 Chinese patients who had received cochlear implantation, 96 with prelingual hearing loss and 4 with postlingual hearing loss, all very severe. Sixteen of the 100 patients had the history of application of aminoglycosides, among which 12 were with prelingual hearing loss and 4 with postlingual hearing loss. PCR was performed and the products were sequenced by automated DNA sequencer. GJB2 mutations were detected in 34 of the 100 cochlear implant recipients (34%), all with prelingual hearing loss, among which 27 (27%) had 235delC mutation. Among the 16 patients who had used aminoglycosides, two had the mutation A1555G, and one carried the mitochondrial genetic mutation delT961Cn. Mutation of GJB2 gene is the major cause of deafness in cochlear implant recipients, with a high frequency of 235delC mutation. Mitochondria genetic mutation A1555G is the common form of mutation in postlingual deafness with a history of aminoglycoside injection.