TheGJB2gene(connexin26)hasbeenshowntoberesponsibleforDFNB1andDFNA3.WescreenedtheGJB2genein488patientswithprelingualdeafness(Group1),124withpostlingualdeafness(Group2),and117normalhearingsubjects(Group3).Wefoundthat,inGroup1,65patients(13.32%)werehomozygotesorcompoundheterozygotesand51patients(10.45%)carriedasinglepathogenicmutation.The235delCmutationwasthemostfrequentmutation,accountingfor73.22%oftheknownpathogenicallelesinGroup1.NohomozygotesorcompoundheterozygotesweredetectedinGroup2orGroup3.Somepostlingualdeafpatients(2.42%)andnormalhearingsubjects(4.27%)were235delCcarriers.Ourpreliminarydataindicatethat235delC,themostfrequentmutationidentifiedinthisstudy,isamajorcauseforprelingualdeafness.
