MutationsinGJB2genearethemostfrequentlyfoundmutationsinpatientswithnonsyndromichearingimpairment.However,thespectrumandprevalenceofmutationsinthisgenevaryamongdifferentethnicgroups.InChina,30,000infantsarebornwithcongenitalhearingimpairmentannually.Inordertoprovideappropriategenetictestingandcounselingtothefamilies,weinvestigatedthemolecularetiologyofnonsyndromicdeafnessin103unrelatedschoolchildrenattendingNantongSchoolfortheDeafandMuteinJiangsuProvince,China.ThecodingexonoftheGJB2genewasPCRamplifiedandsequenced.SixtytwoGJB2mutantalleleswereidentifiedin35.9%(37/103)ofthepatients.Twentyfivepatientscarriedtwopathogenicmutationsand12patientscarriedonemutantallele.The235delCwasthemostcommonmutationaccountingfor69.4%(43/62)ofGJB2mutantalleles.TheGJB2mutantallelesaccountedfor30.1%(62/206)ofallchromosomesresponsiblefornonsyndromichearingimpairment.Testingofthe3mostprevalentdeleteriousframeshiftmutationsinthiscohortdetected100%ofallGJB2mutantalleles.TheseresultsdemonstratethataneffectivegenetictestingofGJB2geneforpatientsandfamilieswithnonsyndromichearingimpairmentispossible.
