Autosomal recessive hereditary auditory neuropathy

(整期优先)网络出版时间:2003-01-11
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Objectives:Auditoryneuropathy(AN)isasensorineuralhearingdisordercharacterizedbyabsentorabnormalauditorybrainstemresponses(ABRs)andnormalcochlearouterhaircellfunctionasmeasuredbyotoacousticemissions(OAEs).Manyriskfactorsarethoughttobeinvolvedinitsetiologyandpathophysiology.ThreeChinesepedigreeswithfamilialANarepresentedhereintodemonstrateinvolvementofgeneticfactorsinANetiology.Methods:Probandsoftheabove-mentionedpedigrees,whohadbeendiagnosedwithAN,wereevaluatedandfollowedupintheDepartmentofOtolaryngologyHeadandNeckSurgery,ChinaPLAGeneralHospital.Theirfamilymemberswerestudiedandthepedigreediagramswereestablished.Historyofillness,physicalexamination,puretoneaudiometry,acousticreflex,ABRsandtransientevokedanddistortion-productotoacousticemissions(TEOAEsandDPOAEs)wereobtainedfrommembersofthesefamilies.DPOAEchangesundertheinfluenceofcontralateralsoundstimuliwereobservedbypresentingasetofcontinuouswhitenoisetothenon-recordingeartoexamthefunctionofauditoryefferentsystem.Somesubjectsreceivedvestibularcalorictest,computedtomography(CT)scanofthetemporalboneandelectrocardiography(ECG)toexcludeotherpossibleneuropathydisorders.Results:Inmostaffectedsubjects,hearinglossofvariousdegreesandspeechdiscriminationdifficultiesstartedat10to16yearsofage.TheiraudiologicalevaluationshowedabsenceofacousticreflexandABRs.AsexpectedinAN,thesesubjectsexhibitednearnormalcochlearouterhaircellfunctionasshowninTEOAE&DPOAErecordings.Pure-toneaudiometryrevealedhearinglossrangingfrommildtosevereinthesepatients.Autosomalrecessiveinheritancepatternswereobservedinthethreefamilies.InPedigreeⅠandⅡ,twoaffectedbrotherswerefoundrespectively,whileinpedigreeⅢ,2sisterswereaffected.Allthepatientswereotherwisenormalwithoutevidenceofperipheralneuropathyatthetimeofth