《线粒体疾病》ppt课件

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1、13线粒体疾病mitochondrialdiseasesMutations(changes)inthemitochondrialchromosomeareresponsibleforanumberofdisorders.Mitochondrialdiseaseisachronic,geneticdisorderthatoccurswhenthemitochondriaofthecellfailstoproduceenoughenergyforcellororganfunction.Theincidenceabout1:3000-4000individualsintheUS.C

2、haracteristicsUnlikenucleargenes,whichareinheritedfrombothparents,mitochondrialgenesareinheritedonlyfromthemother.Inmammals,99.99%ofmitochondrialDNA(mtDNA)isinheritedfromthemother.Thisisbecausethespermcarriesitsmitochondriaaroundaportionofitstailandhasonlyabout100mitochondriacomparedto100,0

3、00intheoocyte.Thresholdeffect%ofmutantmtDNAsmustbeaboveathresholdtoproduceclinicalmanifestations%ofmutantmtDNAsneededtocausecelldysfunctionvariesaccordingtotissueoxidativerequirementsDiseasesignsespeciallymanifestinTissueswithahighenergyexpenditure:DependentonoxidativemetabolismSpecifictiss

4、ues:Brain,Heart&MuscleMitoticsegregation%ofmutantmtDNAsindaughtercellscanshiftatcelldivisionProducesrapidchangesofgenotypethatmayleadtocrossingofthresholdTherearemanyformsofmitochondrialdisease.Mitochondrialdiseasepresentsverydifferentlyfromindividualtoindividual.Mitochondrialdiseaseisinher

5、itedinanumberofdifferentways.Theremaybeoneindividualinafamilyormanyindividualsaffectedoveranumberofgenerations.Ifthereisamutationinamitochondrialgene,itispassedfromamothertoallofherchildren;sonswillnotpassiton,butdaughterswillpassitontoalloftheirchildren,andsoon.3.LHONLHON=Leber's;Hereditar

6、y;Optic;NeuropathyGenetic-Clinicalcorrelations:MaternalInheritanceRecurrencerisks:Brother30%;Sister8%;Nephew46%;Niece10%;Malecousin31%;Femalecousin6%40%ofpatientswithcommonestmutation(G11778A)havenegativefamilyhistoryLargefamilieswithmaternalinheritance:G11778&T14484CmutationsMutations(Gene

7、ral)3Mutationsaccountfor96%ofcasesAllinComplexIgenesMutations:G11778A(69%),G3460A(13%),T14484C(14%)Clinicalfeatures(General)Malepredominance:NorelationtoanyX-linkedgenesOnset:Midlife:Mean30years;Range1to70VisuallossClinicalfeaturesPainlessVisuallosspatte