《遗传疾病的分类》PPT课件

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1、ClassificationofGeneticDisordersThisPowerPointfilecontainsanumberofslidesthatmaybeusefulforteachingofgeneticsconcepts.Youmayusetheseslidesandtheircontentsfornon-commercialeducationalpurposes.Fig.13.3©ScionPublishingLtdEtiologyofdiseases.Foranyconditiont

2、heoverallbalanceofgeneticandenvironmentaldeterminantscanberepresentedbyapointsomewherewithinthetriangle.ClassificationofgeneticdisordersMultifactorialSinglegeneChromosomalMitochondrialSomaticmutations(cancer)Male+environmentFig.1.15©ScionPublishingLtdCo

3、ntinuumofpenetrance.Thereisacontinuumofpenetrancefromfullypenetrantconditions,whereothergenesandenvironmentalfactorshavenoeffect,throughtolow-penetrancegenesthatsimplyplayasmallpart,alongwithothergeneticandenvironmentalfactors,indeterminingaperson’ssusc

4、eptibilitytoadisease.Multiplesclerosisisusedasanexampleofamultifactorialconditionwheregeneticfactorsplayamajorpartindeterminingsusceptibility,butcurrentresearchsuggeststhateachindividualfactorhasaverylowpenetrance.GeneticfactorsMaleMutationsinsinglegen

5、es(oftencausinglossoffunction)VariantsingenescausingalterationoffunctionChromosomalimbalancecausesalterationingenedosageClassificationofgeneticdisordersMaleMutationsinsinglegenesVariantsingenesChromosomalimbalanceSingleGeneDisordersMultifactorialdisease

6、sChromosomedisorders+environmentRecessiveHomozygoteswithtwocopiesofthealteredgeneareaffectedDominantHeterozygoteswithonecopyofthealteredgeneareaffectedX-linkedrecessiveMaleswithonecopyofthealteredgeneontheX-chromosomeareaffectedMaleGeneticdisordersMulti

7、factorial(common)-“Environmental”influencesactonageneticpredispositiontoproducealiabilitytoadisease.-Oneorgansystemaffected.-Personaffectedifliabilityaboveathreshold.Singlegene(1%liveborn)-Dominant/recessivepedigreepatterns(Mendelianinheritance).-Canaf

8、fectstructuralproteins,enzymes,receptors,transcriptionfactors.Chromosomal(0.6%liveborn)-Thousandsofgenesmaybeinvolved.-Multipleorgansystemsaffectedatmultiplestagesingestation.-Usuallydenovo(trisomies,deletions,duplications)butc