临床遗传学-冬1、1.2课堂版

4．X连锁隐性遗传病

X-linkedRecessiveTheincidenceismuchhigherinmalesthaninfemales.Thetraitispassedfromanaffectedmanthroughallhisdaughterstothehalftheirsons,nevertransmitteddirectlyfromfathertoson.HemophiliaA甲型血友病AnX-linkedrecessivedisorderNewmutationsinapproximately1/3rdofpatientsMutationsinFVIIIgene,mappedonchromosomeXq28AbsentordecreasedfactorVIII(FVIII)procoagulantfunction

FragileXsyndrome(FRAX)MostcommonformofXlinkedmentalretardationProminentjaws,largeearsandlongface,mentalretardationAfolate-sensitivefragilesiteonXq26-28DMD(3)Polygenicdisorder

多基因遗传病

Multifactorialdisorders:ResultingfromcomplexfunctionsofbothmultiplegenesandmultipleenvironmentalfactorsFamilyhistory,butincidenceismuchlowerthanMendel’smodelPolygenicdisorder

Common50%congenitalabnormality,hypertension(高血压)、rheumatoidarthritis(风湿性关节炎),psychopathy(精神病)

,childdyslexia(阅读困难),specificlanguageimpairment(言语能力不全),attentiondeficit-hyperactivitydisorder(多动症)

AsingletypeofDNAduplex:16.6kb,37genes,(2rRNAgenes,22tRNAgenes,13polypeptide-encodinggenes.(4)Mitochondrialgeneticdisorder

线粒体基因病ThemutationisintheencodingregionsofmitochondrialDNASinglegenemutationTransmitwithmitochondrialDNA-MaternaltransmittingLeber‘shereditaryopticneuropathy视神经疾病MaternaltransmittingMitochondrialgeneticdisorder二、体细胞遗传病Accumulatingresultsofchangesofmultiplegenesandenvironmentalfactorsinacertainduration.MutationsnormallylimitedinsomaticcellsMutationtransmittedbymitosisCancer

肿瘤

MosttypicalsomaticgeneticdisorderComplexchromosomalaberrationsandDNAmutationsintumorcellsHereditarycancer:1%Sporadiccancer：99%，theabnormalphenotypeofproliferatedcellscanbetransmittedthroughcellgenerationsbymitosis-somaticcellgeneticdisorders.MendelianInheritanceinMen

MIM(McKusick)1966,1stedition:15001998,20ndedition:85872000,Webedition:OMIM:>12000Now,renewalmosteverydayReflectionofmoredeeplyunderstandingofhumaningeneticsanddiseasesTherelationshipbetweengeneticandenvironmentalfactorsonhumandiseases四、临床遗传学的特殊诊断

（一）系谱分析SymbolsCommonlyUsedinPedigreeCharts32?affectNumberofchildprobandmalefemaleunsuspectdeceasedmarriagedivorceConsan-guinityNonpenetrantcarriercarriermultipleunionsMono-twindi-twinunknown-zygotetwinSterilityStillbirthmiscarriageabortionAdoptedinto/outfamilyA.Convenientkaryotyping:CellcultureMetaphasearrest-colcemidHypotonictreatment-chromosomespreadChromosomepreparationandbandingKaryotypingforthediagnosisofchromosomalabnormalities（二）细胞遗传学分析

1．染色体检查、染色体核型分析ChromosomesindifferentstagesofphasesofcellcycleMoredetailedanalysis染色体核型分析：染色体数目异常，染色体结构异常（>4MB)High-resolutionbands2．荧光原位杂交,

FISH(FluorescenceInSituHybridization)

FISHDetectingmicro-deletionormicro-duplicationsyndrome.DetectingcrypticrearrangementsBandingcouldnotbedetected<4MbDiGeorge‘s

22q11.2-Williams’s

7q11.23-Kallmann's

Xp22.3-Diagnosisofmicro-deletionsyndromeswithspecificprobesformicrodeletionComparativeGenomicHybridizationDNAfortestlabeledgreen1:1mixedhybridizedontothesamenormalmalemetaphasenormalDNALabeledredCot-1DNACGHComparetheintensityoftwofluorochromesalongthechromosomeset.Detectionofduplicationordeletionofchromosomalsegment.ArrayCGH，aCGHPGS24sure产前FocusConstitutional产后CytoChipOligoScanwholegenomeinaresolutionof1MbDetectionofcopynumberin143lociin97diseasesregisteredinOMIMinaresolutionof100KbMicroarraysCGHMonogenicDisordersMutipogenicDisordersNF-1多发性神经纤维瘤ⅠPrader-Willi普拉德威利综合征-12dert(9q:15q)Chromosome-specificpaintsprobesM-FISH

inhuamanandmouse（三）基因诊断IsolateDNAfromtesttissuesorcellsDetecttheDNAsequenceassociatedwiththediseases.NormallyusingforthediagnosisofmonogenicdisordersDuetogeneticheterogeneity（异质性）,differentdisordersorthesamedisorderindifferentfamilieshavebeenanalyzedbydifferentgeneticdiagnosticmethods

DNAisolationA.DirectlyisolateDNAforanalysis:requirelargeamountoftissueB.AmplifytargetedDNAbypolymerasechainreaction(PCR):requiresmallamountoftissueorevenatsinglecelllevelConvenientPCR,NestedPCRHeminestedPCR,Allele-specificamplificationWholegenomeamplification(DOP-PCR，PEP,ARMSFPCRNestedPCR

OutterprimerInnerprimerPCR3’--3’5’--5’3’-5’--3’-5’OutterprimerPCRInnerprimerDuplexPCRofDMD17,19,44,48exonsandSRYgenefromsingleblastomere

-3’-5’3’-5’-2.Analysesofisolated(amplified)DNADirectorafterthetreatmentwithrestrictedendonucleaseSouthernBlot,AgarosegelHeteroduplexing,SSCPDGGE,SequencingComparativegenomehybridizationMicro-array,DHPLCBlastomere1Blastomere2M17194448SRY

neg-DMD基因诊断AgarosegelXLABKT基因诊断（酶切）SSCPTheproductsofD5S134werenamedasB1,B2,B3,B4accordingtoelectrophoresisvelocityAPCsequencingIII-30e15-12III-16e15-12Next-generationsequencing第二代测序技术：对传统Sanger法测序的一次革命性的改变，是一次可对几十万到几百万条DNA分子进行序列测定的高通量的测序技术，同时高通量测序使得对一个物种的转录组和基因组进行细致全貌的分析成为可能，所以又被称为深度测序(deepsequencing)。

Now:$1,000-10,000小结一、临床遗传学定义和特点

应用遗传学原理和方法开展人类遗传性疾病诊断、治疗和预防的科学。其特点有:1．遗传病起因于遗传物质的突变,

基因和染色体诊断——重要的诊断手段2．遗传病具有家系成员反复发生的风险,家谱分析、遗传咨询——重要内容3．遗传病多症重而无有效治疗方法，产前遗传学诊断预防遗传病患儿出生——最为有效的技术手段。Gene:基本结构Codingregion:Exons,Introns

Regulatoryregions:Promoter,Enhancer,TerminatorStartpointTerminatepointGeneStructureCodingregionCAATBoxTATAboxFromDNA，ChromatintoChromosomeChromosomeisthecarrierofgenes.Genesarearrangedlinearlyonthechromosomes.经典遗传学：Mendelism遗传的基本单位——基因（gene）呈线状串联排列在染色体上位二条同源染色体(homologouschromosome)相同位点的一对基因是等位基因（allele），控制同一性状，显性（dominant）或隐性（recessive）这对等位基因在减数分裂(meiosis)时会随同源染色体的分离（segregation）而分别进入不同的配子排列在不同染色体上的非等位基因，通常控制不同的遗传性状，在减数分裂时自由组合(independentassortment)，进入不同的配子。排列同一染色体上的非等位基因，虽然控制不同的遗传性状，但在减数分裂中一起运动、相互连锁（linkage）进入同一配子。连锁基因可通过同源染色体之间同源片段的互换而发生交换（crossover）。Penetrance（外显率）:theprobabilityofageneexpressionExpressivity（表现度）:theseverityofphenotypeexpressionPleiotropy（多效性）:onegene,morethanoneeffectGeneticheterogeneity（异质性）:thesamephenotypicchangesresultedfromdifferentmutations三、遗传性疾病的概念和分类

Geneticdisorder:thediseasescausedbygenemutationorhumanchromosomalaberration.ClassicorMendeliangeneticdisorders经典遗传性疾病Somaticandmitochondrialgeneticdisorders体细胞和线粒体遗传疾病Classicgeneticdisorders1.Mutationistransmittedfromthegermcellsofparentsoroccurredintheearlystageoffertilizedoocyte.2.Mutationexistsinthewholetissuesofthebodyandremainsforthewholelifetimeoftheindividual.3.Mutationwilltransmittedtothenextgeneration.Chromosomal,monogenic,polygenicdisorders(1)染色体病

DuplicationordeletionofthecertainchromosomesorthecertainchromosomalsegmentsNumberabnormalityStructureabnormality0.6%inlivebornand50%inspontaneousabortionsinfirst-trimesterinmicroscopicobservation1．染色体数目异常(Heteroploidy,异倍体)Achromosomecomplementwithchromosomenumberotherthan46整倍体异常:Achromosomecomplementwithanexactmultipleofthehaploidchromosomenumber非正倍体:

AchromosomecomplementwithchromosomenumberotherthananmultipleofthehaploidchromosomenumberAutosome:onlytrisomy21,18and13foundinlive-birth,nomonosomySexchromosomeinlivebirth:XO,XXX,XXY,XYY,XXXX,XXXXXXchromosomeinactivationmechanism(mechanism)Resultedfromchromosomebreakageandreunion.Unbalancedstructuralabnormality

不平衡染色体结构异常

WithlossorgainofchromosomalmaterialDeletion,duplication,insertion,isochromosomeandringchromosome2．染色体结构异常StructuralAbnormalitiesChromosomedisordersNumerical+unbalancedchromosomalabnormalitiesInvolvingthechromosomeorchromosomalsegmentdeletionorduplicationResultinginthechangesofagroupsofgenesLeadingcomplicatedsymptom,Syndrome:

Featuredbyseriousmentalretardation,structuralabnormalityofface,bodyandmultipleorgansBalancedstructuralabnormality

平衡染色体结构异常Inversion(inv,倒位）,reciprocaltranslocation(t,相互易位),Robertsoniantranslocation(rob,罗伯逊易位)WithoutlossorgainofchromosomalmaterialsUsuallyphenotypicnormalRepeatedabortion,intrauterousfetaldeath,stillbirthandbirthdefectsduetotheabnormalsegregationofinvolvedchromosomesinmeiosisSinglegenedefectsCausedbyanindividualmutantgeneandtransferthroughthegenerationsaccordingtoMendeliangeneticsIndividualincidencerateisrareTotalincidenceis1.00%inlivebirthsand6-8%inhospitalizedchildren(2)单基因病Monogenicdisorder

1．常染色体显性遗传病

AutosomalDominantThetraitappearsineverygenerationAnychildofanaffectedpersonhasa50percentriskofinheritingthetrait.UnaffectedfamilymembersdonottransmitthetraittotheirchildrenTheoccurrenceandtransmissionofthetraitarenotinfluencedbysex2．常染色体隐性遗传病

AutosomalRecessiveThetraitcharacteristicallyappearsonlyinsibs,notintheirparents.Ontheaverage,onefourthofthesibsoftheprobandareaffectedTheparentsofaffectedchildmaybeconsanguineous.Malesandfemalesareequallylikelytobeaffected.3．X连锁显性遗传病

X-linkeddominantAffectedmaleshavenonormaldaughtersandnoaffectedsons.Affectedheterozygousfemalestransmittheconditiontohalftheirchildrenofeithersex..Affectedfemalesaremorecommonthanaffectedmales,butastheyarealmostalwaysheterozygotestheyusuallyhavemilder(butVariable)expression.4．X连锁隐性遗传病

X-linkedRecessiveTheincidenceismuchhigherinmalesthaninfemales.Thetraitispassedfromanaffectedmanthroughallhisdaughterstothehalftheirsons,nevertransmitteddirectlyfromfathertoson.(3)Polygenicdisorder

多基因遗传病

Multifactorialdisorders:ResultingfromcomplexfunctionsofbothmultiplegenesandmultipleenvironmentalfactorsFamilyhistory,butincidenceismuchlowerthanMendel’smodelPolygenicdisorder

Common50%congenitalabnormality,hypertension(高血压)、rheumatoidarthritis(风湿性关节炎),psychopathy(精神病)

,childdyslexia(阅读困难),specificlanguageimpairment(言语能力不全),attentiondeficit-hyperactivitydisorder(多动症)

AsingletypeofDNAduplex:16.6kb,37genes,(2rRNAgenes,22tRNAgenes,13polypeptide-encodinggenes.(4)Mitochondrialgeneticdisorder

线粒体基因病ThemutationisintheencodingregionsofmitochondrialDNASinglegenemutationTransmitwithmitochondrialDNA-Maternaltransmitting四、临床遗传学的特殊诊断

（一）系谱分析A.Convenientkaryotyping:CellcultureMetaphasearrest-colcemidHypotonictreatment-chromosomespreadChromosomepreparationandbandingKaryotypingforthediagnosisofchromosomalabnormalities（二）细胞遗传学分析

1．染色体检查、染色体核型分析

2．荧光原位杂交,

FISH(FluorescenceInSituHybridization)

Detectingmicro-deletionormicro-duplicationsyndrome.DetectingcrypticrearrangementsBandi