臨床遺傳學(xué)-冬1、1.2課堂版

4．X連鎖隱性遺傳病

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

多基因遺傳病

Multifactorialdisorders:ResultingfromcomplexfunctionsofbothmultiplegenesandmultipleenvironmentalfactorsFamilyhistory,butincidenceismuchlowerthanMendel’smodelPolygenicdisorder

Common50%congenitalabnormality,hypertension(高血壓)、rheumatoidarthritis(風(fēng)濕性關(guān)節(jié)炎),psychopathy(精神病)

,childdyslexia(閱讀困難),specificlanguageimpairment(言語能力不全),attentiondeficit-hyperactivitydisorder(多動癥)

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

線粒體基因病ThemutationisintheencodingregionsofmitochondrialDNASinglegenemutationTransmitwithmitochondrialDNA-MaternaltransmittingLeber‘shereditaryopticneuropathy視神經(jīng)疾病MaternaltransmittingMitochondrialgeneticdisorder二、體細(xì)胞遺傳病Accumulatingresultsofchangesofmultiplegenesandenvironmentalfactorsinacertainduration.MutationsnormallylimitedinsomaticcellsMutationtransmittedbymitosisCancer

腫瘤

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

MIM(McKusick)1966,1stedition:15001998,20ndedition:85872000,Webedition:OMIM:>12000Now,renewalmosteverydayReflectionofmoredeeplyunderstandingofhumaningeneticsanddiseasesTherelationshipbetweengeneticandenvironmentalfactorsonhumandiseases四、臨床遺傳學(xué)的特殊診斷

（一）系譜分析SymbolsCommonlyUsedinPedigreeCharts32?affectNumberofchildprobandmalefemaleunsuspectdeceasedmarriagedivorceConsan-guinityNonpenetrantcarriercarriermultipleunionsMono-twindi-twinunknown-zygotetwinSterilityStillbirthmiscarriageabortionAdoptedinto/outfamilyA.Convenientkaryotyping:CellcultureMetaphasearrest-colcemidHypotonictreatment-chromosomespreadChromosomepreparationandbandingKaryotypingforthediagnosisofchromosomalabnormalities（二）細(xì)胞遺傳學(xué)分析

1．染色體檢查、染色體核型分析ChromosomesindifferentstagesofphasesofcellcycleMoredetailedanalysis染色體核型分析：染色體數(shù)目異常，染色體結(jié)構(gòu)異常（>4MB)High-resolutionbands2．熒光原位雜交,

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產(chǎn)前FocusConstitutional產(chǎn)后CytoChipOligoScanwholegenomeinaresolutionof1MbDetectionofcopynumberin143lociin97diseasesregisteredinOMIMinaresolutionof100KbMicroarraysCGHMonogenicDisordersMutipogenicDisordersNF-1多發(fā)性神經(jīng)纖維瘤ⅠPrader-Willi普拉德威利綜合征-12dert(9q:15q)Chromosome-specificpaintsprobesM-FISH

inhuamanandmouse（三）基因診斷IsolateDNAfromtesttissuesorcellsDetecttheDNAsequenceassociatedwiththediseases.NormallyusingforthediagnosisofmonogenicdisordersDuetogeneticheterogeneity（異質(zhì)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基因診斷AgarosegelXLABKT基因診斷（酶切）SSCPTheproductsofD5S134werenamedasB1,B2,B3,B4accordingtoelectrophoresisvelocityAPCsequencingIII-30e15-12III-16e15-12Next-generationsequencing第二代測序技術(shù)：對傳統(tǒng)Sanger法測序的一次革命性的改變，是一次可對幾十萬到幾百萬條DNA分子進(jìn)行序列測定的高通量的測序技術(shù)，同時高通量測序使得對一個物種的轉(zhuǎn)錄組和基因組進(jìn)行細(xì)致全貌的分析成為可能，所以又被稱為深度測序(deepsequencing)。

Now:$1,000-10,000小結(jié)一、臨床遺傳學(xué)定義和特點

應(yīng)用遺傳學(xué)原理和方法開展人類遺傳性疾病診斷、治療和預(yù)防的科學(xué)。其特點有:1．遺傳病起因于遺傳物質(zhì)的突變,

基因和染色體診斷——重要的診斷手段2．遺傳病具有家系成員反復(fù)發(fā)生的風(fēng)險,家譜分析、遺傳咨詢——重要內(nèi)容3．遺傳病多癥重而無有效治療方法，產(chǎn)前遺傳學(xué)診斷預(yù)防遺傳病患兒出生——最為有效的技術(shù)手段。Gene:基本結(jié)構(gòu)Codingregion:Exons,Introns

Regulatoryregions:Promoter,Enhancer,TerminatorStartpointTerminatepointGeneStructureCodingregionCAATBoxTATAboxFromDNA，ChromatintoChromosomeChromosomeisthecarrierofgenes.Genesarearrangedlinearlyonthechromosomes.經(jīng)典遺傳學(xué)：Mendelism遺傳的基本單位——基因（gene）呈線狀串聯(lián)排列在染色體上位二條同源染色體(homologouschromosome)相同位點的一對基因是等位基因（allele），控制同一性狀，顯性（dominant）或隱性（recessive）這對等位基因在減數(shù)分裂(meiosis)時會隨同源染色體的分離（segregation）而分別進(jìn)入不同的配子排列在不同染色體上的非等位基因，通?？刂撇煌倪z傳性狀，在減數(shù)分裂時自由組合(independentassortment)，進(jìn)入不同的配子。排列同一染色體上的非等位基因，雖然控制不同的遺傳性狀，但在減數(shù)分裂中一起運動、相互連鎖（linkage）進(jìn)入同一配子。連鎖基因可通過同源染色體之間同源片段的互換而發(fā)生交換（crossover）。Penetrance（外顯率）:theprobabilityofageneexpressionExpressivity（表現(xiàn)度）:theseverityofphenotypeexpressionPleiotropy（多效性）:onegene,morethanoneeffectGeneticheterogeneity（異質(zhì)性）:thesamephenotypicchangesresultedfromdifferentmutations三、遺傳性疾病的概念和分類

Geneticdisorder:thediseasescausedbygenemutationorhumanchromosomalaberration.ClassicorMendeliangeneticdisorders經(jīng)典遺傳性疾病Somaticandmitochondrialgeneticdisorders體細(xì)胞和線粒體遺傳疾病Classicgeneticdisorders1.Mutationistransmittedfromthegermcellsofparentsoroccurredintheearlystageoffertilizedoocyte.2.Mutationexistsinthewholetissuesofthebodyandremainsforthewholelifetimeoftheindividual.3.Mutationwilltransmittedtothenextgeneration.Chromosomal,monogenic,polygenicdisorders(1)染色體病

DuplicationordeletionofthecertainchromosomesorthecertainchromosomalsegmentsNumberabnormalityStructureabnormality0.6%inlivebornand50%inspontaneousabortionsinfirst-trimesterinmicroscopicobservation1．染色體數(shù)目異常(Heteroploidy,異倍體)Achromosomecomplementwithchromosomenumberotherthan46整倍體異常:Achromosomecomplementwithanexactmultipleofthehaploidchromosomenumber非正倍體:

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

不平衡染色體結(jié)構(gòu)異常

WithlossorgainofchromosomalmaterialDeletion,duplication,insertion,isochromosomeandringchromosome2．染色體結(jié)構(gòu)異常StructuralAbnormalitiesChromosomedisordersNumerical+unbalancedchromosomalabnormalitiesInvolvingthechromosomeorchromosomalsegmentdeletionorduplicationResultinginthechangesofagroupsofgenesLeadingcomplicatedsymptom,Syndrome:

Featuredbyseriousmentalretardation,structuralabnormalityofface,bodyandmultipleorgansBalancedstructuralabnormality

平衡染色體結(jié)構(gòu)異常Inversion(inv,倒位）,reciprocaltranslocation(t,相互易位),Robertsoniantranslocation(rob,羅伯遜易位)WithoutlossorgainofchromosomalmaterialsUsuallyphenotypicnormalRepeatedabortion,intrauterousfetaldeath,stillbirthandbirthdefectsduetotheabnormalsegregationofinvolvedchromosomesinmeiosisSinglegenedefectsCausedbyanindividualmutantgeneandtransferthroughthegenerationsaccordingtoMendeliangeneticsIndividualincidencerateisrareTotalincidenceis1.00%inlivebirthsand6-8%inhospitalizedchildren(2)單基因病Monogenicdisorder

1．常染色體顯性遺傳病

AutosomalDominantThetraitappearsineverygenerationAnychildofanaffectedpersonhasa50percentriskofinheritingthetrait.UnaffectedfamilymembersdonottransmitthetraittotheirchildrenTheoccurrenceandtransmissionofthetraitarenotinfluencedbysex2．常染色體隱性遺傳病

AutosomalRecessiveThetraitcharacteristicallyappearsonlyinsibs,notintheirparents.Ontheaverage,onefourthofthesibsoftheprobandareaffectedTheparentsofaffectedchildmaybeconsanguineous.Malesandfemalesareequallylikelytobeaffected.3．X連鎖顯性遺傳病

X-linkeddominantAffectedmaleshavenonormaldaughtersandnoaffectedsons.Affectedheterozygousfemalestransmittheconditiontohalftheirchildrenofeithersex..Affectedfemalesaremorecommonthanaffectedmales,butastheyarealmostalwaysheterozygotestheyusuallyhavemilder(butVariable)expression.4．X連鎖隱性遺傳病

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

多基因遺傳病

Multifactorialdisorders:ResultingfromcomplexfunctionsofbothmultiplegenesandmultipleenvironmentalfactorsFamilyhistory,butincidenceismuchlowerthanMendel’smodelPolygenicdisorder

Common50%congenitalabnormality,hypertension(高血壓)、rheumatoidarthritis(風(fēng)濕性關(guān)節(jié)炎),psychopathy(精神病)

,childdyslexia(閱讀困難),specificlanguageimpairment(言語能力不全),attentiondeficit-hyperactivitydisorder(多動癥)

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

線粒體基因病ThemutationisintheencodingregionsofmitochondrialDNASinglegenemutationTransmitwithmitochondrialDNA-Maternaltransmitting四、臨床遺傳學(xué)的特殊診斷

（一）系譜分析A.Convenientkaryotyping:CellcultureMetaphasearrest-colcemidHypotonictreatment-chromosomespreadChromosomepreparationandbandingKaryotypingforthediagnosisofchromosomalabnormalities（二）細(xì)胞遺傳學(xué)分析

1．染色體檢查、染色體核型分析

2．熒光原位雜交,

FISH(FluorescenceInSituHybridization)

Detectingmicro-deletionormicro-duplicationsyndrome.DetectingcrypticrearrangementsBandi