SAMENVATTING HUMANE
MOLECULAIRE GENETICA
Academiejaar 2023-2024
NONA MOREELS
,Inhoudsopgave
1. Humaan Genoom & Genetische Variatie ................................................................................ 4
1.1 Complexiteit & Organisatie Humaan Genoom ................................................................. 4
1.1.1 Ontrafeling DNA Structuur & Menselijke Chromosomenkaart ...................................................... 4
1.1.2 Functionele & Structurele Opbouw Humane Genoom .................................................................. 4
1.2 Humane Genetische Variantie ......................................................................................... 6
1.2.1 Basisbegrippen .............................................................................................................................. 6
1.2.2 Classificatie Genetische Variatie ................................................................................................... 7
1.2.3 Nomenclatuur Genetische Varianten .......................................................................................... 11
1.2.4 Evalueren Pathogeniciteit Variaten ............................................................................................. 12
1.2.5 Classificatie Genetische Varianten .............................................................................................. 12
1.2.6 Functionele Effecten Varianten ................................................................................................... 13
1.3 Klinische Effecten Varianten .......................................................................................... 15
1.3.1 Hemoglobinopathieën ................................................................................................................. 15
1.3.2 Genetische Defecten in Enzymen................................................................................................. 18
1.3.3 Genetische Defecten in Structuureiwitten ................................................................................... 19
1.3.4 Genetische Defecten Membranaire Eiwitten – Mucoviscidose (CF) ............................................ 22
Overzicht classificatie mutaties ............................................................................................................ 23
2. Technieken voor Genoomanalyse ........................................................................................ 24
2.1 Inleiding ........................................................................................................................ 24
2.2 Materiaal Moleculair Genetisch Onderzoek ................................................................... 24
2.3 Technieken Genetische Testing & Genoomanalyses ....................................................... 25
2.3.1 Polymerase Kettingreactie (PCR) ................................................................................................. 25
2.3.2 1ste Generatie Sequenering – Sanger Sequenering ...................................................................... 26
2.3.3 2de Generatie Sequencing – Massive Parallele Sequencing – Next-Generation Sequencing ...... 28
2.3.4 3de Generatie Sequencing – Real-Time – Single Molecule Sequencing ........................................ 30
2.3.5 Klinische Toepassingen: Medische Genoomanalyse .................................................................... 31
2.3.6 Bijkomende Genetische- & Genoomanalytische Technieken ....................................................... 34
3. Genetisch Bepaalde Ziekten: Chromosomale Afwijkinken & Structurele Varianten .............. 38
3.0 Inleiding ........................................................................................................................ 38
3.1 Cytogenetische/cytogenomische Nomenclatuur & Technologie ..................................... 38
3.1.1 Humaan Karyotype...................................................................................................................... 38
3.1.2 Chromosoomonderzoek .............................................................................................................. 39
3.1.3 Morfologie Chromosomen........................................................................................................... 40
3.1.4 Cytogenetische Nomenclatuur .................................................................................................... 41
3.2 Klinische Cytogenetica & Chromosomale Afwijkingen .................................................... 41
3.2.1 Numerieke Afwijkingen ............................................................................................................... 42
3.2.2 Structurele Afwijkingen ............................................................................................................... 46
3.3 Moleculaire Cytogenetica .............................................................................................. 49
3.3.1 Fluorescentie In Situ Hybridisatie (FISH) ...................................................................................... 49
3.3.2 Moleculaire Karyotypering – array CGH ...................................................................................... 50
3.3.3 Next Generation Sequencing ....................................................................................................... 51
4. Genetisch Bepaalde Ziekten: Monogenische Aandoeningen................................................. 52
4.1 Inleiding ........................................................................................................................ 52
4.2 Mendeliaanse Overervingsvormen ................................................................................ 53
4.2.1 Autosomaal Dominant (AD) ........................................................................................................ 53
4.2.2 Autosomaal Recessief (AR) .......................................................................................................... 54
NM 1
, Vergelijking .......................................................................................................................................... 54
4.3 Complicerende Factoren ................................................................................................ 55
4.3.1 De Novo Mutaties........................................................................................................................ 55
4.3.2 Gereduceerde Penetrantie .......................................................................................................... 55
4.3.3 Leeftijdsgebonden Penetrantie ................................................................................................... 56
4.3.4 Variabele Expressie ..................................................................................................................... 56
4.3.5 Pleiotropie ................................................................................................................................... 57
4.3.6 Locus Heterogeniteit ................................................................................................................... 57
4.4 Niet-Mendeliaanse Overerving ...................................................................................... 58
4.4.1 X-Inactivatie – Lyonisatie ............................................................................................................ 58
4.4.2 X-Gebonden Recessieve Overerving ............................................................................................ 59
4.4.3 X-Gebonden Dominante Overerving............................................................................................ 61
4.4.4 Y-Gebonden Overerving .............................................................................................................. 64
4.4.5 Mitochondriale Overerving ......................................................................................................... 65
4.4.6 Somatisch & Germinaal Mosaïcisme ........................................................................................... 66
4.4.7 Genomische Imprinting ............................................................................................................... 66
4.4.8 Uniparentale Disomie .................................................................................................................. 68
4.4.9 Anticipatie ................................................................................................................................... 68
5. Genetisch Bepaalde Aandoeningen: Complexe (Multifactoriële) Aandoeningen .................. 71
5.1 Definitie & begrippen .................................................................................................... 71
5.1.1 Inleiding ....................................................................................................................................... 71
5.1.2 Belangrijke Begrippen ................................................................................................................. 71
5.2 Opsporen Ziektegenen met Genoomwijde Associatie Studies (GWAS) ............................ 72
5.2.1 Inleiding ....................................................................................................................................... 72
5.2.2 Linkage Disequilibrium (LB) & Haplotype Blocks ......................................................................... 73
5.2.3 GWAS .......................................................................................................................................... 75
5.3 Hoe Oefenen Genetische Varianten Hun Effect Uit? ....................................................... 76
6. Genetische Basis van Kanker ............................................................................................... 78
6.1 Moleculaire Basis van Kanker ........................................................................................ 78
6.1.1 Inleiding ....................................................................................................................................... 78
6.1.2 Kankergenetica............................................................................................................................ 79
6.1.3 Zes Fundamentele Eigenschappen Kankercellen ......................................................................... 79
6.1.4 Kanker is een Genetische Aandoening ........................................................................................ 81
6.1.5 (Proto-)oncogenen ...................................................................................................................... 83
6.1.6 Tumorsuppressor-genen.............................................................................................................. 85
6.1.7 Oncogenen + Tumorsupressor-genen in Hallmarks van Kanker .................................................. 87
6.1.8 Genetische Prolifering Tumoren .................................................................................................. 88
6.2 Erfelijke Kankersyndromen ............................................................................................ 89
6.2.1 Tweelingsstudies ......................................................................................................................... 90
6.2.2 Familiale & Erfelijke Vorm Kanker ............................................................................................... 90
6.2.3 Knudson Model & LOH ................................................................................................................ 91
6.2.4 Frequent Familiale Kanker Syndromen........................................................................................ 94
7. Statistische Genetica ......................................................................................................... 100
7.1 Humane Populatiegenetica ......................................................................................... 100
7.1.1 Gen- of Allelfrequentie & Genotype Frequentie ........................................................................ 100
7.1.2 Wet Hardy-Weinberg ................................................................................................................ 100
7.1.3 Consanguiniteit & Inteelt .......................................................................................................... 101
7.2 Risicoberekening in Monogenische Ziekten .................................................................. 102
7.2.1 Herhalingsrisico ......................................................................................................................... 102
7.2.2 Theorema van Bayes ................................................................................................................. 102
NM 2
, 7.3 Mappen van Genen ..................................................................................................... 103
7.3.1 Genetisch Landschap Genoom .................................................................................................. 103
7.3.2 Linkage Analyse ......................................................................................................................... 105
7.3.3 Segregatie-analyse met Gekoppelde Merkers........................................................................... 106
8. Klinische Toepassingen Humane Genetica ......................................................................... 107
8.1 Genetische Testing in Klinische Praktijk ....................................................................... 107
8.1.1 Diagnostisch Onderzoek ............................................................................................................ 107
8.1.2 Dragerschapsonderzoek ............................................................................................................ 107
8.1.3 Predictief of Presymptomatisch Onderzoek .............................................................................. 107
8.1.4 Prenatale Diagnostiek ............................................................................................................... 107
8.1.5 Screening ................................................................................................................................... 110
8.1.6 Ethisch, Juridische, Sociale Implicaties ...................................................................................... 110
NM 3
MOLECULAIRE GENETICA
Academiejaar 2023-2024
NONA MOREELS
,Inhoudsopgave
1. Humaan Genoom & Genetische Variatie ................................................................................ 4
1.1 Complexiteit & Organisatie Humaan Genoom ................................................................. 4
1.1.1 Ontrafeling DNA Structuur & Menselijke Chromosomenkaart ...................................................... 4
1.1.2 Functionele & Structurele Opbouw Humane Genoom .................................................................. 4
1.2 Humane Genetische Variantie ......................................................................................... 6
1.2.1 Basisbegrippen .............................................................................................................................. 6
1.2.2 Classificatie Genetische Variatie ................................................................................................... 7
1.2.3 Nomenclatuur Genetische Varianten .......................................................................................... 11
1.2.4 Evalueren Pathogeniciteit Variaten ............................................................................................. 12
1.2.5 Classificatie Genetische Varianten .............................................................................................. 12
1.2.6 Functionele Effecten Varianten ................................................................................................... 13
1.3 Klinische Effecten Varianten .......................................................................................... 15
1.3.1 Hemoglobinopathieën ................................................................................................................. 15
1.3.2 Genetische Defecten in Enzymen................................................................................................. 18
1.3.3 Genetische Defecten in Structuureiwitten ................................................................................... 19
1.3.4 Genetische Defecten Membranaire Eiwitten – Mucoviscidose (CF) ............................................ 22
Overzicht classificatie mutaties ............................................................................................................ 23
2. Technieken voor Genoomanalyse ........................................................................................ 24
2.1 Inleiding ........................................................................................................................ 24
2.2 Materiaal Moleculair Genetisch Onderzoek ................................................................... 24
2.3 Technieken Genetische Testing & Genoomanalyses ....................................................... 25
2.3.1 Polymerase Kettingreactie (PCR) ................................................................................................. 25
2.3.2 1ste Generatie Sequenering – Sanger Sequenering ...................................................................... 26
2.3.3 2de Generatie Sequencing – Massive Parallele Sequencing – Next-Generation Sequencing ...... 28
2.3.4 3de Generatie Sequencing – Real-Time – Single Molecule Sequencing ........................................ 30
2.3.5 Klinische Toepassingen: Medische Genoomanalyse .................................................................... 31
2.3.6 Bijkomende Genetische- & Genoomanalytische Technieken ....................................................... 34
3. Genetisch Bepaalde Ziekten: Chromosomale Afwijkinken & Structurele Varianten .............. 38
3.0 Inleiding ........................................................................................................................ 38
3.1 Cytogenetische/cytogenomische Nomenclatuur & Technologie ..................................... 38
3.1.1 Humaan Karyotype...................................................................................................................... 38
3.1.2 Chromosoomonderzoek .............................................................................................................. 39
3.1.3 Morfologie Chromosomen........................................................................................................... 40
3.1.4 Cytogenetische Nomenclatuur .................................................................................................... 41
3.2 Klinische Cytogenetica & Chromosomale Afwijkingen .................................................... 41
3.2.1 Numerieke Afwijkingen ............................................................................................................... 42
3.2.2 Structurele Afwijkingen ............................................................................................................... 46
3.3 Moleculaire Cytogenetica .............................................................................................. 49
3.3.1 Fluorescentie In Situ Hybridisatie (FISH) ...................................................................................... 49
3.3.2 Moleculaire Karyotypering – array CGH ...................................................................................... 50
3.3.3 Next Generation Sequencing ....................................................................................................... 51
4. Genetisch Bepaalde Ziekten: Monogenische Aandoeningen................................................. 52
4.1 Inleiding ........................................................................................................................ 52
4.2 Mendeliaanse Overervingsvormen ................................................................................ 53
4.2.1 Autosomaal Dominant (AD) ........................................................................................................ 53
4.2.2 Autosomaal Recessief (AR) .......................................................................................................... 54
NM 1
, Vergelijking .......................................................................................................................................... 54
4.3 Complicerende Factoren ................................................................................................ 55
4.3.1 De Novo Mutaties........................................................................................................................ 55
4.3.2 Gereduceerde Penetrantie .......................................................................................................... 55
4.3.3 Leeftijdsgebonden Penetrantie ................................................................................................... 56
4.3.4 Variabele Expressie ..................................................................................................................... 56
4.3.5 Pleiotropie ................................................................................................................................... 57
4.3.6 Locus Heterogeniteit ................................................................................................................... 57
4.4 Niet-Mendeliaanse Overerving ...................................................................................... 58
4.4.1 X-Inactivatie – Lyonisatie ............................................................................................................ 58
4.4.2 X-Gebonden Recessieve Overerving ............................................................................................ 59
4.4.3 X-Gebonden Dominante Overerving............................................................................................ 61
4.4.4 Y-Gebonden Overerving .............................................................................................................. 64
4.4.5 Mitochondriale Overerving ......................................................................................................... 65
4.4.6 Somatisch & Germinaal Mosaïcisme ........................................................................................... 66
4.4.7 Genomische Imprinting ............................................................................................................... 66
4.4.8 Uniparentale Disomie .................................................................................................................. 68
4.4.9 Anticipatie ................................................................................................................................... 68
5. Genetisch Bepaalde Aandoeningen: Complexe (Multifactoriële) Aandoeningen .................. 71
5.1 Definitie & begrippen .................................................................................................... 71
5.1.1 Inleiding ....................................................................................................................................... 71
5.1.2 Belangrijke Begrippen ................................................................................................................. 71
5.2 Opsporen Ziektegenen met Genoomwijde Associatie Studies (GWAS) ............................ 72
5.2.1 Inleiding ....................................................................................................................................... 72
5.2.2 Linkage Disequilibrium (LB) & Haplotype Blocks ......................................................................... 73
5.2.3 GWAS .......................................................................................................................................... 75
5.3 Hoe Oefenen Genetische Varianten Hun Effect Uit? ....................................................... 76
6. Genetische Basis van Kanker ............................................................................................... 78
6.1 Moleculaire Basis van Kanker ........................................................................................ 78
6.1.1 Inleiding ....................................................................................................................................... 78
6.1.2 Kankergenetica............................................................................................................................ 79
6.1.3 Zes Fundamentele Eigenschappen Kankercellen ......................................................................... 79
6.1.4 Kanker is een Genetische Aandoening ........................................................................................ 81
6.1.5 (Proto-)oncogenen ...................................................................................................................... 83
6.1.6 Tumorsuppressor-genen.............................................................................................................. 85
6.1.7 Oncogenen + Tumorsupressor-genen in Hallmarks van Kanker .................................................. 87
6.1.8 Genetische Prolifering Tumoren .................................................................................................. 88
6.2 Erfelijke Kankersyndromen ............................................................................................ 89
6.2.1 Tweelingsstudies ......................................................................................................................... 90
6.2.2 Familiale & Erfelijke Vorm Kanker ............................................................................................... 90
6.2.3 Knudson Model & LOH ................................................................................................................ 91
6.2.4 Frequent Familiale Kanker Syndromen........................................................................................ 94
7. Statistische Genetica ......................................................................................................... 100
7.1 Humane Populatiegenetica ......................................................................................... 100
7.1.1 Gen- of Allelfrequentie & Genotype Frequentie ........................................................................ 100
7.1.2 Wet Hardy-Weinberg ................................................................................................................ 100
7.1.3 Consanguiniteit & Inteelt .......................................................................................................... 101
7.2 Risicoberekening in Monogenische Ziekten .................................................................. 102
7.2.1 Herhalingsrisico ......................................................................................................................... 102
7.2.2 Theorema van Bayes ................................................................................................................. 102
NM 2
, 7.3 Mappen van Genen ..................................................................................................... 103
7.3.1 Genetisch Landschap Genoom .................................................................................................. 103
7.3.2 Linkage Analyse ......................................................................................................................... 105
7.3.3 Segregatie-analyse met Gekoppelde Merkers........................................................................... 106
8. Klinische Toepassingen Humane Genetica ......................................................................... 107
8.1 Genetische Testing in Klinische Praktijk ....................................................................... 107
8.1.1 Diagnostisch Onderzoek ............................................................................................................ 107
8.1.2 Dragerschapsonderzoek ............................................................................................................ 107
8.1.3 Predictief of Presymptomatisch Onderzoek .............................................................................. 107
8.1.4 Prenatale Diagnostiek ............................................................................................................... 107
8.1.5 Screening ................................................................................................................................... 110
8.1.6 Ethisch, Juridische, Sociale Implicaties ...................................................................................... 110
NM 3
