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Flashcards in Single Gene Disorders Deck (78):
1

What is haploinsufficiency?

half of gene dosage may not be enough for cell to carry out functions

2

Would a disease on the Y chromosome be dominant or negative?

Dominant

3

What is the relationship of an X-linked disease regarding father to daughter transfer? Sons?

all daughters will have it

no sons will have it

4

What is penetrance?

genotype does not manifest as phenotype

5

What is expressivity?

how strong the phenotype manifests itself

6

What type of disease is Huntington's?

Autosomal Dominant

7

What is the triplet repeat present in Huntingtons?

CAG

8

What amino acid does the triplet repeat code for? What is the end product?

glutamine

poly-glutamine

9

The severity and age of onset of HD depends on what?

extent of the triplet expansion

10

What kind of mutations takes place in achondroplasia?

dominant

11

What gene is affected in achondroplasia?

fibroblast growth factor receptor

12

What kind of receptor is the FGFR?

transmembrane tyrosine kinase

13

What is the function of the FGFR?

to inhibit chondrocyte proliferation

14

What do mutations in FGFR do?

constitutive expression of the receptor that inhibits bone growth

15

What is a mutation hotspot?

chromosomal region where mutations occur frequently

16

What is a typical chromosomal region for a mutation hotspot?

GC repeat

17

Dominant forms of EDS are caused by what?

mutations in collagen genes

18

Less severe forms of EDS are caused by what?

mutations in the genes for collagen processing

19

Familial Hypercholesterolemia is what kind of mutation?

autosomal dominant

20

The RET gene encodes what?

tyrosine kinase receptor

21

Loss of function of the RET gene causes what?

Hirschsprung Disease

22

Why does the loss of RET cause Hirschprung Disease?

impairs the ability of neural crest cells to populate the colon with ganglia

23

A gain of function mutation in the RET gene causes what?

Multiple Endocrine Neoplasia

24

Constitutive activation of the RET gene causes an increase in what cells?

Neuroendocrine Cells

25

Are mutations in the RET gene dominant or negative?

dominant

26

What are two hallmarks of an X-linked recessive disorder?

no father to son transmission

boys affected more than girls

27

What is the most common X-linked recessive disease?

Duchenne Muscular Dystrophy

28

What gene is affected in DMD?

dystrophin

29

What if the function of dystrophin?

attachment of cytoskeleton to ECM in muscle

30

What is more severe, DMD or Beckers Muscular Dystrophy?

DMD

31

Dystrophin is linked by what protein to the ECM?

beta-dystroglycan

32

What is a hallmark of X-linked dominant diseases?

father to daughter transmission

33

Mitochondrial genes affects what two types of tissues predominantly?

muscles and nerves

34

What is the mode of mitochondrial gene transmission?

mothers to all daughters

35

Mutations rates are higher where, mitochondria or nuclear genes?

mitochondrial

36

What is heteroplasmy?

presence of a mixture of more than one type of organeller genome

37

What is the most prevalent mitochondrial disorder?

Lebers Hereditary Optic Neuropathy

38

What gene is defective in LHON? What protein does this affect?

ND1

Complex I

39

Why can consanguineous matings be so detrimental?

closely related individuals often care the same mutant allele

40

What does the coefficient of inbreeding describe?

homozygosity of a child

41

What is an autosomal dominant disease with variable expressivity?

neurofibromatosis

42

The severity and age of onset of Huntingtons depend on what?

triplet expansion

43

What kind of mutation is present in achondroplasia? What receptor is affected?

dominant

fibroblast growth factor

44

What is a common mutation hotspot sequence?

CG dinucleotide repeat

45

Is EDS dominant, recessive or both?

both

46

Is osteogenesis imperfecta dominant or recessive?

dominant

47

The dominant negative effect often targets what types of proteins?

proteins in complexes

48

Is familial hypercholesterolemia dominant or recessive?

dominant

49

What is the RET gene product?

tyrosine kinase receptor

50

Loss of function of RET causes what disease?

Hirchsprung Disease

51

RET protein functions in the development of what type of cells?

neural crest cells

52

A gain of function in the RET gene causes what disease?

Multiple Endocrine Neoplasia

53

Are both mutations of the RET gene dominant or recessive?

both are dominant

54

What is the most common X-linked recessive disease?

Duchenne Muscular Dystrophy

55

What is the function of dystrophin?

to link the cytoskeleton to the extracellular matrix

56

What two types of proteins often feature recessive inheritance patterns?

enzymes and proteins involved in transport/storage

57

What is a proband?

person serving as the starting point of genetic study of a family

58

What are two autosomal recessive diseases?

CFTR and PKU

59

What is the acronym for remembering autosomal dominant diseases?

HNA - OFL

60

What is a key feature of autosomal dominant inheritance?

one parent is likely effected

61

How do CAG repeats correlate with Huntingtons Disease?

more CAG repeats = more severe of disease

62

What is the most common X-linked recessive disease?

DMD

63

Which disease almost exclusively rises from a mutation hotspot?

anchondroplasia (523)

64

What is the major source for maternal mutations?

non-disjunction

65

What is the major source of paternal mutations?

replication errors

66

What type of collagen is defective in osteogenesis imperfecta?

Type I

67

What does the dominant negative effect mean?

one mutated protein may destroy the entire complex

68

Defects in what protein cause Li-Fraumeni?

p53

69

What is a Barr Body?

inactive female X-chromosome in a somatic cell

70

Where do Barr bodies condense?

at the periphery of the nucleus

71

What is a common X-linked dominant disease?

Incontinentia Pigmenti

72

Incontinentia Pigmenti features what defective protein?

NFKB Essential Modulator (NEMO)

73

How much higher is the mutation rate in mitochondria than it is genomic DNA?

10x

74

What is heteroplasmy?

presence of more than one type of organeller genome within a cell

75

How is mitochondrial DNA passed down?

from mother to all offspring

76

What receptor is mutated in achondroplasia?

FGFR3

77

What disease features a defective ND1 gene? What protein does this defective gene affect?

ND1

Complex I

78

Inborn errors of metabolism are what kind of genetic disorder?

autosomal recessive