Principles of Genetic Disease Flashcards

1
Q

Hereditary factor that determines a particular trait. Found on a specific region on a chromosome:

A

Gene

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2
Q

A variety of a gene (i.e. homozygous or heterozygous)

A

Allele

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3
Q

A structure made up of proteins and DNA and organized into genes

A

chromosomes

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4
Q

The genetic makeup of an indiviual consisting of the genes on all 46 chromosomes

A

genotype

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5
Q

observable characteristics or traits of an individual resulting from the genotype:

A

phenotype

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6
Q

One variant of a gene on a chromosome overrides the effect of a different variant of the same:

A

autosomal dominant

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7
Q

Two copies of an abnormal gene must be present for the disease or trait to develop

A

autosomal recessive

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8
Q

Structure of DNA:

A

double helix

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9
Q

DNA winds around ____ to form ____

A

histones; core particles

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10
Q

____ folds into a thicker zigzag fiber

A

chromatin

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11
Q

In dividing cells ___ forms into thick ____ visible to light microscope

A

chromatin; chromatids

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12
Q

Midpoint of cell division:

A

metaphase

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13
Q

Core particle=

A

nucleosome

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14
Q

Sister chromatids are connected by:

A

kinetochore

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15
Q

Shot arm =

A

p

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16
Q

long arm =

A

q

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17
Q

An individuals complete set of chromosomes:

A

karyotype

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18
Q

In a karyotype, chromosomes are arranged according to:

A

size and banding patterns

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19
Q

Same version of a gene is inherited from each parent

A

homozygous

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20
Q

different versions of a gene inherited from each parent

A

heterozygous

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21
Q

Single set of chromosomes in an organism

A

haploid

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22
Q

Two copies of each chromosome

A

diploid

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23
Q

genetic disease of familial inheritance, transmitted through generations

A

hereditary disorders

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24
Q

genetic disease present at birth:

A

congenital disorder

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25
Q

result from mutations in single genes:

A

mendelian disorders

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26
Q

Involve multiple genes, also including environmental influence

A

complex disorders

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27
Q

Change in # or structure of chromosomes

A

chromosomal abnormalities

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28
Q

Single gene hereditary mutation:

A

mendelian disorder

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29
Q

The three patterns of inheritance of mendelian disorders include:

A
  1. autosomal dominant
  2. autosomal recessive
  3. x-linked
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30
Q

Mendelian disorders are associated with a ___ of phenotypic effects

A

wide range

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31
Q

In mendelian disorders, the mutated gene can be influenced by:

A

modifier genes

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32
Q

In this type of inheritance, usually one parent is affected, and it is NOT sex dependent

A

autosomal dominant inheritance

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33
Q

Autosomal dominant inheritance may also occur due to new mutations within:

A

the sperm or egg

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34
Q

In Autosomal dominant inheritance, clinical features are modified by:

A

reduced penetrance and variable expressivity

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35
Q

in Autosomal dominant inheritance, the age of onset may be delayed from childhood, such as in:

A

Huntington disease

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36
Q

____ inheritance is manifested in the homozygous state

A

autosomal recessive

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37
Q

In autosomal recessive inheritance to occur, how many parents must be carriers?

A

both

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38
Q

Autosomal recessive inheritance onset:

A

usually early in life

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39
Q

Complete penetrance is common with ___ type of inheritence

A

autosomal recessive

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40
Q

With what type of inheritance are new mutations rarely detected clinically?

A

autosomal recessive

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41
Q

One copy of the x-chromosome is inactivated

A

lyonization

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42
Q

Inactivated x-chromosome observed in nucleus

A

barr body

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43
Q

The process of lyonization is considered:

A

random

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44
Q

Almost all sex-linked disorders are:

A

x-linked

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45
Q

Most x-linked disorders are:

A

recessive

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46
Q

Female carriers transmit only to sons (50%)

A

recessive transmission

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47
Q

Affected males do not transmit disorders to sons but all daughters are carriers:

A

x-linked disorder

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48
Q

Familial hypercholesterolemia has an AD prevalence of:

A

1/500

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49
Q

Disease characterized by loss of function mutations in gene encoding LDL receptor:

A

familial hypercholesterolemia

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50
Q

LDL receptor is involved in:

A

transport and metabolism in cholesterol

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51
Q

Familial hypercholesterolemia results in elevated levels of _____ —-> _____ —-> ____

A

cholesterol; premature atherosclerosis; MI risk

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52
Q

Clinical feature of familial hypercholesterolemia involving the skin:

A

skin xanthomas

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53
Q

Normal levels of LDL:

High LDL (hypercholesterolemia):

A

less than 100 mg/dL

More than 160 mg/dl

54
Q
A

skin xanthomas (hypercholesterolemia)

55
Q

What type of inheritance is seen with familial hypercholesterolemia?

A

Autosomal dominant

56
Q

Connective tissue disease:

A

Marfan syndrome

57
Q

What type of inheritance is seen with Marfan syndrome?

A

Autosomal dominant

58
Q

What is the prevalence of Marfan syndrome?

A

1/5000

59
Q

Inherited defect in fibrillin-1, glycoprotein in extracellular matrix:

A

marfan syndrome

60
Q

Marfan syndrome is characterized by an inherited defect in:

A

fibrillin-1 (glycoprotein in ECM)

61
Q

Clinical features:

  • skeletal abnormalities (slender habitus, long legs/arms/fingers
  • High arched palate
  • flat feet
  • hyperextensibility of joints
  • ocular changes
  • enlarged heart
  • stretch marks
  • aneurysmal dilation, aortic dissection -> aortic rupture
A

Marfan syndrome

62
Q

Individuals with Marfan syndrome are at an increased risk of:

A

aortic rupture

63
Q

What is the inheritance pattern of neurofibromatosis type 1?

A

Autosomal dominant

64
Q

What type of neurofibromatosis is most common?

A

type 1

65
Q

What is the prevalence of neurofibromatosis type 1?

A

1/3000

66
Q

Neurofibromatosis type 1 occurs due to mutations in :

A

NF1 gene (50% represent new mutations)

67
Q

NF1 gene is associated with what protein?

A

Neurofibromin (tumor suppressor protein)

68
Q

In this disease, patients may have multiple neurofibromas:

A

Neurofibromatosis type 1

69
Q

Common peripheral nerve neoplasm:

A

Neurofibroma (seen in neurofibromatosis type 1)

70
Q

In Neurofibromatosis type 1, the neurofibromas present most commonly on the:

A

skin-but can also occur in the oral cavity (tongue and buccal mucosa)

71
Q

Clinical features:
- multiple neurofibromas (varies in size, small papule to masses - elephantiasis neuromatosa of the skin)
- Few tumors to hundreds/throusands
- cafe au lait macules on the skin
- 2/3 have relatively mild disease

A

type 1 neurofibromatosis

72
Q

Describe the oral manifestations seen in neurofibromatosis type 1: (3)

A
  1. neurofibromas (tongue & buccal mucosa)
  2. enlargement of fungiform papillae
  3. enlargement of mandibular canal (radiograph)
73
Q

Treatment of Neurofibromatosis type 1:

A

directed at managing complications

74
Q

What occurs in 5% of Neurofibromatosis type 1 cases?

A

Neurofibrosarcoma development

75
Q
A

neurofibroma (Neurofibromatosis type 1)

76
Q
A

neurofibromas (Neurofibromatosis type 1)

77
Q
A

neurofibroma (Neurofibromatosis type 1)

78
Q
A

cafe au lait macules

79
Q
A

cafe au lait macules

80
Q

What is the inheritance pattern of cystic fibrosis?

A

Autosomal recessive

81
Q

A disorder affecting ion transport:

A

CF

82
Q

Abnormal fluid secretion in exocrine glands

A

CF

83
Q

What organ systems does CF affect?

A
  1. respiratory
  2. GI
  3. reproductive
84
Q

What is the prevalence of CF?

A

1/2500

85
Q

What gene is mutated in CF? What does this cause?

A

CFTR gene- abnormal function of chloride channel regulator protein

86
Q

Clinical features:
- viscous mucus secretions that block airway and pancreatic ducts
- recurrent pulmonary infections
- pancreatic insufficiency
- High NaCl level in sweat
- Sinusitis
- Liver cirrhosis
- male infertility

A

CF

87
Q

What is a common type of bacterial infection for CF patients?

A

Pseudomonas infection (lungs)

88
Q

CF treatment:

A
  1. antimicrobial therapies, enzyme replacement, bilateral lung transplant
  2. drugs to increase CFTR function
89
Q

What is the inheritance pattern of PKU?

A

Autosomal recessive

90
Q

What is the prevalence of PKU?

A

1/10k

91
Q

What disease is characterized by high phenylalanine (amino acid) levels?

A

PKU

92
Q

PKU is caused by a mutation in _____ resulting in ___

A

PAH gene; lack of PAH enzyme

93
Q

The mutation in the PAH gene creating a lack of PAH enzyme does not allow for: (in PKU)

A

phenylalanine to be converted tyrosine

94
Q

If this disease goes untreated in infants it leads to impaired brain development development delay, seizures, and reduced pigmentation:

A

PKU

95
Q

PKU individuals must regulate ____ to prevent signs/symptoms

A

diet

96
Q
  • fish
  • milk
  • meat
  • dairy
  • beans
  • diet soda
  • wheat
  • nuts
  • legumes
  • beans
  • high protein foods

These foods are

A

high in Phenylalanine

97
Q
  • corn
  • tomatos
  • most veggies
  • most fruits
  • special breads, cookies, and crackers
  • sugars
  • low protein foods

These foods are:

A

low in phenylalanine

98
Q

Lysosomal storage disease:

A

Tay-Sachs Disease

99
Q

What is the inheritance pattern of Tay-Sachs?

A

Autosomal recessive

100
Q

What is the prevalence of Tay-Sachs?

A

1/3500

101
Q

Tay-Sachs disease is caused by a mutation in:

A

Hexosamindiase A

102
Q

In Tay-Sachs disease, a mutation in Hexoasminidase A results in:

A

accumulation of gangliosides

103
Q

In Tay-Sachs Disease, the accumulation of gangliosides primarily affects ____ & ____, but can also also accumulate in other tissues such as:

A

neurons& retina; heart, liver, spleen

104
Q

Clinical features:
- infantile form- severe, infants show signs 3-6 months of age
- development impairment
- seizures
- blindness
- death by 2,3 years

A

Tay-Sachs disease

105
Q

What is the inheritance pattern of Hemophilia A?

A

X-linked

106
Q

An x-linked inherited bleeding disorder:

A

Hemophilia A

107
Q

What is the prevalence of Hemophilia A?

A

1/5000 (U.S. Males)

108
Q

Hemophilia A is caused by a deficiency in:

A

Factor VIII (8)

109
Q

Clinical features:
- failure of hemostasis after circumcision (common 1st sign)
- significant hemorrhage after Timor trauma
- hemarthrosis
- increased coagulation time

A

Hemophilia A

110
Q

Symptom of hemophilia A that may result in crippling deformity of joints:

A

Hemarthrosis

111
Q

Treatment of hemophilia A:

A
  1. replacement therapy with clotting factor
112
Q

What should you do prior to oral or perio surgery on an individual with hemophilia A?

A

consult with physician

113
Q

What is the inheritance pattern of Duchenne muscular dystrophy?

A

x-linked

114
Q

Duchenne muscular dystrophy is characterized by:

A

skeletal muscle defects

115
Q

What is the prevalence of Duchenne muscular dystrophy?

A

1/3500 (U.S. Males)

116
Q

Individuals with Duchenne muscular dystrophy, have a mutation in what? What does this affect?

A

Dystrophin gene; defects in dystrophin protein

117
Q

Dystrophin protein that is defected in Duchenne muscular dystrophy is found in:

A
  1. skeletal muscle
  2. cardiac muscle
  3. brain
  4. peripheral nerves
118
Q

Clinical features:
- muscle weakness
- cardiac muscle damage –> arrhythmias and HF
- cognitive impairment

A

Duchenne muscular dystrophy

119
Q

Results from alterations in the number or structure of chromosomes:

A

cytogenic disorders

120
Q

cytogenic disorders may affect:

A

autosomes OR sex chromosomes

121
Q

With cytogenic disorders, we can observe:

A

abberation on a karyotype

122
Q

Exact multiple of haploid cells:

A

Euploid

123
Q

More than one pair of chromosomes (i.e.3n, 4n)

A

Polyploid

124
Q

Polyploid generally results in:

A

spontaneous abortion

125
Q

abnormal number of chromosomes, not an exact multiple of n:

A

Aneupoloid

126
Q

Aneuploid is often due to:

A

nondisjunction during meiosis

127
Q

Trisomy 21 is also known as:

A

down syndrome

128
Q

Extra copies of genes on chromosome 21=

A

trisomy 21

129
Q

95% of individuals with trisomy 21 have got this due to:

A

meiotic nondisjunction

130
Q

Clinical features:
- flat facial profile
- epicanthic folds and upward pointed eyes
- mental retardation
- congenital heart defects (40%)
- increased leukemia risk
- increased infections

A

Trisomy 21

131
Q

These are characteristic of:

A

Tay-Sachs disease (lysosome accumulation)

132
Q
A