Principles of Genetic Disease Flashcards
1
Q
Hereditary factor that determines a particular trait. Found on a specific region on a chromosome:
A
Gene
2
Q
A variety of a gene (i.e. homozygous or heterozygous)
A
Allele
3
Q
A structure made up of proteins and DNA and organized into genes
A
chromosomes
4
Q
The genetic makeup of an indiviual consisting of the genes on all 46 chromosomes
A
genotype
5
Q
observable characteristics or traits of an individual resulting from the genotype:
A
phenotype
6
Q
One variant of a gene on a chromosome overrides the effect of a different variant of the same:
A
autosomal dominant
7
Q
Two copies of an abnormal gene must be present for the disease or trait to develop
A
autosomal recessive
8
Q
Structure of DNA:
A
double helix
9
Q
DNA winds around ____ to form ____
A
histones; core particles
10
Q
____ folds into a thicker zigzag fiber
A
chromatin
11
Q
In dividing cells ___ forms into thick ____ visible to light microscope
A
chromatin; chromatids
12
Q
Midpoint of cell division:
A
metaphase
13
Q
Core particle=
A
nucleosome
14
Q
Sister chromatids are connected by:
A
kinetochore
15
Q
Shot arm =
A
p
16
Q
long arm =
A
q
17
Q
An individuals complete set of chromosomes:
A
karyotype
18
Q
In a karyotype, chromosomes are arranged according to:
A
size and banding patterns
19
Q
Same version of a gene is inherited from each parent
A
homozygous
20
Q
different versions of a gene inherited from each parent
A
heterozygous
21
Q
Single set of chromosomes in an organism
A
haploid
22
Q
Two copies of each chromosome
A
diploid
23
Q
genetic disease of familial inheritance, transmitted through generations
A
hereditary disorders
24
Q
genetic disease present at birth:
A
congenital disorder
25
result from mutations in single genes:
mendelian disorders
26
Involve multiple genes, also including environmental influence
complex disorders
27
Change in # or structure of chromosomes
chromosomal abnormalities
28
Single gene hereditary mutation:
mendelian disorder
29
The three patterns of inheritance of mendelian disorders include:
1. autosomal dominant
2. autosomal recessive
3. x-linked
30
Mendelian disorders are associated with a ___ of phenotypic effects
wide range
31
In mendelian disorders, the mutated gene can be influenced by:
modifier genes
32
In this type of inheritance, usually one parent is affected, and it is NOT sex dependent
autosomal dominant inheritance
33
Autosomal dominant inheritance may also occur due to new mutations within:
the sperm or egg
34
In Autosomal dominant inheritance, clinical features are modified by:
reduced penetrance and variable expressivity
35
in Autosomal dominant inheritance, the age of onset may be delayed from childhood, such as in:
Huntington disease
36
____ inheritance is manifested in the homozygous state
autosomal recessive
37
In autosomal recessive inheritance to occur, how many parents must be carriers?
both
38
Autosomal recessive inheritance onset:
usually early in life
39
Complete penetrance is common with ___ type of inheritence
autosomal recessive
40
With what type of inheritance are new mutations rarely detected clinically?
autosomal recessive
41
One copy of the x-chromosome is inactivated
lyonization
42
Inactivated x-chromosome observed in nucleus
barr body
43
The process of lyonization is considered:
random
44
Almost all sex-linked disorders are:
x-linked
45
Most x-linked disorders are:
recessive
46
Female carriers transmit only to sons (50%)
recessive transmission
47
Affected males do not transmit disorders to sons but all daughters are carriers:
x-linked disorder
48
Familial hypercholesterolemia has an AD prevalence of:
1/500
49
Disease characterized by loss of function mutations in gene encoding LDL receptor:
familial hypercholesterolemia
50
LDL receptor is involved in:
transport and metabolism in cholesterol
51
Familial hypercholesterolemia results in elevated levels of _____ ----> _____ ----> ____
cholesterol; premature atherosclerosis; MI risk
52
Clinical feature of familial hypercholesterolemia involving the skin:
skin xanthomas
53
Normal levels of LDL:
High LDL (hypercholesterolemia):
less than 100 mg/dL
More than 160 mg/dl
54
skin xanthomas (hypercholesterolemia)
55
What type of inheritance is seen with familial hypercholesterolemia?
Autosomal dominant
56
Connective tissue disease:
Marfan syndrome
57
What type of inheritance is seen with Marfan syndrome?
Autosomal dominant
58
What is the prevalence of Marfan syndrome?
1/5000
59
Inherited defect in fibrillin-1, glycoprotein in extracellular matrix:
marfan syndrome
60
Marfan syndrome is characterized by an inherited defect in:
fibrillin-1 (glycoprotein in ECM)
61
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
Marfan syndrome
62
Individuals with Marfan syndrome are at an increased risk of:
aortic rupture
63
What is the inheritance pattern of neurofibromatosis type 1?
Autosomal dominant
64
What type of neurofibromatosis is most common?
type 1
65
What is the prevalence of neurofibromatosis type 1?
1/3000
66
Neurofibromatosis type 1 occurs due to mutations in :
NF1 gene (50% represent new mutations)
67
NF1 gene is associated with what protein?
Neurofibromin (tumor suppressor protein)
68
In this disease, patients may have multiple neurofibromas:
Neurofibromatosis type 1
69
Common peripheral nerve neoplasm:
Neurofibroma (seen in neurofibromatosis type 1)
70
In Neurofibromatosis type 1, the neurofibromas present most commonly on the:
skin-but can also occur in the oral cavity (tongue and buccal mucosa)
71
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
type 1 neurofibromatosis
72
Describe the oral manifestations seen in neurofibromatosis type 1: (3)
1. neurofibromas (tongue & buccal mucosa)
2. enlargement of fungiform papillae
3. enlargement of mandibular canal (radiograph)
73
Treatment of Neurofibromatosis type 1:
directed at managing complications
74
What occurs in 5% of Neurofibromatosis type 1 cases?
Neurofibrosarcoma development
75
neurofibroma (Neurofibromatosis type 1)
76
neurofibromas (Neurofibromatosis type 1)
77
neurofibroma (Neurofibromatosis type 1)
78
cafe au lait macules
79
cafe au lait macules
80
What is the inheritance pattern of cystic fibrosis?
Autosomal recessive
81
A disorder affecting ion transport:
CF
82
Abnormal fluid secretion in exocrine glands
CF
83
What organ systems does CF affect?
1. respiratory
2. GI
3. reproductive
84
What is the prevalence of CF?
1/2500
85
What gene is mutated in CF? What does this cause?
CFTR gene- abnormal function of chloride channel regulator protein
86
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
CF
87
What is a common type of bacterial infection for CF patients?
Pseudomonas infection (lungs)
88
CF treatment:
1. antimicrobial therapies, enzyme replacement, bilateral lung transplant
2. drugs to increase CFTR function
89
What is the inheritance pattern of PKU?
Autosomal recessive
90
What is the prevalence of PKU?
1/10k
91
What disease is characterized by high phenylalanine (amino acid) levels?
PKU
92
PKU is caused by a mutation in _____ resulting in ___
PAH gene; lack of PAH enzyme
93
The mutation in the PAH gene creating a lack of PAH enzyme does not allow for: (in PKU)
phenylalanine to be converted tyrosine
94
If this disease goes untreated in infants it leads to impaired brain development development delay, seizures, and reduced pigmentation:
PKU
95
PKU individuals must regulate ____ to prevent signs/symptoms
diet
96
- fish
- milk
- meat
- dairy
- beans
- diet soda
- wheat
- nuts
- legumes
- beans
- high protein foods
These foods are
high in Phenylalanine
97
- corn
- tomatos
- most veggies
- most fruits
- special breads, cookies, and crackers
- sugars
- low protein foods
These foods are:
low in phenylalanine
98
Lysosomal storage disease:
Tay-Sachs Disease
99
What is the inheritance pattern of Tay-Sachs?
Autosomal recessive
100
What is the prevalence of Tay-Sachs?
1/3500
101
Tay-Sachs disease is caused by a mutation in:
Hexosamindiase A
102
In Tay-Sachs disease, a mutation in Hexoasminidase A results in:
accumulation of gangliosides
103
In Tay-Sachs Disease, the accumulation of gangliosides primarily affects ____ & ____, but can also also accumulate in other tissues such as:
neurons& retina; heart, liver, spleen
104
Clinical features:
- infantile form- severe, infants show signs 3-6 months of age
- development impairment
- seizures
- blindness
- death by 2,3 years
Tay-Sachs disease
105
What is the inheritance pattern of Hemophilia A?
X-linked
106
An x-linked inherited bleeding disorder:
Hemophilia A
107
What is the prevalence of Hemophilia A?
1/5000 (U.S. Males)
108
Hemophilia A is caused by a deficiency in:
Factor VIII (8)
109
Clinical features:
- failure of hemostasis after circumcision (common 1st sign)
- significant hemorrhage after Timor trauma
- hemarthrosis
- increased coagulation time
Hemophilia A
110
Symptom of hemophilia A that may result in crippling deformity of joints:
Hemarthrosis
111
Treatment of hemophilia A:
1. replacement therapy with clotting factor
112
What should you do prior to oral or perio surgery on an individual with hemophilia A?
consult with physician
113
What is the inheritance pattern of Duchenne muscular dystrophy?
x-linked
114
Duchenne muscular dystrophy is characterized by:
skeletal muscle defects
115
What is the prevalence of Duchenne muscular dystrophy?
1/3500 (U.S. Males)
116
Individuals with Duchenne muscular dystrophy, have a mutation in what? What does this affect?
Dystrophin gene; defects in dystrophin protein
117
Dystrophin protein that is defected in Duchenne muscular dystrophy is found in:
1. skeletal muscle
2. cardiac muscle
3. brain
4. peripheral nerves
118
Clinical features:
- muscle weakness
- cardiac muscle damage --> arrhythmias and HF
- cognitive impairment
Duchenne muscular dystrophy
119
Results from alterations in the number or structure of chromosomes:
cytogenic disorders
120
cytogenic disorders may affect:
autosomes OR sex chromosomes
121
With cytogenic disorders, we can observe:
abberation on a karyotype
122
Exact multiple of haploid cells:
Euploid
123
More than one pair of chromosomes (i.e.3n, 4n)
Polyploid
124
Polyploid generally results in:
spontaneous abortion
125
abnormal number of chromosomes, not an exact multiple of n:
Aneupoloid
126
Aneuploid is often due to:
nondisjunction during meiosis
127
Trisomy 21 is also known as:
down syndrome
128
Extra copies of genes on chromosome 21=
trisomy 21
129
95% of individuals with trisomy 21 have got this due to:
meiotic nondisjunction
130
Clinical features:
- flat facial profile
- epicanthic folds and upward pointed eyes
- mental retardation
- congenital heart defects (40%)
- increased leukemia risk
- increased infections
Trisomy 21
131
These are characteristic of:
Tay-Sachs disease (lysosome accumulation)
132
