Principles of genetic diseases Flashcards
1
Q
Hereditary factor that determines a particular trait; found on a specific region on a chromosome:
A
Gene
1
Q
A variety of a gene (i.e. homozygous or heterozygous)
A
Allele
2
Q
A structure made up of proteins and DNA and organized into genes:
A
Chromosome
3
Q
The genetic makeup of an individual consisting of the genes on all 46 chromosomes:
A
Genotype
4
Q
Observable characteristics or traits of an individual resulting from the genotype:
A
Phenotype
5
Q
One variant of a gene on a chromosome overrides the effect of a different variant of the same:
A
Autosomal dominant
6
Q
Two copies of an abnormal gene must be present for the disease or that to develop:
A
Autosomal recessive
7
Q
Structure of DNA:
A
Double helix
8
Q
DNA winds around ____ to form ____
A
histones; core particles
9
Q
_____ folds into a thicker zig-zag fiber
A
chromatin
10
Q
In dividing cells, ______ forms into thick ___ to light microscope
A
looped chromatin; chromatids
11
Q
Midpoint of cell division:
A
metaphase
12
Q
Core particle=
A
nucleosome
13
Q
sister chromatids are connected by:
A
Kinetochore
14
Q
Short arm=
A
p
15
Q
Long arm=
A
q
16
Q
An individuals complete set of chromosomes:
A
karyotype
17
Q
In a karyotype chromosomes are arranged according to:
A
size & banding patterns
18
Q
Same version of a gene is inherited from each parent:
A
Homozygous
19
Q
Different versions of a gene is inherited from each parent:
A
Heterozygous
20
Q
Single set of chromosomes in an organism:
A
haploid
21
Q
Two copies of each chromosome:
A
diploid
22
Q
Genetic disease of familial inheritance, transmitted through generations:
A
Hereditary disorder
23
Q
Genetic disease present at birth:
A
congenital disorder
24
Result from mutations in single genes:
Mendelian disorders
25
Involve multiple genes, also including environmental influence:
Complex disorders
26
Change in number or structure of chromosomes:
Chromosomal abnormalities
27
Single gene hereditary mutation:
Mendelian disorder
28
The three patterns of inheritance of a mendelian disorder:
1. autosomal dominant
2. autosomal recessive
3. X-linked
29
Mendelian disorders are associated with a ______ of phenotypic effects
wide range
30
In mendelian disorders, the mutated gene can be influenced by:
modifier genes
31
In this type of inheritance, usually one parent is affected, and it is NOT sex dependent:
autosomal dominant inheritance
32
Autosomal dominant inheritance may also occur due to new mutations within:
the sperm or egg
33
In Autosomal dominant inheritance clinical features are modified by:
reduced penetrance and variable expressivity
34
in Autosomal dominant inheritance age of onset may be delayed from childhood such as in:
Huntington disease
35
____ inheritance is manifested in the homozygous state
autosomal recessive inheritance
36
In order for autosomal recessive inheritance to occur, how many parents must be carriers?
Both parents
37
Autosomal recessive inheritance onset:
usually early in life
38
Complete pentrance is common with _____ type of inheritence
autosomal recessive
39
With what type of inheritance are new mutations rarely detected clinically
autosomal recessive
40
One copy of the X-chromosome is inactivated:
Lyonization
41
Inactivated X-chromosome observed in nucleus:
Barr body
42
The process of lyonization is considered:
Random
43
Almost all sex-linked disorders are:
X-linked
44
Most X-linked disorders are:
Recessive
45
Female carriers transmit only to sons (50% chance):
Recessive transmission
46
Affected males do not transmit disorders to sons, but all daughters are carriers:
X-linked disorders
47
Familial hypercholestermia has an AD prevalence of:
1/500
48
Disease characterized by loss of function mutations in gene encoding LDL receptor:
Familial hypercholesteremia
49
LDL receptor is involved in:
transport & metabolism of cholesterol
50
Familial hypercholesteremia results in elevated levels of _____ ----> ________ & ______
cholesterol; premature athersclerosis; MI risk
51
Clinical feature familial hypercholesterolemia involving the skin:
Skin xanthomas
52
Normal levels of LDL:
High LDL: (hypercholesterolemia)
normal= less than 100mg/dL
High= more than 160mg/dL
53
skin xanthomas- familial hypercholesterolemia
54
What type of inheritance is see in familial hypercholesterolemia:
Autosomal dominant
55
Connective tissue disease:
Marfan syndrome
56
What type of inheritance is seen in Marfan syndrome?
Autosomal dominant
57
What is the prevalence of Marfan syndrome?
1/5000
58
Inherited defect in fibrillan-1, glycoprotein in ECM:
Marfan syndrome
59
Marfan syndrome is characterized by inherited defect in:
Fibrillin-1 (glycoprotein in ECM)
60
Clinical features:
-skeletal abmormalities (slender habitus, long legs/arms/fingers)
-high arched palate
-flat feet
-hyperextinsibility of joints
-ocular changes
-aneurysmal dilation, aortic dissection ---> aortic rupture
-enlarged heart
-stretch marks
Marfan syndrome
61
Individuals with Marfan syndrome are at an increased risk of:
Aortic rupture
62
What is the inheritance pattern of neurofibromatosis type-1:
Autosomal dominant
63
What type of neurofibromatosis is most common?
Type-1
64
What is the prevalence of neurofibromatosis Type-1?
1/3000
65
Neurofibromatosis Type-1 occurs due to mutations in:
NF1 gene (50% represent new mutations)
66
NF1 gene is associated with what gene?
Neurofibromin (tumor suppressor protein)
67
In this disease, patients may have multiple neurofibromas:
Neurofibromatosis Type-1
68
Common peripheral nerve neoplasm:
Neurofibroma (seen in Neurofibromatosis Type-1)
69
In Neurofibromatosis Type-1 the neurofibromas present most commonly on the:
skin but also can occur in the oral cavity (tongue & buccal mucosa)
70
Clinical features:
-multiple neurofibromas (varies in size, small papules to masses- elephantiasis neuromatosa of the skin)
-few tumors to hundreds/thousands
-Cafe au Lait macules on the skin
-2/3rds have relatively mild disease
Neurofibromatosis Type-1
71
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)
72
Treatment of Neurofibromatosis Type-1:
directed at managing complications
73
What occurs in 5% of Neurofibromatosis Type-1 cases:
Neurofibrosarcoma development
74
Oral neurofibroma (Neurofibromatosis Type-1)
75
Neurofibromas (Neurofibromatosis Type-1)
76
Neurofibromas (Neurofibromatosis Type-1)
77
Cafe au Lait macules (Neurofibromatosis Type-1)
78
(Neurofibromatosis Type-1)
79
What is the inheritance pattern of cystic fibrosis?
autosomal recessive
80
A disorder affecting ion transport:
CF
81
Abnormal fluid secretion in exocrine glands:
CF
82
what organ systems does CF affect?
1. respiratory
2. GI
3. Reproductive
83
What is the prevalence of CF?
1/2500
84
What gene is mutated in CF? What does this cause?
CFTR gene- abnormal function of chloride channel regulatory protein
85
Clinical features:
-viscous mucus secretions (block airway & pancreatic ducts)
-recurrent pulmonary infections
-pancreatic insufficiency
-high NaCl level in sweat
-sinusitis
-liver cirrhosis
-male infertility
CF
86
What is a common type of bacterial infection seen in CF patients:
Pseudomonas infection (lungs)
87
Treatment of CF:
1. antimicrobial therapies, enzyme replacement, B/L lung transplant
2. Drugs to increase CFTR function
88
What is the inheritance pattern of PKU?
Autosomal recessive
89
What is the prevalence of PKU?
1/10,000
90
What disease is characterized by high phenylalanine levels:
PKU
91
PKU is caused by a mutation in ____ resulting in ____
PAH gene; lack of PAH enzyme
92
The mutation in the PAH gene creating a lack of PAH enzyme does not allow for; (in PKU):
Phenylalanine to be converted to Tyrosine
93
If this disease is left untreated in infants, it leads to impaired brain development, developmental delay, seizures & reduced pigmentation:
PKU
94
PKU individuals must regulate _____ to prevent signs/symptoms
Diet
95
-fish
-milk
-meat
-dairy
-beans
-diet soda
-wheat
-eggs
-nuts
-legumes
-high protein foods
These foods are:
high in phenylalanine
96
-corn
-tomatos
-most veggies
-most fruits
-special breads/cookies/crackers
-sugars
-low protein foods
These foods are:
low in phenylalanine
97
Lysosomal storage disease:
Tay-Sachs disease
98
What is the inheritance pattern of Tay-Sachs disease?
Autosomal recessive
99
What is the prevalence of Tay-Sachs disease?
1/3500
100
Tay Sachs disease is caused by a mutation in:
Hexosaminidase A
101
In Tay Sachs disease in hexosaminidase A results in:
accumulation of gangliosides
102
In Tay Sachs disease, the accumulation of gangliosides primarily affects ____ & ____ but can also accumulate in other tissues such as:
Neurons & retina; heart, liver, spleen
103
Clinical features:
-infantile form: severe- infants show signs at 3-6 months of age
-developmental impairment
-seizures
-blindness
-death by 2-3 years
Tay-sachs disease
104
What is the inheritance pattern of hemophilia A?
X-linked
105
An X-linked inherited bleeding disorder:
hemophilia A
106
What is the prevalence of hemophilia A?
1/5000 (U.S. males)
107
Hemophilia is caused by a deficiency in:
Factor VIII
108
Clinical features:
-failure of hemostasis after circumcision (common first sign)
-significant hemorrhage after minor trauma
-hemarthrosis
-increased coagulation time
Hemophilia A
109
Symptom of hemophilia A that may result in crippling deformity of joints:
Hemarthrosis
110
Treatment of hemophilia A:
Replacement therapy with clotting factor
111
What should you do prior to oral or perio surgery on an individual with hemophilia A?
Consult with physician
112
What is the inheritance pattern of Duchenne muscular dystrophy?
X-linked
113
Duchenne muscular dystrophy is characterized by:
skeletal muscle defects
114
What is the prevalence of Duchenne muscular dystrophy?
1/3500 (U.S. Males)
115
Individuals with Duchenne muscular dystrophy have a mutation in what gene? What does this affect?
Dystrophin gene; defects in dystrophin protein
116
Dystrophin protein (that is defective in Duchenne muscular dystrophy) is found in: (4)
1. skeletal muscle
2. cardiac muscle
3. brain
4. peripheral nerves
117
Clinical features:
-muscle weakness
-cardiac muscle damage (arrhythmias & heart failure)
-cognitive impairment
Duchenne muscular dystrophy
118
Result from alterations in the number or structure of chromosomes:
Cytogenic disorders
119
Cytogenic disorders may affect:
Autosomes or sex chromosomes
120
With Cytogenic disorders we can observe:
aberration on karyotype
121
Exact multiple of haploid cells:
Euploid
122
More than one pair of chromosomes: (i.e. 3n or 4n)
Polyploid
123
Polyploid generally results in:
spontaneous abortion
124
abnormal number of chromosomes, not an exact multiple of n:
aneuploid
125
Aneuploid is often due to:
nondisjunction during meiosis
126
Trisomy 21 is also known as:
Down syndrome
127
Extra copies of genes on chromosome 21:
Trisomy 21
128
95% of individuals affected by trisomy 21 is due to:
meiotic nondisjunction
129
Clinical features:
-flat facial profile
-epicanthic folds and upward pointed eyes
-mental retardation
-congenital heart defects (40%)
-increased leukemia risk
-increased infections
Trisomy 21
130
Tay-Sachs disease (lysosome accumulation)
131
