Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

SP16- Gen Path Exam 2 > Genetic Diseases > Flashcards

Genetic Diseases Flashcards

1
Q

There are ____ pair of autosomes and ____ pair of sex chromosomes.

A

22 autosome

1 sex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How many protein-coding genes are there in the human genome (roughly)?

A

19,000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

True or False: Alterations in the genetic code results in mutation.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Where do genes reside?

A

on chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Where are chromosomes?

A

in the nucleus of the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the four letters of genetic code?

A

A, C, G, and T

adenine, cytosine, guanine, thymine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Each gene contains the genetic information required to produce ______.

A

a protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

True or False: Mutations of a certain gene locus will only affect one chromosome of the pair.

A

False: could affect one OR both

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

When one chromosome of the pair is affected, the individual is ______ for the disorder.

A

Heterozygous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

If both chromosomes at a given gene locus are affected, the individual is _______.

A

homozygous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Neoplasms affect _____ cells; whereas, inherited conditions affect ______ cells.

A

somatic

germ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is a point mutation?

A

also known as “Missense”

a single base substitution (such as in Sickle Cell Anemia)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a frameshift mutation?

A

an insertion OR deletion of 1 or 2 base pairs that results in alteration of the reading frame of the DNA strand (typically results in early stoppage)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is a “trinucleotide repeat” mutation?

A

amplification of a 3-nucleotide sequence (ex: Fragile X Syndrome)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

____________: variation in just one nucleotide (for example A or T) at a single site on the DNA molecule.

A

Single Nucleotide POLYMORPHISM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Over 6 million polymorphisms have been identified, but most are within _____, _______, or intergenic regions.

A

exons

introns

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Polymorphisms may be markers for multigenic diseases such as ______ or hypertension.

A

diabetes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the two types of polymorphisms?

A
  1. single nucleotide

2. copy number variations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are copy number variations?

A

different number of large contiguous stretches of DNA (anywhere from 100 to millions of base pairs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

About how many “copy number variations” involve gene coding sequences that may result in phenotypic variation?

A

half

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

________: modulation of gene expression without altered DNA sequence.

A

Epigenetic changes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

True or False: Epigenetic changes will disrupt homeostasis.

A

False: Epigenetic changes are important in development and in normal homeostasis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Methylation of the promoter region makes it inaccessible to _______ and thus reduces protein synthesis.

A

RNA polymerase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What do MicroRNA do?

A

inhibit translation of their target messenger RNA and thus control or block transcription of the protein
(aka: strands of RNA that DO NOT code for anything themselves but regulate transcription of other proteins….gene silencing)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are the three types of Mendelian Disorders (diseases caused by single-gene defects)?

A
  1. Autosomal Dominant
  2. Autosomal Recessive
  3. Sex-Linked Disorders
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are polygenic disorders?

A

disorders with multifactorial inheritance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What are cytogenetic disorders?

A

chromosomal aberrations (autosomes, sex chromosomes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

True or False: The production of an abnormal protein can alter phenotype.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is an autosomal dominant disorder?

A

the altered gene is on an autosome and the disease will be clinically evident when only one of the chromosomes in the pair is affected at a particular gene locus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Autosomal Dominant disorders present with _________ changes and may exhibit a(n) _______ age of onset.

A

outward physical changes

delayed age of onset (ex. Huntington’s Disease)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

With AD disorders, are one or both parents usually affected?

A

one

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

True or False: With AD disorders, only males can have the disorder and transmit the mutated gene.

A

False: BOTH males and females can have the disorder and transmit the mutation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

If only one parent is affected with an AD disorder, what percentage of the offspring will have the disease?

A

50%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is “reduced or incomplete penetrance”?

A

person has a mutant gene but DOESN’T or only PARTIALLY expresses it phenotypically

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is “variable expressivity”?

A

trait is seen phenotypically in all individuals having the mutant gene but is EXPRESSED differently among individuals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is “de novo mutation”?

A

affected individuals may not have affected parents because their disease arose from a NEW mutation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What is an example of an A.D. disease with nearly 100% penetrance?

A

neurofibromatosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

True or False: 100% penetrance means that everyone who has the mutation will show evidence of the condition and express it fully.

A

True/False: Everyone WILL show evidence of the condition but the EXPRESSIVITY will be highly variable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What is “Autosomal Recessive Disorder”?

A

the trait is expressed only if BOTH genes at the given locus are affected (ie: homozygous for the defect)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

True or False: A.R. disorders are the most common of Mendelian disorders.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

True or False: One parent of an affected individual with an A.R disorder will show the disease.

A

False: Neither parent will appear affected

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What is the chance that heterozygous parents for an AR disorder will have offspring with the disorder? What is the chance that the offspring will be a carrier?.

A

disease: 25% chance
carrier: 50% chance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What does this statement mean: “the recessive gene is rare in the population, the disorder may be a result of consanguinity”?

A

there is a horizontal pattern within families, the disorder will most likely be passed among family members of similar genetic backgrounds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Many AR disorders are ______ defects.

A

enzyme

metabolism errors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

For AR disorders, the age of onset is ____ and ______ penetrance is common.

A

early
complete
(**AD disorders have late onset and variable penetrance)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

On which chromosome are x-linked disorders?

A

sex chromosome (all sex-linked diseases are on the x chromosome)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

True or False: The Y chromosome only carries one significant gene.

A

True, the SRY gene….sex-determining region

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What is the one trait that may be linked to the Y chromosome?

A

hairy ears

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Most sex-linked disorders are ______.

A

recessive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Why are females usually unaffected by sex-linked disorders?

A

females are XX and these disorders are usually recessive which means they would have to inherit two mutated copies, males are XY (hemizygous) and will express a disease when they inherit one defective X

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What is an important X-linked disorder?

A

Hemophilia A

52
Q

What is lyonization?

A

sixteen days after conception, about 75% of one x-chromosome (maternal or paternal) is randomly inactivated in all of the cells within the zygote

53
Q

What is unfavorable lyonization?

A

inactivation of an abnormally high percentage of normal x chromosomes, leading to clinical evidence of a recessive disease in a heterozygous female (i.e.: x-linked)

54
Q

What is formed from the x-chromosome that is randomly inactivated in the female zygote?

A

Barr Body

55
Q

Mutations in Structural Proteins cause mutations in genes that encode proteins necessary for formation of normal ____ and ______.

A

bone

connective tissues

56
Q

Marfan Syndrome is an _____ ______ disorder of connective tissue due to mutation of the _______ gene.

A

autosomal dominant

FBN1

57
Q

Mutation of the FBN1 gene, Marfan Syndrome, results in abnormal ________.

A

fibrillin (a glycoprotein necessary for normal elastic fiber production)

58
Q

What are the physical traits of Marfan Syndrome?

A

tall, thin body habitus
abnormally long legs, arms and fingers (arachnodactyly)
dislocation of the lens of the eyes
aortic aneurysm and dissection leading to heart failure and aortic rupture
(Abe Lincoln! Sudden death of bball players!)

59
Q

There are at least ____ clinical variants of Ehlers-Danlos syndrome.

A

six (dominant and recessive)

60
Q

Why are there different variants of Ehlers-Danlos?

A

the disease is a result of defective collagen synthesis…there are about 30 different types of collagen and variable tissue distribution

61
Q

What are the clinical traits associated with Ehlers-Danlos?

A 
Hyperextensible (stretchy) skin
Hyper-mobile joints
Skin fragility
Poor wound healing
Colon Rupture
Large Arteries
Hernias
62
Q

What are two diseases caused by mutations in Receptor Proteins?

A
  1. Hypercholesterolemia

2. Cystic Fibrosis

63
Q

True or False: Hypercholesterolemia is one of the more commonly inherited disorders.

A

True (1 in 500 in the population)

64
Q

Which gene is mutated in Hypercholesterolemia?

A

the gene that encodes for the LDL receptor (results in impaired metabolism and increased LDL cholesterol in the plasma)

65
Q

What would be the result of a mutated LDL receptor?

A

xanthomas of the skin

premature atherosclerosis

66
Q

True or False: Homozygotes of Familial Hypercholesterolemia will often die of MI before 20 years of age.

A

True

67
Q

Understanding the role of the LDL receptors has led to the design of which family of drugs used to control cholesterol levels?

A

Statin Family

68
Q

What is Cystic Fibrosis?

A

a disease caused by mutations in genes that encode for the chloride channel (receptor protein channels); causes viscous excretions in the lungs with extensive mucous plugging and dilation of tracheobronchial trees

69
Q

What type of infection is commonly found in the lungs of someone who dies from Cystic Fibrosis complications?

A

Pseudomonas (pneumonia)

70
Q

Phenyketonuria, Galactosemia, and Lysosomal Storage Disease are three examples of diseases caused by mutations in ________.

A

enzyme proteins

71
Q

What is Phenylketonuria?

A

an autosomal RECESSIVE disorder that causes a severe lack of phenylalanine hydroxylase and can lead to PKU or hyperphenylalaninemia

72
Q

How common is Phenylketonuria?

A

1 in 10,000 Caucasian infants

73
Q

True or False: Affected infants with phenylketonuria are normal at birth, but have impaired brain development due to decreased phenylalanine levels.

A

False: due to INCREASED phenylalanine (its not broken down)

74
Q

How quickly does phenylketonuria cause mental retardation?

A

6 months of age

75
Q

True or False: Restricting dietary sources of phenylalanine will prevent the development of mental retardation in those affected with phenylketonuria.

A

True

early screening is mandatory in the US

76
Q

Lysosomal storage diseases commonly affect _____ and _____.

A

infants

young children

77
Q

What accumulates in those children affected by lysosomal storage diseases?

A

accumulation of LARGE, insoluble molecules in macrophages (sphingolipids, mucopolysaccharides)
*this leads to hepatosplenomegaly

78
Q

True or False: Lysosomal Storage diseases commonly involve the CNS.

A

True

79
Q

Describe the pathogenesis of Lysosomal Storage Disease.

A

Normally, complex substrates are degraded by a series of lysosomal enzymes into soluble end products. If the enzymes are deficient or malfunctioning, catabolism is incomplete and the INSOLUBLE intermediates accumulate in the lysosome

80
Q

What are three diseases that are associated with myelinated biproducts and sphingolipids?

A

Tay-Sachs
Niemann-Pick
Gaucher

81
Q

Most mucopolysaccharide storage diseases (type of lysosomal storage disease) are autosomal _______.

A

recessive

lack enzymes for degrading mucopolysaccharides

82
Q

Patients affected by mucopolysaccharide storage diseases will often have _________, ________, _________, and mental retardation.

A

coarse facial hair
clouding of the cornea
joint stiffness

83
Q

How many mucopolysaccharide storage disease variants are there?

A

seven

84
Q

MPS type I is called _______ Disease.

A

Hurler

85
Q

Hurler Disease (MPS 1) is caused by a deficiency of which enzyme?

A

alpha-L-iduronidase (laronidase)

86
Q

If untreated, what is the life expectancy of Hurler Disease?

A

6-10 years

87
Q

The cost of the Laronidase enzyme is more than $_________. What are other treatment options that could improve the outlook of the disease (not cure though)?

A

$300,000

bone marrow transplant

88
Q

MPS type II is called _______ Syndrome.

A

Hunter

89
Q

Hunter Syndrome is caused by a deficiency of which enzyme?

A

L-iduronate sulfatase

90
Q

Hunter and Hurler are similar. Other than the enzyme deficit, how do they differ?

A

Hunter (type II)= no corneal clouding and milder clinical course than Hurler (type I)

91
Q

What does it mean when a disorder is multifactorial (polygenic)?

A

two or more genes responsible, PLUS environmental influences

92
Q

True or False: Many physiologic traits are multifactorial.

A

True, height, weight, blood pressure, and hair color

93
Q

True or False: Many common diseases such as diabetes, hypertension, gout, schizophrenia, and bipolar disorder are purely genetically induced.

A

False, those listed disorders may all have polygenic influences from multiple genes and the environment

94
Q

_______ is a composite of stained human chromosome strand pairs.

A

Karyotype

95
Q

What is the normal chromosome count? Is it the same for males and females?

A

46

yes, it is the same. 23 pair total= 1 sex (either XX or XY) and 22 autosomal

96
Q

How common are chromosomal abnormalities?

A

1 in 200 newborns

97
Q

In as much as ____% of first trimester spontaneous abortions, the fetus has a chromosomal abnormality.

A

50

98
Q

A normal chromosome count (2x23=46) is termed ______.

A

euploid

Eu and Me…we have 23

99
Q

An increased chromosome count that is a multiple of the normal (3 x 23, or 4 x 23) is termed _______.

A

polyploidy

100
Q

True or False: Polypoidy typically results in spontaneous abortion.

A

True

101
Q

Any number of chromosmes that is not an exact multiple of the normal number is termed _______. Give an example.

A

Aneuploidy

  • extra chomosome: trisomy = 2 x 23 +1 = 47
  • absence of chromosome: monosomy = 2 x23 -1 = 45
102
Q

Chromosome abnormalities can be of what two types?

A
  1. numeric

2. structural

103
Q

What are structural abnormalities of chromosomes?

A

usually these result from chromosome breakage followed by loss or rearrangement of material

104
Q

_______ is transfer of a part of one chromosome to another non-homologous chromosome

A

translocation

105
Q

What is reciprocal translocation?

A

when fragments are exchanged between two chromosomes

106
Q

What is chromosome inversion?

A

chromosome breaks in two points, then the released fragment is reunited after a complete turnaround

107
Q

True or False: Trisomy 21 is a cytogenetic disorder involving autosomes.

A

True

108
Q

What is the most common of chromosomal disorders?

A

Down’s Syndrome (trisomy 21)

109
Q

Down Syndrome is most closely related to what maternal characteristic?

A

AGE

45 years old = 1 in 25

110
Q

Trisomy 21 results from ______ of chromosome 21 during formation of the ovum.

A

nondisjunction

111
Q

What are the physical/clincal traits that are associated with Down Syndrome?

A 
mental retardation
epicanthic folds
flat facial profile
cardiac malformations
increased susceptibility to infection
large tongue
increased risk of acute leukemia
112
Q

True or False: Patients with Down Syndrome have increased susceptibility to severe periodontal disease in childhood.

A

True

113
Q

Down Syndrome increases the risk for Leukemia by _____ to _____ times.

A

10 to 20 times

114
Q

What are two cytogenetic disorders that involve sex chromosomes?

A
  1. Klinefelter Syndrome

2. Turner Syndrome

115
Q

How is the sex chromosome affected in Klinefelter?

A

two X chromosomes (at least) and one Y chromosome results in XXY genotype resulting in HYPOGONADISM

116
Q

What are the physical characteristics that appear with Klinefelter Syndrome?

A 
increased length of lower limbs
reduced body hair
gynecomastia
hypogonadism (male sterility)
increased frequency of TUARODONTISM (large pulp chambers, be aware!)
117
Q

Turner Syndrome results from _______.

A

partial or complete absence of one of the X chromosomes

118
Q

True or False: Those patients with Turner Syndrome have a markedly tall stature.

A

False, markedly short

119
Q

How many chromosomes will a patient of Klinefelter Syndrome have? Turner Syndrome?

A

Klinefelter: 47 chromosmes
Turner: 45 chromosomes

120
Q

What are the physical characteristics associated with Turner Syndrome?

A 
markedly short stature
webbing of the neck
low posterior hairline
shield-like chest
high-arched palate
congenital cardio malformations
primary amenorrhea and failure to develope secondary sex characteristics
121
Q

Which cytogenic disorder of sex chromosomes will affect males? Which will affect females?

A

Turner: females (45, X)
Klinefelter: males (47, XXY)

122
Q

What is FISH?

A

Fluorescence in Situ Hybridization

- uses fluorescent dye-labled probes that recognize sequences specific to chromosomal regions

123
Q

What is comparative genomic hybridization?

A

uses different colored dyes attached to large segments of the test DNA and normal DNA, followed by hybridization. Relative amounts of each DNA sample are assessed on the color of the product and gene amplification or deletion can be identified in genetic diseases

124
Q

What is a common method for molecular diagnosis of genetic disorders?

A

PCR

-amplification of DNA, then comparison of nucleotide order to normal DNA

125
Q

If a woman is greater than ____ years old when pregnant, she should get genetic counseling.

A

34

SP16- Gen Path Exam 2 (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions