Brainscape's Knowledge GenomeTM

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


See full index

Clinical Genetics > Genetics Midterm Study Guide > Flashcards

Genetics Midterm Study Guide Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What percea dentage of recognized pregnancies end in spontaneous abortion?

A

15

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

What percentage of spontaneously aborted fetuses have a major chromosomal abnormality?

A

50

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

what percentage of pregnancies end in real births with significant defects?

A

3-4%

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

5 uses/interpretations of pedigrees

A

a. chromosomal abnormality
b. autosomal dominant condition, fully or partially penetrant, autosomal recessive
c. X linked condition, recessive or dominant
d. Mitochondrial DNA mutation
e. multifactorial condition or non-genetic cause

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

allele

A

version of a gene mutation at a particular locus along a chromosome

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

hemizygous

A

for X chromosome, single X allele

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

variable expression of same allele

A

independent of pentrance, related to degree of expression (neurofibromatosis)

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

what does 76-78del mean?

A

a deletion in coding region, nucleotides 76-78

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

X in an mRNA stop sequence

A

means stop codon

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

C.92+5G>A means

A

outside coding region by +5, change the G to A

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

allelic heterogeneity

A

the situation in which mutations in the same gene cause the same disease possibly with different effects

same gene:same disease;different effects

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

compound heterozygote

A

an individual who has two different abnormal alleles at a particular locus, one on each chromosome of a pair

different abnormal alleles

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

phenotypic heterogeneity

A

different mutations in same genes cause different phenotype

mutations: same gene: different phenotypes

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

locus heterogeneity

A

situation in which mutations in genes at different chromosomal loci cause the same phenotype

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

penetrance

A

proportion of individuals with a mutation causing a particular disorder who exhibit clinical symptoms of that disorder

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

expressivity

A

degree to which a phenotype is expresed

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

sex-limited

A

disease is lethal in the affected hemizygous males

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

lyonization

A

x-chromosome inactivation

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

autosomal dominant disease Causes (4)

A

a. gain of function
b. dominant negative
c. haplosufficiency
d. loss of heterozygosity

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

haplosufficiency

A

loss of function; decrease in activity of cell

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

aautosomal dominant disease pedigree reading

A

a. vertical pedigree pattern
b. each affected person has one affected parent
c. each child of affected parent has 50% of having disease
d. males and females equally affected/likely to be carriers
e. at least one affected parent (reduced penetrance and variable expressivity.

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

achondroplasia type

A

autosomal dominant

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

familiar hypercholesterolemia type

A

AD

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

huntington’s disease type

A

AD

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

Marfan’s syndrome type

A

AD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

neurofibromatosis type

A

AD

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

achondroplasia mutation

A

gain of function with receptor having an overactive tyrosine kinase

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

achondroplasia mutation and occurrence of mutation

A

fibroblast growth factor receptor 3 gene / spermatogenesis

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

achondroplasia penetrance

A

complete

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

achondroplasia presentation

A

short stature; shortening of limps,facies with frontal bossing and midface hypoplasia, exggerated lumber lordosis, gene varum and trident hands

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

Familial hypercholesteremia three genes responsible

A

2 LOF, 1 GOF

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

Familiar hyeprcholesterolemia haploinsufficiency

A

LDL receptor binding domain of apolipoprotein B100

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

Treat familial hypercholesterolemia

A

with statins

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

symptoms of familial hypercholesterolemia

A

aortic valve stenosis
corneal arcus
tenosyvitis

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

Huntington’s Disease cause

A

dominant negative

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

Huntington disease description

A

progressive disorder of motor, cognitive, and psychiatric disturbances

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

mean age of HD, survival time

A

35 to 44 mean age, survival time 15-18 years after onset

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

HD and CAG repeats

A

> 35, risk for developing HD
36-39 incompletely penetrate
40 completely penetrate

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

anticipation

A

usually correlated with paternal transmission of mutated allele. phenomenon in which increasing disease severity or decreasing age of onset is observed in successive generations

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

neurofibromatosis physical expression

A

variable expression from cafe au lait to dermal neurofribromas

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

neurofibromatosis symptoms

A

learning disabilities, short stature, scoliosis, high BP and tumor prone

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

neurofibromatosis mutation

A

NF1 gene (regulates ras signal transduction pathway)

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

neurofibromatosis incidence

A

1/3500 incidence, 1/2 cases are new

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

autosomal recessive pedigree

A

horizontal pedigree with one or more sibs affected
parents and children of affected people not affected
nonaffected children have 2/3 chance of being a carrier and 1/3 are normal non-carriers
-look for no family history

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

albinism type

A

AR

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

beta thalassemia type

A

AR

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

cystic fibrosis type

A

AR

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

phenylketonuria type

A

AR

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

Sickle Cell Anemia

A

AR

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

Tay-Sachs Disease

A

AR

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

What kind of autosomal recessive disease is CF?

A

loss of function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

CF: what can go wrong

A

4 things with CFTR gene; product is chloride channel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

70 percent of CF caused by what mutation?

A

loss of codon Phe508

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

meconium ileus in CF

A

meconium becomes thickened and congested in the ileum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

frequency of lethality of CF in children

A

1/3700

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

CF: what leads to infection and lung damage

A

abnormal mucus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

pseudomonas aeruginosa

A

major pathogen in CF lung opportunistic bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

CF symptoms in pancreas

A

cause exocrine pancreas dysfunction, malabsorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

CF in liver:

A

hepatobiliary tract; biliary cirrhosis; gallstones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

CF in sweat glands

A

elevated Cl and Na in sweat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

CF in reproductive tract

A

congenital bilateral absence of vas deferens. males infertile but not sterile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

Phenylketonuria expression depends on

A

protein degradation, transport and disposal of Phe, blood-brain transport and brain sensitivity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Phenylketonuria symptoms

A

mental retardation during development

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

Phenylketonuria treatment

A

restrict phenylalanine in diet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

what kind of disease is Tay Sachs?

A

lysosomal storage disease

66
Q

what does Tay Sachs affect

A

beta-hexosaminidase hydrolyzes GM2 ganglioside; accumulates ganglioside in the lysosome

67
Q

acute infantile form of Tay Sachs disease. 4 symptoms

A

a. progressive weakness
b. loss of motor skills
c. decreased attentiveness
4. increased startle response

68
Q

by when do infants die of Tay Sachs?

A

age four

69
Q

juvenine and chronic, adult onset Tay Sachs is caused by

A

variant of hexosaminadase A deficiencies; slower progression and more variable neurologic findings

70
Q

symptoms of juvenile and chronic Tay Sachs(4)

A

progressive dystonia, spinocerebellar degeneration, motor neuron disease; bipolar form of psychosis

71
Q

Tay sachs acute infantile phenotype

A

three major null alleles

72
Q

Tay sachs juvenine phenotype

A

later onset
survival into late childhood or adolescence
compound heterozygotes for null allele and allele that results in low enzyme activity

73
Q

chronic and adult onset Tay Sachs phenotype

A

long term survival, missense alleles

74
Q

X linked recessive diseases most common in

A

MALES

75
Q

Most x linked disorders are

A

recessive

76
Q

alpha thalassemia type

A

x linked recessive

77
Q

color blindness type

A

x linked recessive

78
Q

craniofrontasal (cellular intereference) type

A

x linked recessive

79
Q

Duchene’s muscular dystrophy type

A

x linked recessive

80
Q

Fragile X type

A

x linked recessive

81
Q

alpha thalassemia cause

A

locus heterogeneity
hemoglobin made of alpha2beta2, alpha on 16p, beta on 11p
mutation deleted ATRX gene located on Xq13

82
Q

what is ATRX gene?

A

helicase

83
Q

symptoms of alpha thalassemia (2)

A

mild jaundice; microcytic hypochromic hemolytic anemia

84
Q

craniofrontonasal symptoms

A

mental and psychomotor retardatoin

seizures

85
Q

craniofrontonasal mutation

A

defect in EFNB1 gene, which encodes receptor for tyrosine kinase ligand

86
Q

craniofrontonasal affects

A

mosaic female

87
Q

Frequency of Duchene’s

A

1/3000

88
Q

when do DMD symptoms appear

A

before age 5

89
Q

how do DMD symptoms progress?

A

progressive muscular weakness - proximal greater thabn distal, often with calf hypertrophy

90
Q

Gower’s maneuver

A

using upper body to stand up

91
Q

Becker muscular dystrophy onset

A

later onset than Duckene’s

92
Q

Becker symptoms

A

muscle loss in hips and pelvic area, thighs and shoulders
heart can be affected
patient can develop cardiomyopathy
lungs weaken and make it difficult to breathe and clear secretions

93
Q

Rett Syndrome type

A

X linked dominant

94
Q

Hypophosphatemia type

A

x linked dominant

95
Q

what is Rett syndrome?

A

neurodevelopmental disordfer that occurs mostly in females

96
Q

Rett syndrome symptoms

A

qwringing of hands/feet

97
Q

Rett syndrome starts

A

at about 6-18 months

98
Q

in whom is Rett syndrome lethal

A

hemizygous males

99
Q

What is hypophosphatemia

A

inability of kidneys to retain phosphate

100
Q

what does hypophsphatemia affect?

A

Vitamin D metabolism

101
Q

How is hypophosphatemia variably expressive?

A

more severe in males

102
Q

symptoms of hypophosphatemia

A

Vitamind D resistant rickets

short stature

103
Q

What are Y linked diseases?

A
  1. diseases associated with y chromosome

have male infertility

104
Q

hypertrichosis pinnae

A

hairy ears (y linked disease)

105
Q

what is mitochondrial disease?

A

only passed from mother to all her children/ reduced penetrance

106
Q

What type of disease is Leber Hereditary Optic neuropathy?

A

mitochondrial disease

107
Q

What causes LHON?

A

one of three mutations in ND1, ND4 and ND6

108
Q

four confounding factors of autosomal and sex linited diseases?

A
  1. sex limited
  2. cellular interference - only in heterozygotes
  3. mosaicity
  4. penetrance (fully penetrant to reduced to multifactorial) MS
109
Q

what do chromosomal abnormalities cause?

A

infertility and recurrent miscarriages

110
Q

50% of spontaneous abortions during first trimester are caused by

A

chromosomal abnormalities

111
Q

what is most common category of genetic disease observed in prenatal analysis

A

chromosomal abnormalities

112
Q

most chromosomally abnormal babies are born to

A

normal parents

113
Q

homologous chromosome

A

individual chromosome inherited from mother or father

114
Q

G banding

A

standard staining procedure to obtain a karyotype

115
Q

acrocentric

A

chromosome that his its centromere chose to one end: 13, 14, 15,21, 22, Y

116
Q

aneuploidy

A

abnormal number of chromosomes (normal 46)

117
Q

polyploidy

A

containing more than normal multiples of chromosomes

118
Q

nondisjunction

A

migration to same daughter instead of normal disjunction

119
Q

result of nondisjunction in meiosis 1

A

two babies with trisomies and two with monosomny

120
Q

result of nondisjunction in meosis 2

A

one monosomy, one trisomy, two normal

121
Q

triploidy 69, XXX, XYY, YYY

A

common at conception but abort

occur from multiple sperm fertilizing the ovum or chromosome segregation error

122
Q

47, XX or XY, + 21 Down Syndrome frequency

A

1/8000 births

123
Q

fertility of Downs patients

A

females are fertile; males are sterile

124
Q

function of chromosome 21

A

controls mental functions, stature, and morphogenesis of hearts, fingers and facial musculature

125
Q

downs characteristics

A

flat face, down turned mouth and widely spaced eyes

126
Q

downs congenital malformations

A

heart, GI tract, dudenal stenosis/atresia, imperforate anus and hishsprung disease

127
Q

47, XX or XY, +18 is

A

Edwards syndrome

128
Q

frequency of Edwards syndrome

A

1/6000 births

129
Q

characteristics of edwards syndrome

A

rare long term survivors and show little developmental progress

130
Q

47, XX or XY, + 13 is

A

Patau syndrome

131
Q

Patau syndrome frequency

A

1/10,000 births

132
Q

symptoms of Patau

A 
mental and motor deficiencies
polydactyl
heart defects
cleft palate
eye defects
133
Q

45, X or 45, XO is

A

turner syndrome

134
Q

characters of turner syndrome

A

short stature (HOX gene missing)
sexual infantilism and ovarian dysgenesis
puffy feet
redundant skin at back of neck

135
Q

congenital defects of turner syndrome

A

heart and kidney

136
Q

turner syndrome histology

A

cortical stroma without germ cells - no follicles

137
Q

cause of Turner syndrome

A

60-80% due to absence of fraternal X/Y chromosome due to loss during meiosis in the father. Loss during mitosis in embryo causes mosaic 45,X/46, XX

138
Q

SHOX gene

A

at tips of X and Y chromosomes. encodes transcription factor in embryonic limbs

139
Q

can turner syndrome be diagnosed at birth?

A

yes

140
Q

47, XXY is

A

klinefelter syndrome

141
Q

How many barr bodies in klinefelter syndrome?

A

1

142
Q

klinefelter syndrome frequency

A

1/500 - 1/1000

143
Q

characteristics of Klinefelter syndrome

A

hypogonadism, and taller and longer arms
low testosterone
reduced muscle mass and IQ
gynecomastia

144
Q

Are klinefelter syndrome patients fertile?

A

most are sterile due to atrophy of seminiferous tubules

145
Q

what are 48, XXXY and 49,XXXXY

A

klinefelter syndrome

146
Q

47,XXX- is

A

trisomy X

147
Q

trisomy X frequency

A

1/1000 felames

148
Q

what causes trisomy X

A

90% due to nondisjunction in mother; increases with age

149
Q

Is trisomy x usually benign?

A

yes

150
Q

characteristics of trisomy X

A

sterility
menstrual irregularities
mild retardation

151
Q

What increases severity of trisomy X

A

increasing Xs (48, XXX or 49, XXX)

152
Q

47, XYY is

A

47, XYY syndrome

153
Q

47, XYY syndrome characteristics

A

taller
IQ reduction by 10-15 points
high in prison

154
Q

in 47, XYY, what is xtra Y related to?

A

ADD and learning issues

155
Q

46 XX male or 46 XY female caused by

A

error in cross over between X and Y chromosome exchange in the Sry gene
x chromosome has larger portion ochromosome with SRY
Y chromosome is missing SRY gene

156
Q

XX male, XY female gametes

A

have no gametes

157
Q

SRY gene

A

on y chromosome

sex determining gene

158
Q

when does SRY activate

A

SRY starts expression after week 6. gonad formation week 7.

159
Q

what does SRY activate?

A

SOX9 gene (for skeletal and testis formation)

160
Q

Where is SHOX gene

A

tip of X and Y chromosome in pseudoautosomal region

Clinical Genetics (3 decks)

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