Genetics 1 Flashcards
1
Q
degree (%) to which a trait is expressed among those with gene
A
Penetrance
2
Q
gene whose effects are not always seen despite gene presence
A
Incomplete penetrance
3
Q
variability (or not) or phenotype for those with gene
A
Expressivity
4
Q
Describes a single gene with many traits associated with it
A
Pleiotropism
5
Q
Describes when many genes lead to a single trait
A
Genetic heterogeneity
6
Q
Structure of hemoglobin
A
2 alpha and 2 beta globin chains
7
Q
Chromosome with 2 hemoglobin alpha genes
A
16
8
Q
Chromosome with 1 hemoglobin beta gene
A
11
9
Q
1:1 ratio of these in hemoglobin structure allow for solubility
A
1:1 ratio of alpha and beta chains
10
Q
Mutation in sickle cell anemia occurs in this gene
A
Chromosome 11 beta-globin gene
11
Q
Amino acid substitution in sickle cell anemia
A
Val –> glu
12
Q
Type of point mutation that occurs in Sickle cell anemia
A
Missense (amino acid switch)
13
Q
Does the mutation in the beta globin gene in Sickle Cell Anemia show pleiotropism or genetic heterogeneity?
A
Pleiotropism
14
Q
Type of point mutation that occurs in thalassemia
A
Nonsense
15
Q
In thalassemia, there is a lack in production of this
A
Beta-globin
16
Q
2 mutations that can cause Beta-thalassemia
A
Nonsense point mutation
Abnormal splicing due to mutation in non-coding regions
17
Q
Some breast cancers have extra gene copies of this
A
Her2 gene (product is a growth factor receptor)
18
Q
The kind of mutation results in extra gene copies of Her2 in breast cancer
A
Amplification mutation
19
Q
Entire regions of these two chromosomes are transposed in chronic myeloid leukemia
A
9 and 22
20
Q
In chronic myeloid leukemia, this promoter because adjacent to ABL (tyrosine kinase) and acts as a perpetual on switch
A
BCR
21
Q
In chronic myeloid leukemia, BCR promoter becomes adjacent to this
Results in unregulated cell proliferation
A
ABL (a tyrosine kinase)
22
Q
Type of mutation that occurs in chronic myeloid leukemia
A
Translocation
(Entire regions of chromosome 9 and 22 are transposed)
23
Q
Phenomenon involving earlier onset and increasing severity of disease with each generation
Often occurs in diseases involving trinucleotide repeats
A
Genetic anticipation
24
Q
Disease caused by an expansion of CTG repeats at the 3’ untranslated region of DMPK gene, a protein kinase
Results in muscle generation with slowed relaxation phase
A
Myotonic dystrophy
25
Myotonic dystrophy is broadly caused by this
Expansion of trinucleotide repeats
26
In myotonic dystrophy, there is an expansion of CTG repeats in this gene
DMPK (protein kinase)
27
Gain of function changes are usually from this type of inheritance
Autosomal dominant
28
Presence of an autosomal dominant disorder in a patient with no family history may be due to this
Spontaneous mutation
29
Gene that encodes polycystin
PKD-1
30
PKD-1 gene encodes this protein
Polycystin
31
Cilia-related protein that is responsible for sensing pressure and fluid flow, especially in the kidney
Polycystin
32
Autosomal dominant polycystin disease involves a loss of function of polycystin due to mutation in this gene
PKD-1
33
Adenomatous polyposis is caused by a mutation in the adenomatous polyposis coli (APC) gene, and exhibits this inheritance pattern
Autosomal dominant
(although both gene copies must be lost)
34
Adenomatous polyposis coli (APC) is involved in cellular signaling and this pathway
WNT pathway (promotes cell proliferation --> cancer)
35
The WNT pathway promotes this
Cell proliferation (leads to cancer, often colon cancer)
36
a1-Antitrypsin (A1AT) deficiency exhibits this type of inheritance
Autosomal recessive
37
A1AT protein turns off this activity
Results in inappropriate digestion of patient’s tissue proteins
WBC protease
38
Wild type A1AT gene
PiM
39
Non-functional A1AT gene
PiZ
40
Loss of the wild type gene (PiM) of A1AT results in this
Improper protein folding and loss of activity
41
Glucose-6-phosphate dehydrogenase deficiency exhibits this inheritance
X-linked recessive
42
X-linked recessive condition that results in inability to inactive ROS, shortening RBCs lifespan
Glucose-6-phosphate dehydrogenase deficiency
43
Enzyme defects tend to exhibit this inheritance
Recessive
44
Term for the presence of two or more cell lineages with different genotypes arising from a single zygote in a single individual
Genetic mosaicism
45
Cellular organelle involved in breakdown/recycling of macromolecules
lysosomes
46
Type of lysosomal storage disease resulting from inability to degrade glycosaminoglycans
Mucopolysaccaridoses
47
Heparan sulfate, chondroitan sulfate, and keratan sulfate are this type of compound
Glycosaminoglycans (GAGs)
48
This compound gets degraded into GAGs and proteins
Proteoglycans
49
All mucopolysaccharidoses result in these 2 main symptoms
Coarse facial features and Skeletal dysplasia
50
X-linked recessive deficiency of iduronate-2-sulfatase
Hunter syndrome
51
Mucopolysaccharidoses involving no corneal clouding and Death >10 years, some into adulthood
Hunter syndrome
52
autosomal recessive deficiency of alpha-1-iduronidase
Hurler syndrome
53
Hunter syndrome is due to a deficiency in this enzyme
Iduronate-2-sulfatase
54
Hurler syndrome is due to a deficiency in this enzyme
Alpha-1-iduronidase
55
Mucopolysaccharidosis involving Normal appearance at birth, Hepatosplenomegaly begins at 6-12 months, Corneal clouding, Heart valve insufficiency, Macroglossia, Skeletal dysplasia and coarseness
Death 6-10 years
Hurler syndrome
56
Which mucopolysaccharidosis involves corneal clouding and earlier death?
(More severe form)
Hurler syndrome
57
Autosomal recessive sphingolipidosis caused by a Glucocerebrosidase deficiency
Gaucher disease
58
Gaucher disease is due to a deficiency in this enzyme that is involved in degradation of cell membranes of RBCs and WBCs
Glucocerebrosidase
59
In Gaucher disease, this compound accumulates in macrophages and bone marrow
Glucocerebrosides
60
Levels of RBC, WBC, and platelets in Gaucher disease
All low (cytopenia)
61
Wrinkled tissue paper look from distended lysosomes is seen in this disease
Gaucher disease
62
Wrinkled tissue paper appearance to macrophages in Gaucher disease is caused by an accumulation of this in lysosomes
Glucocerebrosides
63
Sphingolipidosis that involves adult onset and 20x risk of Parkinson's disease
Splenomegaly, cytopenias, bone fracture risk
Gaucher disease
64
Autosomal recessive sphingolipidosis caused by a beta-hexosaminidase A deficiency
Tay-Sachs disease
65
Tay-Sachs disease results in an accumulation of this in all cells of the body
GM2 gangliosides
66
Most important symptom in Tay-Sachs disease
Neuronal accumulation of Gm2 gangliosides --> neurodegeneration
67
Sphingolipidosis where patients are normal appearance and physical exam at birth except for markedly increased startle reflex
Tay-Sachs disease
68
Tay-Sachs disease is most common in this ethnic population
East European Jewish
69
East European Jewish population have a high rate of these 2 diseases
Tay-Sachs disease and Niemann-Pick disease
70
In Tay-Sachs disease, GM2 gangliosides accumulate in the brain and result in these 2 main symptoms
Macrocephaly
Cherry-red macula
71
Which of the following sphingolipidoses involves a cherry-red macula?
Gaucher, Tay-Sachs, Niemann-Pick
Tay-Sachs and Niemann-Pick Type A
72
Which of the following sphingolipidoses involves adult onset?
Gaucher, Tay-Sachs, Niemann-Pick
Gaucher disease
73
Sphingolipidosis that is an autosomal recessive deficiency of sphingomyelinase
Niemann-Pick disease
74
In Niemann-Pick disease, sphingomyelin accumulate in lysosomes of these 2 organs
Brain and liver
75
In Niemann-Pick disease, this accumulates in lysosomes of brain and liver
sphingomyelin
76
Whorled myelin bodies are characteristic of this sphingolipidosis
Tay-Sachs disease
77
Type of Niemann-Pick disease that involves severe mental deterioration; death by 3 years
CNS deterioration, hepatosplenomegaly, lymphadenopathy
Type A
78
Type of Niemann-Pick disease that involves Hepatosplenomegaly and minimal CNS involvement
Milder; survive to adulthood
Type B
79
Type of Niemann-Pick disease that involves alveolar thickening (leading to dyspnea (short of breath) and low pO2)
Type B
80
Lifespan of Hurler disease
6-10 years
81
Lifespan of Hunters disease
>10 years, some into adulthood
82
Lifespan of Gaucher disease
Near normal lifespan
83
Lifespan of Tay Sachs disease
3 years
84
Lifespan of Niemann-Pick Type A disease
3 years
85
Lifespan of Niemann-Pick Type B disease
Adulthood
86
Macrophage foam cell filled with sphingomyelin is seen in this disease
Niemann-Pick disease
87
Autosomal recessive deficiency of muscle phosphorylase
Involves exercise intolerance, fatigue, inability to mobilize glucose (no elevation of lactate with exercise), muscle cramps/pain with exercise (elevated CK due to muscle damage)
Muscle cell damage --> myoglobin release --> myoglobinuria
McArdle disease
88
Enzyme deficient in McArdle disease
Muscle phosphorylase
89
Autosomal recessive deficiency of hepatic glucose-6-phosphatase
Inability to mobilize glucose from liver to blood (hypoglycemia), Hepatomegaly
Von Gierke disease
90
Enzyme deficient in Von Gierke disease
Hepatic glucose-6-phosphatase
91
Autosomal recessive deficiency of alpha-glucosidase, a lysosomal enzyme (multisystem disorder)
Inability to cleave glycogen (glucose deficiency in heart)
Muscle weakness, cardiomyopathy (death in early childhood), vacuolar myopathy
Pompe disease
92
Enzyme deficient in Pompe disease
Alpha-glucosidase (lysosomal glycogen cleavage enzyme)
93
Condition caused by a point mutation resulting in replacement of a glycine residue with another amino acid in collagen molecule
Results in weak collagen, which is a major structural protein in all solid connective tissues
Frequent bone fractures, even in utero
Hearing loss due to defective ossicles
Translucent ocular sclera
Poor dentition
Osteogenesis imperfecta
94
First amino acid in the collagen side chain that when mutated prevents the formation of stable, compact collagen fibers
Glycine
95
Abnormal allele prevents function of normal allele
Negative dominance
96
Autosomal dominant disorder caused by a defect in fibrillin protein
Involves dolichostenomelia (overgrowth of long bones), Pectus excavatum/carinatum, scoliosis, long face, prominent supraorbital ridges
Cardiovascular (mitral valve prolapse, aortic regurgitation, aortic aneurysm)
Marfans syndrome
97
Protein that is a scaffold for elastic fibers in ECM
Defective in Marfans syndrome
Fibrillin
98
Inheritance pattern of Marfans syndrome
Autosomal dominant
99
Abnormal fibrillin in Marfans syndrome results in decreased sequestration and increased levels of this which is involved in inflammation
TGF-beta
100
Symptom seen in Marfans syndrome where weak ciliary zonules lead to dislocation of lens
Ectopia lentis
101
Defective fibrillin protein in Marfans syndrome leads to defect in this type of tissue, causing cardiovascular problems
Connective tissue
102
Genetic disorder resulting in defective collagen
AR, AD, X-linked forms
Produced by many genes (genetic heterogeneity)
Very variable but common thread is fragile collagen
Susceptible to trauma, poor wound healing, susceptible to organ rupture, corneal rupture, hypermobile joints (dislocations), hyperextensible skin
Ehlers-Danlos syndrome
103
Autosomal dominant disorder with loss/reduced function of LDL cholesterol receptor
Homozygosity has additive effect (codominance)
Early cardiovascular diseases
Tendon xanthomas
Familial hypercholesterolemia
104
Inheritance pattern of Familial hypercholesterolemia
Autosomal dominant
105
Describes when homozygosity has an additive effect
Codominance
106
Buildup of fats, cholesterol and other substances in and on the artery walls
Higher risk in Familial hypercholesterolemia
Atherosclerosis
107
Process where abnormal allele prevents function of normal allele
Negative dominance
108
Disorder of defective collagen that can be caused by many genes (genetic heterogeneity)
Ehlers-Danlos
109
Term that describes an overgrowth of long bones; seen in Marfans syndrome
Dolichostenomelia
110
Fragile X syndrome is caused by this
FMR gene on Xq27.3 has increased numbers of CGG trinucleotides
111
CGG trinucleotides on the FMR gene on Xq27.3 elongate in this
Maternal oocyte
112
Cytogenetic hallmark of Fragile X syndrome is a fragile site here
Xq27.3
113
Condition caused by FMR gene on Xq27.3 has increased numbers of CGG trinucleotides
X-linked disorder but does not show classic X-linked inheritance: normal carrier males --> carrier females --> grandsons exhibit full phenotype
Disorder expressed in males
Dysmorphic ears
Long face with prominent jaw
Macroorchidism after puberty
Mental retardation (most common cause in males)
Fragile X syndrome
114
In Huntington disease, the trinucleotide repeat expansion occurs during this
Spermatogenesis
115
Inheritance pattern of Huntington disease
Autosomal dominant
116
When does genetic imprinting occur
Occurs in either sperm or egg before fertilization
117
Condition where the maternal gene on region 15q12 is silenced by imprinting and the paternal gene is lost by deletion
Prader-Willi syndrome
118
Is the maternal or paternal gene deleted in Prader-Willi syndrome?
Paternal
119
Condition where the paternal gene on region 15q12 is silenced by imprinting and the maternal gene is lost by deletion
Angelman syndrome
120
Is the maternal or paternal gene deleted in Angelman syndrome?
Maternal
121
Does this describe Prader-Willi or Angelman syndrome:
Intellectual disability, short stature, hyperphagia, obesity, small hands/feet, hypogonadism
Prader-Willi syndrome
122
Does this describe Prader-Willi or Angelman syndrome:
Intellectual disability, microcephaly, ataxia, seizures, inappropriate laughter
Angelman syndrome
123
Phenomenon in which both members of a chromosome pair are inherited from one parent, and the other parent's chromosome for that pair is missing
Uniparental disomy
124
Describes how mutations mtDNA will exist in varying proportions in each mitochondrion and therefore in each cell
Heteroplasmy
125
Condition involving progressive bilateral loss of central vision
+/- also cardiac conduction and other neurologic signs
Leber hereditary oculomotor neuropathy
