Brainscape's Knowledge GenomeTM

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


See full index

Mechanisms of Disease > Genetic Disorders > Flashcards

Genetic Disorders Flashcards

1
Q

Sickle-cell anemia is caused by a mutation in which chain of hemoglobin?

A

Beta chain

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

What is the product of FMR1? What is its function?

A

FMR protein (FMRP)

RNA binding protein associated with polysomes; regulate protein synthesis at synapses

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

Do chromosomal abnormalities have high or low penetrance?

A

High

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

Do Mendelian disorders have a high or low penetrance?

A

High

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

Why does sickling lead to decreased NO?

A

Released Hb binds to NO, thereby depleting it

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

What is a neurofibroma and what is it composed of?

A

Peripheral nerve sheath tumors composed of a mixture of Schwann cells and fibroblasts

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

People with 22q11.2 deletions are at an increased risk of:

A

Schizophrenia

Bipolar disorder

ADHD

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

What is a nondisjunction mutation?

A

Failure of two homologous chromosomes (or two sister chromatids) to separate at metaphase of meiosis I (or meiosis II/mitosis)

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

Define polymorphism

A

the occurrence of different forms among the members of a population or colony, or in the life cycle of an individual organism.

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

What does it mean when FMR1 is said to have “nonclassic inheritance”?

A

Mutations don’t cause loss of function

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

How is phenylketonuria inherited?

A

Autosomal recessive

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

What is the function of CTLA4?

A

Cytotoxic T-lymphocyte associated protein 4

Negative regulator of immune response

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

Describe the clinical presentation of PKU.

A

Postnatal growth retardation

Moderate to severe intellectual disability

Recurrent seizures

Hypopigmentation

Eczematous skin rashes

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

What are some of the lesser-known symptoms of Down syndrome aside from intellectual disability and physical abnormalities?

A

40% have congenital heart disease

Digestive problems

10-20x increased risk of leukemia

Abnormal immune responses of unknown etiology (thyroid autoimmunity and lung infections)

Degenerative neurological disorder similar to Alzheimer’s

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

What is the significance of “sticky patches” in HbS?

A

Causes aggregation of deoxygenated sites

Caused by hydrophobic reside being replaced with a hydrophilic residue

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

Aside from the brain, what is the other major location for FMRP expression?

A

Testes

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

What causes symptom onset in Amyloidosis?

A

Amyloid build-up impinging on neighboring structures

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

How many gene candidates have been implicated in Type 1 diabetes? Which ones are most important?

A

20-30

Insulin gene

HLA region on Chr 6p21

PTPN22

IL2RA

CTLA4

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

Characteristic physical appearances for Fragile X Syndrome are not always present. What are they when they ARE present?

A

Long face

Large jaw

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

Why can PKU cause seizures?

A

Accumulation of Phe inhibits amino acid transport across the blood-brain barrier

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

What are the two hallmark symptoms of Ehlers-Danlos syndrome?

A

Elastic skin that bruises easily

Overly flexible joints

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

95% of cases of Trisomy 21 are a result of _____. 4% of cases are caused by ______.

A

95%: three chromosome 21

4%: translocation of extra chromosomal material

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

What environmental exposures would be required for someone that has a genetic predisposition as a result of polymorphisms to develop Type 1 diabetes?

A

Hypersensitivity reactions

Certain autoimmune diseases (ex: Lupus)

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

Describe the clinical presentation of Neurofibromatosis I

A

Neurofibromas

Optic nerve gliomas

Lisch nodules

Cutaneous hyperpigmented macules

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

Most phenotypical characteristics are a result of ______.

A

interaction of multiple polymorphisms

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

What is the function of Ras?

A

Promotion of survival and proliferation

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

What is Amyloidosis?

A

Progressive degenerative disease characterized by fibrillar protein deposits

28
Q

What are some serious internal complications of Ehlers-Danlos syndrome?

A

Colon rupture

Large blood vessel rupture

Cornea rupture or retinal detachment

Diaphragmatic hernia

29
Q

What is the location of the FMR1 gene?

A

Xq27.3

30
Q

Describe how FMR1 is mutated in Fragile X syndrome and what the result is.

A

Multiple tandem CGG repeats in the 5’ UTR

More repeats promote DNA methylation

31
Q

Single mutation (monogenic) disorders follow what type of inheritance?

A

Mendelian

32
Q

What are the similarities and differences between DiGeorge Syndrome and velocardiofacial syndrome?

A

Both involve deletion of 22q11.2

DGS: nonspecific facial changes, T-cell immunodeficiency, hypocalcemia

VCS: specific facial changes, mild immunodeficiency, cardiac defects

33
Q

What subunits make up normal adult hemoglobin (HbA)?

A

α2β2

34
Q

What are the two qualifiers for a complex multigenic disorder?

A

Familial clustering

Not monogenic or chromosomal

35
Q

Genetically speaking, what is the reason for the range of different presentations of 22q11.2 deletion?

A

Variations in size and position of the deletion

36
Q

Phenylketonuria develops as a result of a mutation in what gene? What reaction does it catalyze?

A

Phenylalanine hydroxylase

Phe –> Tyr

37
Q

Why does sickling cause bone marrow proliferation?

A

Compensation for loss of RBCs

38
Q

What is amyloid?

A

Deposits of misfolded proteins

39
Q

The pain associated with sickle-cell can be masked as ________ in young children.

A

Osteomyelitis (bone infection)

40
Q

A mutation in what gene is responsible for Fragile X syndrome?

A

Familial mental retardation 1 (FMR1)

41
Q

What is the function of IL2RA?

A

T cell activation

42
Q

What is DiGeorge Syndrome?

A

Part of a spectrum of disorders associated with chromosomal deletion of 22q11.2

43
Q

A glioma is described as _____.

A

A mass of glial cells

44
Q

What subunits make up sickle hemoglobin (HbS)?

A

α2βs2

45
Q

Loss of neurofibromin would result in ______.

A

Unregulated cell growth

46
Q

What enzyme does PTPN22 code for?

A

Lymphoid protein Tyr phosphatase

47
Q

Describe the “vicious cycle” of sickle-cell

A

Blockages in blood vessels cause localized hypoxia, which induces HbS aggregation, which leads to blockages, which leads to localized hypoxia……………………………………………

48
Q

What is the function of lysyl hydroxylase?

A

Cross-linkage of collagen fibers in the extracellular space

49
Q

What is the function of neurofibromin 1?

A

Negative regulator of Ras; tumor suppressor

50
Q

What are the primary effects of sickling?

A

Chronic hypoxia

Hemolytic anemia

Bone marrow hyperproliferation

Decreased NO (vasodilator)

51
Q

Neurofibromatosis type I involves a mutation in what gene?

A

Neurofibromin

52
Q

What is the cause of Trisomy 21?

A

Meiotic non-disjunction of chromosome 21

53
Q

What is the function of procollagen N-peptidase?

A

Cleavage of propeptides from collagen after being secreted into the extracellular space.

54
Q

Describe “penetrance”

A

Whether or not the variant genotype (that produces a phenotype) can be inferred on the basis of defined phenotypic criteria

55
Q

What gene is mutated in Neurofibromatosis I?

A

Neurofibromin I (NF1)

56
Q

What is the inheritance of neurofibromatosis?

A

Autosomal dominant

57
Q

What are Lisch nodules?

A

Pigmented nodules of the iris

58
Q

What are the most common organs to experience vaso-occlusion due to sickled RBCs? Why?

A

Kidney, lung, spleen, liver

Large amount microvasculature

59
Q

What subunits make up fetal hemoglobin (HbF)?

A

α2γ2

60
Q

More than ____ disease-associated PAH alleles have been discovered, yet only a mutation in ____ will cause PKU.

A

500; 1

61
Q

Define “opsonization”.

A

Binding of antibodies and complement molecules to allow recognition by phagocytes

62
Q

What is the result of DNA methylation?

A

Represses DNA expression by reducing availability for transcription

Packages chromatin

63
Q

What mutations could give rise to Ehlers-Danlos syndrome?

A

Mutations in collagens I, III, and V

Lysyl Hydroxylase

Procollagen N-Peptidase

64
Q

Which gene on the deleted region (22q11.2) is thought to be responsible for DiGeorge syndrome? What does it do?

A

TBX1

Transcription factor that targets PAX9, which is associated with the palate, parathyroid, and thymus

65
Q

How does the number of CGG repeats in the FMR1 gene vary between the normal population, affected individuals, and carriers?

A

Normal population: 6-55

Carriers: 50-200

Affected: 200-400

66
Q

What is the primary phenotype of Fragile X Syndrome?

A

Intellectual disability

Mechanisms of Disease (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions