Brainscape's Knowledge GenomeTM

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


See full index

Quiz 2 > Q2-FUN17/Cytogenetics (human chromosomes and chromosomal disorders) > Flashcards

Q2-FUN17/Cytogenetics (human chromosomes and chromosomal disorders) Flashcards

1
Q

What is the leading indication of a pre-natal of a potential disease?

A

mother is older

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

The lab methods for pre-and post natal diagnosis are similar, but they have different ____________ methods

A

sampling

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

Typically, we start with ________ methods and then to confirm the diagnosis, we move to _______ clinical procedures

A

non-invasive, invasive

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

What are the 2 types of prenatal invasive methods?

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

What is chorionic villus sampling?

A

it is a prenatal, invasinve test where a sample of chorionic villi is removed from the placenta for testing

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

What is amniocentesis?

A

prenatal invasive procedure used to take out a small sample of the amniotic fluid for testing

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

invasive procedures incur ________

A

risk!

Doctors have to ask themselves if the risk of procedure is greater than the risk of fetal abnormality?

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

noninvasive prenatal diagnosis is relevant to screening for __________

A

down syndrome

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

What are the non invasive tests done during the first trimester of pregnancy?

A
  • Maternal serum proteins + ultrasound (subcutaneous edema of fetal neck)

– PAPP-A (pregnancy associated plasma protein A)

– fβHCG (free-beta human chorionic gonadotropin)

– Maternal Serum α-fetoprotein,

– hCG,

– unconjugated estriol

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

What is the Harmony test?

A

it is a non-invasive prenatal tests (NIPT), it analyses cell-free DNA (cfDNA) in maternal blood plasma.

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

Why does the harmoney test work?

A

It works because blood plasma of a pregnany woman consists of a combination of both maternal (95%) and fetal (5%) DNA.

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

What advancements have occured regarding the Harmony test since 2012?

A

it is now possible to analyse cell free fetal DNA (cffDNA) in the maternal blood using Next Generation Sequencing (NGS)

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

What does the harmony test look for?

A

gives a strong indication of whether the baby is at high or low chance of having trisomy 21 (Down syndrome), trisomy 18 (Edwards syndrome) or trisomy 13 (Patau syndrome).

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

CVS is a biopsy of the villi in the _____________ via a __________ under _________ guidance

A

chorion frondosum, catheter, ultrasound

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

What are the advantages of CVS?

A

It happens in the first trimester

yields 10-50mg of tissue for quick analysis

tissue culture isnt nessessary to inc. cell numbers

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

What are the disadvantages of CVS?

A

no a-fetoprotein for diagnosing NTD (neural tube defect)

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

What is the risk of miscarriage for CVS?

A

1% above 2-5% baseline

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

Is the risk of miscarriage greater for CVS or amniocentesis?

A

CVS

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

Amniocentesis is the withdrawl of amniotic fluid (____-____ ml) under _____ guidance

A

10-20 ml, ultrasound

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

CVS occurs trans______ or trans_______

A

transcervically or transabdominally

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

Amniocentesis occurs trans_________

A

transabdominally

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

When would someone perform an amniocentesis?

A

early second trimester (15-20 weeks)

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

Since amniocentesis collects fluid and that amniotic fluid contains cells, it can be ___________

A

cultured

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

what can be measured from amniotic fluid?

A

alpha-fetoprotein, used to test for neural tube defects

can also find enzymes and viruses

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

how long do you have to culture cells that you got from amniocentesis for?

A

culture them from 4-6 weeks, most are nonviable cells

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

what is the risk of miscarriage of amniocentesis?

A

approx. 0.2% above the baseline 1-2%

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

What are the differences between metacentric, submetacentric, and acrocentric?

A

where the centromere is located

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

Explain banding nomenclature for chromosomes.

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

What are the 2 types of chromosomal abnormalities?

A

numberical aberrations and structural aberrations

30
Q

What is a numerical chromosome aberration?

A

Numerical abnormalities are whole chromosomes either missing from or extra to the normal pair.

31
Q

What are the 2 types of strutural aberrations?

A

involving 1 chromosome and involving 2 chromosomes

32
Q

What are the types of structural aberrations involving 1 chromosome?

A

duplication, deletion, inversion, ring chromosome

33
Q

What are the types of structural aberrations involving 2 chromosomes?

A

reciprocal translocations and robertsonian translocations

34
Q

What is a robertsonian translocation?

A

A Robertsonian translocation is one in which, effectively, the whole of a chromosome is joined end to end with another. This type of translocation involves only chromosomes 13, 14, 15, 21 and 22.

35
Q

What is a reciprocal translocation?

A

Reciprocal translocation is a form of gene rearrangement where portions of two chromosomes are simply exchanged with no net loss of genetic information.

36
Q

Aneuploidy arises from ______________

A

chromosomal non-disjunction

37
Q

What is a chromosomal non-disjunction?

A

it is the failure of homologous chromosomes to separate and segregate normally in either mitosis and meiosis

38
Q

What happens when chromosomal non-junction occurs in meiosis?

A

Non-disjunction results in imbalanced gametes. If one of those gametes get fertilized, all of the cells that come from the resulting embryo will have a chromosome imbalance.

39
Q

What happens when chromosomal non-junction occurs in mitosis?

A

Non-disjunction produces two cell-lineages derived from a single zygote (known as ‘Mosaicism’)

40
Q

What is mosaicism?

A

Mosaicism occurs when a person has two or more genetically different sets of cells in his or her body.

41
Q

Individuals who are mosaic for a particular chromosomal aberration usually have _____________ than those who are non-mosaic

A

less severe symptoms

42
Q

Mosaicism occurs when non-disjunction happens during a ______________

A

mitotic cell devision

43
Q

Explain meiotic non disjunction.

A
44
Q

When are the 2 times nondisjunction can occur in meiosis?

A

first and second meiotic division

45
Q

What happens when non disjunction occurs in the first meiotic division?

A

gametes contain either both parental chromosomes which didnt separate, or neither

46
Q

What happens when non disjunction occurs in the second meiotic division?

A

gametes contain 2 identical copies of the same chromosome, or neither

47
Q

What are some clinical features of down syndrome?

A

Developmental delay

Variable intellectual disability

Characteristic facial features

Congenital heart defects

Premature ageing

Risk of leukaemia

48
Q

What are the 2 main causes of Down syndrome and their respective percentage chance of causing Down syndrome?

A

Trisomy 21 (95%) and Robertsonian translocation (5%)

49
Q

What is the incidence of trisomy 21?

A

1/650 live births

50
Q

The risk of trisomy 21 increases with maternal _____

A

age

51
Q

What are some physical characteristics of someone with edwards syndrome?

A

rocker bottom feet, death usually within 1 year

52
Q

What are some physical characteristics of someone with Patau syndrome?

A

polydactyly, death usually within 1 year

53
Q

What are some physical characteristics of someone with Turner syndrome?

A

short stature, low set eyes

54
Q

What are the 2 types of structural chromosome abnormalities?

A

unbalanced and balanced

55
Q

Explain an unbalanced structural chromosome abnormality?

A

An unbalanced abnormality involves loss or gain of genetic material. Individuals with unbalanced abnormalities usually have developmental delay or congenital malformations.

56
Q

Explain a balanced structural chromosome abnormality?

A

Balanced abnormalities do not have gain or loss of genetic material, but heterozygous individuals could be at risk for passing on the abnormality to offspring in an unbalanced form.

57
Q

What are the various outcomes of gametes for a robertsonian translocation?

A
58
Q

What are some clinical indications for prenatal cytogenetics?

A
  1. Abnormal ultrasound
  2. Advanced maternal age/biochemical test
  3. Previous birth of child with trisomy
  4. Infertility, recurrent spontaneous abortion
  5. Carrier of heritable chromosome abnormality
59
Q

What are some clinical indications for postnatal cytogenetics?

A
  1. Dysmorphic features, congenital malformations
  2. Developmental delay
  3. Clinical features of specific chromosomal syndrome, e.g. Turners, Downs, Edwards etc.
60
Q

What are microdeletion syndromes?

A

microdeletion syndromes involve deletions that are too small to be detected by G banding

61
Q

microdeletion syndromes require _______ for diagnosis

A

molecular cytogenetic methods

62
Q

each microdeletion syndrome has a pattern of ____________ that leads the clincian to query a particular syndrome

A

different malformations

63
Q

Since microdeletions are too small to be detected by G-band cytogenetics, what type of test do we use to find microdeletions?

A

fluorescence in situ hydridization (FISH)

64
Q

What does imprinting mean?

A

there is a different expression of the same chromosomal region, depending on whether the region came from the mother versus father.

65
Q

What is the difference between prader willi and angelman syndrome?

A

Prader Willi syndrome: deletion occurs on paternal chr 15

Angelman syndrome: deletion occurs on maternal chr 15

For PWS only 15q11 genetic material from mother is present

For AS only 15q11 genetic material from father is present

66
Q

What is an Array CGH?

A

it detects a very subtle gain or less of genetic material, it is much more sensitive than G-banded karyotyping

67
Q

Array CHG has the same resolution as _______, but it uses a ___________ method

A

FISH, genome-wide detection

68
Q

Array CGH should be used for all cases of …………..

A

unexplained developmental delay/intellectual disability

autism spectrum disorders

multiple congenital anomalies

69
Q

What is the abnormality detection rate for Array CGH and G-banded Karyotyping respectively?

A

15%-20% - Array

3%- G band karyotyping

70
Q

Array CGH is more/less expensive than G-band karyotyping

A

more

Quiz 2 (18 decks)

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