Brainscape's Knowledge GenomeTM

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


See full index

EHD Block 1 > Clinical Cytogenetics > Flashcards

Clinical Cytogenetics Flashcards

1
Q

What is the p arm?

A

The shorter arm in a chromosome

*Centromere in the middle

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

What is the q arm?

A

The longer arm in a chromosome

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

What is metacentric?

A

The centromere is a little off set

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

What is Submetacentric?

A

The centromere is closer to the end toward the p arm

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

What is Acrocentric?

A

The centromere is very close to the end of the p arm

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

What is telocentric

A

The centromere is all the way to the end of the p arm (No p arm)

*No telocentric in HUMANS (only mice)

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

What is Karyotype?

A
  1. Arrange chromosomes by size and position of centromere (arranged in descending order)
  2. 46 chromosomes (diploid)
  3. 22 pairs of autosomes
  4. 2 sex chromosomes

*Ideogram is organized by size

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

What is Giemsa or G-banding?

A
  1. Pretreat with typsin to digest protein
  2. Stains AT rich region
  3. Inexpensive
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are 3 types of stains for visualizing chromosomes?

A
  1. Giemsa or G banding
  2. Quinacrine or Q-banding
  3. Reverse or R-banding
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is Quinacrine or Q-banding?

A
  1. Stains AT rich regions

2. Visualize with ULTRAVIOLET LIGHT

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

What is Reverse or R-banding?

A
  1. Uses Giemsa

2. Chromosomes treated at HIGH TEMPERATURE and LOW pH

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

What is Aneuploidy?

A

Change in the copy of individual chromosomes (Trisomy 21)

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

What is Fluorescent In Situ Hybridization (FISH)?

A

Labeling a region with a fluorescent probe detected with a fluorescent microscope

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

What is Chromosome Painting or Spectral Karyotyping (SKY)?

A

Labeling for each chromosome with a separate color detected with a spectrophotometer

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

How do you identify a chromosome?

A
  1. By Chromosome number
  2. Region
  3. Band
  4. Sub-band

Ex: Chr 16p11.2

a. Chromosome 16
b. Region 1
c. Band 1
d. Sub-band 2 on the p arm

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

What are 3 structural changes in chromosomes?

A
  1. Deletions/Addition
    a. Single nucleotides
    b. Several nucleotides
    c. Microdeletion syndromes
  2. Duplications
  3. Rearrangements (translocation: one piece of a chromosome gets stuck to another)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is Rearrangements?

A
  1. Two types
    a. Balanced
    b. Unbalanced
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is Balanced rearrangement?

A
  1. All genetic information is present in this individual
  2. However, a problem might be present in the offspring
  3. Reciprocal translocation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is Unbalanced rearrangement?

A
  1. Genetic information is missing
20
Q

What is Mosaicism?

A

Cells should have one compliment of DNA

*Mosaicism occurs when an individual has
two or more cell lines that are derived from
a single zygote but that have different genetic
characteristics.

21
Q

What is Chromosomal Mosaicism?

A
  1. Presence of an extra chromosome

2. Development of a new mutation during early development

22
Q

What is Germline Mosaicism?

A
  1. Mutation occurs in a developing germ cell that is not present in other parental cells
23
Q

What is a Barr Body?

A
  1. Identified by Murray Barr (dark staining body in interphase cells)
  2. Also Known as Sex chromatin (One X chromosome in each cell is inactivated, and condensed)
  • Normal females: 1 Barr Body
  • Normal Males: NO Barr Body
24
Q

What is Lyonization?

A
  1. Barr bodies is an extra X chromosome
  2. The X chromosome are inactive (occurs in blastocyst; early development)

*Lyon Hypothesis: explains dosage compensation in males and females

25
Q

How does Inactivation Chromosomes occur?

A
  1. X-Chromosome Inactivating Center (XIC) occur at the proximal end of Xq
  2. XIST Gene within the XIC
  3. XIST RNA binds to X Chromosome to inactivate it
26
Q

What is nondisjunction?

A
  1. When chromosomes in Meiosis 1 doesn’t separate (Two “x” chromosomes are stuck together and continue to meiosis 2)
27
Q

What is Etiology?

A

Nondisjunction

28
Q

What is Trisomy 13?

A
  1. Third most common trisomy; “Patau syndrome”
  2. 50% die by age 1; 75% die by 6 months
  3. Trisomy 75-80%

*The more normal the mosaic the more physically normal the baby will be

29
Q

What is Trisomy 18?

A
  1. Second most common; “Edwards syndrome”
  2. 90% die by age one
  3. Trisomy: 95%
30
Q

What is Trisomy 21?

A
  1. Most common live born trisomy (DOWN SYNDROME)
  2. Trisomy: 93%

*The smaller the chromosome thats being affect the more dangerous the condition

31
Q

What is Microcephaly?

A

Small head

32
Q

What occurs in Trisomy 13?

A
  1. Severe intellectual and motor development delay
  2. Seizures
  3. Microcephaly
  4. Scalp defects (Absent skin)
  5. Microphthalmia (eye disorder)
  6. Cleft lip/palate
  7. Congenital hearts (80%)
  8. Dextrocardia (heart on the wrong side of the body)
  9. Omphalocele (belly button outty)
  10. Holoprosencephaly (no separation between the two hemispheres of the brain)
  11. 25% have extra toes

*Trisomy 13: 47,XX+13

33
Q

What is Trisomy 18?

A
  1. Clenched fist (trigger finger)
  2. Intrauterine growth retardation (IUGR)
  3. Rocker bottom feet(no arch on the foot)
  4. Low set ears
  5. Cardiac defects
  6. Renal anomalies
  7. Intellectual development delay
  8. Broad forehead
  9. Sternum is short
  10. Missing toenails

*Trisomy 18: 47,XY+18

34
Q

What is “General Failure to Thrive”?

A
  1. Cardiac and renal malformations
  2. Feeding difficulties
  3. Sepsis
  4. Apnea caused by CNS defects
35
Q

What is Trisomy 21?

A
  1. Down syndrome (translocation most common; instead of true 21)
  2. Intellectual development
  3. Short stature
  4. Brushfield spots (on the eye)
  5. Simian crease (one line on the hand)
  6. Wide space between toes
  7. Poor muscle tone
  8. Small ears
36
Q

What are 3 most important translocations?

A
  1. Down syndrome
  2. Chronic myelogenous leukemia
  3. Burkitt lymphoma
37
Q

What is Klinefelter Syndrome?

A
  1. Trisomy
  2. Common cause for male hypogonadism
  3. 47, XXY (XXXY-Lyonization )
  4. Birth and childhood normal
  5. Puberty- may be delay (shows until the blastoid stage)
  6. Small penis/testes
  7. Elevated gonadotropin levels
  8. Infertility
  9. Decrease testosterone levels
  10. Decrease facial/pubic hair
  • Abnormal skeletal proportions (lower segment is larger)
  • Dissocial behavior
  • Increased risk for autoimmune disorders (diabetes)
38
Q

What are monosomies?

A
  1. Autosome monosomies are lethal
  2. Y Chromosome monosomy is lethal (45, Y)
  3. X Chromosome monosomy is viable (45, X)
39
Q

What is Turner Syndrome?

A
  1. Monosomy (45,X)
  2. Normal intelligence
  3. Lack of ovarian development (NEVER HAVE A MENSTRUAL CYCLE)
  4. Elevated LH/FSH
  5. Webbed neck
  6. Shield-like chest with widely spaced nipples
  7. Edema of hands and feet
  8. Decreased Estrogen
  9. Infertile

*Increased diabetes mellitus, inflammatory bowel disease, and autoimmune disease

40
Q

What is Uniparental Disomy?

A

The situation in which 2 copies of a chromosome come from the same parent,
3. Nondisjuction

Ex: Angelman syndrome (AS) and Prader-Willi syndrome (PWS)

*CpG Island Methylation: Inhibits Transcription

41
Q

What is Genomic Imprinting?

A

The expression of a gene is dependent upon the parent of origin

42
Q

What is Disomy?

A

2 chromosomes from the same parent

43
Q

What is Isosomy or isodisomy?

A

2 identical chromosomes from same parent

*Nondisjunction in meiosis 2

44
Q

What are the 2 first microdeletion syndromes recorded?

A
  1. Prader Willi Syndrome
  2. Angelman Syndrome

*Chromosome 15q11-15 deletion

45
Q

What is Prader Willi Syndrome?

A
  1. Deletion of paternal origin (Large deletion of SNRPN and UBE3A)
  2. Hypotonic (no muscle tone)
  3. Feeding difficulties
  4. Hypogonadism (micro-gonads)
  5. Scoliosis
  6. Almond shaped eyes
  7. Small hands and feet
  8. Obesity

*Patients scratch themselves

46
Q

What is Angelman Syndrome?

A
  1. Deletion of the Maternal Origin (deletion of SNRPN and UBE3A)
  2. Severe developmental delay and intellectual disability
  3. Severe speech impairment
  4. Microcephaly
  5. Inappropriate happy demeanor

EHD Block 1 (6 decks)

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