Lab Tests

Question 1

What does the FISH test look for?

Answer 1

the presence or absence of DNA on chromosomes

Question 1

What does CMA do?

Answer 1

uses 1.8 million “normal” probes to analyze a genome for any variations

Question 2

What does FISH stand for?

Answer 2

Fluorescent in situ hybridization

Question 3

DNA methylation is carried out by which 2 mechanisms?

Answer 3

1) maintenance methylation 2) de novo methylation

Question 4

What are copy number variations?

Answer 4

deletions or duplications of chromosomes

Question 5

What does CMA stand for?

Answer 5

chromosomal microarray analysis

Question 5

What does SNP microarray stand for?

Answer 5

single nucleotide polymorphism microarray

Question 6

What test should be ordered before an SNP microarray and why?

Answer 6

chromosome analysis because this can diagnose common aneuploidies first

Question 7

________ activity is necessary to preserve DNA methylation after every cellular DNA replication cycle.

Answer 7

Maintenance methylation

Question 8

What does DNA methylation analysis screen for?

Answer 8

1) Prader-Willi 2) Angelman Syndrome

Question 9

Chromosome studies are performed concurrently with _____,

Answer 9

FISH testing

Question 10

How does SNP microarray work?

Answer 10

it detects both copy number variation (deletions or duplications) and copy-neutral structural variants such as regions of homozygosity (ROH) and uniparental disomy (UPD)

Question 12

Where does methylation occur?

Answer 12

at the C5 position of CpG dinucleotides

Question 13

What are the steps to perform an SNP microarray?

Answer 13

1) hybridize DNA to bead chips 2) label with probes 3) scan with laser and interpret with software

Question 13

What phase of the cell cycle does FISH use?

Answer 13

metaphase or interphase

Question 14

What are the steps to perform a standard chromosome analysis?

Answer 14

1) examine at least 20 cells in metaphase 2) compile at least 3 karyotypes

Question 16

What diseases did we learn about that are diagnosed with FISH? (6)

Answer 16

1) Prader-Willi 2) Angelman 3) 22q13 deletion syndrome 4) CML and ALL (leukemias) 5) Down Syndrome 6) 15q duplication

Question 16

Why is SNP microarray used instead of a karyotype?

Answer 16

It can detect submicroscopic abnormalities, including microdeletions and microduplications

Question 17

What phase of the cell cycle is used to perform standard chromosome analysis?

Answer 17

metaphase

Question 18

FISH steps

Answer 18

1) fix cells 2) add complementary fluorescent RNA probes 3) look at fluorescence under microscope, which tells if hybridization occurred and therefore the chromosome/location was present and where

Question 19

What kinds of specimens are commonly used for cytogenetic studies? (4)

Answer 19

1) bone marrow 2) blood 3) tissues- lymph nodes, tumors 4) fluids- CSF, amniotic fluid

Question 21

SNP microarray does not detect ______, _______, _______, or __________.

Answer 21

balanced rearrangements (i.e., inversions, translocations), heterodisomy, very low level mosaicism, or single nucleotide mutations/polymorphisms

Question 22

What is analyzed in amniocentesis and chorionic villi sampling?

Answer 22

chromosomes

Question 23

What is DNMT and what does it do?

Answer 23

DNA methyltransferase; it is the maintenance methyltransferase that copies DNA methylation patterns to the newly synthesized daughter strand

Question 25

What are examples of copy-neutral structural variants?

Answer 25

1) regions of homozygosity 2) uniparental disomy

Question 26

________ are performed concurrently with FISH testing,

Answer 26

Chromosome studies

Question 27

Standard chromosome analysis is used to detect ___ (6 things).

Answer 27

Trisomies, Monosomies, Larger partial deletions, duplications, some translocations, inversions