clinical cytogenetics

Question 1

clinical cytogenetics

Answer 1

1. cancer cytogenetics
   - -important for leukemia and lymphomas
2. chromosomal microarrays
   - -used in dx or children with delays

Question 2

Chromosome & FISH analyses can reveal ____________

Answer 2

can reveal common genetic aberrations, e.g., Down syndrome

Question 3

Chromosome & FISH studies important in investigating ____________

Answer 3

causes of leukemia & lymphoma

Question 4

____________ studies important in investigating causes of leukemia & lymphoma

Answer 4

Chromosome & FISH

Question 5

Specimens For Cytogenetic Studies

Answer 5

•  Bone Marrow
•  Blood
    –  Unstimulated
    –  Constitutional
•  Tissue
    –  Lymph node
    –  Solid tumor –  POC
•  Fluids –  CNS
   –  Amniotic fluid

Question 6

FISH =

Answer 6

FISH = fluorescence in situ hybridization

In cases of pediatric B-cell acute lymphocytic leukemia (ALL)

Question 7

FISH probe: centromere

Answer 7

name: cen
used for: enumeration
example: all panel, prenatal dx

Question 8

FISH probe: locus specific

Answer 8

name: LIS
used for: deletion/duplication
example: p53, cancer

Question 9

FISH probe: dual fusion, fusion:

Answer 9

name: DF, F
used for: translocation
example: BCR; ABL, PML:RARa (cancer)

Question 10

FISH probe: break apart

Answer 10

name: BAP
used for: Translocation rearrangement
example: MLL (cancer)

Question 11

FISH probe: Whole chromosome paint

Answer 11

name: WCP
used for: Identifying markers, translocations
example: WCP 1-22, X, Y (all studies)

Question 12

Some rearrangements are cryptic by ______ and require ________

Answer 12

standard cytogenetics

require FISH interpretation

Question 13

AML

Answer 13

acute myelogenous Leukemia

seen more frequently in adult

Question 14

CML treatmeant with Imantinib mesylate(ST1 57, Gleevec)

Answer 14

1. targeted, biological therapy specific for CML cells
2. Molecular antagonist: binds at ATP binding site in abl tyrosine kinase and bcr/able tyrosine kinase
3. Inhibits cell proliferation and apoptosis

Question 15

Chromosomal Microarry (CMA)

Answer 15

1. Target DNA on slide (chip) is single- stranded oligomers
2. CMA detects gains and losses ONLY “ not balanced rearrangements
3. Limited ability to detect mosaicism “ (15-20%)

Question 16

two most important leukemia translocation

Answer 16

1. acute promyeloid leukemia

2. chronic myelogenous leikemia

Question 17

acute pro myeloid leukemia is a _____

Answer 17

15/17 translocation

Question 18

acute pro myeloid leukemia can be treated with

Answer 18

retinoid acid because mutated fusion of retioic receptor with PML gene does not allow for myeloid cells to differentiate and thus acid pushes it down a certain path

Question 19

chronic myelogenous leukemia is a ____

Answer 19

9/22 translocation

Question 20

chronic myelogenous leukemia treated with

Answer 20

gleevec (tyrosine kinase inhibitor)

which treats the out of control tyrosine kinase bcr/abl

Question 21

high hyper diploid

Answer 21

over 50 chrome good prognosis

Question 22

low hypoploidy

Answer 22

bad prognosis

Question 23

cen used for

Answer 23

leukemia

centromere

Question 24

lsi used for

Answer 24

deletions in leukemia

locus specific

Question 25

F or DF used for

Answer 25

fusion of dual fusion in translocation leukemia

Question 26

CMA detects

Answer 26

net gain or loss of DNA using oligomer probe

Question 27

CMA cannot detect

Answer 27

balanced translocations

because the assay is set up to tell you the amount, not where things are expressed

Question 28

CMA is mildly useful for

Answer 28

mosacism

Question 29

CMA can tell us

Answer 29

specifically what the gene sequence has been added or deleted

Question 30

CMA cannot tell you about

Answer 30

SNPs

Question 31

lab test for children with learning disabilities, developmental delays, autism, dysmorphic failure to thrive

Answer 31

1. if deletion, by CMA, consult DGV
2. parental FISH studies if rare normal, familial variant
3. if del/dup in one or both parents, test other family members
4. if del/dup not in either parent, and not in database, further database/literature mining done