Genetic Testing for PCPs

Question 1

what is MaterniT21 PLUS? what has it ‘accidentally’ tested for?

Answer 1

first noninvasive prenatal test
shows DNA abn in fetus as well as in the mother
found that it is ‘accidentally’ testing for CA in mom

Question 2

advantages and disadvantages of DTC genetic test?

Answer 2

reliability is variable
interpreting test results is not easy, might not be complete, might be false and may give a false sense of security or stress
cost can be very high and are not covered by private health insurance plans
these tests are not confidential

Question 3

what do BNP, NT-proBNP and soluble ST2 test for?

Answer 3

heart failure

Question 4

what is cardio IQ apolipoprotein B used to test?

Answer 4

assess risk for atherosclerotic cardiovascular dz, identify pts suitable for drug therapy, guide drug therpay

Question 5

what is cardio IQ hs-CRP used for?

Answer 5

test used to reclassify intermediate CVD risk pts into a high-risk category and assess risk of CVD and recurrent CV events in pts w/CHD

Question 6

what is cardio IQ lipoprotein(a) used for?

Answer 6

to assess risk of coronary heart dz

Question 7

what is cardio IQ omega -3 and -5 fatty acids, plasma used to determine?

Answer 7

used to determine FA associated risk for CV events, screen for omega-3 FA deficiency and monitor omega-3 FA intake

Question 8

what is cardio IQ ProBNP, N-terminal used for?

Answer 8

dx heart failure, predict outcomes in pts w/heart failure and guide pharmacologic txs of pts w/heart failure

Question 9

why would it be indicated to do genetic testing?

Answer 9

1. confirm clinical dx
2. expected phenotype expression
3. family hx
4. prenatal dx for an at risk fetus
5. carrier testing
6. presymptomatic testing (Huntington dz)
7. confirm consumer direct testing

Question 10

who do you test?

Answer 10

fetus w/1 or multiple anomalies
newborns w/anomalies or dysmorphic features
child growth deficiency
developmental delay
autism
delayed pubertal development
FHx of childhood onset d/o

Question 11

cytogenic types of tests?

Answer 11

karyotype
FISH
chromosome microarray

Question 12

what does karyotyping assess for? when is it used?

Answer 12

deletions
rearrangements
translocations
duplications
used to assess for trisomy, monosomy, multiple miscarriages

Question 13

what does FISH detect? when do you use?

Answer 13

detects microdeletions
counts chromosomes in a lg # of cells, used when you suspect mosaicism like Turners syndrome
used to assess for microdeletions: prader-willi, angelman syndrome

Question 14

what can methylation testing be used to test for?

Answer 14

uniparental disomy - prader willi syndrome or angelman syndrome

Question 15

what can PCR be used to detect and dx?

Answer 15

multiple repeat syndromes: fragile X, myotonic dystrophy

Question 16

what is an inborn error of metabolism?

Answer 16

diverse collection of d/os of intermediate (carbs, amino acids, lipids) metabolism that are caused by dysfunction of an enzyme encoded by a single gene

Question 17

what can inborn errors of metabolism present as?

Answer 17

static encephalopathy but can also be suspected on the basis of historical features (affected family members, parental consanguinity, episodic decompensation, developmental regression), physical findings (coarse facial features, organomegaly) or neuroimaging findings (abn myelination, striatal necrosis)

Question 18

what can chromosome microarray be used to detect?

Answer 18

measures how much DNA is there so can look for very small deletions (< 1 MB)

Question 19

what does global developmental delay mean?

Answer 19

that a child is delayed in 2 or more important areas of development including: motor skills, speech and language, ability to learn, social and personal skills, daily activities (eating or dressing)

Question 20

what is the MC development d/o? 2nd MC form? 3rd?

Answer 20

MC is mental retardation
more than 1/100 school children in the US have some form of mental retardation
2nd MC form is cerebral palsy followed by autism spectrum d/os

Question 21

typical recommendations for children with developmental delays ?

Answer 21

G-banded karyotype, fragile X molecular genetic testing and aCGH

Question 22

what is the MC global developmental delay?

Answer 22

fragile X

screen both boys and girls for fragile X if suspected global developmental delay

Question 23

what is a leading diagnosable cause of global developmental delay in girls?

Answer 23

Rett syndrome

appear developmentally normal until 6-18 mos then lose their developmental abilities

Question 24

what is XLID?

Answer 24

X-linked genetic testing, X-linked intellectual disability is estimated to account for ~10% of all cases of ID (intellectual disability)
more than 70 genes responsible for XLID

Question 25

in pts with GDD/ID microarray testing is diagnostic in what %age? G-banded karyotyping abn in what %age? FISH positive in what %age? testing for XLID has a yield of up to what %age with an appropriate FHx?

Answer 25

microarray: 7.8%
G-banded karyotyping: 4%
FISH: 3.55
XLID: 42%

Question 26

DNA sequencing does not detect what?

Answer 26

deletions or duplications

may miss changes in areas such as promoter regions or introns that affect gene fxn

Question 27

why use DNA sequencing?

Answer 27

establish a dx in a single gene d/o

test at risk family members w/a known familial mutation

Question 28

what do you need to counsel a pt about before genetic testing?

Answer 28

explain the benefits and limitations of the test
risk of test for insurance (no coverage vs coverage)
non-paternity
negative test does not r/o the condition

Question 29

if CGH microarray negative what is follow-up?

Answer 29

have them back and re-test in 1-2 years because the CGH microarray will be better then and new things will have been added