Ch. 3 Prenatal Genetics Flashcards

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1
Q

What is Roberstonian translocation?

A

structural rearrangement involving one or mroe acrocentric chromosomes (13, 14, 15, 21, 22)

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2
Q

What is considered advanced maternal age?

A

woman is 35 years or older at time of delivery

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3
Q

What are the 3 major categories of prenatal genetic screening?

A

ultrasound | maternal serum screening | noninvasive prenatal screening (NIPS)

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4
Q

What are soft markers?

A

subtle changes that alter a woman’s risk for specific types of aneuploidy

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5
Q

At what fetal age does nuchal translucency measurement via ultrasound need to be done?

A

11wks 1 day to 13wks 6 days

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6
Q

What are some possible indications of a thick nuchal translucency? What is the next step if thick NT is shown?

A

structural anomaly, cardiac defect, pending fetal demise | fetal echocardiogram during 2nd trimester

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7
Q

What are the 7 things an ultrasound evaluates for?

A

fetal number and presentation | amniotic fluid volume | fetal biometry | cardiac activity | placental position | anatomic survey | due date

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8
Q

What is the earliest gestation time an ultrasound is done?

A

18-22wks

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9
Q

What is the gestation period for high miscarriage zone (spontaneous abortion)?

A

8-10 wks

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10
Q

What is non-invasive prenatal screening entail?

A

cell free DNA screening = evaluates fragment DNA in mother’s blood from placenta | highest detection rate and lowest false positive rate

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11
Q

What does non-invasive prenatal screening detect?

A

DNA fragments associated with aneuploidy conditions

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12
Q

What gestation age can NIPS be done?

A

10 wks

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13
Q

What is nuchal translucency?

A

how much can you see through the region to see the fetus

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14
Q

What is maternal serum screening and what is it used for?

A

analysis of analytes found in pregnant woman’s blood to assess risk of aneuploidy and ONTDs

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15
Q

What is open neural tube defects?

A

problems with how the brain, spinal cord/spine forms during gestation

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16
Q

What are the 3 analytes measured with maternal serum screening during the 1st trimester?

A

human chorionic gonadotropin (hCG) | pregnancy-associated plasma protein A (PAPP-A) | alpha-fetal protein (AFP)

17
Q

What is pregnancy-associated plasma protein A (PAPP-A)?

A

regulator insulin-like growth factor; helps with fetal and placenta development

18
Q

What is human chorionic gonadotropin (hCG)?

A

produced in placenta, tells body to regulate estrogen to make womb more suitable for pregnancy | indicates if pregnancy is on track

19
Q

Where is alphafeto protein produced?

A

yolk sac and fetal liver

21
Q

What is uE3? What is its importance?

A

estriol | unconjugated estrogen produced/converted by placenta | supports fetal and placenta development

21
Q

Where is Inhibin A produced and what is it used for?

A

placenta and ovaries | fetal growth

22
Q

What is the analyte pattern for Down Syndrome in 1st and 2nd trimesters and what does it indicate?

A

1st trimester = ↑hcG, ↓PAPP-A, ↓AFP | 2nd trimester = ↑hCG, ↑inhibin-A, ↓uE3, ↓AFP | indicates increased risk for T21

23
Q

What is a Quad screen and when is it done?

A

measures hCG, estriol (uE3), inhibin, and AFP to assess T21, T18, and ONTDs

24
Q

What gestational age is quad screening done? What prenatal screening does this fall under?

A

16-18wks; maternal serum testing

25
Q

What is the relationship with prenatal screening and multi-fetuses?

A

results will be one whole and not specific for each = unable to determine which may be aneuploidy = false positives

26
Q

What is the analyte pattern for Trisomy 18 in 1st and 2nd trimesters and what does it indicate?

A

EVERYTHING decreases | indicates increased risk for T18

27
Q

What is the analyte pattern for Trisomy 13 in 1st and 2nd trimesters and what does it indicate?

A

1st trimester = everything decreases ; 2nd trimester -= none | indicates increased risk for T13

28
Q

What are the 2 prenatal diagnostic testing techniques? What do these tests indicate?

A

chorionic villus sampling | amniocentesis

29
Q

What is the difference between screening tests and diagnostic tests?

A

Screening tests assess possible risks for diseases | diagnostic tests provide more concrete evidence

30
Q

At what gestation age can chorionic villus sampling be done?

A

10-13 weeks

31
Q

At what gestation age can amniocentesis be done?

A

after 15 wks

32
Q

What are the disadvantages of prenatal diagnostic testing?

A

invasive | risk of miscarriage

33
Q

Which diagnostic testing poses a higher risk of miscarriage?

A

chorionic villus sampling