Lecture 18 - Prenatal Genetic Testing

Question 1

An important indication for pre-pregnancy diagnosis are previous child with ________ or previous child with ______.

Answer 1

1. autosomal trisomy

2. neural tube defect (NTD)

Question 2

What kind of test (generally - there are two overarching types) would be optimal patients at increased risk?

Answer 2

Diagnostic test

Question 3

What kind of test (generally - there are two overarching types) would be optimal patients at low risk?

Answer 3

Screening test

Question 4

The ______ of Down Syndrome increases with advancing maternal age.

Answer 4

incidence

Question 5

What are the 4 proteins in the maternal serum screened in the 2nd trimester?

Answer 5

1. Alpha-fetoprotein (AFP)
2. Human chorionic gonadotrophin (hCG)
3. Unconjugated estriol
4. Inhibin-A

Question 6

Which one of the 4 proteins screened during the second trimester shows LOWER levels, rather than higher, in pregnancies with Down Syndrome?

Answer 6

Unconjugated estriol

Question 7

What two general screens are performed in the 1st trimester for Down Syndrome?

Answer 7

1. Proteins in maternal serum (PAPP-A; hCG)

2. Subcutaneous edema in the fetal neck (via ultrasonography)

Question 8

In __________, a sample of amniotic fluid is removed transabdominally by syrine.

Answer 8

traditional amniocentesis

Question 9

In _________, a biopsy of villous area of the chorion is removed transcervically or transabdominaly by syringe.

Answer 9

Chorionic villus sampling (CVS)

Question 10

What are two risks of chorionic villus sampling?

Answer 10

1. Spontaneous abortion

2. Birth defects (although studies suggest no increased risk of this)

Question 11

___________ allows access to fetal blood and is performed after 18-20 weeks.

Answer 11

Cordocentesis

Question 12

Traditional amniocentesis, but not CVS (chorionic villus sampling), is recommended under what circumstance?

Answer 12

a previous child has a neural tube defect (NTD)