CGC Prenatal Genetics & Reproductive Options

Question 1

Cell-free DNA (cfDNA) screening in pregnancy MOST accurately screens for which condition?

Accepted Answer

Trisomy 21 (Down syndrome)

Answer

Neural tube defects

Answer

Single-gene disorders such as cystic fibrosis

Answer

Structural heart defects

Question 2

A patient with a positive cfDNA result for trisomy 18 should be counseled that:

Accepted Answer

Diagnostic confirmation via amniocentesis or CVS is recommended before clinical decisions are made

Answer

The result confirms the diagnosis and no further testing is needed

Answer

The fetus definitely has trisomy 18

Answer

The test result is unreliable and should be repeated

Question 3

The procedure-related pregnancy loss risk associated with amniocentesis is approximately:

Accepted Answer

1 in 100 to 1 in 200

Answer

1 in 10

Answer

1 in 1,000

Answer

Less than 1 in 5,000

Question 4

Chorionic villus sampling (CVS) is typically performed at which gestational age?

Accepted Answer

10–13 weeks

Answer

15–20 weeks

Answer

22–24 weeks

Answer

After 28 weeks

Question 5

A patient of advanced maternal age asks about the risk of chromosomal abnormalities. The counselor explains that the baseline risk for trisomy 21 at age 35 is approximately:

Accepted Answer

1 in 385

Answer

1 in 50

Answer

1 in 1,000

Answer

1 in 2,000

Question 6

Preimplantation genetic testing for aneuploidy (PGT-A) is used to:

Accepted Answer

Screen embryos created through IVF for chromosomal abnormalities before transfer

Answer

Diagnose chromosomal abnormalities in an ongoing pregnancy

Answer

Predict the sex of a naturally conceived fetus

Answer

Replace the need for prenatal diagnosis