Genetic Screening and Prenatal Diagnosis

Question 1

What is th eoccurrence of 1 or more extra or missed chromosome

Answer 1

Aneuploidy

Question 2

What are 5 indications for referral to a genetic counselor?

Answer 2

1. Pregnant person >35 y/o
2. Related parents
3. Pregnant person was exposed to teratogenic chemicals (lab work)
4. Structural abnormalities on US
5. A parent has genetic condition or HX of SIDS

Question 3

This genetic disorder has characteristic facial changes, hypotonia, ID and cognitive delay; congenital heart defects, hearing/vision issues; hypothyroid

Answer 3

Trisomy 21 or down syndrome

Question 4

This genetic disorder presents with slow intrauterine growth, LBW; heart defect; overlapping fingers; & MOST fetuses die before birth or within 1st month of life?

Answer 4

Trisomy 18 or Edwards syndrome

Question 5

This genetic disorder presents with brain/spinal cord abnormalities; heart defects; & microphthalmia (one/both eyes don’t develop correctly so are small)?

Answer 5

Trisomy 13 or Patau syndrome

Question 6

What is the sex chromosome abnormality that effects speech and motor functions, causes gynecomastia and low body hair?

Answer 6

47, XXY - or - Klinefelter’s

Question 7

What sex chromosome abnormality presents with short stature, dysfunctional ovaries, and aortic coarctation?

Answer 7

45, X or Turner’s syndrome

Question 8

What two conditions can neural tube defects cause?

Answer 8

Anencephaly: brain/skull don’t develop; fetus dies usually

Spina bifida: spine doesn’t close leaving spinal cord exposed

Question 9

When do NTD usually occur during gestation?

Answer 9

1st month

Question 10

What type of test can indicate risk of fetus for certain conditions?

Answer 10

Screening

Question 11

This screening test can detect all trisomy conditions, is done between 10-26 weeks, and uses mothers blood?

Answer 11

Prenatal cell-free DNA

Question 12

What is a major disadvantage of the prenatal cell free dna screening?

Answer 12

Doesn’t detect NTD

Question 13

This is a 2 part test that uses US to test nuchal translucency and the mother serum for hCG, PAPP-A, & MFAP; done between 11-13 weeks?

Answer 13

First Trimester Screen (FTS)

Question 14

What screening test requires skill ultrasound staff to complete?

Answer 14

First trimester screening

Question 15

A nasal bone is absent on US in 7/10 fetuses with this disorder?

Answer 15

Trisomy 21 or DS

Question 16

What happens to hCG levels when a patient is carrying a fetus with trisomy 21?

Answer 16

2x higher than normal

Question 17

This screening test looks for NTD, should be done in the 2nd trimester, ideally between 16-18 weeks when levels peak?

Answer 17

Maternal serum alpha fetal protein test (MSAFP)

Question 18

What screening test is indicated for people who seek prenatal care in 2nd trimester?

Answer 18

Maternal serum or Quad Screening

Question 19

This screening test doesn’t detect trisomy 13?

Answer 19

Maternal serum or Quad Screening

Question 20

What are the two types of diagnostic tests?

Answer 20

1. Chorionic villus sampling (from placenta)
2. Amniocentesis: amniotic fluid aspiration

Question 21

This diagnostic test is done at 10-13 weeks, takes placental sample via abdomen or vagina, and poses a risk of miscarriage?

Answer 21

CVS or Chorionic villus sampling