# Clinical Case Examples (Prenatal)

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PAPP-A is a protein that is used in 1st trimester screening protocols for Down syndrome. PAPP-A has the following characteristics:

A. It is secreted by the fetal liver
B. It is detectable as early as 8 weeks of pregnancy
C. It peaks at 13 weeks of pregnancy and then decreases thereafter
D. It is increased in Down syndrome pregnancies with a multiple of the median of 2.0
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Terms in this set (20)
PAPP-A is a protein that is used in 1st trimester screening protocols for Down syndrome. PAPP-A has the following characteristics:

A. It is secreted by the fetal liver
B. It is detectable as early as 8 weeks of pregnancy
C. It peaks at 13 weeks of pregnancy and then decreases thereafter
D. It is increased in Down syndrome pregnancies with a multiple of the median of 2.0
Human chorionic gonadotropin is a serum marker that is useful for both 1st and 2nd trimester screening for Down syndrome. The following are characteristics of hCG in pregnancy:

A. It rises rapidly throughout gestation and peaks at 32 weeks of pregnancy
B. It rises rapidly until 10 weeks and declines to approximately 25% of maximum levels by 20 weeks of pregnancy
C. It is elevated in both Down syndrome and trisomy 18 pregnancies
D. It is elevated in pregnancies complicated by neural tube defects
Of all of the various screening protocols available for Down syndrome screening and pregnancy, the following statements are all true except:

A. First trimester screening alone is superior to 2nd trimester screening but it is extremely operator dependent
B. Integrated screening is the most efficient screening protocol thus far identified
C. Sequential screening has a high detection rate and a low false positive rate
D. Contingent screening has a detection rate of approximately 90% with a false positive rate of 5%
If seen on ultrasound, echogenic bowel increases what risks?

A. Risk of DS and Noonan syndrome by 3%
B. Risk of DS, CF and congenital infections by 5%
C. Risk of DS and CF by 3%
D. Risk of DS, CF, congenital infections and GI abnormalities by 3%
E. Risk of DS, CF, congenital infections and GI abnormalities by 5%
Genomic imprinting is an epigenetic mechanism that restricts the expression of a gene to one of the two parental chromosomes.
Are the following statements about genomic imprinting true (A) or false (B)?

I. Paternal genes are necessary for embryonic development
II. Maternal genes are necessary for extraembryonic tissue development
III. Gynogenetic embryos are defective in extraembryonic tissues that contribute to the placenta
IV. Androgenetic embryos are defective in embryonic tissue
Answer: False, False, True, True I. B II. B III. A IV. A

Maternal genes are necessary for normal embryo growth and development.
Paternal genes are necessary for placenta development and health.
Gynogenetic embryos (those with two maternal genomes) have better embryonic development than placental development. This means maternal genes are necessary for embryonic development.
Andryogenetic embryos (those with two paternal genomes) have better placental development than embryonic development. This means paternal genes are necessary for extraembryonic tissue development.