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
Answer: B

A= PAPP-A is secreted by the placenta
C= PAPP-A rises throughout pregnancy
D= PAPP-A is decreased in Down syndrome pregnancies with a multiple of the median of 0.4
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
Answer: B

hCG rises rapidly until 10 weeks of gestation then declines
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%
Answer: C

Sequential screening has a high detection rate but also a very high false positive rate
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%
Answer: D
What is NOT true about cystic hygroma?

A. It has a higher risk of aneuploidy if seen in 1st trimester
B. It is a marker for Noonan syndrome, T21 and Turner syndrome
C. Can progress to hydrops and fetal death
D. The majority of cases have adverse outcomes
Answer: A

Higher risk if seen in 2nd trimester. 40-60% risk aneuoploidy in 1st trim, 60-70% risk in 2nd trimester.
AFP is low in what conditions?

I. Trisomy 13
II. Trisomy 18
III. Trisomy 21
IV. ONTD

A. II and IV
B. I and II
C. II only
D. I, II and III
Answer: D
True or false- diandry means two maternal copies.

True
False
False: Digyny is 2 maternal copies, diandry is two paternal copies
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.
Match the deletion to the condition it is associated with:

I. 16p13.3
II. 15q11-13
III. 7q11.23
IV. 17p11.2
V. 11p13

A. Williams syndrome
B. Angelman syndrome/Prader-Willi syndrome
C. Smith Magenis syndrome
D. Rubinstein-Taybi syndrome
E. WAGR syndrome
Answer:
I. D
II. B
III. A
IV. C
V. E
Which of the following is NOT true about neural tube defects?:

A. NTDs occur in 1/1,000 newborns
B. Open NTDs are more common than closed NTDs
C. The most common NTD's are spina bifida and encelphalocele
D. An example of an ONTD is a myelomeningocele
Answer: C

The most common NTD's are spina bifida and anencephaly, which account for up to 95% of all NTD's.
A genetics consultation was requested for a newborn male in the nursery. He was born with unilateral clubfoot. What is the most likely etiology? A. Trisomy 18 B. Spina bifida C. Postural clubfoot D. Multifactorial E. ArthrogryposisAnswer: D While all are potential causes of clubfoot, most cases are caused by a combination of genetic and environmental factors that are not well understood. Arthrogryposis can have lack of fetal movement that causes clubfoot.What is NOT true about clubfoot? A. Risk factors include family history, CP, ONTDs and oligohydramnios B. It has a frequency of 1/1,000 C. Males are affected 2x more than girls D. 25% of cases are bilateral E. There is a 4% recurrence riskAnswer: D ~50% of cases are bilateral.A routine 20 week ultrasound reveals a single umbilical artery. What do you NOT tell the patient about this finding? A. It has a frequency of 1/200 B. There is an increased risk of cardiovascular issues C. This is a soft marker for aneuploidy D. Further testing is availableAnswer: C The others are true. Further testing could include a fetal EKG to evaluate for heart defectsWhich of the following is true about miscarriages? A. 1/5 of pregnancies end in miscarriage B. ¼ of pregnancies end in miscarriage C. 1/3 of pregnancies end in miscarriage D. 1/6 of pregnancies end in miscarriageAnswer: A 20% of pregnancies result in miscarriage, most often due to chromosome abnormalitiesA women believes she is pregnant and complains of edema and vaginal bleeding. Examination reveals high plasma hCG levels and placental tissue, but no evidence of an embryo. What would explain this condition? A. A hydratiform mole B. An ectopic pregnancy C. A complete mole D. Pregnancy demiseAnswer: CWhat is NOT true about ectopic pregnancies? A. They occur in 1/50 pregnancies B. Age is a risk factor C. Getting pregnant while having a IUD is a risk factor D. 40% occur in a fallopian tube E. Must be abortedAnswer: D Most occur in a fallopian tube. Rarely can occur in ovary, abdomen or cervix.The risks of preterm birth for multiple gestation are: A. 5% for twins and triplets B. 10% for twins and triplets C. 5% for twins, 10% for triplets D. 20% for twins, 30% for triplets E. 10% for twins, 30% for tripletsAnswer: EWhich of the following is NOT true about Turner syndrome? A. 55% are (45,X) B. The majority of 45,X karyotypes result from loss of the paternal X chromosome C. There is a liveborn incidence of 1 in 2,500 D. 10% are mosaic E. Frequency of 1-2% pregnancies affected but less than 1% result in live birth, high rate of miscarriageAnswer: D 15-20% of cases are mosaic.What tests are included in the FTS and the quad screen? A. AFP B. uE3 C. Inhibin A D. hCG E. PAPP-AAnswer: D D and E are part of the FTS, A, B, C and D are part of the quad screen (MSS).Which of the following Hb profiles is suggestive of alpha thal? A. Low levels HbA, high levels HbF B. High levels HbA2, high levels HbF C. Low levels HbH D. Proportional decrease in all Hb levels (HbA, HbA2, HbF)Answer: D A and B are both suggestive of beta thal. C is incorrect because alpha thal can have HbH when someone has HbH disease caused by deletion or dysfunction of 3 alpha globin alleles (HbH is characterized by 4 beta globin chains).