HRR: genetic screening I

Question 1

What maternal age concurs risk?

Answer 1

35 or older at delivery

Question 2

What does a maternal age of 35 increase risk for?

Answer 2

Aneuploidy

Question 3

What is the screening detection rate of maternal age?

Answer 3

30% so not great

Question 4

What are components of first trimester screening?

Answer 4

Ultrasound and blood test for analysis of hCG and PAPP-A

Question 5

Which disorders are screened for in the first trimester screening?

Answer 5

Down syndrome, trisomy 13, trisomy 18

Question 6

What does high NT on first trimester indicate?

Answer 6

Risk for down syndrome and trisomy 13/18

Question 7

What do different levels of hCG indicate in first trimester screening?

Answer 7

High levels convey risk for down syndrome, low levels convey risk for trisomy 13/18

Question 8

What do different levels of PAPP-A indicate in first trimester screening?

Answer 8

Low levels convey risk for both down syndrome and trisomy 13/18

Question 9

What value for NT is an automatic screen positive result?

Answer 9

More than 3.5 mm

Question 10

What is in the second trimester screening?

Answer 10

Marker screening, maternal serum, quad screening

Question 11

What 4 analytes are looked at in second trimester screening?

Answer 11

AFP, hCG, uE3, DIA

Question 12

What makes the metabolite uE3?

Answer 12

Placenta and fetal liver

Question 13

What makes the metabolite DIA?

Answer 13

Placenta

Question 14

What conditions are screened for via second trimester screening?

Answer 14

Neural tube defects, down syndrome, trisomy 18 (NOT 13)

Question 15

What are the metabolite levels when screening for trisomy 18?

Answer 15

Low AFP, hCG, and uE3 with absent DIA

Question 16

What are the metabolite levels when screening for down syndrome?

Answer 16

Low AFP and uE3, high hCG

Question 17

What are the metabolite levels when screening for open neural tube defects?

Answer 17

High AFP

Question 18

What does the measurement multiple of the median mean?

Answer 18

Ratio of measured analyte to expected quantity

Question 19

Which metabolite do diabetics have a lower level of?

Answer 19

AFP

Question 20

What is true of AFP in white vs black patients?

Answer 20

Higher in black populations

Question 21

What can cause high AFP?

Answer 21

Improper dating, placental insufficiency, low amniotic fluid, birth defects (neural tube defects, abdominal wall defects)

Question 22

What abdominal wall defects may cause high AFP?

Answer 22

Omphalocele and gastroschisis

Question 23

What neural tube defects may cause high AFP?

Answer 23

Spina bifida, acephaly

Question 24

What do we do if a high AFP is detected?

Answer 24

Second trimester ultrasound

Question 25

What is cell free DNA screening?

Answer 25

A noninvasive screen that is really accurate and can be done after 9 weeks; it has a low false positive and negative rate

Question 26

What does cell free DNA not screen for?

Answer 26

Neural tube defects

Question 27

How does cell free DNA screening work?

Answer 27

During pregnancy, placental cells break down and release fetal DNA fragments into maternal blood. The fragments are sequenced to determine the chromosome of origin and are analyzed for chromosome material.

Question 28

Cell free DNA can detect which aneuploidy?

Answer 28

21, 18, 13, and sex chromosomes

Question 29

What procedural diagnostic tests are done during pregnancy?

Answer 29

Chorionic villus sampling in the first trimester or amniocentesis in the second trimester

Question 30

What are benefits of carrier screening?

Answer 30

Early treatment, higher quality of life, informed family planning

Question 31

Carrier screenings look for…

Answer 31

Autosomal recessive or X linked conditions

Question 32

What are ACOG carrier screening recommendations?

Answer 32

1. Offer screening to everyone, ideally before pregnancy. 2. Obtain history. 3. Encourage people to share results with family members.

Question 33

What conditions are screened for in everyone, no matter ethnicity?

Answer 33

CF and spinal muscular atrophy

Question 34

What do we screen for in AJ ancestry?

Answer 34

CF, familial dysautonomia, Canavan, Tay-Sachs

Question 35

What warrants AJ carrier testing?

Answer 35

One grandparent who is full AJ

Question 36

What populations is Tay-Sachs common in?

Answer 36

AJ and French Canadian

Question 37

What is the inheritance of spinal muscular atrophy?

Answer 37

Autosomal recessive

Question 38

What is spinal muscular atrophy?

Answer 38

Progressive degeneration of anterior horn cells leading to muscle weakness

Question 39

What gene is involved in spinal muscular atrophy?

Answer 39

SMN1; you should have two or three copies of it, but if you are a carrier you have one and have zero if affected

Question 40

What is SMN2?

Answer 40

A backup gene for SMN1 in spinal muscular atrophy