Chapter 55 Prenatal Diagnosis Of Congenital Anomalies

Question 1

There are two categories of genetic testing they can be either ____ or ______

Answer 1

Invasive or noninvasive

Question 2

Ultrasound guided biopsy of the placenta or chorion frondosum

Answer 2

Chorionic Villus Sampling (cvs)

Question 3

Chorionic villus sampling(cvs) tests are performed ___

Answer 3

10-14 weeks

Question 4

Results from the chorionic villus sampling(cvs) are available within ____

Answer 4

1 week

Question 5

In the chorionic villus sampling(cvs) how are chromosomal abnormalities detected?

Answer 5

By growing and analyzing the sampled villi

Question 6

chorionic villus sampling; association with limb reduction defect when procedure is performed ____

Answer 6

Before 8 weeks

Question 7

The risk of fetal loss with chorionic villus sampling(CVS) is

Answer 7

About 1%

Question 8

Invasive procedure that allows analysis of fetal chromosomes from fetal cells in amniotic fluid

Answer 8

Amniocentesis

Question 9

Amniocentesis results are available in

Answer 9

1-3 weeks

Question 10

The risk for having a child with a chromosomal defect is greater in women _____

Answer 10

Of advanced maternal age (ama)

Question 11

For genetic reasons an amniocentesis is ideally performed between

Answer 11

15-20 weeks

Question 12

Amniocentesis may be done as early as ________ but this may lead to the development of fetal scoliosis or club foot due to _______

Answer 12

12 weeks

Due to reduced amount of amniotic fluid

Question 13

Always obtain ______ after amnio is complete

Answer 13

Fetal heart rate

Question 14

Optimal collection site for amniotic fluid

Answer 14

Away from the fetus

away from the central position portion of the placenta

away from the umbilical cord

near the maternal midline to avoid maternal uterine vessels

Question 15

When performing an amniocentesis for multiple gestational pregnancies the first sac will be punctured and then what is injected into the first sack?

Answer 15

Indigo carmine dye

Question 16

The use of ______ has also been reported in amniocentesis with multiple gestations(dye)

Answer 16

Methylene-blue and sterile air

Question 17

Fetal blood is obtained through needle aspiration of the umbilical cord

Answer 17

Cordocentesis

Question 18

Karyotype results from a cordocentesis are processed within ____

Answer 18

2-3 days

Question 19

The fastest invasive procedure for genetic testing

Answer 19

Cordocentesis

Amniocentesis rapid results can be available within 24 hours, but only limited results are available (13, 18, 21, X/Y)

Question 20

What are cordocentesisis typically used for?

Answer 20

Guidance for transfusions to treat fetal isoimmunization

Question 21

Major protein in fetal serum

Answer 21

AFP

Question 22

AFP is produced by what in early gestation?

Answer 22

yolk sac

Question 23

AFP is produced by what in later gestation

Answer 23

fetal liver

Question 24

AFP may be measured in _____ or from _______

Answer 24

maternal serum(MSAFP) or amniotic fluid(AFAFP)

Question 25

common reason for elevated AFP

Answer 25

neural tube defects, anencephaly, open spina bifida

Question 26

Why are neural tube defects common reasons for elevated AFP?

Answer 26

AFP leaks from the defect to enter the amniotic fluid and diffuses into maternal blood stream

Question 27

elevation of AFP is based on levels:

Answer 27

greater than/equal to 2-2.5 multiples of the median(MOM)

Question 28

MSAFP levels peak at

Answer 28

15-18 weeks gestation

Question 29

2 common abdominal wall defects produce elevated AFP:

Answer 29

omphalocele and gastroschisis

Question 30

Omphalocele: AFP leaks through the membrane that is encasing the herniated bowel or liver: ____ defect

Answer 30

closed defect

Question 31

Gastrochisis: AFP diffuses directly into the serum and amniotic fluid from herniated bowel, lacks covering membrane: ____ defect

Answer 31

open defect

Question 32

A fetus with a _____ lesion may produce increased levels of AFP

Answer 32

kidney lesion

Question 33

polycystic kidneys and UT obstruction may lead to significantly higher levels of AFP because:

Answer 33

abnormal filtration of AFP, kidney maldevelopment and UT leakage.

Question 34

frequent cause of high MSAFP levels ____

Answer 34

fetal death

Question 35

When the AFP is elevated (greater than 3 MOM) & the cranium and spine appear normal, the risk of the fetus having a spinal defect is:

Answer 35

cut in half

Question 36

low levels of AFP are associated with

Answer 36

trisomy 13, 18, 21, incorrect dates, fetal death, hydatidiform moles

Question 37

quad screen includes:

Answer 37

AFP, hCG, Unconjugated estriol, inhibin-A

Question 38

improves the sensitivity in detecting down syndrome ____(lab value)

Answer 38

inhibin-A

Question 39

Lab values for trisomy 21

Answer 39

high hCG, low/decreased AFP & estriol levels

Question 40

Trisomy 18 lab values

Answer 40

decreased hCP, AFP, & Estriol

Question 41

PAPP-A levels are decreased in pregnancies affected by _____

Answer 41

aneuploidy

Question 42

glycoprotein derived from trophoblastic tissue that is diffused into maternal circulation:

Answer 42

PAPP-A

Question 43

glycoprotein derived from the placenta:

Answer 43

hCG

Question 44

Normal karyotype consists of ____ chromosomes

Answer 44

46

Question 45

abnormality in number of chromosomes:

Answer 45

Aneuploidy

Question 46

cause of trisomy is usually:

Answer 46

failure of normal chromosomal division at meiosis

Question 47

condition caused by a single defective gene

Answer 47

autosomal dominant

Question 48

caused by a pair of defective genes

Answer 48

autosomal recessive

Question 49

disorders inherited by boys from their mothers:

Answer 49

X-linked disorders

Question 50

example of an X-linked condition in male fetuses:

Answer 50

aqueductal stenosis

Question 51

occurrence of gene mutation or chromosomal abnormality in portion of an individual's cells

Answer 51

mosaicism

Question 52

NT is performed:

Answer 52

between 11-14 weeks gestation

Question 53

One of the most common chromosomal disorders

Answer 53

trisomy 21

Question 54

trisomy 21 is also known as

Answer 54

down syndrome

Question 55

trisomy 21 features:

Answer 55

duodenal atresia(double bubble sign), brachycephaly, flattened nasal ridge, hypertelorism(increased space between eyes), cystic hygroma(enlarged space behind neck), sandal gap foot, hypoplasia or absence of the middle phalanx of the 5th digit, clinodactyly(curving of 5th finger inward)

Question 56

trisomy 18 is also known as

Answer 56

Edwards syndrome

Question 57

2nd most common chromosomal abnormality

Answer 57

trisomy 18

Question 58

trisomy 18 features:

Answer 58

microcephaly(small head), choroid plexus cysts, clenched hands, rocker-bottom feet, cleft lip/palate, clubfoot

Question 59

trisomy 18: _____% of infants die within the first year of life

Answer 59

90%

Question 60

Trisomy 13 is also known as

Answer 60

Patau syndrome

Question 61

chromosomal abnormality that mainly involves the brain

Answer 61

trisomy 13

Question 62

trisomy 13 features:

Answer 62

holoprosencephaly, rocker-bottom feet, polydactyl(extra digits)

Question 63

trisomy 13: ___% of infants usually die within first months of life

Answer 63

80%

Question 64

complete extra set of chromosomes:

Answer 64

triploidy

Question 65

triploidy most often occurs as a result of:

Answer 65

the ova being fertilized by 2 sperm

Question 66

holoprosencephaly:

Answer 66

hypotelorism(close eyes) proboscis(tube-like structure in middle of face) cyclopia single nostril nose

Question 67

triploidy is associated with (disease)

Answer 67

gestational trophoblastic disease/molar pregnancy, theca-lutein cyst, preeclampsia

Question 68

genetic abnormality marked by absence of X or Y chromosome

Answer 68

Turner's syndrome

Question 69

genetic abnormality not associated with AMA

Answer 69

Turner's syndrome

Question 70

most common finding in Turner's syndrome:

Answer 70

cystic hygroma(fluid around back of neck)

Question 71

female infants who survive with Turner's syndrome will have

Answer 71

``` immature sexual development amenorrhea short stature webbed neck abnormal elbow angle shield chest ```

Question 72

associated with 1st trimester increased NT and tachycardia

Answer 72

Turner's syndrome

Question 73

most common cardiac anomaly with Turner's syndrome

Answer 73

coarctation of the aorta

Question 74

identification of female gender with ______ strongly suggests Turner's syndrome

Answer 74

cystic hygroma