Prenatal diseases

Question 1

Embrogenesis: WHat is happening at each week:
Week 0
Week 1
Week 2
Week 3
Weeks 3-8
Week 4
Week 8

Answer 1

Week 0 : fertilization, cell division (blastula → morula → blastocyst)
Week 1: implantation + β-HCG secretion
Week 2: bilaminar disc (epiblast + hypoblast)
Week 3: gastrulation (3 tissues), neurulation
Week 3-8: organogenesis (most susceptible to teratogens)
Week 4: heart (4 chambers), limbs (4 limbs)
Week 8: fetus

Question 2

What does each layer become:
endoderm
mesoderm
ectoerm

Answer 2

endoderm = GI and respiratory systems

mesoderm: CV, MSK, GU
ectoderm: CNS, skin

Question 3

when does neural tube close

Answer 3

4 wks

Question 4

what can cause the defective neural tube closure?

Answer 4

folate def

mutation methyl-THF-reductase

Question 5

↑αFP, confirm U/S shows lemon sign (concave frontal bones) and banana sign (flat caudal cerebellum)

Answer 5

myeloneningocele

Question 6

asx lumbar tuft of hair

Answer 6

spina bifida occulta

Question 7

calcification of papillary muscle on U/S

Answer 7

echogenic intracardiac focus (EIF), usually insignificant

Question 8

presentation of R to L shunts vs L to R shunts

Answer 8

R to L have early cyanosis

L to R have late cyanosis (dev PAH = eisenmerger syndrme)

Question 9

What are the R to L shunts? L to R?

Answer 9

R to L = TOF, transposition great vessels

L to R = ASD, VSD, PDA

Question 10

cardiac defect often seen with Congenital Rubella Syndrome

Answer 10

PDA

Question 11

presents as low-grade systolic murmur, fixed S2, and frequent colds

Answer 11

ASD

Question 12

presents as pansystolic harsh-sounding murmur with failure to thrive

Answer 12

VSD

Question 13

presents as cyanosis and clubbing in a 5 y/o child who squats for relief;

Answer 13

TOF

Question 14

prognosis of TOF determined by

Answer 14

degress of pulmonic stenosis

Question 15

What is pathophys of Potter’s sequence

Answer 15

failure of mesonephros and metanephros to meet at ureteropelvic junction → bilateral renal agenesis → anhydramnios (no amniotic fluid) → pulmonary hypoplasia + limb contractures

Question 16

How is potters seq diagnosed?

Answer 16

U/S shows anhydramnios or oligohydramnios (AFI <5)

Question 17

treatment for potters seq?

Answer 17

none

Question 18

insert needle transabdominally into uterus

and withdraw amniotic fluid

Answer 18

amniocentesis

Question 19

insert catheter into intrauterine cavity and

aspirate chorionic villi from placenta

Answer 19

chorionic blood sampling (CVS)

Question 20

insert needle transabdominally into uterus

and withdraw umbilical cord blood

Answer 20

percutaneous umbilical blood sampling

Question 21

what prenatal sampling metho is best for rapid karyotype analysis of fetus

Answer 21

percutaneous umbilical blood sampling (PUBS)

Question 22

amniocentesis or chorionic blood sampling assc with greater risk of PROM, PTL, and injury

Answer 22

chorionic blood sampling (CVS)

Question 23

what prenatal sampling technique is best in 1st trimester

Answer 23

chorionic blood sampling (CVS)

Question 24

how is CF diagnosed prenatally?

Answer 24

screen mom and dad for ΔF508/G542X, and confirm with fetal dx

Question 25

How is sickle cell dz diagnosed prenatal?

Answer 25

screen mom w/ Hb electrophoresis, then dad if positive, then confirm w/ fetal dx

Question 26

mutation assc with tay sachs

Answer 26

AR ΔHexA → ganglioside accumulation →progressive neurodegeneration, developmental delay, “cherry red spot” on macula, onion-skin lysosomes

Question 27

Beta thal vs alpha thal mutations

Answer 27

beta = AR deletion in Beta chain = inc alpha:beta hgb ratio alpha: cummulative deletions in alpha chain = dec alpha:beta ratio! Silent carrier: 1-2 gene deletion; asx HbH disease: 3 gene deletion → ↑HbH (β4) → severe microcytic anemia Barts disease: 4 gene deletion → ↑HbBarts (γ4) → hydrops fetalis (IUFD)

Question 28

how are thalasemmias diagnosed?

Answer 28

screen w/ CBC, if microcytic anemia then confirm w/ Hb electrophoresis

Question 29

trisomy 21

Answer 29

down

Question 30

trisomy 13

Answer 30

patau

Question 31

trisomy 18

Answer 31

edwards

Question 32

45, Xo

Answer 32

turners ``` Coarctation of aorta Lymphedema Ovarian dysgenesis Webbed neck (cystic hygroma) Nipples spread (shield chest) Short stature ```

Question 33

47, XXY

Answer 33

klienfleters female traits on a man (long legs, gyno, highpitched voice, female habitus, etc.)

Question 34

5p-

Answer 34

cri-du-chat syndrome microcephaly, cardiac problems, high-pitched meowing, epicanthal folds, MR

Question 35

7q-

Answer 35

williams Elfin facies, Extreme friendliness w/ strangers, well-developed English, MR

Question 36

22q11

Answer 36

Digeorge ``` Cleft palate Abnormal facies Thymic aplasia Cardiac defects Hypocalcemia ```

Question 37

diagnosed with quad screen at 15-20 wk (↑β-HCG, ↑inhibin, ↓αFP, ↓estriol) + nuchal translucency on U/S ;

Answer 37

downs

Question 38

diagnosed with triple screen (↓β-HCG, ↓αFP, ↓estriol)

Answer 38

edwards

Question 39

trisomy found on routine US

Answer 39

patau

Question 40

cleft lip/Palate, holoProsencephaly, Polydactyly, | rocker-bottom feet, MR; death by 1 y/o

Answer 40

patau

Question 41

micrognathia, clenched hands, rocker-bottom | feet, MR; death by 1 y/o

Answer 41

edwards