Genetics/Prenatal Screening Flashcards
define malformation
congenital morphologic anomaly of single organ or body part from alteration of primary development of the organ
teratogen exposure at 15-25 days has wha two effects?
CNS or cardiac
teratogen exposure at 20-30 days has what effects?
axial skeleton, limbs and muscles
teratogen exposure at 25-40 days has what issues?
eyes heart and lower limbs
teratogen expposure after 60 days has what implication?
inhibited fetal growth
ACE and ARBs cause what in fetus?
2/3rd trimester cause oligohydramnios, renal failure and pulmonary hypoplasia
warfarin causes what in fetus?
fetal bleeding, malformed bones, ID and microcephaly
lithium in fetus leads to what?
ebstein anomaly
what is ebstein anomaly?
abnormally large and poorly functional tricuspid valves
what does nicotine cause in fetus?
growth restriction
what is classic triad of congenital toxoplasmosis?
chorioretinities
hydrocephalus
intracranial calcifications
what is classic triad of congenital rubella?
sensorineural deafness
ocular defects (catracts)
cardiac anomalies (PDA)
blueberry muffin
what are common congenital CMV issues?
hearing loss microcephaly periventricular calcifications chorioretinitis petichiae
what can happen wiht maternal PKU?
if phenylalanine builds up it is toxic to developing brain
trisomy 18 is called what?
edward syndrome
what happens to babies with edward syndrome?
die in a year
what are the classic physical finding of edward syndrome?
small head and jaw
low set ears
clenching of hands
rocker bottom feet
what is name of trisomy 13?
patau syndrome
what are classic physical findings of patau syndrom?
polydactyly
holoprosencephaly
cleft lip/palate
what does CVS stand for?
chorionic villus smapling
what is sampled in CvS?
placental biopsy
when do you perform a CVS?
10-14 weeks
what can CVS not test for?
NTDs
when is amniocentesis performed?
15 weeks and beyond
what can you test for in amniocentesis?
NTDs
what is amniocentesis a measurement of?
fetal cells in the amniotic fluid
what is quad screening?
measurement of AFP, hCG, DIA and uE3 at 15-22 weeks gestation
what are typical values of AFP, uE3, hCG, and inhibin A in positive down syndrome quad screen?
low AFP and uE3
high hCg and inhibin A
name some causes of elevated AFP in screening
NTDs, anencephaly abdominal wlal defects GI defects multiple gestations
what makes hCG?
syncytiotrophoblasts
when does hcg peak?
at 8 weeks gestation then decreases and plateaus
what is most sensitive marker for down syndrome?
hCG
where is uE3 made?
placenta
what happens to uE3 levels throughout pregnancy?
steadily increase
what are levels of AFP, uE3 and hCG in T18
all low
what are levels of AFP, uE3 and hCg in T13?
all low
what is AFP level in NTDs?
HIGH
what is cfDNA screening?
cell free screening
explain how we think cfDNA screening works
cell free fetal DNA circulates in maternal plasma as cells turnover during development so we can use this to sequence the genome and map it
when is cfDNA screening able to determine the most?
third trimester
what can effect the levels of cfDNA in maternal circulation?
obesity
what do you do to confirm results of cfDNA screening?
CVS or amniocentesis
what are some ultrasound signs of DS in 2nd trimester?
nuchal fold
duodenal atresia
AV canal
absent nasal bone
which of T21, 18 and 13 can be well detected by fetal ultrasound?
18 and 13 are best
what are findings of T18 on ultrasound?
growth restirciton
clenched fists
cardiac defects
