Genetic Counseling & Screening Flashcards
what is genetic counseling
communication dealing with problems associated with genetic disorders
Who is the consultand
patient
Consulting is always _____ when counseling the patient
non-directive
don’t make the decision for them, just give them information for them to make informed decision
What is the first step in genetic counseling
diagnosis
what is the second step in genetic counseling
risk assessment
What is the third step in genetic counseling
discuss options with patient, non-directive
What is the fourth step in genetic counseling
communication & long-term support
What is targeted screening doing
looking for those at high risk for disorder (like huntingtons)
indicates a positive family history
what is population screening
screening done for all population
low risk
what are the three major types of screening
prenatal screening/diagnosis
newborn screening
heterozygote (carrier) screening
what are the two types of prenatal screening/diagnosis
noninvasie
invasive
what are the advantages ot noninvasive screening
don’t go into uterus, no risk
what are the disadvatnages of noninvasive screening
false positives an dnegatives
not always accurate
what are the three noninvasive prenatal screening types
FIRST (1st trimester)
Maternal Serum Screening (2nd trimester)
Ultrasound
Should all pregnancies have noninvasive screening
yes - new standard of care
What does FIRST stand for
First Trimester Integated Screening for Trisomies
when is FIRST performed
weeks 11-14
What tests are combined to prform FIRST
biochemical analysis of maternal serum
ultrasound
maternal age
what is looked at in maternal serum in FIRST test
hCG
PAP-A
what does hCG stand for
human chorionic gonadotropin
What does PAP-A stand for
pregnancy Associated protein-A
What do they look for in ultrasound for down syndrome in FIRST
nuchal translucency
What are the detection rates for Down Syndrome in FIRST
80%
What does it mean that FIRST test is standard of care
should be offered to all pregnant woman
all insurance should cover
What does maternal serum screen looking for
look at levels of proteins in the blood
When is maternal serum screening perofrmed
15-20 weeks (it is also perfeomed in first trimester, but some things are only tested for in second trimester)
In second smester what is Maternal Serum Screening testing for in triple Screen Test
AFP
uE3
hCG
Why is AFP looked at
neural tube defects
what is advantage of maternal serum screening in second sesmeter
tests for nerual tube defects
what does testing for uE3 and hCG looking for
trisomy 18 & 21
What is the quad screen test
same as triple screen test of maternal serum screening + tests for Inhibin-A
What does AFP stand for
alpha-fetoprotein
What is the major blood protein in the fetus
AFP
When there are neural tube defects what happens
AFP is released into maternal blood - if it is elevated more than normal strong correlation for NTD
When can AFP be measured to truly detecft if there is NTD
16.5-17.5 weeks
What are the three invasive prenatal diagnosis method
chorionic villus sampling
Amniocentesis
Cordocentesis
What is the advantage and disadvantage of invasive prenatal diagnosis
advantage diagnostic
disadvantage: risk
What does PND stand for
invasive prenatal diagnosis
all invasive PND are associated with what
elevated risk of miscarriage
ideally, PND is preformed when & why
early as possible - they still have option to terminate pregnancy the earlier it is, esp. in 1st trimester
What does CVS stand for
chorionic villus sampling
what is CVS
sampling of chorion of placenta (embryonic tissue) for genetic testing
how does needle go in for CVS
transcervical or transabdmooinal
What is disadvantage of CVS
can’t yet test for NTD
what is advantage of CVS
performed early at 10-14 weeks
when is CVS performed
10-14 weeks
When is amniocentesis perofmred
16-20 weeks
what is amniocentesis
sampling of amniotic fluid (has fetal origin)
WHere does needle go for amniocentesis
abdomen
what is advantage of amnioventesis
can also test for NTD
What is risk for amniocentesis
.1%
what is risk in CVS
.5%
when is cordocentesis perofrmed
19-21 weeks
what is cordocentesis
sampling fetal blood from umbilical cord
what is risk of cordocentesis
1.4-1.9&=%
why is cordocentesis performed
if the other two methods didn’t work, f they didn’t get conclusive results
What is preimplantation genetic diagnosis
option if parents are carrier or high risk for a disease.
Do IVF and test the cell (take a cell from blastocyst) before they implant into mother to see if they have disease, they only choose the blastocysts without the disease
Describe the emerging technology for fetal cell/DNA in maternal blood
fetal cells & cell-free DNA can be detected in maternal plasma, they are trying to isolate fetal cells and do genetic testing on it
what is newborn screening
newborns are tested for diseases which depends on where test is done, normally the diseases tested are most common in the region.
what is the cirteria for newborn screening
treatment available early treatment testing necessary to detect disease good testing available w/ low false positives and negatives common enough that cost is worth it
what is carrier screening
targeted at high risk individuals who might be carriers for disease
what are examples of carrier screening test available and in use
tay-sachs
sickle cell
beta thalassemia
what mutations are tested for when testing for diseases
test for the most common mutant alleles in subpopulation being tested
a basic cystic fibrosis panel tests for which mtuations
deltaF508 + 22 other common mutations
what has carrier screening in israel been able to do
almost eliminated tay sachs
