Genetics Lec 47: Prenatal Diagnosis And Gene Therapy

screening

Ultrasound falls under what type of test?

screening

Maternal serum marker screening falls under what type of test?

screening

Non-invasive prenatal testing (NIPT) falls under what type of test?

diagnostic

Chorionic villus sampling (CVS) falls under what type of test?

diagnostic

Amniocentesis falls under what type of test?

both 1st and 2nd trimester

during what trimester can you perform a blood screening?

both 1st and 2nd trimester

during what trimester can you perform a non-invasive prenatal testing?

1st trimester

during what trimester can you perform a nuchal translucency ultrasound?

2nd trimester

during what trimester can you perform a fetal survey ultrasound?

1st trimester

during what trimester can you perform a chorionic villus sampling (CVS)?

2nd trimester

during what trimester can you perform an amniocentesis test?

11-13+ weeks

when is a nuchal translucency screening performed?

Nuchal Translucency Ultrasound

Test:
Measures nuchal translucency: fluid under the skin behind the fetal neck?

Nuchal Translucency Ultrasound

identify the test:

18-22 weeks

when is a fetal anatomic survey performed?

Fetal Anatomic Survey

Test:
•Can detect structural fetal anomalies such as congenital heart defects
•Can detect "soft markers" for aneuploidy such as echogenic intracardiac foci

Fetal Anatomic Survey

identify the test that can survey for this heart defect:

Maternal Serum Marker Screening

Test:
-Measurement of proteins and hormones produced by the fetus and placenta, circulating in maternal blood

Maternal Serum Marker Screening

Test:
•Can evaluate the chances for Down syndrome, trisomy 18, and open neural tube defects

11-13+ weeks

when is the 1st trimester Maternal Serum Marker Screening performed?

15-21 weeks

when is the 2nd trimester Maternal Serum Marker Screening performed?

Non-invasive prenatal testing (NIPT)

Test:
Evaluation of cell-free DNA in maternal serum
•Can evaluate the chances for trisomies 21, 18, 13, monosomy X in the fetus/placenta
•Significantly higher detection rates and lower false positive rates than traditional maternal serum marker screening

Nuchal Translucency Ultrasound

results from a material serum marker can be combined with what test for a better prediction?

anytime after 10 weeks

when is a Non-invasive prenatal testing (NIPT) performed?

13, 18, 21

a fetus with a trisomy can survive if it occurs at what 3 chromosomes?

10-13 weeks

when is a fetal anatomic survey performed?

15+ weeks

when is an amniocentesis test performed?

Pre-Implantation Genetic Screening (PGS)

Test:
•Embryos obtained through an in vitro fertilization cycle can be screened for aneuploidy or single gene disorders
•Embryos grow into a multi-cell state then biopsied for testing

false

t/f: Pre-implantation genetic screening can be used diagnostically to determine chance of aneuploidy

true

t/f: Pre-implantation genetic "diagnosis" is not a diagnostic test

Pre-implantation genetic "diagnosis" (PGD)

Test:
-typically uses a family-specific test to screen for a single gene disorder in embryos
-Offered to couples at increased risk for a single gene disorder
-A family-specific molecular test is developed for each couple

trisomy 21

The Amniocentesis and FISH result shows as following. What is the most likely possible karyotype?
Red: chromosome 21
Yellow: chromosome 14
Green: chromosome 12

severe combined immunodeficiency disease (SCID)

•Caused by mutation in ADA gene coding for the blood enzyme adenosine deaminase

germline therapy

gene therapy involving corrected nuclear transfer

false

t/f: both somatic and germline therapy are approved in the US

true

t/f: Most fetuses with an increased nuchal translucency do not have aneuploidy

FISH or karyotype analysis

what two tests are mostly used on the results of a CVS or amniocentesis sample?

3

oA nuchal translucency measurement of >__ mm is associated with an increased risk for aneuploidy and fetal heart defects