Genetic screening

Question 1

Compare and contrast procedures used in amniocentesis and CVS:

Answer 1

Similarities:
-They both use a needle and used to for genetic screening to detect illnesses
-Both done after embryo is implanted

Differences:
-Amniocentesis via abdomen and CVS can be done through vagina or abdomen
-Amniocentesis collects fetal cells from amniotic fluid and CVS collects fetal cells from placental tissue

Question 2

Advantages of CVS over amniocentesis:

Answer 2

-Can be performed earlier than amniocentesis meaning it allows earlier decision to abort, less traumatic
-First CVS results available sooner, amniocentesis takes about the 2-3 weeks

Question 3

Advantages of amniocentesis over CVS:

Answer 3

-Lower risk of miscarriage (1%) compared to CVS (1-2%)
-CVS can’t detect gene problems on X chromosomes, amniocentesis can

Question 4

When is amniocentesis and CVS carried out?

Answer 4

-CVS carried out at around 11-14 weeks of pregnancy
-Amniocentesis carried out at around 15-20 weeks of pregnancy

Question 5

Advantages of pre-implantation genetic diagnosis:

Answer 5

Avoids abortion as it’s carried out before implantation of the embryo

Question 6

Purpose of genetic screening:

Answer 6

Identifying allele at a gene locus for a particular disorder