fetal health

Question 1

what is the role of a genetic counselor

Answer 1

• provide up-to-date information and emotional support

- obtain informed consent, the patient should be aware of risks, benefits, the current legal framework around privacy

Question 2

describe CVS

Answer 2

done at 11-12 weeks

• takes fetal cells from placenta (contains fetal DNA)
• done under ultrasound guidance
• 1% risk of miscarriage

Question 3

describe amniocentesis

Answer 3

done at 15-19 weeks

• collects fluid which contains fetal cells
• needs to be cultured in the lab before analysis
• needed is inserted under ultrasound guidance
• 1% risk of miscarriage

Question 4

give two examples of genetic abnormalities that may be detected using FISH

Answer 4

Chronic myeloid leukemia - chromosomal translocation at Philadelphia chromosome

breast cancer - amplification of her2 gene

Question 5

define heterogeneity and how it affects diagnosis

Answer 5

heterogeneity is the idea that multiple different genetic abnormalities have been associated with a given disease phenotype e.g. hemophilia can be caused by various point mutations
affects diagnosis because you usually need to know the type of genetic abnormality that’s present in a given family to diagnose it

Question 6

define dynamic mutation

Answer 6

is the progressive expansion of repeat sequences, commonly triplet repeats

Question 7

how can gene therapy be used to treat Huntington’s disease

Answer 7

gene therapy may be used to treat various genetic conditions as theoretically a faulty gene could be excised out of a genome and replaced with a functional gene. currently, have the ability to selectively cut DNA at specific locations using CRISPR

Question 8

current limitations with gene therapy

Answer 8

there are a lot of unknowns around
what effect gene editing will have, as well as obvious legal and ethical issues.
Importantly, we also still do not fully understand how gene expression is regulated.

Question 9

what is preimplantation genetic diagnosis and how is it performed?

Answer 9

PGD involves the analysis of DNA that will go on to form the embryo and fetus, following fertilization of the oocyte by sperm prior to implantation of the blastocyte in the uterine walls. DNA is isolated from the cell and analyzed using methods such as FISH and PCR and genetic sequencing to determine if a genetic abnormality is present