Aspects of Clinical Genetics

Question 1

What are the 6 stages of genetic counselling?

Answer 1

1) collection of info
2) pre testing counseling
3) assessment
4) post testing counselling
5) referral
6) follow up

Question 2

Why is counselling before and after testing important?

Answer 2

Before - to explain the testing process, discuss possible outcomes, ensure that the patient has social support

After - explain the results, help patient deal with it if positive, help patient deal with it if negative

Question 3

What can genetic testing help us diagnose?

Answer 3

pre-symptomatic diagnosis = am I going to get the disease?

carrier testing = do I carry a disease mutation?

Question 4

What can we not determine with genetic counselling?

Answer 4

We cannot measure complex/common diseases -measured as heritable -
i.e) myocardial infarction , cancers (except BRCA), diabetes, obesity, hypertension etc.

Question 5

What are the advantages and disadvantages of karyotyping?

Answer 5

including inc array CGH, and FISH
advantages = can assay large deletions /duplications

disadvantages = cannot assay individual bases of DNA

Question 6

what are the advantages and disadvantages of inc. Sanger and next generation sequencing?

Answer 6

advantages = ultimate resolution and can identify actual mutations - applicable for any disease for which gene is known

disadvantages = not always suitable for large deletions/duplications - slow and expensive

Question 7

What prenatal tests do we do ?

Answer 7

1) chorionic villus sampling (CVS) - biopsy of the villi of the chorion frondosum (via catheter transcervically or transabnominally)
2) amniocentesis - incurs risk of miscarriage - withdrawal of amniotic fluid - transabdominally
3) non-invasive prenatal tests - (NIPT) - take blood from mother analyse foetal DNA

Question 8

In ireland, with bloodspot tests post birth, what do we look for?

Answer 8

PKU, maple syrup urine disease 
homocystinuria 
classical galactosaemia 
cystic fibrosis 
congenital hypothyroidism