Genetics

Question 1

when are trisomies screened for?

Answer 1

week 8

Question 2

which trisomies are screened for?

Answer 2

13
18
21

Question 3

which trisomy can be tested for 2nd trimester?

Answer 3

only 21

Question 4

how accurate is NIPT and why?

Answer 4

foetal DNA in mother’s serum comes from placenta, not baby so only >90% accurate

Question 5

role of QFPCR

Answer 5

counts chromosomes

Question 6

role of foetal chromosome microarray

Answer 6

look at entire chromosome

Question 7

role of karyotyping and NGS

Answer 7

picks up balanced rearrangments

Question 8

role of TORCH screen?

Answer 8

infections

Question 9

what is given for severe neural tube defects above 24 weeks?

Answer 9

potassium chloride for cardiac death of the foetus (TOP)

Question 10

define anticipation

Answer 10

generations are affected earlier and earlier

Question 11

define compound heterozygote

Answer 11

2 mutations in the same gene that are different

Question 12

what is someone’s genetic risk if you aren’t told it?

Answer 12

population risk

Question 13

genetic risk factors for breast cancer

Answer 13

mutations such as:

• BRCA1/2
• TP53
• PTEN

Question 14

low risk (population risk) screening programme for breast cancer

Answer 14

national screening with 3 yearly mammograms for 50-70

Question 15

moderate risk screening programme for breast cancer

Answer 15

annual mammograms 40-50s before entering national screening

Question 16

high risk screening programme for breast cancer

Answer 16

begins at 30

Question 17

testing criteria for BRCA1/2 genes

Answer 17

epithelial ovarian cancer
breast cancer <45
bilateral breast cancer, both <60
triple negative breast cancer