Genetics Flashcards
Chorionic villous sampling - which area of the body do you get the sample from?
Placenta
Amniocentesis - which area of the body do you get the sample from?
Skin/urine cells
Chorionic villus sampling - at what gestation?
11.5 weeks
Amniocentesis - at what gestation?
16 weeks +
Which carries the biggest risk of miscarriage - chorionic villus sampling OR amniocentesis?
Chorionic villus sampling
Why are whole genome tests useful?
They can identify mutations (genetic changes that cause disease)
What limits the effectiveness of whole genome tests
They can also identify polymorphisms (genetic variations that are not necessarily disease causing)
Name a whole genome test
Array CGH
Array CGH - mode of action
Looks at all the chromosomes and detects if there are any abnormalities
Array CGH - when is it required
When there is high risk of chromosomal trisomy on screening
When there is foetal abnormality on scanning
If the parent has a balanced chromosomal rearrangement
What would array CGH look like in the parent with a balanced translocation?
Normal
- aCGH only detects imbalance
Name a targeted genome test
FISH
When is US scan with serum biochemistry and nuchal thickness carried out?
around 12 weeks gestation
When is serum screening carried out?
Around 16 weeks
When is the detailed US scan carried out ?
20 weeks
