genetics Flashcards
when taking a sample from mum what are the tests called when taken from placenta and skin/urine cells
placenta - chorionic villus biopsy
amniocentesis
Can you get fetal DNA from mothers serum? how much?
Yes
about 10% is placental DNA most is mothers
What is free fetal DNA in mothers serum used for?
Sex determination and fetal testing - allowed to see sex of baby if the baby is likely to carry some sort of specific sex linked genetic defect
how is free fetal DNA in mother screened for trisomy?
Check how much chromosome 21 is floating about
What test is used to see single gene changes?
PCR/sequencing
When do you do chromosome analysis
high risk of trisomy on screening - fetal on scan (small, increased nuchal thickness (bit on the back)
Why is chromosome microarray sometimes bad?
Can find polymorphisms and make incidental findings
how could you describe a floppy baby
Rag doll like; lack of head control
Name some differentials to being a floppy baby
HIE, intracranial haemorrhage, cerebral malformations, downs
What is de novo
A single gene mutation that directly causes a disease
Why is SMA important to diagnose in the womb
Early intervention is crucial
How much of the genome is exons?
only 2-3% the rest is unknown
Which mode of inheritance are most severe neonatal genetic conditions ?
De novo
