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Flashcards in Genetics Deck (30)
1

how can fetal tissue be accessed

placental - chorionic villus biopsy
skin/urine cells - amniocentesis
blood - fetal blood sampling

2

when can CVS be done

after 11. 5 weeks

3

when can amniocentesis be done

after 15 weeks

4

when can fetal blood sampling be done

after 18 weeks 2 pecent miscarriage risk

5

when can fetal dnA from maternal blood be sample

after 8 weeks

6

what is the disadvantage of CVS

you may have confined placental mosiciasm

7

Which tests analyse the whole genome

Karyotypte
Array CGH
Quantification of fetal DNA in maternal serum
Whole genome sequencing

8

at what stage of the the cell cycle is karyotyping done

metaphase

9

What tests look for targeted problems

point mutation testing
FISH
Quantitative fluorescent PCR

10

What kind of problem will array not show

balanced translocation

11

what is a polymorphism

genetic variation that is not disease causing per-se

12

what is a copy number variation

insertions or deletions of DNA segments - a type of polymorphism

13

what is a single nucleotide polymorphism

single base changes

14

when is fish used

when missing bit of chromosome is too small to see on karyotype - when you know what part you are looking at

15

when is QF-PCR used

when you know what chromosomes you want to specifically look at

16

when would you do array or chromosome analysis in a fetus

high risk of trisomy
fetal abnormality on scan
balance chromosomal rearrangement

17

what type of IUGR would worry you towards a genetic mutation

SYMMETRICAL

18

what can fetal dna in maternal circulation be used to find

sex determination
trisomy testin


occasionally picks up chromosome or single gene deletions

only 10 percent of the dna sampled is fetus - harder to see mutations

19

Why is aCGH the best genetic test in looking for downs etc

will detect small deletions

20

why is sex chromososne aneuploidy better tolerated eg XXX, xxy

x inactivation

21

what are the features of turners

webbed neck and oedema

22

what features occur in patau

bilateral ceft lip
postaxial polydactyly
can have cyclopia

23

what is a robertsonian translocation

two acrocentric chromosomes stuck end to end

24

what do robertsonian translocations increase the risk of

trisomy

25

what is aneuploidy

too many chromosomes
too few chromosomes

26

when is array used

deletions/duplications

27

when is chromosome analysis used

when you think it is a big mutation

28

when is next generation sequency

for very very small mutations down to 1 base pair

29

when can cardiac defects be seen on a scan

12-20 weeks

30

when can microcephaly and short limbs be seen on a scan

usually not until after 22 weeks