Genetics

Question 1

What do you need to do a DNA or chromosome test on baby in utero?

Answer 1

Tissue with same genetic make-up

Question 2

What tissues can be used for DNA/ chromosome testing?

Answer 2

Placenta - chorionic villus biopsy
Skin/urine cells - amniocentesis
Blood - fetal blood sampling

Question 3

What risk is associated with getting tissue for testing?

Answer 3

Miscarriage

Question 4

What analysis techniques can be used to test whole genome?

Answer 4

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

Question 5

What analysis techniques can be used to test targeted parts of genome?

Answer 5

Point mutation testing
FISH
Quantitative fluorescent PCR (GF-PCR)

Question 6

When would you do aCGH or chromosome analysis?

Answer 6

High risk of chromosomal trisomy
Fetal abnormality on scanning - small size/ increased Nuchal thickness/ structural malformation
Parent has balanced chromosomal rearrangements

Question 7

What is a robertsonian translocation? And what does it increase risk of?

Answer 7

2 Actocentric chromosomes stuck end to end

Increased risk of trisomy

Question 8

Id parent affected with autosomal dominant what is risk to child?

Answer 8

50%

Question 9

If parents carrier of autosomal recessive, what is risk to child?

Answer 9

25%