genetics

Question 1

what samples do you need to complete DNA/chromosome test on a baby

Answer 1

chorionic villus biopsy
amniocentesis
foetal blood
foetal DNA from maternal serum

Question 2

when can foetal blood sampling be conducted

Answer 2

after 18 weeks

Question 3

when can foetal dna from maternal serum be extracted

Answer 3

after 8 weeks

Question 4

con of foetal dna from maternal serum

Answer 4

can only do limited no. of tests

Question 5

first line tests for high risk chromosomal trisomy and foetal abnormality on scan

Answer 5

array CGH (amniocentesis)
FISH

Question 6

trisomy 21

Answer 6

down’s syndrome

Question 7

trisomy 13

Answer 7

patau syndrome

Question 8

signs of down’s syndrome

Answer 8

single palmar crease 
5th finger clinodactyly
short stature
low bridge of nose 
low set ears 
learning disabilities 
cardiac defects

Question 9

signs of patau syndrome

Answer 9

bilateral cleft lip
postaxial polydactyly - extra finger
holoprosencephaly sometimes resulting in cyclopia (single lobed brain)

Question 10

outcome of patau syndrome

Answer 10

always bad news
most miscarry
some die within one week

Question 11

genetic makeup of turner syndrome

Answer 11

45X

Question 12

signs of turner syndrome

Answer 12

neck webbing

oedema

Question 13

what is aCGH used for

Answer 13

chromosome deletions/duplications

chromosome analysis for balanced arrangements

Question 14

what is next generation sequencing used for

Answer 14

specific tests

Question 15

con of next generation sequencing

Answer 15

find lots of polymorphs

Question 16

when is sex of baby seen

Answer 16

8 weeks

Question 17

if history of x linked disease, what tests are carried out

Answer 17

sexing at 8 weeks

if boy - chorionic villus biopsy

Question 18

what disorders are pre-implantation genetic diagnosis considered

Answer 18

X linked disorders
robertsonian/reciprocal translocation
spinal muscular atrophy
huntington’s disease