Genetics

Question 1

when is CVS carried out

Answer 1

11-12 weeks

Question 2

when is an amniocentesis carried out

Answer 2

16 weeks

Question 3

what carries greater risk miscarriage - amnio or CVS

Answer 3

CVS

Question 4

what is a non-invasive method of genetic sampling on a foetus

Answer 4

free foetal DNA in maternal circulation

Question 5

what can free foetal DNA in maternal circulation be used for, and what is it made up of

Answer 5

its made up of 90% maternal DNA and 10% foetal

trisomy test, sex determination, some chromosome deletions and single gene mutations

Question 6

what may be used to look for chromosome abnormalities

Answer 6

microarray

karyotyping

Question 7

what may be used to look for single gene changes

Answer 7

PCR

NGS

Question 8

when would you do chromosome analysis

Answer 8

high risk trisomy
foetal abnormality
screening
parent has balanced chromosome arrangement

Question 9

appearance of floppy baby?

Answer 9

lack head control
frog legged
feel like out of grasp
breathing issues

Question 10

central causes floppy baby

Answer 10

HIE 
intracranial haemorrhage 
malformation 
chromosome abnormality 
TORCH
acquired infection 
drug

Question 11

spinal causes floppy baby

Answer 11

birth trauma

syringomyelia

Question 12

ant horn cell causes floppy baby

Answer 12

spinal muscular atrophy

pompes disease

Question 13

NMJ causes floppy baby

Answer 13

infantile botulism

myaesthenia gravis

Question 14

muscular causes floppy baby

Answer 14

myotonic dystrophy

congenital myopathies

Question 15

metabolic causes floppy baby

Answer 15

carnitine deficiency

acid maltase deficiency

Question 16

important features of history to take on floppy baby?

Answer 16

miscarriage before?
consanguinity
decreased foetal movements

Question 17

early intervention to floppy baby?

Answer 17

respiratory and feeding support
physiotherpay
OT
parent involvement

Question 18

describe the process of microarray

Answer 18

put patient DNA and ‘normal’ into sample
if there is greater hybridisation of patient DNA then there is a duplication
if there is greater hybridisation of normal DNA then it is deletion

Question 19

true/false - microarray can be used for deletions/insertions to the single base pair

Answer 19

false

Question 20

NGS shows huge numbers of mutations/polymorphisms. how can these be narrowed down to a possible causative mutation.

Answer 20

filter
remove polymorphisms
does it affect the gene?
is it a gene affecting phenotype?