Chromosome

Question 1

Chromosomal disorders structural changes

Addition or missing some sequences

Answer 1

Karyotype eg trisomy 21 turners Big ones >5-10mb
Fish if you know the syndrome sometimes this is the one to do
CMA chromosomal microarray most commonly done now
DD/ID/ASD/Epilepsy/
Picks up micro deletions/duplications
Problems is you can get VOUS variants of unknown significance ( test the parents)
CMA gives you an answer in 15% of cases vs karyotype 3% of cases

Question 2

Single gene disorders

Answer 2

Fragile x ( CMA wont pick up )
Fredricks ataxia
Huntington’s
Myotonic dystrophy