Genetics

Question 1

What is myotonic dystrophy

Answer 1

AD multisystem progressive disease with impaired muscle relaxation and muscle wasting

Question 2

What is spinal muscular atrophy

Answer 2

Autosomal recessive
progressive loss of anterior horn cells in spinal cord and brainstem nuclei
SMN1 deficiency

Question 3

Features of SMA

Answer 3

Floppy
Hypotonia 
areflexia 
muscle wasting 
tongue fasciculations

Question 4

inheritance of Huntington’s disease

Answer 4

autosomal dominant

Question 5

cause of Huntington’s disease

Answer 5

trinucleotide CAG repeat resulting in polyglutamine and caudate nucleus atrophy

Question 6

what is the inheritance of Duchenne muscular dystrophy

Answer 6

X linked recessive - males affected

Question 7

how does Duchenne muscular dystrophy present

Answer 7

motor developmental delay 
Gowers sign positive 
Calf pseudohyptertropy 
excessive lumbar lordosis 
wheelchair bound in teens 
death in 20s from cardiorespiratory muscle dysfunction and failure

Question 8

where is the mutation in Duchenne muscular dystrophy

Answer 8

dystrophin gene in X chromosome

Question 9

what investigations are used for Duchenne muscular dystrophy

Answer 9

EMG
muscle biopsy
CK
genetic testing

Question 10

what are levels of CK like in Duchenne muscular dystrophy

Answer 10

very high

Question 11

what is the pathology in Huntingtons disease

Answer 11

trinucleotide repeat of CAG leading to polyglutamine and atrophy in caudate nucleus of basal ganglia

Question 12

when do symptoms in Huntingtons disease present

Answer 12

30-50s generally but can be variable due to age dependent penetrance

Question 13

what is genetic anticipation in Huntingtons disease

Answer 13

with each generation, symptom onset is earlier and worse

Question 14

how do you diagnose Huntingtons disease

Answer 14

PCR

Question 15

What are genetic causes that predispose to Alzheimers disease

Answer 15

Trisomy 21 - Downs
presenelin 1/2 mutations
ApoE4
APP mutations