Huntingtons

Question 1

define Huntington’s disease?

Answer 1

autosomal dominant trinucleotide repeat disease (CAG) characterised by progressive chorea and dementia, typically commencing in middle age

Question 2

what is the aetiology of Huntingtons disease?

Answer 2

• The huntingtin gene codes for a protein called huntingtin
• In the huntingtin gene there is a trinucleotide repeat expansion (CAG) that results in toxic gain of function
• Autosomal DOMINANT

Question 3

how does huntingtons progress with generations?

Answer 3

• Earlier age of onset with each successive generation

Question 4

what is the epidemiology of huntingtons?

Answer 4

• Average age of onset: 30-50 yrs

Question 5

presenting symptoms of huntingtons?

Answer 5

• INSIDIOUS onset in middle-age
• Chorea
• Personality changes
• Intellectual impairment
• Dystonia
• Saccadic eye movements

Question 6

signs of huntingtons disease?

Answer 6

• Chorea
• Dysarthria
• Slow voluntary saccades
• Supranuclear gaze restriction
• Parkinsonism
• Dystonia

Question 7

investigations for huntingtons disease?

Answer 7

• Genetic Analysis
o Diagnostic if there are > 39 CAG repeats in the HD gene
• Imaging
o Brain MRI or CT may show symmetrical atrophy of the striatum
• Bloods
o To exclude other pathology
o No liver disease