Huntingtons Disease

Question 1

What is Huntingtons Disease?

Answer 1

AD trinucleotide repeat disease characterised by progressive chorea + dementia, typically commencing in middle age

Question 2

Explain the aetiology of Huntington’s disease

Answer 2

Huntingtin gene Chr4, codes for huntingtin protein
In the huntingtin gene there is a trinucleotide repeat expansion (CAG) that results in toxic gain of function
Autosomal DOMINANT
Earlier age of onset with each successive generation

Question 3

Describe characteristics of onset/ nature of Huntington’s disease

Answer 3

FH
INSIDIOUS onset in middle-age
Progressive
Peak age onset: 30-50

Question 4

List 3 motor symptoms of Huntington’s disease

Answer 4

Fidgeting
Clumsiness
Involuntary, jerky, dyskinetic movements often accompanied by grunting + dysarthria

Question 5

List 5 symptoms of early cognitive changes in Huntington’s disease

Answer 5

Lability  
Dysphoria (a state of unease/ generalised dissatisfaction with life)  
Mental inflexibility 
Anxiety 
Develops into dementia

Question 6

List 3 symptoms of late stage Huntington’s disease

Answer 6

Rigid
Akinetic
Bed-bound

Question 7

List 7 signs of Huntington’s disease

Answer 7

Chorea  
Dysarthria  
Slow voluntary saccades 
Supranuclear gaze restriction  
Parkinsonism 
Dystonia  
MMSE shows cognitive + emotional deficits

Question 8

List 3 investigations performed for suspected Huntington’s disease

Answer 8

Genetic Analysis: Diagnostic if > 39 CAG repeats in the HD gene
Brain MRI or CT: symmetrical atrophy of the striatum + butterfly dilation of the lateral ventricles
Bloods: To exclude other pathology

Question 9

What specific drugs should you ask a patient about previous use in Huntingtons disease?

Answer 9

Cocaine

Anti-psychotics