Huntington's Disease Flashcards
Define Huntington’s Disease?
Autosomal dominant trinucleotide repeat disease characterised by progressive chorea and dementia, typically commencing in middle age
What is the aetiology of Huntington’s Disease?
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
Earlier age of onset with each successive generation
What is the epidemiology of Huntington’s Disease?
Average of onset: 30-50 yrs
What are the presenting symptoms of Huntington’s Disease?
INSIDIOUS onset in middle-age Progressive Fidgeting Clumsiness Involuntary, jerky, dyskinetic movements often accompanied by grunting and dysarthria
What are the early cognitive changes in Huntington’s Disease?
Lability Dysphora (a state of unease or generalised dissatisfaction with life) Mental inflexibility Anxiety Develops into dementia
What are the late stages of Huntington’s Disease?
Rigid
Akinetic
Bed-bound
What do you ask about in the history for Huntington’s Disease?
Drug history (especially cocaine and anti-psychotics) Family History
What are the signs of Huntington’s Disease?
Chorea Dysarthria Slow voluntary saccades Supranuclear gaze restriction Parkinsonism Dystonia MMSE shows cognitive and emotional deficits
Why do we do Genetic Analysis for Huntington’s Disease?
Diagnostic if there are > 39 CAG repeats in the HD gene
Reduced penetrance leads to an intermediate number of CAG repeats
What imaging do we do for Huntington’s Disease?
Brain MRI or CT may show symmetrical atrophy of the striatum and butterfly dilation of the lateral ventricles
Why do we do bloods for Huntington’s Disease?
Exclude other pathology