Huntingon's disease (Huntington's chorea) Flashcards
What is Huntington’s disease?
Anautosomal dominantgenetic condition that causes progressive neurological dysfunction
What is the usual age of onset of Huntington’s disease?
30-50
Describe the genetics of Huntington’s disease
Autosomal dominance with age dependant penetrance
It is caused by a trinucleotide repeat disorder, involving a CAG (Glutamine) repeat expansion mutation in the HTT gene on chromosome 4, which codes for the huntingtin (HTT) protein
The number of these repeats affects the penetrance of disease
What is anticipation in Huntington’s disease?
A feature of trinucleotide repeat disorders
This is where successive generations have more repeats in the gene, resulting in:
- Earlier age of onset
- Increased severity of disease
What is the life expectancy from onset of symptoms in Huntington’s disease?
10-20 years
What often causes death in Huntington’s disease?
- Aspiration pneumonia
- Suicide
Describe the pathophysiology of Huntington’s disease
- Loss of cells from the basal ganglia
- Flattening of the normal convex curve of the lateral walls if the lateral ventricles
- Cells are lost from other areas including the cerebral cortex
Describe the pattern of disease in Huntington’s disease
Huntington’s disease presents with an insidious, progressive worsening of symptoms
It begins with cognitive, psychiatric or mood problems
It will then progress into movement disorders
What are some symptoms of Huntington’s disease?
- Chorea
- Dystonia
- Rigidity
- Eye movement disorders
- Dysarthria
- Dysphagia
What is chorea?
Involuntary, random, irregular body movements
What is dystonia?
Abnormal muscle tone
What is rigidity?
Increased resistance to passive joint movement
What is dysarthria?
Speech difficulties
Why may some people request genetic screening for Huntington’s disease prior to symptoms?
This may help with family planning, employment planning and may have some financial implications
What are the supportive management options for those with Huntington’s disease?
- Genetic counselling
- Physiotherapy
- Speech and language therapy
- Tetrabenazine - Used to manage chorea
- Antidepressants
- End-of-life care