Huntingon's disease (Huntington's chorea)

Question 1

What is Huntington’s disease?

Answer 1

Anautosomal dominantgenetic condition that causes progressive neurological dysfunction

Question 2

What is the usual age of onset of Huntington’s disease?

Answer 2

30-50

Question 3

Describe the genetics of Huntington’s disease

Answer 3

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

Question 4

What is anticipation in Huntington’s disease?

Answer 4

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

Question 5

What is the life expectancy from onset of symptoms in Huntington’s disease?

Answer 5

10-20 years

Question 6

What often causes death in Huntington’s disease?

Answer 6

• Aspiration pneumonia
• Suicide

Question 7

Describe the pathophysiology of Huntington’s disease

Answer 7

• 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

Question 8

Describe the pattern of disease in Huntington’s disease

Answer 8

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

Question 9

What are some symptoms of Huntington’s disease?

Answer 9

• Chorea
• Dystonia
• Rigidity
• Eye movement disorders
• Dysarthria
• Dysphagia

Question 10

What is chorea?

Answer 10

Involuntary, random, irregular body movements

Question 11

What is dystonia?

Answer 11

Abnormal muscle tone

Question 12

What is rigidity?

Answer 12

Increased resistance to passive joint movement

Question 13

What is dysarthria?

Answer 13

Speech difficulties

Question 14

Why may some people request genetic screening for Huntington’s disease prior to symptoms?

Answer 14

This may help with family planning, employment planning and may have some financial implications

Question 15

What are the supportive management options for those with Huntington’s disease?

Answer 15

• Genetic counselling
• Physiotherapy
• Speech and language therapy
• Tetrabenazine - Used to manage chorea
• Antidepressants
• End-of-life care