Huntington's disease

Question 1

A 47-year old male presents following the gradual onset of involuntary hyperkinetic movement affecting all 4 limbs. Clinical examination demonstrates generalised chorea. There is a family history of Huntington’s disease.

Answer 1

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Question 2

1. Name 3 causes of chorea other than Huntington’s disease

Answer 2

1. Drug-induced / tardive (eg dopamine antagonist prescription)
2. L-dopa induced chorea in Parkinson’s disease
3. Sydenham’s chorea
4. Wilson’s disease
5. SLE
6. Paraneoplastic disorder
7. Benign hereditary chorea

Question 3

2.What is the pattern of inheritance seen in Huntington’s disease?

Answer 3

Autosomal dominant

Question 4

3. In addition to chorea name 2 other clinical features of Huntington’s disease.

Answer 4

1. Dementia
2. Mood disturbance
3. Personality change / impulsivity
4. Eye movement difficulties
5. Ataxia

Question 5

4. Huntington’s disease can clinically manifest at an earlier in successive generations of an affected kindred. What is this phenomenon called and why does it happen in Huntington’s disease?

Answer 5

Genetic anticipation

Progressive generation inherit larger numbers of CAG / triplet repeats of Huntingtin gene

Question 6

Genetic testing confirms that the patient has Huntington’s disease. He has a daughter aged 24 years

5. What medication could be prescribed to improve his chorea?

Answer 6

Tetrabenazine

Question 7

6. What should his daughter be offered?

Answer 7

Pre-symptomatic genetic counselling