Huntingtons disease

Question 1

Type of inheritance, onset, death from onset

Answer 1

Autosomal dominant with genetic anticipation
onset 30-40
death 17 years from onset

Question 2

Symptoms

Answer 2

Progressive chorea (involutanry movement)
Dementai
Psychiatric symptoms
Weight loss (constantly moving and difficulty eating)

Question 3

Aetiology

Answer 3

1. atrophy of neurons in the caudate putamen and globus pallidus
2. leading to unstable length mutation in gene (huntingtin HTT)

“trinucelotide (CAG) repeat expansion in HTT gene on chromosome 4”

Question 4

Testing

Answer 4

No cure
DNA testing possible
Only after full discussion of pros/cons + Consent

Question 5

Genetic anticipation

Answer 5

Prone to expansion during meiosis
Size prone to increase if passed from father

No of repeating units
up to 35- not affected
36-39 - incomplete penetrance
40+ - affected younger

Question 6

Chorea

Answer 6

incodes polyglutamate that is insoluble

blocks move of particles through axons