16 Huntingtons + predictive testing.

Question 1

What is the genetic change in Huntington’s disease?

Answer 1

4q16.3.

>40 CAG repeats - polyglutamine expansion.

Question 2

Which aggregates form in Huntington’s disease?

Answer 2

PolyQ cellular protein.

Question 3

Define anticipation:

Which type of genetic change is it associated with?

Answer 3

Onset of disorder occurs at a younger age in each generation.
Triplet repeat disorders.

Question 4

Name three diseases in which anticipation occurs and the sex of the parent it is linked to:

Answer 4

Huntington’s: paternal.
Myotonic dystrophy: maternal.
Fragile X syndrome: maternal.

Question 5

What is predictive testing?

Answer 5

Use of a test in an asymptomatic person to predict future risk of the disease.

Question 6

Name 4 diseases for which predictive testing is available:

Answer 6

Huntington’s.
Breast cancer.
HNPCC.
Myotonic dystrophy.