Genetics of CNS disease

Question 1

What is the inheritence pattern of duchenne muscular dystrophy?

Answer 1

X linked recessive

Question 2

What is the genetic problem in duchenne muscular dystrophy?

Answer 2

Large scale deletions in the dystrophin gene (70%)

Point mutations, small insertions and deletions in the dystrophin gene (30%)

Question 3

What gene is faulty is duchenne muscular dystrophy?

Answer 3

Dystophin

Question 4

What is the difference at a molecular level between duchenne muscular dystrophy and becker muscular dystrophy?

Answer 4

In DMD the dystophin protein is absent in BMD it is abnormal

Question 5

What 4 tests are useful in the diagnosis of duchenne muscular dystrophy?

Answer 5

Serum creatanine kinase
EMG
Muscle biopsy
Molecular genetic testing

Question 6

What is the inheritence pattern of huntingtons disease?

Answer 6

Autosomal dominant

Question 7

What is the exact genetic problem in huntingtons disease?

Answer 7

Excessive numbers of CAG repeats on chromosome 4

Question 8

With regard to huntingtons disease; what protein does CAG code for?

Answer 8

Glutamine

Question 9

With regard to huntingtons disease; what chromosome is the abnormality found on?

Answer 9

Chromosome 4

Question 10

What chromosome is related to the amyloid beta protein plaques seen in alzheimers disease?

Answer 10

Chromosome 21

Question 11

What deposits are found in alzheimers disease?

Answer 11

Amyloid beta protein

Question 12

Approximately what % of alzheimers disease is due to an autosomal dominant genetic trait?

Answer 12

5 - 10%

Question 13

What other genetic condition predisposes someone to alzheimers in the 3rd or 4th decade?

Answer 13

Downs syndrome

Question 14

What gene is amyloid beta protein (seen in alzheimers disease) a fragment of?

Answer 14

The APP (Amyloid precursor protein) gene on chromosome 21

Question 15

What is most common gene where there is a mutation leading to alzheimers disease?

Answer 15

APP (Chromosome 21)

Question 16

Name 3 genes where there is known mutations that can lead to alzheimers disease and are passed on in an autosomal dominant fashion?

Answer 16

APP (Chromosome 21)
Presenilin 1 (Chromosome 14)
Presenelin 2 (Chromosome 1)

Question 17

What is the risk of MS for someone who has a first degree relative with the condition?

Answer 17

3%