Predisposition to adult onset disease

Question 1

What are the methods of genetic inheritance?

Answer 1

Single gene
Chromosomal
Mitochondrial
Multifactorial

Question 2

What are the genetics of ALS?

Answer 2

Generally sporadic but 5-10% familial

Incomplete penetrance

Question 3

What is the mean onset of ALS?

Answer 3

55 years

Younger in familial forms

Question 4

What are the clinical features of ALS?

Answer 4

Progressive muscle weakness and wasting
Increased reflexes
Cognition spared
Death due to rest failure

Question 5

When is onset of Huntington’s?

Answer 5

Usually late 30s to early 40s but variable

Question 6

What are the genetics of huntington’s?

Answer 6

CAG expansion

Fully penetrant

Question 7

What are the clinical features of huntington’s?

Answer 7

Movement disorder- chorea, athetosis, myoclonus, rigidity
Cognitive- poor planning and memory, subcortical dementia
Personality- irritable, apathetic, loss of empathy, disinhibition, self centres
Psych- depression, paranoia, psychosis

Question 8

Advantages of genetic testing?

Answer 8

If +- make plans for future, arrangements surveillance/treatment, inform children
If - concern reduced

Question 9

Disadvantages of genetic testing?

Answer 9

If +- Known risk to offspring, uncertainty as to “when”, impact on relationships, insurance/mortgage issues
If - survivors guilt