Genetic Predisposition to adult onset disordres

Question 1

It’s easier to estimate a person’s risk of developing a genetic disorder if it’s based on a single gene and has high penetrance. What are the problems with multifactorial conditions?

Answer 1

Polygenic genetic component means:

• Can’t identify all the risk alleles
• Predictive value of each is small

Interacts with environmental factors so even with genetic testing uncertainty is high

Question 2

Should children be tested for uncertain genetic disorders?

Answer 2

Only if there are potential medical benefits of testing them (in childhood, if they might as well be tested as adults then wait)

Question 3

Do 3rd parties have access to genetic test results?

Answer 3

No! Insurers and employers etc shouldn’t have access to such results

Question 4

What are the guidelines on predictive testing for multifactorial genetic disorders?

Answer 4

1) Test info must be usuable for prevention/treatment
2) Adequate info about uncertainty
3) Proper counselling must be provided re risk, implications and coping with any fear/anxiety

Question 5

Why might we not want to do predictive testing on a patient?

Answer 5

+ve results even with uncertainty:

• Remove hope
• Impacts relationships
• Potential insurance/employment problems
• Stress/anxiety
• ve results:
• survivor guilt (E.g. if sibling tests +Ve)