Lecture 4 - ethical issues with prenatal testing

Question 1

How can Bayersian statistics be misleading?

Answer 1

Statistics can be misleading
- false positive & false negatives
- depends on how common the disease is

Question 2

What does a genetic counsellor do?

Answer 2

Ethical provider of NIPT would also provide genetic counselling. They can help understand risks and benefits of having a genetic test (can be before test) and explain what the results mean. They may discuss what the affect on the family can be and the risk (e.g. inherited condition).

Question 3

What are the 2 parts of genetic counsellor?

Answer 3

• understand risk (understand genetics and statistics)
• being able to communicate that.

Question 4

How can a test be both 99% accurate and 20% wrong?

Answer 4

• Misleading of accuracy
• high accuracy isn’t to be confused with test performance
• False positives
• NIPT was a screening test not a diagnostic test

Question 5

What does negative for NIPT test mean?

Answer 5

• accuracy is misleading
• low risk doesn’t mean no risk (negative NIPT indicates low risk)
• Not diagnostic
• Maternal age and other risk factors important

Question 6

What are 3 key points regarding NIPT?

Answer 6

• Imperative that genetic counselling goes hand in hand with pre-natal testing
• Test statistics misleading
• Increase in screening comes at a time where people with Down syndrome are achieving more than ever.

Question 7

How can NIPT miss the ‘extra’ genetic material that would indicate trisomy 21 (Down syndrome)?

Answer 7

If Down syndrome has manifested as a result of nondisjunction during mitosis, this could lead to a mosaic genotype. As a result, whether Down syndrome was identified during NIPT would be dependent on what part of the sample was taken.

Question 8

What are 6 points (in order) that MPs need to consider around widespread use of NIPT?

Answer 8

(Most important at the top):

• potential expansion to non-medical traits
• informed choice and balanced information
• people living with genetic conditions
• increased termination and societal attitudes towards disability
• potential harms (to pregnant women, couples, foetuses, future people, disabled people, healthcare professionals)
• NHS Resources