Explain genetic screening examples
Outline screening for BRCA1/2 variants, Huntington’s disease and cystic fibrosis.
A Level; Cambridge International Biology 9700, 2028–2030. This is curriculum teaching, not medical advice or a claim that a treatment is suitable for an individual. Written responses are self-checked
Before you begin
- DNA stores genetic information; genes can be expressed to produce RNA and protein.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
What can a positive genetic screen provide?
What you will learn
- Describe potential advantages of screening for the specified conditions
- Distinguish risk information from certainty of future disease
Build the explanation
Genetic screening can identify variants associated with increased risk or inherited conditions. BRCA1 and BRCA2 variants can inform breast-cancer risk management; Huntington’s disease testing can identify an inherited variant; cystic-fibrosis testing can support diagnosis or carrier and reproductive decisions. Results may enable surveillance, planning or earlier support.
Use the evidence carefully
A risk-associated variant does not always mean disease will occur at a specific time, and screening can have uncertain or emotionally difficult results. Testing requires informed consent, privacy protection and appropriate genetic counselling; results can also have implications for relatives.
Pause and explain
Give one ethical concern with storing genetic-screening results.
Worked example
A person tests positive for a BRCA1 risk variant. What can the result support?
Show the worked solution
- It changes risk information.
- It can inform a discussion of management options.
Answer The result can inform a risk discussion and possible surveillance or management choices; it does not mean breast cancer is certain.
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How can screening for Huntington’s disease support family decisions?
Give me a hint
Identify the relevant material or technology and explain each step.
Compare my reasoning
- It can identify a disease-associated variant.
- People can make informed plans with counselling.
It may provide information relevant to health and family planning decisions, with informed consent and appropriate counselling.
Look for these in your work
- Method identified
- Steps linked to function
Why is carrier testing for cystic fibrosis relevant to reproductive decisions?
Give me a hint
Use the stated example to justify a conclusion.
Compare my reasoning
- Two carrier parents may have an affected child.
- Screening informs risk, not certainty for every conception.
Carrier information can help assess the risk of an affected child and support informed reproductive choices; counselling explains the probabilities and limits.
Look for these in your work
- Evidence interpreted
- Limits stated
Give one ethical concern with storing genetic-screening results.
Give me a hint
Apply the idea to a new application or trade-off.
Compare my reasoning
- Results can reveal sensitive information.
- Privacy or discrimination risk.
Genetic data are sensitive and may affect relatives; secure privacy and protection from inappropriate disclosure or discrimination are important.
Look for these in your work
- Application explained
- Claim appropriately bounded
Common mistakes
- Equating risk with certainty
- Ignoring consent and family implications
What can you explain now?
What can a positive genetic screen provide?
Compare with the explanation
Information about a specified variant or risk
Interpretation depends on the condition and test.
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Make it stick
How can screening inform choices while leaving uncertainty and ethical concerns?
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.