Genetic risk reports from direct-to-consumer testing companies — or from clinical whole-genome sequencing — are increasingly common. They offer probabilistic risk estimates for conditions like heart disease, certain cancers, diabetes and Alzheimer's. Understanding what these reports can and cannot tell you is essential for interpreting them without undue alarm or false reassurance.
What genetic risk scores measure
Most commercial genetic reports use polygenic risk scores (PRS) — calculations based on thousands of common genetic variants, each of which contributes a tiny increase or decrease in risk. A high PRS for coronary artery disease doesn't mean you'll have a heart attack; it means your genetic background places you in the higher-risk portion of the population, which should inform — not dictate — lifestyle and screening decisions.
Monogenic variants — single-gene mutations with large effects — are different and rarer. BRCA1/BRCA2 mutations significantly raise breast and ovarian cancer risk; APOEε4 substantially raises Alzheimer's risk; familial hypercholesterolaemia mutations cause very high LDL. These are typically identified through clinical genetic testing rather than consumer reports.
What genetic risk scores cannot tell you
- They cannot tell you if you will develop a condition — only that your risk is higher or lower than average
- They don't account for the full extent of environmental factors — diet, exercise, smoking, stress — which often outweigh genetic risk
- Current PRS were largely trained on European-ancestry populations and are less predictive for other groups
- A low genetic risk score does not mean you can ignore symptoms or skip screening
What to do with a high-risk result
Discuss it with your GP before making any changes. For significant findings — particularly BRCA mutations — a referral to a clinical geneticist or specialist screening programme is appropriate. Many risk factors respond well to lifestyle intervention regardless of genetic background, and knowing your risk can be a powerful motivator when channelled productively.