A single gene rarely decides a common condition like heart disease or type 2 diabetes. Instead, thousands of positions each nudge your risk a little. Add those nudges up and you get a polygenic risk score, usually reported as a percentile. It's useful, and it's also easy to misread. Here's how to hold it sensibly.
What a percentile means
If your score is in the 80th percentile, it means your genetic tendency for that trait is higher than 80% of the reference population's. It does not mean you have an 80% chance of the condition. It's relative position, not a probability of outcome.
Three things a score can't do
- It can't diagnose. A high score is a tendency, not a condition. Plenty of high-percentile people never develop the trait.
- It can't see your life. Diet, activity, sleep, and environment often matter as much as genetics for common conditions, and unlike your genes, those are levers you can pull.
- It isn't equally accurate for everyone. Many scores were built mostly on European-ancestry data and are less precise for other ancestries. A good report says so.
What a score can do
Used well, a polygenic score helps you prioritise. If your cardiovascular tendency is elevated, that's a reason to take a cholesterol check seriously, not a reason to panic. The best use is to turn a vague "I should look after my heart someday" into a specific "I'll ask about a lipid panel at my next visit."
On the Max Plan, GeneLab pairs polygenic scores with your uploaded labs, so an elevated LDL score is read next to your actual measured LDL, not in a vacuum.
Read it as one input
Your genome is one input among several, family history, labs, and lifestyle are the others. A polygenic score earns its place when it changes a question you ask your clinician, and nothing more dramatic than that. See how we present scores ›