Polygenic Risk Scores

Each person has millions of genetic variants, each having a small effect. But together, these variants can increase the risk of getting a condition.

A polygenic risk score estimates the overall risk someone has of getting a disease by adding up variants in multiple genes. The eMERGE study provides participants with their polygenic risk scores for all tested conditions except colorectal cancer. These scores are based on existing knowledge about genetic factors that affect a person's risk of these conditions.

The risk scores were created using mostly data from people of European ancestry. These scores may not be as effective at estimating the risk in those of non-European ancestry. Where possible, the study team has validated polygenic risk score results in people from four ancestries: Asian, African, European, and Hispanic or Latino. The team validated each score using genetic information from other research studies with people of different ancestries.

If a participant's polygenic risk score for a certain condition is in the top 5%, for example, that person's genetic risk of this condition is much greater than that of the remaining 95% of people.

Polygenic risk scores are not used to diagnose diseases. Some people who don't have a high-risk score for a certain disease still can be at risk of getting the disease or might already have the disease. Other people with high-risk scores may never get the disease.

People with the same genetic risk can have different outcomes depending on other factors such as lifestyle.