Importance Polygenic risk scores (PRS) are predictors of the genetic susceptibilities of
individuals to diseases. All individuals have DNA risk variants for all common diseases, but
genetic susceptibility differences between people reflect the cumulative burden of these.
Polygenic risk scores for an individual are calculated as weighted counts of thousands of
risk variants that they carry, where the risk variants and their weights have been identified in
genome-wide association studies. Here, we review the underlying basic science of PRS …