The polygenic model of human phenotypes has long been hypothesized, but only in recent years have the results from genome-wide association study (GWAS) revealed that much of the genetic basis for most complex traits comprises small effects of hundreds or even thousands of variants. For clinical outcomes, this polygenic effect can be considered a genetic liability to disease risk. While prediction of phenotype from an individual’s genetic profile is compromised by this polygenicity, the application of polygenic risk scores (PRS) has shown that prediction is sufficiently accurate for a number of applications.
