In genetics, a polygenic score (PGS) is a number that summarizes the estimated effect of many genetic variants on an individual's phenotype. The PGS is also called the polygenic index (PGI) or genome-wide score; in the context of disease risk, it is called a polygenic risk score (PRS or PR score[1]) or genetic risk score. The score reflects an individual's estimated genetic predisposition for a given trait and can be used as a predictor for that trait.[2][3][4][5][6] It gives an estimate of how likely an individual is to have a given trait based only on genetics, without taking environmental factors into account; and it is typically calculated as a weighted sum of trait-associated alleles.[7][8][9]
Recent progress in genetics has developed polygenic predictors of complex human traits, including risk for many important complex diseases[10][11] that are typically affected by many genetic variants, each of which confers a small effect on overall risk.[12][13] In a polygenic risk predictor the lifetime (or age-range) risk for the disease is a numerical function captured by the score which depends on the states of thousands of individual genetic variants (i.e., single-nucleotide polymorphisms, or SNPs).
Polygenic scores are widely used in animal breeding and plant breeding due to their efficacy in improving livestock breeding and crops.[14] In humans, polygenic scores are typically generated from data of genome-wide association study (GWAS). They are an active area of research spanning topics such as learning algorithms for genomic prediction; new predictor training; validation testing of predictors; and clinical application of PRS.[15][16][17][4][11] In 2018, the American Heart Association named polygenic risk scores as one of the major breakthroughs in research in heart disease and stroke.[18]
^Yanes T, Meiser B, Kaur R, Scheepers-Joynt M, McInerny S, Taylor S, et al. (March 2020). "Uptake of polygenic risk information among women at increased risk of breast cancer". Clinical Genetics. 97 (3): 492–501. doi:10.1111/cge.13687. hdl:11343/286783. PMID31833054. S2CID209342044.
^Torkamani A, Wineinger NE, Topol EJ (September 2018). "The personal and clinical utility of polygenic risk scores". Nature Reviews. Genetics. 19 (9): 581–590. doi:10.1038/s41576-018-0018-x. PMID29789686. S2CID46893131.