[Twitter] polygenic scores quantify inherited risk by integrating information from many common sites of DNA variation into a single number. Rapid increases in the scale of genetic association studies and new statistical algorithms have enabled development of polygenic scores that meaningfully measure—as early as birth—risk of coronary artery disease.
These newer-generation polygenic scores identify up to 8% of the population with triple the normal risk based on genetic variation alone, and these individuals cannot be identified on the basis of family history or clinical risk factors alone.
For those identified with increased genetic risk, evidence supports risk reduction with least two interventions, adherence to a healthy lifestyle and cholesterol-lowering therapies, that can substantially reduce risk.
Alongside considerable enthusiasm for the potential of polygenic risk estimation to enable a new era of preventive clinical medicine is recognition of a need for ongoing research into how best to ensure equitable performance across diverse ancestries, how and in whom to assess the scores in clinical practice, as well as randomized trials to confirm clinical utility.
Figure 2: Utility of polygenic scores. (a) Distribution of a polygenic score with shading reflecting the proportion of the population with 3× increased risk for prevalent coronary artery disease (CAD) versus the remainder of the population. (b) Cumulative lifetime risk of CAD by age 75 stratified by quintiles of the polygenic score distribution. (c) Cumulative risk of CAD by age 90 stratified by Pooled Cohort Equations risk category. (d) Predicted probability of CAD by age 75 in each percentile of the polygenic score distribution stratified by carrier status for a familial hypercholesterolemia variant. Horizontal dashed lines show the probability of disease for people with average polygenic score.
Figure 5: Associations of polygenic scores and risk-enhancing factors with coronary artery disease (CAD). Hazard ratios with corresponding 95% confidence intervals for incident CAD associated with risk-enhancing factors in the UK Biobank, calculated using Cox proportional-hazard models with covariates of enrollment age and sex in base model (red), or enrollment age, sex, and Pooled Cohort Equations 10-year risk estimate (blue).