A new generation of tests is moving towards clinical use in the diagnosis of common diseases in the adult population, namely the “polygenic risk score” (PRS).

This tool calculates risk using hundreds or even thousands of genetic markers (not mutations) which only have very little effect on the disease individually. Using a mathematical formula, it becomes possible to estimate the effect that these variants have together. Indeed, together, these variants have a weight entirely comparable to a gene mutation, but while mutation is rare, these markers are present in everyone, and can therefore be used to diagnose the risk of disease and especially to implement risk reduction measures that are effective in these situations.

The PRS has two main practical spheres of application:

The first consists of screening individuals at risk of developing one of the illnesses frequent in the general population, in particular a cardiovascular disease (e.g. coronary disease) or a metabolic disease (e.g. type II diabetes). It has been demonstrated that risk reduction measures (e.g. physical activity) are able to reduce people's risk levels to the extent of placing them in a lower risk category (N Engl J Med 2016; 375: 2349-2358). Similarly, the risk of certain complications such as retinopathy (a vascular disease affecting the back of the eye that may occur in diabetics) may be predicted and makes these individuals eligible for special monitoring and targeted therapy in the future (Nat Genet (2020). https://doi.org/10.1038/s41588-020-0637-y).
The second application concerns predispositions to certain cancers (e.g. breast cancer, prostate cancer).

Genesupport - Genetic predispositions