Shifting to the world of precision medicine. What is a Polygenic Risk Score and why is it important?

In recent years, we have been hearing more and more about genetics and precision medicine. Not long ago, it seemed like a dream that one could simply take a test and learn about their predispositions to illnesses. But this is becoming a reality thanks to tests that combine socio-demographic factors (ex. age) and clinical data (ex. weight) with polygenic risk scores (PRS) — a value used to estimate a person’s genetic predisposition to certain traits or conditions.

Unlike single-gene disorders, which are relatively rare and caused by mutations in a few genes—most common health problems, such as asthma, type 2 diabetes, heart disease, or pregnancy complications, are influenced by many genetic variants, each contributing a small effect. A PRS works by combining these small effects together, sometimes thousands (or even millions) of genetic markers, into a single score. The result is a number that reflects a person’s inherited risk for a given trait compared to the general population.

How can PRS be useful? PRS can be used in preventive health care by helping to identify those who are at a higher genetic risk for certain conditions. For example, if someone has a high genetic risk for heart disease, they may benefit from earlier monitoring, such as more frequent screenings or tests. In addition, PRS can guide lifestyle changes, like adjusting diet or exercise habits, to lower the risk of developing these conditions. It may also allow for more personalized medical advice, such as the use of preventive treatments tailored to an individual’s unique genetic profile — even if they are currently healthy. This proactive approach aims to catch potential issues early and improve long-term health outcomes. However, it is important to understand that a polygenic risk score is not a diagnosis. It only estimates probability, and it needs to be interpreted alongside other factors like environment exposures, lifestyle, and medical history.

In the BiSC cohort, we calculated polygenic risk scores (PRS) for several traits related to preeclampsia and cardiovascular diseases, and tested their associations with maternal pre-existing cardiovascular conditions, pregnancy complications and placental hemodynamics. The final aims are: (i) to investigate the shared genetic background across traits (ie. blood pressure vs pre-eclampsia) and (ii) stratify mothers according to their genetic predisposition when investigating the effects of environmental factors.

 

This news has been written by Waleria Popowska, a master student in Project BiSC.