Today, understanding our genetic code is more straightforward than ever. By simply providing a saliva sample, we can discover information about our ancestry, our risk for certain diseases, and even some of our behavioural traits. One tool employed in this expanding field is the Polygenic Risk Score (PRS), which is a figure that estimates our likelihood of inheriting conditions such as depression, ADHD, schizophrenia, or autism.
But what exactly is a PRS, and where does it come from? A Polygenic Risk Score (PRS) is created by looking at many tiny changes in our DNA, called single nucleotide polymorphisms (SNPs). These changes add a small bit to the overall chance of getting a specific health condition. When you combine and adjust these changes, you get one number that represents your risk: your PRS. It’s a score that doesn’t determine your fate — but claims to reflect your statistical susceptibility based on how people with similar genetic profiles have fared in large-scale studies.
And yet, this concept — while seductive in its precision — is widely misunderstood.
Here’s the issue: PRS (Polygenic Risk Scores) are often misunderstood. People usually think of these scores as predictive. A high PRS? That probably means the condition is in your genes. A low PRS? You might think you’re safe. But that’s not quite how biology works — or how life progresses. PRS shows something more nuanced and significant: a sensitivity that depends on circumstances. Genes don’t directly cause outcomes. Instead, they can show what might happen, but only if the environment allows it.
Simply put, a Polygenic Risk Score doesn’t determine your future. Instead, it shows how much your environment might activate a certain biological…