An Everyday DNA blog article
Written by: Sarah Sharman, PhD
Illustrated by: Cathleen Shaw
Have you ever wondered why some health conditions seem to run in families, even if everyone has different lifestyles? Or why you might be more prone to certain illnesses than your friends? The answer often lies within your DNA, the invisible blueprint that influences everything from your eye color to your likelihood of developing conditions like heart disease or cancer.
Imagine your health as a complex game. You start with a unique set of inherent advantages and vulnerabilities, your genetic risk. But just like in any good game, your decisions, environment, and strategy all influence how things play out.
Thankfully, modern science gives us incredible tools to decode this blueprint and take proactive steps to manage or reduce those risks. Let’s explore what genetic risk truly means, how tools like polygenic risk scores and everyday environmental factors shape your health, and how knowledge, not luck, can become your strongest health strategy.
What is genetic risk?
Think of your DNA as a detailed instruction manual for your body. While the vast majority of our DNA is identical, each of us carries tiny, unique variations in our DNA code. Some of these genetic differences are entirely harmless, explaining why your hair is a certain color or how tall you are. Others, however, are linked to an increased or decreased likelihood of developing certain diseases. This inherent predisposition is what we call your genetic risk.
Researchers have identified specific gene variants that increase disease risk in certain diseases. In some cases, changes in a single gene can lead to rare but serious diseases like cystic fibrosis or Huntington’s disease. These are known as monogenic or Mendelian conditions.
In contrast, most common health conditions, such as heart disease, diabetes, and many cancers, are influenced by many genes acting together. These so-called polygenic conditions involve a constellation of genetic factors that combine with your lifestyle and environmental factors to affect disease risk. This collective influence is what we refer to as polygenic risk.
Historically, family history was our primary tool for assessing inherited risk. If your parents or grandparents had heart disease, you might assume you’re at higher risk, too. While valuable, family history can be incomplete (we don’t always know everything about our ancestors’ health) and doesn’t pinpoint the specific genetic factors at play.
What’s a Polygenic Risk Score?
Imagine that your genetic risk for disease is like the outcome of a board game, not determined by one factor, but by a long series of tiny moves, each contributing to the final result. A polygenic risk score (PRS) works by analyzing a wide range of genetic variants, each with a small effect on health, and calculating an overall risk estimate for certain conditions.
Researchers conduct large-scale studies, called Genome-Wide Association Studies (GWAS), to find small genetic changes that appear more often in people with a particular disease. Once identified, researchers can then analyze your individual DNA to generate a single score. This score indicates your relative genetic predisposition compared to a population, giving you a clearer picture of your inherited likelihood for certain conditions.
While still evolving, PRS already holds exciting potential. For instance, it could help identify individuals at higher genetic risk for conditions like early-onset heart disease or type 2 diabetes, even before symptoms appear. This allows for personalized screening recommendations or identifying who might benefit most from targeted preventive strategies. It’s a powerful tool to complement, not replace, traditional risk assessments.
Genes Aren’t Destiny: Environment Matters Too
Your DNA provides a starting point, but it doesn’t work alone. Your environment, lifestyle, and daily choices all influence which genetic risks may or may not become reality.
When we talk about “environment”, we’re speaking broadly about things including:
1. Lifestyle choices: Your diet, how much you exercise, whether you smoke, alcohol consumption, and even your sleep habits.
2. Social factors: Chronic stress, access to nutritious food, quality healthcare, and socioeconomic status.
3. Physical environment: Exposure to pollution or certain toxins.
This interplay is known as gene-environment interaction. Think of it this way: someone might have a high genetic risk for type 2 diabetes. However, if they consistently maintain a healthy diet, exercise regularly, and manage stress, they might effectively “buffer” that genetic predisposition, perhaps never developing the disease. Conversely, someone with a lower genetic risk might still develop type 2 diabetes if they consistently engage in unhealthy lifestyle choices. Your choices and surroundings can amplify or mute your genetic predispositions.
Benefits of Knowing Your Genetic Risk
Knowing your genetic risk serves as a powerful blueprint for building a healthier life. It doesn’t provide certainty, but it adds clarity, helping you identify possible vulnerabilities early and take specific action. Think of it as switching from guessing to navigating with a GPS.
Some advantages of understanding your genetic risk include:
- Personalized Screening: Elevated genetic risk may warrant earlier or more frequent health screenings. For example, women with a BRCA variant generally begin breast cancer screenings earlier than the general population.
- Informed Prevention: Genetic knowledge can guide decisions about diet, exercise, medication, or preventive treatments.
- Reduced Uncertainty: For individuals with unclear or limited family history, genetic testing offers clarity about risks that might otherwise remain hidden.
- Empowered Decision-Making: Genetic insight supports autonomy and confidence in making decisions, whether it’s choosing proactive surgery or planning a family.
Ready to Explore Your Genetic Health?
If you’re interested in understanding your personal genetic risk, organizations like The Smith Family Clinic for Genomic Medicine, LLC, part of the HudsonAlpha Institute for Biotechnology, are dedicated to the practice of genomic medicine. They offer general health risk screening, among other genetic tests. After undergoing general health risk screening, their board-certified genetic counselors analyze and interpret your results in the context of your medical and family history. Depending on your results, they can recommend personalized lifestyle changes or preventative screening measures. Taking that first step could help you better plan for your future, on your terms, with your unique blueprint in mind.
