How does DNA increase your risk of developing a disease? 

We are more than 7 billion on this planet and yet only identical twins that share the same DNA will look the same. Essentially, your DNA is what makes you different from everyone else in the world. Your DNA stores all the instructions your body needs to develop and function properly, although your environment and lifestyle have a big impact too. Your DNA contains information about various traits like blood group¹, eye colour², height³ or athletic performances⁴. In some cases, all of the information about a trait will be in your DNA; in other cases, the combination of your DNA with the environment and lifestyle habits will determine the trait.

How are diseases linked to DNA?

Many variations in the DNA are possible which can affect these traits and lead to diversity. Unfortunately, these variations in the DNA can also lead to diseases. In fact, a variation in a single gene can lead to rare diseases like cystic fibrosis. It is also possible that the sum of genetic, environmental and lifestyle factors can lead to the development of a disease. For diseases such as hypertension or cancer, there is no single genetic variation that can cause the disease by itself. These types of diseases are called multifactorial or complex diseases as they are caused by a sum of factors. No factor will be able to cause a disease independently; however, an accumulation of these factors can. Each factor therefore increases the risk of developing a disease. 

An example of a multifactorial disease is pulmonary hypertension which has genetic, environmental and lifestyle risk factors⁵. For instance, several genetic variations in different genes are linked to an increased risk of developing the disease⁶ as are environmental factors such as asbestos exposure, lifestyle habits like smoking, and other factors like older age and other medical conditions⁵. This does not imply that everyone who has been in contact with asbestos or has a genetic variation associated with the disease will develop pulmonary hypertension, but their risk is higher than the general population. 

Do all the risk factors have the same impact? 

It is important to note that not all risk factors for a disease have the same weight, as some might increase the risk more than others. This is the case for breast cancer where, after the age of 50, women with a mutation in the BRCA2 gene will have a disease risk of 28%, and this number goes up to 51% for women who have a mutation in the BRCA1 gene⁷. Although variations in BRCA1 increases the risk of having breast cancer more than BRCA2, other risk factors need to be present in both cases for the disease to appear. The difference is that fewer additional risk factors need to be present alongside BRCA1 than BRCA2 mutations for breast cancer to occur. Overall, multiple risk factors need to be present for a disease to develop and a single risk factor cannot cause the disease by itself. 

How much can DNA tell me about my risk for a disease?

Although the current state of science cannot say for sure if you will develop a disease, it is possible to identify your risk factors and genetic predispositions. Knowing this type of information can lead to preventive steps to be taken just like knowing what the weather will be like before going on a trip to pack appropriate clothing. Science has advanced enough to identify factors that are linked to diseases and cause them, but there are still many risk factors being identified each day. The past years’ findings and the pace of research today make the progress of genetics in the medical field very promising. With the right teams and scientific partners, the commercialisation of life-changing solutions is accelerating. Through the evolution of science and breakthroughs, it will become increasingly possible to predict if and when someone will get a disease.

Today, genetic variations remain risk factors for diseases. However, knowing your own genetic predisposition for diseases enables you to worry about the right environmental and lifestyle factors to consider. This is what we call personalised prevention. Hyperion’s DNA test is now available to learn more about genetic predispositions for a variety of diseases and to allow personalised prevention actions to be taken through your doctor or one of our genetic counsellors. Read our article dedicated to the process of a DNA test to learn more. 

References:

1. Baylor Scott & White Health. “Blood Type Genetics and Compatibility.” . Accessed 21 June, 2021. https://www.bswhealth.com/patient-tools/blood-center/blood-type-genetics-and-compatibility. 

2. Sturm, Richard A. and Mats Larsson. “Genetics of Human Iris Colour and Patterns.” Pigment Cell and Melanoma Research 22, no. 5 (Oct, 2009): 544-562. doi:10.1111/j.1755-148X.2009.00606.x. https://api.istex.fr/ark:/67375/WNG-LGP1FV2Q-6/fulltext.pdf. 

3. Lettre, Guillaume. “Recent Progress in the Study of the Genetics of Height.” Human Genetics 129, no. 5 (May, 2011): 465-472. doi:10.1007/s00439-011-0969-x. https://www.ncbi.nlm.nih.gov/pubmed/21340692. 

4. Ahmetov, Ildus I., Emiliya S. Egorova, Leysan J. Gabdrakhmanova, and Olga N. Fedotovskaya. “Genes and Athletic Performance: An Update.” In Genetics and Sports. Vol. 61, 41-54. Basel, Switzerland: S. Karger AG, 2016. 

5. National Heart, Lung, and Blood Institute, National Institutes of Health and U.S. Department of Health and Human Services. “Pulmonary Hypertension.” . Accessed 21 June, 2021. https://www.nhlbi.nih.gov/health-topics/pulmonary-hypertension. 

6. Girerd, Barbara, Edmund Lau, David Montani, and Marc Humbert. “Genetics of Pulmonary Hypertension in the Clinic.” Current Opinion in Pulmonary Medicine 23, no. 5 (Sep, 2017): 386-391. doi:10.1097/MCP.0000000000000414. https://www.ncbi.nlm.nih.gov/pubmed/28661905. 

7. Varol, Umut, Yuksel Kucukzeybek, Ahmet Alacacioglu, Isil Somali, Zekiye Altun, Safiye Aktas, and Mustafa Oktay Tarhan. “BRCA Genes: BRCA 1 and BRCA 2.” Journal of B.U. ON. 23, no. 4 (Jul, 2018): 862-866. https://www.ncbi.nlm.nih.gov/pubmed/30358186.