To learn about DNA, it helps to start with our genes. We inherit our genes from our parents. Genes contain instructions for all of our traits – such as hair color, eye color, aspects of our health – many things that make us who we are. Although we cannot see them, genes are in the millions of cells throughout our bodies. Genes are found in structures called chromosomes, which are also in our cells.

Genes are made up of chemical building blocks called DNA, abbreviated as “A,” “C,” “T” and “G,” which are spelled in a very specific order to make up a gene. Since genes have instructions for our health, small changes in the way our DNA is spelled in a gene – like a typo – can impact our health. These small changes are called DNA variants.

One type of genetic testing is called DNA sequencing, which studies the DNA within our genes to look for DNA variants. Some DNA variants cause minor traits in us, like the color of our eyes. Other DNA variants can impact our health, such as DNA variants that cause us to have an increased risk for cancer.

Genetic testing looks for DNA variants to figure out a genetic cause or risk for health problems. Knowing if you have a genetic health risk can help you and your doctors plan for any medical checks or tests you should have to maintain your health, and also about any health risks to your family members.