Each of us contains many slight variations in our genomes that make us unique. Most of these variations have little or no impact on our health. But that’s not always the case.
Sometimes if a DNA letter is missing or wrong in a gene’s instructions, it may produce a damaged protein, extra protein or no protein at all. Such changes in genes are called genetic mutations.
Genetic mutations can cause serious health problems because they affect proteins, which are the workhorses of your body.
For example, proteins form special scaffolds that help your cells keep their shapes. They serve as enzymes that help your stomach digest food. The molecule that carries oxygen in your blood is a protein, as are estrogen, testosterone, and other hormones.
The transmission of genetic mutations from one generation to the next helps to explain why many diseases run in families. If a certain disease runs in your family, doctors say you have a family history of the condition.
What genetic tests available for diseases?
Many rare diseases, such as cystic fibrosis and sickle cell anemia, are caused by mutations in a single gene. Single genes also are responsible for some of the rare, inherited types of cancer. Over the past couple of decades, researchers have developed genetic tests to detect mutations in many single-gene disorders. This has led to ways to prevent or reduce symptoms of some of these diseases.
Genetic tests also are available to help couples learn if they carry genetic mutations for rare diseases and if they are likely to have a child affected by the disease. If you are interested in such tests, a good place to start is talking to a genetic counselor or an obstetrician.
Most genetic tests involve taking a small sample of blood or saliva and sending it to a lab. At the lab, technicians purify DNA from the sample and use various technologies to see if it contains a specific genetic mutation. One approach involves placing DNA on tiny chips, called microarrays, that resemble the chips used in computers. The situation is far more complex for most common diseases, such as cancer, diabetes and heart disease.
Researchers are finding that multiple genes — along with lifestyle and environmental factors — interact to determine the risk of these and many other disorders. Another complication is that our genomes also contain genetic variations that protect us against certain diseases.
So, it will take some time before genetic tests are developed to provide a complete picture of your risks for common diseases. Until then, one important thing you can do for your health — and your family’s health — is to collect your family history.
Knowing what diseases have affected your blood relatives can help your healthcare provider. More information can be reviewed at http://www.surgeongeneral.gov/index.html