The Science Behind Genetic Testing – Unlocking Your Genetic Code
With Katherine Hodson, Certified Genetic Counsellor See Bio
Katherine Hodson specializes in genetic counselling. She is a graduate of Montreal’s McGill University and certified by both the Canadian Association of Genetic Counsellors and the American Board of Genetic Counselling.Hide
What are genes?
Genes are the units of information that tell the body how to grow, develop, and function properly. Our genes often contain changes or variations which are part of what make us different from one another. Genetic variations are shared between members of the same family, which helps to explain why family members often share certain traits.
Sometimes genes contain harmful changes or mutations, which causes them to not work as they should. These genetic changes can also be passed down within a family, which helps to explain why some health conditions such as heart disease or hemophilia, may run in families.
What is genetic testing?
Genetic testing is a medical test which looks at blood, saliva or other tissue samples to identify harmful genetic changes. Because genetic testing is similar to looking in the Vancouver or Toronto phone books for a single spelling error, it can take several weeks or months to complete.
When is genetic testing useful?
Genetic testing is available for more than 2000 health conditions, such as sickle cell anemia, Huntington disease or many others. Because most of these conditions are rare, testing is typically offered only if you have a family history of a condition, or if you are from a part of the world where the condition is more common. Genetic testing may also be helpful in families where there are more cases of common diseases than usual, such as breast cancer, which may suggest an underlying genetic predisposition.
Some people choose to have genetic testing to confirm a diagnosis, or to determine their own risk. Other people may choose to have testing while planning a pregnancy, to learn if a child may be at risk for a health condition that runs in their family. As well, most Canadian provinces also perform Newborn Screening, a special type of genetic testing which looks for rare but treatable genetic conditions which impact infants and children.
Why not test for everything?
Despite the mapping of the human genome more than a decade ago, it is not possible, nor helpful, to test all 20,000 genes. Scientists have only uncovered a fraction of the genetic contribution to many diseases and environmental and lifestyle factors are also known to play a role. While you may test negative for certain harmful genetic changes, other factors may still be at play.
Katherine Hodson specializes in genetic counselling. She is a graduate of Montreal’s McGill University and certified by both the Canadian Association of Genetic Counsellors and the American Board of Genetic Counselling.