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Genetic testing

Chromosomal microarray testing

A chromosomal microarray (array) is a test that looks for any pieces of chromosomes that are missing and any pieces that are extra. These changes to our chromosomes can sometimes cause health or learning concerns.

Your healthcare provider may suggest this test to look for a cause for your or your child's health or learning concerns.

An array is done on a sample of blood. It can give 4 kinds of results:

  • Positive: The array found a genetic cause for your or your child's health or learning concerns. Knowing the genetic cause of these concerns can provide helpful information for you and your healthcare team.
  • Negative: The array did not find anything. There could still be a genetic concern, but the array was not able to find it.
  • Uncertain: The array found a change, but it is not well-understood. The change may or may not explain your health or learning concerns. Your healthcare team will talk with you about next steps to try to better understand this result.
  • Incidental: The array found a genetic condition that is not related to your current concern. This can be surprising to learn about. Although an incidental finding does not explain your current concerns, it may still be medically important for you or your family.

Because the array only looks for missing and extra pieces of genetic material, some genetic causes for health concerns cannot be found by this test. In some cases, your healthcare team might suggest a more detailed test to look at your genes 'up close'.​​


Genetic testing for hereditary cancer​

Genetic testing can be used to find out if the cancer in your family has a hereditary cause. These cancers happen because of a gene that is not working properly and that can be passed along in a family. Only 5 to 10% of cancers have a hereditary cause.

  • If you have already had cancer, genetic testing might tell you why you got cancer.
  • If you are still being treated for cancer, it might be used to make treatment decisions.
  • It might also tell you if you have a high chance of getting other types of cancer and if there are ways to lower your chance of getting cancer or finding it early.

Genetic testing for hereditary cancer: Deciding who to test​

In Alberta, genetic testing is covered by Alberta health care if your personal history or personal and family history is suspicious for hereditary cancer.

Genetic testing usually starts with a family member who has had cancer. If a hereditary cause is found, then other family members can have genetic testing to find out if they're also at high risk of developing cancer.​


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