“I just tested positive. Does my partner need testing?”

If you receive a positive genetic test result for a hereditary cancer gene, one of the most important things that you can do is share this information with close relatives such as siblings, parents, and children. These family members may have a 50% risk to carry the same pathogenic variant and could be at increased risk for cancer. One person who may also be informative to test is your partner. They may not be your biological relative but testing your partner could reveal important risk information for your children (or future children!).

Many hereditary cancer gene mutations are passed down in an autosomal dominant pattern. This means that a person only needs one abnormal copy of the gene to be at increased risk for cancer. Close relatives (brothers, sisters, parents, children) have a 50% risk to carry the same pathogenic variant. However, there are some hereditary cancer genes where it is possible for an individual to inherit two abnormal copies of the gene (one from each parent). If both partners carry mutations in the same gene, there is a 1 in 4 (25%) chance that a child would inherit both abnormal copies. Having two abnormal copies of a gene often leads to a more severe childhood-onset condition. A genetic counselor can inform you if your specific gene mutation is associated with one these syndromes. Here are a few examples:

Even though these conditions are rare, testing your partner can clarify the risk that you may have a child with two abnormal gene copies. This is especially important if your partner has a family history of cancer. There are even technologies that may prevent these conditions, including Preimplantation Genetic Diagnosis (PGD). Learning if your partner also carries a pathogenic variant in a hereditary cancer gene can help you better understand the risks for your children or future children. If you would like to learn more about these conditions you can find a genetic counselor near you through the ‘Find a Genetic Counselor’ search tool available at www.NSGC.org

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