Cascade Testing: Finding Family Members with Genetic Conditions

Cascade testing is the process of informing family members of a genetic condition discovered within the family, followed by family members getting tested for the condition. Many people do not know they have a genetic condition until symptoms of that condition begin to affect their lives. By then, treatments might be less likely to work. Cascade testing offers one way of finding people with genetic conditions before they show symptoms, allowing them to take steps to prevent disease or treat it early.

How Does Cascade Testing Work?

If you have been diagnosed with a genetic condition, your family members are more likely to have it, too. Sharing your diagnosis with your family members allows them to learn more and be checked for the condition. Finding and treating a genetic condition early can lead to better health.

Family members who are most likely to have the same genetic change, or mutation, are tested first. From there, genetic testing “cascades” through the family depending on who has the genetic change and who does not. For example, if genetic testing shows that your mother has the same genetic change that you have, family members on your mother’s side would be tested. Your father’s side would not need to be tested.

How to Share Your Diagnosis with Your Family Members

The first step in cascade testing is to let your family members know about your diagnosis and genetic test results. Here are some tips to getting started:

1. Gather information to share with your family members. This may include the following:
   • Your diagnosis
   • Your genetic test report(s): Providing a copy of your genetic test report for your family members to take to a genetic counselor may help your family members receive testing quicker.
   • Your lab results related to the condition (such as blood work): Some genetic conditions, such as familial hypercholesterolemia, can be diagnosed without genetic testing.
2. Determine which family members should be tested first. A genetic counselor or medical provider can help you with this.
   • Your children, sisters, brothers, and parents are most likely to have the same genetic condition. Testing should start with them, with the limitation that genetic testing for adult-onset conditions is not generally done in children.
   • If a family member is not available for testing (for example, the family member does not want to be tested or has died), then moving to more distant family members is appropriate.
3. Decide how you would like to share the information with your family members. Some options:
   • Talk to your family members directly. Your genetic counselor can help you plan how to tell your family members, including what information is most important.
   • Write a letter explaining your diagnosis, including any related genetic testing and lab results. Sample letters are available for hereditary breast and ovarian cancer, Lynch Syndrome, and familial hypercholesterolemia.
   • Ask a family member to help you tell other members in your family. If you are unsure of how to contact certain family members, having another family member contact them may help you get the information out to more family members.
   • Ask family members to attend a genetic counseling or doctor’s appointment with you. If you are unsure or concerned about how to describe the condition to your family, a genetic counselor or doctor can assist. In addition, your doctor or genetic counselor might be able to provide a family letter explaining your diagnosis. Sample letters are available for hereditary breast and ovarian cancer and Lynch syndrome.

What if My Family Members Do Not Want to Talk about Hereditary Conditions and Cascade Testing?

Talking about having an increased risk of developing cancer, heart disease, or other hereditary conditions may be difficult for some family members. Before talking to family members about their risk of having the same genetic change, it could be helpful to anticipate possible reactions. For example, if you think that a family member might get emotional from learning this information, it might be best to tell them about this in a comfortable, private area.

If a family member refuses to talk about this information, it is important to respect their decision. Some people do not want to know about their risks for developing certain diseases because it will cause them too much anxiety. However, you can offer them other options, so they can get the information on their own terms. For example, you can provide them information on how to talk to a genetic counselor or give them a letter that they can open whenever they are ready. Sample letters are available for hereditary breast and ovarian cancer, Lynch Syndrome, and familial hypercholesterolemia.

How Do I Talk to My Children?

The process of talking to children about hereditary conditions may differ from talking to adult family members. Your children’s immediate concern might be how the condition will affect your health and the impact that will have on them. Your child’s age may affect how you talk to them about your condition and their chances of having it. For younger children, it may be helpful to tell them smaller pieces of information over time to allow them time to process the information you share. Older children may want to learn all the information in one conversation, and then want to talk to a medical provider about their own health risks. A genetic counselor can help you plan how to tell your children about your condition and their risks, and provide information on when your children should get genetic testing.

Next Steps for Family Members 

After sharing this information with your family members, they may ask you what they should do. Below are some tips to help your family members get checked for the genetic condition:

1. Your family members can get genetic counseling. A genetic counselor can help your family members order genetic tests. You can contact your genetic counselor for help, or you can find other genetic counselors using the National Society of Genetic Counselors directory. Genetic counselors are available through in-person and telehealth appointments.
2. Encourage your family members to tell their doctors about your diagnosis. Their doctors can help them determine the best management plan.

Important Topics to Discuss:

Family members may have some concerns after you share this information with them. You and your family members might want to talk to a medical provider or genetic counselor about the following:

• Genetic testing may be free: Some genetic testing companies offer free cascade testing for family members. Contact your genetic counselor or doctor who ordered your testing to see if your family members qualify. In some cases, free testing is only available for a certain amount of time after a family member’s genetic test.
• Insurance Protections: Genetic test results are protected under the Genetic Information Non-discrimination Act (GINA). This legislation prohibits health insurance companies and employers from discriminating against an individual based on their genetic information. However, GINA does not protect individuals from discrimination by life, disability, or long-term care insurance companies.
• Community Support: You and your family members might find it helpful to connect with others with the same genetic condition. One way to do this is through online support groups such as Kintalk, FORCE (Cancer), the Family Heart Foundation (familial hypercholesterolemia), and Genetic Alliance (rare genetic disorders). Your genetic counselor may have additional resources to help you and your family connect to other families. The Disease Info Search database includes information on support groups for several different genetic conditions. 

How cascade testing is done can depend on what diagnosis you have. Learn more about cascade screening for

HEREDITARY BREAST AND OVARIAN CANCER
LYNCH SYNDROME
FAMILIAL HYPERCHOLESTEROLIMIA