Importance of Family History in Genetic Diagnosis

We’ve all heard that genetics plays a big role in the development of cancer, including both your individual genetics and changes acquired over your lifetime, as well as the genetics of what may be running in your family. Family history is one of the most important tools that providers use when estimating your lifetime risk to develop cancer, but we understand the difficulty in obtaining an accurate family history, as Dave highlighted in his blog post earlier this week. Sometimes it’s impossible to determine exactly what type of cancer caused your great aunt Martha’s death at a young age 50 years ago, especially if medical records aren’t available or detailed.  That said, an accurate family history can make a difference in someone’s overall risk assessment to develop cancer. The best you can do is find out as much information as possible about your family history before a genetic counseling appointment.  

Your family history guides the thought process of your genetic counselor and helps direct them towards one hereditarycancer condition, gene, group of genes or another, when discussing genetic testing options. Additionally, we know that genetic testing may not be informative in all families. For example, some families may look very suspicious for hereditary cancer, but the genetic testing will be negative.  In these families, the family history is particularly important in guiding your future cancer screening and risk management, because your providers will base these recommendations off of what cancers are in your family. For example, let’s say you have a very strong family history of colon cancer diagnosed at younger ages, but your genetic testing is negative. Chances are, you will still be followed more closely, and maybe more often, with colonoscopies and you may also start screening for colon cancer at a younger than average age.

So what do you need to ask and know when piecing together your family history? Typically genetic counselors will take a complete, 3-generation family tree (aka a pedigree) . That means they’ll be asking about your siblings, parents, aunts and uncles, grandparents, and cousins on both sides of your family, so it would be most important to gather information about all of those individuals. Your genetic counselor will likely ask whether or not your family members had any history of cancer, what type of cancer, how old they were when they were diagnosed, how old they were when they died, and what their ultimate cause of death was. Being prepared with as much of this information as possible will allow for a more thorough risk assessment and genetic counseling session.

Every family is different, and genetic counselors have likely seen everything from someone with 10 aunts and uncles and 50 cousins, to patients who are adopted with literally no information on their biological family. We also understand that cancer is a sensitive topic, and especially in older generations, was not always a comfortable subject to discuss with family members. Hopefully, the efforts of advocates like Dave will change this trend and encourage more open discussion and sharing about such an important issue.  In the meantime, do the best you can with the information you have, and your genetic counselors and providers will do the same!

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The information, including but not limited to, text, graphics, images and other material contained on this blog are for informational purposes only. The purpose of this blog is to promote broad understanding and knowledge of various health topics. It is not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician or other qualified health care provider with any questions you may have regarding a medical condition or treatment and before undertaking a new health care regimen, and never disregard professional medical advice or delay in seeking it because of something you have read on this blog. Ambry Genetics Corporation does not recommend or endorse any specific tests, physicians, products, procedures, opinions or other information that may be mentioned on this blog. Reliance on any information appearing on this blog is solely at your own risk.


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