Why Family History and Genetic Testing Should Always Go Together

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I have been a genetic counselor for nearly 20 years and in that time, I have worked with everything from prenatal to adult genetics.  No matter which discipline I was working in, family history was always my number one tool. 

Everybody’s personal and family history can hold clues to the types of diseases for which they may be at risk.  Therefore, it is important for genetic counselors to ask family history questions and document the health conditions that run in a patient’s family.

The world of genetics has the ability to sequence a person’s whole genome to inform them how to better prepare for potential health conditions, and perhaps even prevent them.  However, we have barely scratched the surface as far as understanding what all the information means.  Thanks to the evolution of sequencing technology and bioinformatics, genetic testing as a tool is becoming even more accurate every day.

As a practicing Genetic Counselor, I needed to learn how to counsel people through the process of sequencing their genome and decided to experience it first-hand by sequencing my own genome.  Before my blood was drawn, I created a full family tree for myself and discovered approximately five hereditary conditions were present in my family: hemiplegic migraines, hearing loss, celiac disease, hypertrophic cardiomyopathy and hereditary hemochromatosis.  I expected some of these to potentially show up on my genetic test.

As I sat down with my doctor to review my genetic test results, we found the answer to one of the five hereditary conditions running in my family - I am a carrier for hereditary hemochromatosis.  This is a recessive condition, which means that if someone has two faulty genes for hemochromatosis, they may eventually develop high iron levels.  I have only one faulty copy, which is unlikely to ever affect my health. 

We also discovered to our surprise an incidental finding - I am a carrier of MUTYH, a recessive condition characterized by an increased risk to develop colon polyps and colon cancer in those who carry two faulty copies of the gene.  Thankfully, I carry only one faulty copy of this gene, however, people like me may have a slightly higher than average risk for colon cancer. According to NCCN guidelines, I should start colonoscopies at age 40 and repeat them every year to stay ahead of any possible problems. 

Because these genetic traits are inherited, I have warned my family members so they can be tested, know what to watch for and prevent disease.

What does this mean for the other four hereditary conditions in my family? Am I off the hook for these because they did not come up as concerns on my genetic testing?  Sadly, the answer is “no”, and I must still watch for these other issues. 

Because we do not fully understand the human genome, just the basics, it is possible that I carry a mutation that is not detectable by current testing options.  To truly rule out these conditions, some of my affected family members would need to be tested to make sure that the mutation can be identified.  If the mutation can be found in them, and I don’t have it, then I am likely in the clear. But until that happens, I will continue to watch for signs of these conditions, doing what I can to prevent disease when possible.

My family history made me aware of 5 different conditions for which I may be at risk.  My genetic testing was able to rule out one condition, hereditary hemochromatosis.  It also was able to find one condition, MUTYH, which was not obvious in my family history.  Knowing this information has allowed me to be proactive in protecting myself and others in my family from this risk.   

If any diseases run in your family, write them down and discuss it with your doctor, so you too can protect yourself and your family.



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