Preimplantation Genetic Testing Considerations: Should we test for adult onset conditions in the embryo?

Preimplantation genetic testing (PGT) is genetic testing of embryos created with in-vitro fertilization. PGT can test the embryos for the number of chromosomes it has or if the embryo has a genetic condition, like cystic fibrosis. Since PGT, numerous individuals and couples have gone on to have the families they hoped for without the medical complications associated with genetic syndromes. In America, there aren’t limitations put on the conditions that PGT can assess for. However, other countries may put limitations on what conditions can be assessed.  For more information on PGT, please check out our information page on it.


Often, people think we can select eye color and height with PGT. However, the genetics of these traits are complicated, and the technology is not yet there. There is certainly debate on whether we should proceed with trait selection of our embryos and please continue this debate. Today’s focus will be on a different debate which is: should embryos be tested for adult onset conditions?


When someone has an adult onset condition, they usually do not have symptoms until they are in their 20s, 30s, 40s, sometimes 50s. Generally, and arguably, the symptoms can be considered less severe when compared to conditions that start in childhood and end a life within a few months or years such as tay sachs.

The genetics community has debated whether it is permissible to test children for adult onset conditions. The cited reason against this testing is the child’s autonomous choice to know or not know is being taken away from them. Adult onset conditions likely does not have treatment in childhood nor a cure. The child may feel anxious with the knowledge but not being able to “do anything” about it.


A primary example of an adult onset condition involved in this debate is Hereditary Breast and Ovarian Cancer Syndrome (HBOC). HBOC is a cancer predisposition syndrome caused by changes to the BRCA1 or BRCA2 genes. We all have the BRCA1 and BRCA2 genes. However, people with HBOC have a change in one of their genes that causes the gene to no longer complete its function. The function of the gene is to suppress tumor cells from forming. If the gene is not doing this, then it is more likely a tumor cell will form and develop into cancer. People with changes in this gene have a higher chance to have breast, ovarian, prostate, pancreatic, and skin cancer than people who do not have that change. However, this is not to say the person with HBOC will have cancer. 


It is difficult to have a cancer diagnosis due to having HBOC because it increases the chance to have another primary cancer. It is also difficult and a unique experience to know you have HBOC, but have not had a cancer diagnosis. There can be the incessant worry of when, if, and what kind of cancer you may end up developing because of this syndrome.  The argument is: should a child be tested for this condition even though there are no treatments or screening to be done during childhood? We can extend this questioning to the embryo period. Should we test embryos for these kinds of conditions to allow the ability to transfer embryos that do not have the condition avoid passing it on?


What is the harm?

One argued point of harm is that by selecting against the condition, other qualities are also being selected against as well. Many of us know people who have developed cancer and may even have HBOC. The people you know with HBOC would not have been selected to be implanted into a womb, and they would not have come into existence. A person is the sum of all their parts, not the sum of just one feature. By selecting against the possibility of a future cancer diagnosis, the rest of that future person is being selected against as well.


What is the benefit?

The benefit of selecting embryos without HBOC is making sure those future children do not have an increased risk to develop cancer along with the anxiety of knowing you have an increased risk for cancer because of your genetics.

The blog post is not intended to argue against one position for the other, but to pose the question: should there be any question of whether embryos should be tested for adult onset conditions like HBOC? 


* This blog constitutes general information about genetic testing and medical screening. This blog does not offer or provide medical advice or diagnosis, and nothing in this blog/article should be construed as medical advice or diagnosis. Do not rely on the information in this webinar to make medical management decisions. Please consult with a medical professional before making those decisions. Do not delay in seeking professional medical advice if you think you have a medical concern. Do not disregard professional medical advice based on any information received in this blog.