Things to consider prior to genetic testing
There may be several reasons you wish to take a genetic test. In families with suspected hereditary cancer genetic testing is used to determine whether the cancer is caused by a pathogenic variant. Another reason is to identify if you are a carrier of an already known variant in the family.
Regardless of the reason, there are some common aspects that are good to consider before taking a genetic test. As we are all unique individuals, some aspects may feel relevant to you while others may not. There may also be aspects that are important to you that are not covered in this text.
Potential upsides
- Most of the time a genetic test gives a very accurate estimation regarding whether you have an increased risk of developing a condition or disease. While learning that you carry a pathogenic variant can be difficult, there may be relief in knowing. For individuals that do not carry a pathogenic variant, the test result often offers great relief and decreases worry.
- A genetic test can identify a syndrome, disorder, or disease that can be treated or prevented.
- A genetic test gives a possibility to calculate the risk of passing on the pathogenic variant future children. When a prospective parent is a carrier of a pathogenic variant, preimplantory genetic testing can be used to prevent the variant from being passed on to future generations.
- The identification of a pathogenic variant in one individual gives the opportunity for relatives to test if they are carriers too, and thus gives them all the opportunity to the above-described positive aspects.
Potential downsides
- Waiting and getting a result from a genetic test can cause feelings of relief, fear, worry, or guilt.
- A genetic test cannot be undone once you have been informed of the result.
- Genetic tests may reveal family secrets regarding paternity and adoption since the next step after a pathogenic variant has been identified is typically to map out how the variant has been passed down in the family.
- A genetic test will have implications for your family members or relatives in most cases. It may be hard to inform relatives of the risk of being carriers, and there is also a risk that they do not want to know.
- The same pathogenic variant may result in different risk grades, even within the same family. This is usually hard to predict in advance.
- Not all hereditary disorders or diseases can be prevented or treated. For some it still is a relief to know since this gives the opportunity to plan accordingly. Others would rather not have known.
- For some variants, known as VUS’s, there is not enough information as of today to know if they are associated with increased risk. These variants are not typically clinically relevant and are therefore not reported.
- A negative genetic test does not exclude all hereditary risk, as only genes related to moderate or high risk are tested. Some hereditary risk may be due to the accumulation of several low-risk variants. In these cases, family history can be used to assess risk.
- A negative result may give a false sense of security. It is still recommended to participate in nationally available screening programs.
iCellate offers genetic counseling that will help you sort out your thoughts before ordering a genetic test. The purpose of genetic counseling is to help you make an informed decision regarding testing – the decision is ultimately your’s. Genetic counseling also helps you prepare for potential test results.
The genetic counselor cannot assess how likely it is to identify a pathogenic variant associated with an increased risk of cancer in your DNA. While a family history of cancer increases the probability of a pathogenic variant, the family history model is insufficient in finding carriers. Approximately 97% of carriers are consequently unidentified – genetic testing can help to identify more carriers.
Anna Hellquist, Genetic Counselor at iCellate Medical AB, PhD Cell and Microbiology