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Genetic Counselling and What to Consider Before a Genetic Test
Having a genetic test is a big decision which deserves a lot of thought and consideration, especially since the results of your genetic test can impact the rest of your family. As genetic tests highlight the inheritance patterns for a disease, they also help identify other family members who are at risk or potential carriers of the disease. Knowing that you contain mutations responsible for causing IRDs and that you could potentially pass this mutation to your children can be very worrying.
Genetic professionals are health care professionals with specialist expertise in medical genetics and counselling and work as part of a larger health care team. Genetic counsellors provide information and support to individuals or families considering a genetic test and can explain the implications of this decision on your family. Their work includes:
- Assessing the risk of a genetic disorder by researching a family’s history, evaluating medical records, and conducting a physical examination of the patient and other family members when indicated.
- Examining and evaluating the impact of genetic testing from a medical, social and ethical perspective in each case.
- Provide the support and information needed to assist an individual and their family in making a decision about genetic testing.
- To interpret the results of genetic tests and medical data.
- To provide counselling or refer individuals and families to support services.
- To be an advocate for the patient and their family in the healthcare system.
- To explain the next steps for a patient or their family including possible treatments options.
- To discuss life choices including family planning.
As we learn more about genetics and the complexity of genetic conditions including IRDs and REDs, the role of a genetic professional has become more specialised. For example, they may work only on a specific IRD.
A genetic counsellor or genetic nurse can help with testing decisions and support issues, while a medical geneticist will make the actual diagnosis of a disease or condition. In the case of IRDs and REDs, only a geneticist can provide the most complete and current information about your condition.
Benefits
A genetic test has the potential to identify the exact cause of an IRD. It allows people to adjust their lifestyle and manage their particular condition as well as possible. Receiving an accurate diagnosis also makes it possible for an individual to participate in appropriate clinical trials and allows for access to relevant treatments, should they become available. These opportunities are only available to people who receive the results of a genetic test. The results of a genetic test can also be stored on a register that will help to not only populate clinical trials in the future, but help researchers to better understand the molecular basis of the condition.
For some, the results of a genetic test can assist in family planning decisions. Being aware that there is an increased risk of having a child with an IRD can also allow you to talk with your doctor to best plan for your future and prepare yourself, should you choose to have a family.
As most genetic conditions are inherited and affects many generations of a family, information about your genetic makeup (genotype) can be useful to other family members. For example, in some cases the risk of having a baby with a retinal dystrophy is not for the affected person but for a relative, which is evident in IRDs that have an X-linked pattern of inheritance.
Limitations
It must be stressed that taking a genetic test, waiting for and ultimately receiving the results can be a very stressful and emotional experience for an individual and their family. People eventually diagnosed with IRDs often describe the actual diagnosis as a relief, because they now have a definitive answer and feel empowered to make well informed life decisions. However they have also described feelings of anxiety and guilt, particularly if they have passed disease-causing mutations to their children. With this in mind, it is crucial to talk through the possible outcomes, be they positive or negative, of a genetic test with your loved ones.
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As many treatments for IRDs are still in the development phase, a genetically confirmed diagnosis may not lead to an intervention or treatment now or in the future. Although there are over 260 genes described that can be mutated in persons with IRDs, they explain only 60% of the potentially causative genes. It is very important to note that in some cases, the gene(s) responsible for a genetic condition have not been identified. Some genetic mutations are very difficult to find with current laboratory techniques. For those trying to get a diagnosis to enable access to information on inheritance and disease pathways, this can be very frustrating.
As genetic mutations are passed through generations of families the results of your genetic test may have a direct impact on other family members. It is very important to consider this, and talk through these concerns with your family members and genetic counsellor.
Can results be wrong?
Because genetic test have very important implications for the individual and their family, they are treated very carefully. Numerous steps are taken to ensure that the correct result is given. If a mutation is found it is always double checked to ensure that the result is correct. Often, scientists will perform another test to ‘cross check’ the first result. Procedures are also in place to make sure that samples do not get mixed up. Additionally, many laboratories take part in Quality Assurance (QA) schemes which help ensure that they perform good quality, reliable genetic tests.
Note: Unless a patient requests that their sample be discarded after testing, a laboratory will usually store the DNA, and may store chromosome samples. Laboratories will be happy to let you know about your sample, and individuals can request at any time that their DNA be destroyed or returned to them.