Clinical psychologist Dr Kate Hawkins, from Great Ormond Street Hospital, talks about the issues families face when considering genetic testing
The two main reasons for genetic testing for the cardiomyopathies are to confirm a diagnosis in someone showing signs of the condition and to identify family members who are at risk of developing symptoms at some point in their lives.
While these goals sound simple and advantageous, there are a number of issues that need to be considered before deciding whether or not to proceed with testing.
What are the potential benefits?
A positive result identifies family members at risk of developing cardiomyopathy before they start to show symptoms. They can be screened regularly so that any symptoms or changes in heart structure can be identified early and appropriate treatments given as soon as they are needed. Those who are found not to carry the gene mutation need no longer attend screening.
What are the limitations?
Genetic testing predicts the possibility of future illness. It cannot tell you if a person will develop the condition, which particular symptoms he or she will experience, or how severe these symptoms might be. Symptoms, age of onset and severity of the disease vary greatly, even among members of the same family. While some gene carriers have severe, early onset disease, others have only minor heart muscle or rhythm problems, and others never show signs of the condition.
Not enough is known about early treatments to tell if they will be helpful. Although some preventative treatments may improve outcomes for gene carriers, they have not been proven and for some there may be a lack of treatment strategies.
Pre-test considerations
Deciding whether or not to undergo genetic testing raises important personal, social and ethical issues. Testing may create tension in families. For instance, there may be differences of opinion between couples or members of the extended family about whether or not someone has a right not to know. Some people feel strongly that having the information is vital in order to receive appropriate medical care. Others feel that finding out might threaten their identity or sense of themselves, or affect their lifestyle choices.
They may have concerns about being stigmatised and worry about implications for employment and life insurance. Others may choose not to confront the situation just yet and reserve the option for the future - especially if they are unsure how they would use the test results at that time.
Counselling
Genetic counselling is vital. It gives people accurate information about the confidentiality of the results and how testing might affect mortgages, employment rights and insurance. It will also encourage you to consider how different family members might react to the results. How might you feel if you tested positive? How would the information benefit the family as a whole? Who would you want to share the information with?
Post-test implications
People describe experiencing unexpected emotions after hearing test results. They range from feeling reassured and relieved to feeling anxious and guilty. Each of these emotions triggers a range of behavioural responses. When we are anxious, we typically try to avoid the source of the anxiety by pushing it out of our mind and avoiding conversations about it. Some people describe shock, feeling numb or ‘in denial’ about the results. Others may feel anger towards the person who shared the news with them, or resent friends and family members who don’t have to deal with this difficult issue.
Try to remember that all these responses are natural. Prepare yourself for the possibility that family members may not respond like you. Take time to absorb the information and adjust to the implications. Seek clarification from medical professionals and ask questions.
The implications for children
If you carry a specific gene mutation, each of your children has a 50 per cent chance of inheriting the same mutation. Even though we have no control over which genes are passed on to our children, many parents report feeling angry, scared and even guilty about it. As young children are not able to understand fully the consequences of testing, parents must decide on their behalf whether or not to proceed.
Finding out about a child’s gene status raises important questions for young people’s development. If a child tests positive, parents may encourage him or her to do non-athletic hobbies to avoid having to restrict a favourite sport during adolescence when symptoms of the condition may be found. Others feel it would not be right to influence their child’s lifestyle choices when the prognosis is unclear and they may not develop the condition.
For some parents, learning that their child is at risk of developing cardiomyopathy increases their anxiety and leads them to become overprotective. This may hit a child’s confidence and sense of self. For others, knowing their child is being screened regularly is sufficient reassurance.
Careful consideration is key before deciding whether to proceed. So do discuss your hopes and fears with family members, the CMA, your doctor or nurse, and a genetic specialist before you make a decision.
Dedicated to Damian McLoughlin, who died age 20 of cardiomyopathy. This site is supported by Damian's family and friends.
The