13 May 2013
ByAppeared in BioNews 704
Heart Genetics: Predicting the Future?
Coffee Shop, Royal Brompton Hospital, Sydney Street, London SW3 6NP
Wednesday 8 May 2013
I'd not been to a Cafe Scientifique event before and was a little unsure of what to expect. The Royal Brompton coffee shop setting did at first feel strange; I'm more used to discussions in lecture theatres where there is a clear distinction between audience and speaker.
But the informal setting and refreshments created an open and friendly atmosphere, which is clearly what Cafe Scientifique events are all about. They aim to bring scientists, clinicians and the public together to chat about important scientific topics without the barriers that are often present elsewhere.
The subject on offer was heart disease and genetics, with questions being answered by clinical geneticist Dr Tessa Homfray and Stuart Cook, professor of clinical and molecular cardiology at Imperial College London.
Professor Cook kicked things off with an introduction that focused on that hottest of genetic topics - next generation sequencing (NGS) technology. He spoke of the revolution its development has had on genetic research.
He gave a particularly clear example of its power when discussing a recent breakthrough. For some time, the gene TTN had been thought to play a role in the heart condition dilated cardiomyopathy (DCM), but its status as the largest gene in the human genome proved prohibitive to meaningful examination with old technology. With the advent of NGS, Professor Cook's team were able to fully screen the gene, finding mutations explaining 25 percent of all DCM. This has of course not gone unnoticed – a grant has recently been awarded by the Wellcome Trust so that a test can be developed and brought to clinic.
Dr Homfray's introduction was more patient-focused. She sought to give answers and opinions on some of the most common questions patients ask on the benefits and risks of genetic testing. She explained that genetic testing can be a double-edged sword. In some cases a test can give vital information on the best treatments and drugs to prescribe. However, in others it may prevent a teenager from being permitted to play sports they enjoy for fear of triggering a dangerous heart event. This is because not everyone who inherits a mutation will necessarily develop disease, a phenomenon known as reduced penetrance.
But there's also the reverse of that coin, Dr Homfray pointed out; the value of negative test results should not be underestimated. In the case of inherited heart conditions, a negative result has the potential to take a huge weight off a patient's mind, allowing them a much freer lifestyle.
Many of the questions that followed were from patients and relatives of patients considering the ethical implications of genetic research and testing in conditions such as these. An emotive point was raised by a woman with end-stage hypertrophic cardiomyopathy, who had given blood for research purposes but had never received any feedback. She was also concerned that the rate of discovery in this area had seemed to lag behind DCM research.
Professor Cook explained that it can take many years for results from scientific studies to be published and that even then the path to any treatment is rarely straight. Unfortunately, from a patient perspective, progress may not seem to come fast enough.
Advances are being made, though. Professor Cook and his team are working to produce large databases of patient DNA sequences paired with detailed descriptions of their symptoms. These are being used to show connections and differences between various types of heart conditions. It is Professor Cook's aim to comprehensively describe the genetic underpinnings of cardiac disease, and it is difficult not to be carried away by his enthusiasm.
Dr Homfray responded insightfully to questions relating to sudden cardiac death and screening. She felt that while the sudden death of anyone is a tragedy, routine screening of the population can bring unnecessary fear and treatment. She went on to say even slightly abnormal results sometimes lead to people having to give up active lifestyles. Given the reduced penetrance of heart conditions, there was a suggestion that we may be being over-cautious if testing without prior reason.
I found the event highly enlightening; many important questions on genetic testing were brought up and intelligent, measured responses were given by both speakers. Although I personally would have benefited from a bit more of an introduction to heart disease and the distinction between the different conditions, topics were generally discussed in layman's terms.
Overall it seems there is reason for optimism for those with and at risk of heart conditions. As Professor Cook and Dr Homfray explained, progress is being made in our understanding of genetic disease, and we can be confident that this will ultimately lead to better treatment.