19 February 2016
A new comprehensive genetic test has been developed to diagnose the most prevalent inherited cardiac conditions (ICCs) following international work led by experts at Royal Brompton Hospital and Imperial College London.
The cutting-edge blood test looks for mutations in all of the genes that are currently known to cause ICCs, improving diagnosis for patients.
In one test, 174 faulty genes which are known to be associated with ICCs can be detected. These include heart rhythm problems (arrhythmias), cardiomyopathies (which affect the size and shape of the heart muscle), diseases affecting the aorta (aortopathies) and hyperlipidemias (when patients have a high level of fat in their blood).
ICCs are thought to affect over half a million people in the UK and can be life-threatening. When there is an ICC in a family, the most accurate way to determine which family members may actually develop the condition is through a genetic test. This means that steps can be taken to reduce the risk of sudden death, such as surgery, medication or lifestyle changes.
Research carried out at Royal Brompton Hospital showed that the new test could reliably detect mutations in all known genes associated with ICCs. The findings are published today in the Journal of Cardiovascular Translational Research.
Previous genetic tests for ICCs looked at a smaller number of genes and were only able to identify specific conditions, leading to greater costs and more work, meaning that patients faced a longer wait before a diagnosis could be made. The research found that new test, which is available to all testing labs in the world, is quicker and more reliable, reducing costs and allowing patients to be diagnosed quickly and accurately.
Around 40 patients a month are now being tested in this way at Royal Brompton Hospital.
Dr James Ware, consultant cardiologist at Royal Brompton & Harefield NHS Foundation Trust and clinical senior lecturer in genomic medicine at Imperial College London, is one of the study’s lead researchers. He said:
“Genetic tests are invaluable when managing inherited heart conditions. They can help to make the initial diagnosis, and to choose the best treatment for the affected person. But where they make the biggest impact is in looking after that person's family.
“Without a genetic test, we often have to keep the whole family under regular surveillance for many years, because some of these conditions may not develop until later in life. This is costly both for those being monitored and the health service, and can cause a great deal of anxiety for family members.
“By contrast, when a genetic test reveals the precise genetic abnormality causing the condition in one member of the family, it becomes simple to test other family members. Those who do not carry the faulty gene can be reassured and spared countless hospital visits.
“This new comprehensive test is increasing the number of families who benefit from genetic testing.”
Kelley Allen was diagnosed with Long QT syndrome, an inherited heart condition which causes life-threatening abnormal heart rhythms, after passing out in a swimming pool when she was 10 years old. Kelley’s two-year-old son, Jayson, was tested for the condition at Royal Brompton Hospital soon after he was born.
Kelley, aged 27, from Essex, said:
“Jayson was tested as soon as he was born and diagnosed with Long QT syndrome shortly after. He takes beta blockers every day to control the condition. We are so fortunate that genetic tests exist. It has meant that my mum and brother were also able to be tested and we have peace of mind in the knowledge that my brother does not carry the gene.
“I’m so grateful for the research which means that tests like this exist and I hope they can continue to help many more people like us. Without the test, I can’t imagine what might have happened to Jayson.”
The genetic test is a result of international collaboration between researchers at the NIHR Royal Brompton Cardiovascular Biomedical Research Unit (BRU), Imperial College London, MRC Clinical Sciences Centre, National Medical Research Council of Singapore and Duke-NUS Institute of Precision Medicine (PRISM). It was funded by the British Heart Foundation and the Health Innovation Challenge Fund (HICF), which is a partnership between the Department of Health and the Wellcome Trust.