Blood Test to Diagnose Inherited Heart Conditions

Peter Russell

February 22, 2016

A new genetic test has been developed to help diagnose people with inherited heart conditions, the British Heart Foundation has announced.

Research funded by the charity looked at a particular group of genes that could be reliably checked for all known heart condition genes using one simple test.

Frost Family

The research follows the launch of the Miles Frost Fund last month, a charitable fund in memory of Sir David Frost's son, Miles, who died suddenly last year aged 31 of an undiagnosed heart condition called hypertrophic cardiomyopathy (HCM).

The Frost family believe Miles inherited HCM from his father and aim to raise £1.5 million to ensure genetic testing for HCM and other inherited conditions is available throughout the UK.

The British Heart Foundation says previous genetic tests had limited value because they could only look for a smaller number of genes and were only able to identify specific conditions, leading to greater costs, more work, and delays in diagnosis.

Faster and More Accurate

It says the new test is quicker and more reliable and removes the major barrier to testing being available on the NHS.

The test, which checks 174 genes, has already been trialled at Royal Brompton and Harefield NHS Foundation Trust with approximately 40 patients being tested each month.

In a statement, Dr James Ware, a consultant cardiologist at the Brompton who helped lead the study at Imperial College London and the Medical Research Council's Clinical Sciences Centre, explains: "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 hugely costly for both the families and the health system.

"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 copy can be reassured and spared countless hospital visits.

"This new comprehensive test is increasing the number of families who benefit from genetic testing."

Inherited heart conditions affecting the heart and circulatory system are passed down through families and can affect people of any age. For many people, the first sign that they might have an inherited heart condition comes when a family member died suddenly with no obvious explanation.

'So Fortunate'

Kelley Allen was diagnosed with long QT syndrome, an inherited heart condition which causes life-threatening abnormal heart rhythms in a structurally normal heart. Her diagnosis was made after she passed out while swimming aged 10. Now aged 27, Kelley says she made sure her son, Jayson, was tested for the same condition.

"Jayson was tested as soon as he was born, and diagnosed with long QT syndrome shortly after," she told the British Heart Foundation. "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.

“I’m so grateful for the research which means that tests like this exist, and I hope that they can continue to help many more people like us. Without the test, I can’t imagine what might have happened to Jayson."

Professor Peter Weissberg, medical director at the British Heart Foundation, says in a statement: "As research advances and technology develops, we are identifying more and more genetic mutations that cause these conditions. In this rapidly evolving field of research the aim is to achieve ever greater diagnostic accuracy at ever-reducing cost.

"This research represents an important step along this path. It means that a single test may be able to identify the causative gene mutation in someone with an inherited heart condition thereby allowing their relatives to be easily tested for the same gene."

The research has been published in the Journal of Cardiovascular Translational Research.

Reaction

Commenting on the new study in a statement, Dr Yalda Jamshidi, senior lecturer in human genetics at St George’s, University of London, says: "The current study describes a new test whereby a combination of the genes previously implicated in cardiac conditions are sequenced together. The new panel shows some improvement over existing tests which have more limited numbers of genes included, and also more accurate results than DNA tests which aim to sequence all of the genes in the genome.

"The new panel is more comprehensive than existing smaller DNA test panels, however ultimately the difficulty with screening more and more genes will be in accurately determining which of the variants identified are indeed responsible for the disease."

SOURCES:

British Heart Foundation (BHF).

'Development of a Comprehensive Sequencing Assay for Inherited Cardiac Condition Genes', C Pua et al, Journal of Cardiovascular Translational Research.

Science Media Centre.

Reviewed on February 19, 2016

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