Almost 17,000 people in Northern Ireland may be living with a hidden fatal faulty gene that could lead to developing heart disease or dying suddenly, a leading charity has warned.
British Heart Foundation (BHF) has said that thousands of people could have the deadly inherited heart conditions– but not know.
The condition could span generations – and someone living with an inherited heart condition has a 50:50 chance of passing it on to their children.
The charity today launches its Fight for Every Heartbeat campaign to highlight the importance of urgent research into inherited heart conditions which are hidden within so many family trees.
It says there is an urgent need to accelerate research into inherited heart conditions.
Previous estimates suggested up to 11,000 people here could be living with the gene but under-diagnosis means this figure may be much higher.
Each year around 20 apparently healthy people aged 35 or under are victims of sudden cardiac death with no explanation, leaving their families shocked and distraught.
Despite advancements in research into inherited heart conditions, many faulty genes still remain undiscovered.
Finding those genes is the first step towards developing improved genetic tests to find people at risk.
An early diagnosis can mean the difference between life and death.
Professor Peter Weissberg, Medical Director at the BHF, said: "More research is now urgently needed to identify all the genes responsible for these deadly disorders.
"Pinpointing genes which cause inherited heart conditions will allow affected children to be protected and, in the long term, will lead to new treatments to overcome the effects of the faulty gene."
The campaign on television and online features a baby, Zara, whose mum discovered that she had a faulty gene for an inherited heart condition before she became pregnant.
Two years ago Patricia Sheridan's local football club – St Joseph's in Madden, Co Armagh – held a screening which she sent her oldest son and daughter to. She later received a call to send her son for tests at her GP.
Nothing showed up on an ECG but she pushed for a specialist tests.
Her son underwent further tests which included a genetic blood test.
As a result her husband and another son were diagnosed with Long QT Syndrome after a series of screenings.