A new scientific discovery could help thousands of people affected by a deadly heart condition, researchers have said.

Scientists have found a new type of genetic change in the DNA of people with hypertrophic cardiomyopathy (HCM), a disease in which the heart thickens.

The disease, sometimes inherited in families, affects around 130,000 people in the UK, and can cause sudden cardiac death.

It had never been understood why HCM is so varied among family members with the same mutation and why people without mutations still go on to develop it.

It’s now time we think differently about the way this hidden heart condition is detected and treated

A British Heart Foundation (BHF) professor and his team at the University of Oxford found that a new genetic fault called “common variants” combined with rare mutations determines whether a person is susceptible to the disease.

The discovery means doctors can understand who needs to be monitored for the condition or ruled out from tests or treatment.

People who have HCM due only to the common variants are unlikely to pass the disease on to their children, the scientists found.

It was also revealed that lowering blood pressure in people with the disease could help prevent it from developing.

BHF Professor Hugh Watkins said: “It’s now time we think differently about the way this hidden heart condition is detected and treated.

“We now have a new genetic tool that we believe will better predict which members of affected families will have a bad form of the disease, identifying those who need early intervention.

“It will also take away the worry for many families as it enables us to identify those who are unlikely to pass faulty genes on to their children.

“This will reduce the need for unnecessary genetic testing and regular follow-ups.”

Professor Sir Nilesh Samani, medical director of the BHF and cardiologist, said: “This research is a major step forward in our understanding of the genetics that underpin hypertrophic cardiomyopathy.

These discoveries will bring long-awaited answers to many families, and free many individuals from the need for regular clinical checks and the worry of whether they have also inherited the disease

“It will revolutionise the way we screen people who have family members with this silent killer.

“HCM is one of the most common inherited cardiac conditions, affecting thousands of families across the UK.

“These discoveries will bring long-awaited answers to many families, and free many individuals from the need for regular clinical checks and the worry of whether they have also inherited the disease.”