One in 100 healthy people carries heart-condition gene

One in every 100 healthy people carry a faulty gene that could trigger a dangerous heart condition, scientists have found. Researchers at Imperial College London and the MRC Clinical Sciences Centre say 1% of the population are at risk from heart failure when the organ is placed under abnormal stress – such as through pregnancy or alcoholism – even if they appear otherwise healthy.

The study, published in the journal Nature Genetics on Monday, involved looking at rats with a faulty version of a gene called titin. They found that although the rats appeared healthy, placing abnormal stress on the heart triggered a rare heart muscle condition called dilated cardiomyopathy (DCM), which causes heart failure. DCM is a disease that stretches and thins the heart muscle so it becomes unable to pump blood around the body efficiently. It affects one in 250 people in the UK and is the most common cause of heart transplants.

The researchers also looked at the genes of 1,400 healthy adults and created detailed 3D computer models using scans of their hearts at the MRC centre in London.

As expected, 15 people (about 1%) had the titin gene mutation. From looking at the 3D heart models, the scientists found that healthy people with the titin mutations had a slightly enlarged heart, compared with those who did not have the mutations. Researchers said this supported the findings in mice that suggested titin mutations, even in the absence of DCM, were having an impact on the heart, but that this started in a very subtle way.

Research is under way to find out which genetic factors or environmental triggers may put people with titin mutations at risk of heart failure.

Prof Stuart Cook, who led the study, said: “We now know that the heart of a healthy individual with the titin gene mutation lives in a compensated state and that the heart’s main pumping chamber is slightly bigger. Our next step is to find out which are the specific genetic factors or environmental triggers, such as alcohol or viral infection, [that] may put certain people with titin mutations at risk of heart failure.”

Prof Sir Nilesh Samani, medical director at the British Heart Foundation, which partly funded the study, said: “Most people with titin mutations live a long and healthy life but some will develop DCM.

“This excellent research shows us that there is much more to this condition than we originally thought. We can now use this knowledge to identify preventable or avoidable factors that trigger DCM in those who carry titin mutations and also develop new treatments for DCM [that] target the genetic basis of the disease.”

One in 100 healthy people carries heart-condition gene