An international team, led by scientists from the Victor Chang Cardiac Research Institute has studied around 3000 people affected by the heart disease dilated cardiomyopathy (DCM) – a driver of heart failure and sudden cardiac arrest.
They discovered those who had a mutation in a particular gene called TTN were 21 times more likely to develop the disease than family members who did not carry a mutation.
For the first time, the team found that a person's general health and lifestyle factors; such as being overweight or having high alcohol consumption, contributed to an earlier DCM diagnosis.
The study published in the European Heart Journal involving 1000 families affected by DCM also found men with the mutation were more likely to develop DCM at a younger age than women.
Professor Fatkin, head of the Inherited Heart Diseases Laboratory at the Victor Chang Cardiac Research Institute, says: "Our study reveals just how much mutations in this gene raise the risk of developing DCM. That's a good thing for patients because it means doctors can keep a far closer eye on them, and ensure they have early access to medical treatments.
"We have also crucially shown is that it's not all down to your genes. Maintaining a healthy lifestyle and being on the right medications could help prevent or delay dilated cardiomyopathy for decades. We hope it will incentivise those at risk to exercise, eat well and drink less and better manage other risk factors too."
DCM affects approximately one in 250 people worldwide – that's around 32 million individuals.
Truncating mutations in the TTN gene are the most common genetic cause of DCM and can be tested for through a simple blood test but until now it was not known how much these mutations raised the risk of developing the disease, or how other risk factors, both clinical and lifestyle, contributed to the onset of the disease.
Clinical factors such as having high blood pressure or type 2 diabetes also increased the risk, whilst having a history of atrial fibrillation doubled the chance of getting DCM.
The findings highlight the need for more research and clinical trials to determine if people with TTN mutations would benefit from being given DCM medications before symptoms begin.
"There are still so many questions to be solved – for example should we be giving drug therapies to those at risk far earlier? Could that delay or prevent DCM from developing entirely, and if so when exactly should that therapy start?" adds Professor Fatkin.
About the study
The researchers recruited 3158 patients from 1043 families affected by TTN mutations. It was the largest study of its kind ever done and involved patients from Australia, North America, the UK, Europe and South Korea. Family members were assessed clinically and underwent genetic testing to see if they carried a TTN mutation.
The researchers first examined the link between the age of diagnosis and the type of mutation and then investigated the relationship between age at DCM diagnosis and cardiac risk factors (such as high blood pressure, coronary artery disease, obesity, diabetes, thyroid disease), and lifestyle factors (including alcohol intake and exercise patterns).
About Dilated Cardiomyopathy
Dilated cardiomyopathy causes the heart's main pumping chamber, the left ventricle, to enlarge and weaken .
This enlargement and thinning of the heart muscle affects its ability to pump blood effectively as the disease progresses, it can spread to other chambers of the heart and can lead to several serious complications including heart failure, arrhythmias, blood clots that can cause stroke or heart attack, leaky heart valves, sudden cardiac arrest and kidney disease.
