The study, published in JAMA Cardiology, used data from the UK Biobank to analyse the genes of 469,789 people in the UK and found that one in 1,000 possessed genetic variants with a likely link to cardiac transthyretin (ATTR) amyloidosis. Among study participants with African ancestry, incidence was much higher, with one in 23 (4.3%) having genes thought to be linked to the disease.
Cardiac amyloidosis is where abnormal proteins, called amyloid, build up in the heart tissue, making the heart stiff and less able to pump blood. If left untreated, it is likely to be fatal within four to six years.
First author Dr Nay Aung, from the William Harvey Research Institute said: "Our study showed that people carrying these potentially harmful variants have a two-to-three-fold increase in the risk of heart failure and cardiac rhythm issues. This again highlights the need for early detection and monitoring for disease progression."
Previously, ATTR amyloidosis was considered rare, affecting between one in 120,000 and one in 830,000 people globally. In recent years in the UK, however, the number of people being diagnosed has increased. While some cases do not have a genetic basis, many cases of ATTR amyloidosis are hereditary, caused by a mutation in the transthyretin (TTR) gene. This mutation is much more common in certain populations in Portugal, Japan and Sweden, and among individuals with Black African ancestry.
The new study used 12 years of data from UK Biobank participants, and estimated the prevalence of 62 variants identified as having a possible link to the disease. It was found that people with these variants had a higher risk of heart failure, thickening of the heart muscle, and heart rhythm problems, even after adjusting for factors such as age, sex, BMI and cardiovascular risk factors. Despite this higher risk, hospital data showed only 2.8% of this group had been diagnosed with cardiac amyloidosis.
The researchers called for greater clinical vigilance for possible hereditary ATTR amyloidosis among people with these symptoms or with unexplained thickened heart muscle.
The study received funding from the Medical Research Council, the European Union's Horizon 2020 programme, Queen Mary University of London, the National Institute for Health and Care Research (NIHR) UCLH and Barts Biomedical Research Centre, Barts Health NHS Trust, St George's University Hospitals NHS Foundation Trust and St George's University of London.
