Blood type O may give some heart attack protection
Study finds two genes may be linked to heart disease
15th January 2011 - Investigators have identified two new genes associated with heart disease that could lead to better ways of recognising those at risk and preventing heart attacks in some.
The findings also suggest that people with type O blood have some natural protection against heart attacks, even when they also have plaque-clogged arteries.
Researchers analysed the DNA of nearly 12,400 people who had coronary artery disease (CAD) and 7,400 people who did not. In an effort to identify genes specific for heart attack, they also compared the DNA of almost 5,800 CAD patients who had a history of heart attack with 3,600 patients who had no such history.
The research included data from the British Heart Foundation funded ‘Family Heart Study’.
Type O blood suggests protection
The initial analysis led to the discovery of ADAMTS7, a gene linked to the build up of plaque in the arteries leading to the heart, says study researcher Dr Muredach Reilly of the University of Pennsylvania in the US. The secondary analysis led to the identification of an association at the ABO blood group gene.
When arterial plaque was present, the same enzyme found in people with type O blood appeared to offer protection against heart attack. But this does not mean people with type O blood can ignore other risk factors for heart disease, Reilly says.
The research appears online in the January 15th issue of The Lancet.
“People with this blood type appear to have some mild protection against heart attack, but genes are just one part of the story,” he tells us.
Having high blood pressure, high LDL ‘bad’ cholesterol, being a smoker and being overweight all contribute to heart attack risk regardless of a person’s blood type.
Gene variant linked to plaque
The newly discovered gene variant ADAMTS7 is one of about a dozen genes associated with heart disease risk identified within the last few years, Reilly says.
“Most are associated with plaque build up [known medically as atherosclerosis] and not with other known heart disease risk factors,” he says. “This suggests we may have a more targeted approach to preventing this risk factor in the future.”
He adds that the identification of the heart-attack-specific gene variant is especially significant because atherosclerosis is so common in the elderly.
“Almost everybody over the age of 60 or 65 has plaque,” he says. “This marker could help us identify people with plaque who won’t have problems, or at least won’t have them until they are in their 80s or 90s.”
The hope is that the already identified heart-disease-related genes, along with the discovery of others in the near future, will lead to treatments targeted to a patient’s individual risk, genetic researcher Luca Lotta, tells us.
The genetic research should also lead to better ways of identifying people at risk.
Lotta is a post-doctoral fellow researching the genetics of heart disease at the University of Milan.
“As of today, the benefits of genome-wide profiling have not been established,” he says. “But as our knowledge of the genetic predisposition for cardiovascular disease and other diseases deepens, the impact and importance of genetic testing will increase dramatically.”