Researchers isolate heart attack gene

The first gene to be definitely identified as a cause of heart attacks has been discovered by scientists at a US clinic, researchers said.

The first gene to be definitely identified as a cause of heart attacks has been discovered by scientists at a US clinic, researchers said. Data published in the December 28 issue of Science showed that a mutation of the gene, MEF2A, discovered in an analysis of the genetic makeup of 21 members of an Iowa family, has a direct causal relationship with coronary artery disease and heart attacks. Researchers found that certain elements, representing 21 base pairs of nucleotides and seven amino acids, were missing from the gene in the Iowa family, which had been plagued for generations by incidents of coronary artery disease. “What we discovered is a deletion mutation,” Eric Topol, chairman of the US Department of Cardiovascular Medicine at The Cleveland Clinic said. “This deletion affects coronary artery walls, making them less able to protect themselves from plaque build up and heart disease.” He said it is unlikely other families will be found with the exact same genetic mutation. But researchers will seek to identify smaller mutations involving the same gene that may be less dramatically linked to heart disease. People with the exact genetic mutation of the Iowa family have a 100 per cent chance of having a heart attack or developing coronary artery disease, he said.”For them, it’s not a matter of ‘if’, it is a matter of ‘when’,” he said.”For that reason, we think this specific mutation will prove to be rare. “Most genes that will be discovered to induce heart attack will be more common and not carry as high a risk.”With or without a genetic predisposition to heart disease, there is a vital role to be played in preventing its onset by an individual’s willingness to control their weight, blood pressure and diet, he said. The MEF2A gene makes a regulatory protein that controls the expression of hundreds or even thousands of other genes in the endothelium, the barrier between blood vessels and blood elements, the research shows.The Cleveland scientists suspect that mutations to the gene weaken the endothelium, making it more susceptible to invasions and attacks by certain large cells. That allows the formation of atherosclerotic plaques. “Finding the gene opens a new avenue through which scientists can track the pathway that leads to coronary heart disease and heart attack,” Qing Wang said, in whose laboratory the discovery was made. Future research will focus on pinpointing the roles of the missing nucleotide pairs and amino acids, and of seeking ways of counteracting the affect of the shortfall on the artery walls, the researchers said. (Source: ABC Online News, Reuters, Science Mgazine Online November 2003)