US and Canadian researchers have identified a common genetic variation that can increase the risk of heart disease by up to 40 per cent. The study, published early online in the journal Science, suggests that two genes involved in controlling cell growth, aging and death could influence the risk of heart disease. A separate study by scientists based at Icelandic company deCODE Genetics, also published in Science, pinpointed the same region.
The studies showed that 25 per cent of Europeans have two copies of the variant - a 'single nucleotide polymorphism' (SNP) - which they estimate confer a 30-40 per cent increased risk of heart disease. The Icelandic work also suggests that the variation, which is located on chromosome 9, plays a role in a fifth of all heart attacks. The variant is located close to, but not within, two well known cell growth control genes called CDKN2A and CDKN2B. It is unclear how the newly identified variant exerts its effect, but scientists think it could be related to increased hardening and narrowing of the arteries.
The US/Canadian team looked at DNA samples from 23,000 patients and unaffected people, while the deCODE scientists studied 17,000 individuals. Professor Ruth McPherson, of the University of Ottawa Heart Institute, said that the effect of the variant was less than that of smoking or having a high cholesterol level. But she added that 'nonetheless, screening healthy people for this genetic marker could provide information on future risk of heart disease and help identify those individuals who would benefit most from early applications of strategies to reduce heart disease risk'.
Professor Peter Weissberg, medical director of the British Heart Foundation, told BBC News online that trying to find genes that put some families at an increased risk of heart attacks 'is like trying to find a collection of needles scattered amongst a field full of hay-stacks'. He added: 'The significance of these two studies is that two independent research teams have homed in on the same hay-stack. This makes it very likely that they are close to identifying a needle - an important gene in that region'.