May 3, 2007

experts respond to the discovery of genes which affect heart disease risk

Scientists give their comments on new research published in the journal Science showing that certain genes can increase a person’s risk of developing heart disease.

Dr Tim Chico, a clinician scientist at Sheffield University, said:

“This is very interesting scientifically, but it won’t change the way patients are investigated or treated at the moment.

“However, if we eventually find enough of these genes we might be able to use these to identify people who are at much higher risk of heart disease later in life and try to reduce this with early treatment.

“We must not forget that 90% of the risk of a heart attack comes from things like smoking, cholesterol, diet, lack of exercise and diabetes. Whatever our genetic makeup, we can all reduce our chances of heart disease by improving our lifestyle.”

Keith Frayn, Professor Of Human Metabolism, Oxford University, said:

“Coronary heart disease (CHD) and one of its consequences, myocardial infarction (heart attack), are major causes of death and attempts to understand the underlying mechanisms are very important.

“However, both these studies show the difficulties of finding the genetic variations that underlie the risk of complex conditions such as CHD. The relative risk of CHD conferred by the genetic variants they describe sounds rather impressive but to put this in perspective, it is important to note that each of these studies needed many tens of thousands of participants to show these effects convincingly.

“Both papers conclude that about one fifth of the Caucasian population will have two genetic copies of this genetic variant, and that this increases the risk of CHD (McPherson paper) or heart attack (Helgadottir paper) by around 40 – 60%. This sounds a strong effect but it is important to remember that a 50% increase might still be a low risk for many people.

“The risk of CHD is increased by a range of environmental factors such as smoking, poor diet, sedentary lifestyle and obesity. There are also many factors that operate within individuals that may have genetic or environmental causes, such as (most obviously) high cholesterol level or high blood pressure. So one individual’s risk is determined by a number of factors, and within all that mix the effect of this particular genetic variation will operate.

“Will the results be useful? A genetic test to determine which genotype an individual has would still be less meaningful than an assessment of lifestyle and measurement of blood pressure and blood cholesterol. In fact the results are likely to be far more useful in helping researchers understand the mechanisms that lead to CHD. Ultimately that might lead to new treatments. But that would be a long way off.”