Cholesterol appears to play a key role in heart disease
A third of the population have genes that could help them in the fight against heart disease, say scientists.
A study of 147,000 patients suggests that certain types of the CETP gene might increase the levels of so-called "good" cholesterol.
UK and Dutch research, published in the Journal of the American Heart Association, found a 5% cut in heart attacks for those with the key types.
A UK geneticist said it could point to drugs which help many more people.
Scientists already know that cutting the levels of "bad" cholesterol in the bloodstream protects your heart, and well-established drugs such as statins aim to do precisely this.
The relationship between the levels of "good", or HDL, cholesterol, and heart health are less clear, although there is some evidence that raising these levels is good for you.
The team from Cambridge and Newcastle universities, and the University of Groningen in the Netherlands, merged the results of almost 100 other studies, involving 147,000 people worldwide.
They looked for the effect of having one of six different variations of the CETP gene.
The most popular three all seemed to carry a modest positive effect, raising HDL cholesterol levels by between 3% and 5%, and people with them were less likely to have a heart attack.
Cause and effect
Professor John Danesh, who led the study, said that the findings added weight to the idea that heart disease could be prevented by raising HDL levels, perhaps by drugs that blocked CETP.
A trial into a drug which raised HDL cholesterol by influencing CETP was abandoned in 2006 due to an increase in heart disease and deaths, but some scientists believe it may still be possible to target the gene effectively and safely.
Professor Peter Weissberg, of the British Heart Foundation, which funded the study, said: "Researchers are questioning whether approaches that raise HDL cholesterol could further prevent heart disease.
"This suggests that it may have benefits, but that more studies are needed to determine how much might be derived."
Dr Aroon Hingorani, a lecturer in genetics from University College London, said that the relatively small decrease in risk meant that the presence of a particular variant of the CETP gene could not help predict with any accuracy the risk of an individual falling prey to heart disease.
She said: "What it does provide are important insights into the 'cause and effect' relationship, and if you understand this better, you can develop drugs which target it."