Scientists have found nine genetic variants that are significantly associated with early heart attacks.
A team in the USA studied the DNA of 26,000 people and identified nine variants in their genetic code. Three of the variants, single-letter alterations, had not been described before.
It is hoped that the research will lead to better ways to predict and prevent heart attacks in people who are relatively young.
Advances in genetics made it possible for the researchers to screen 13,000 patients and compare their DNA with the same number of healthy "controls".
They found a link with nine of the single-nucleotide polymorphisms (SNPs) in nine regions of the genome, the complete set of chemical sequences written into DNA.
Patients with the most risk-associated variants were more than twice as likely to suffer an early heart attack as those with the fewest.
Dr Sekar Kathiresan, Director of Preventive Cardiology at Massachusetts General Hospital, said: "Extensive study of that gene region has led to significant insight into the biology of atherosclerosis (artery hardening) and heart attack.
"Individuals at higher genetic risk may benefit from earlier intervention, something that needs to be tested in future studies."