According to researchers in the UK there are six genetic "hotspots" that can double the risk of developing early heart disease.
By using the DNA database of brothers and sisters from across the UK, compiled by the British Heart Foundation (BHF), the scientists were able to identify the genes that make some people more vulnerable to heart problems when they are middle-aged.
In their search for the genetic differences between those with heart disease and those without, the researchers looked at samples from 2,871 siblings from 930 families.
They came to the conclusion that with certain variations there was more than double the risk of heart disease for some family members.
The team presented the results of the Genetic Risk of Acute Coronary Event (GRACE) study, at the European Society of Cardiology Congress in Stockholm.
The researchers say they have found variations in three genes that are important in the body's natural defence to infections that appear to confer protection to heart disease, while another three variations, which are also part of the immune responses, appear to contribute to causing disease.
According to the researchers they found that although variations in individual genes increased the chance of heart disease, the cumulative effect of carrying a lot of "bad" genes and fewer "good" genes could double the risk.
Dr Ben Brown says the findings are "really exciting", and the study is one of the first studies to examine such a large number of families affected by heart disease.