A genetic trait present in one quarter of the population reduces their natural level of LDL cholesterol, which in turn lowers their risk of MI by around 40%.
Earlier work had used a technique called a genome-wide association study (GWAS) to scan for types of genes that are more common in people who suffer cholesterol-related diseases.
This identified a strong link between cholesterol production and certain genes, one of which is called SORT1.
Scientists already knew that people possessing a particular type of the gene SORT1 had 10-fold higher levels of a protein called sortilin, which is manufactured in the liver.
Now, researchers from University of Pennsylvania have shown that sortilin works by reducing the amount of LDL cholesterol produced and transported by the body, as well as increasing the rate at which it is broken down.
Their experiments on mice showed that sortilin lowers production of apolipoprotein B. This protein is vital in the formation and movement of LDL cholesterol around the body.
Sortilin also increased the rate of LDL catabolism – the breakdown of cholesterol by the body.
Researchers concluded that sortilin and the SORT1 gene, which are the same in humans as in mice, accounts for lower cholesterol levels in people with this genetic trait.