Genes That Protect the Heart

Dave: Apparently, Icelanders have a mutation that protects them from heart disease!

Norbert: Well, I guess it's only fair considering those bitter winters they endure.

Dave: Actually... I hear it's not that bad and it's really beautiful there.

Norbert: Yeah... not fair huh?

And now we know one of their genes lacks twelve letters in the genetic code that reduces their heart attack risk.

We don't yet understand why the mutation causes this health benefit. The gene is called ASGR1 found on chromosome 17. The deletion of 12 letters of genetic code on ASGR1 lowered their risk of heart disease by a whopping 34-percent.

The effect of the mutation is that the protein it makes is shortened and nonfunctional. It's not clear how this lowers the amount of LDL-cholesterol, which is a factor in the plaque that clogs up arteries. One possibility is that the mutation ups the number of receptors in the liver that uptakes LDL cholesterol, reducing its level in the blood. But researchers believe the ASGR1 mutation goes beyond lowering LDL, affecting other mechanisms that lower heart disease risk.

Their goal is to design new drugs within two years to target ASGR1. The race is on since six other gene mutations have also been found to lower cholesterol levels. Among them is the gene PCSK9 and studies of it have already led to two drugs. These mutations all seem to reduce heart disease by altering proteins involved in moving fats in the blood.

Scientists' ability to identify these mutations is only possible because the cost and speed of sequencing human genomes have dramatically fallen. Some 17.3 million people die of heart disease every year, making it the number one cause of death worldwide. Imagine the impact these new drugs could have.