What Is KIF6?
KIF6 is a gene. Its job is to make a protein involved in moving things around inside your body's cells. In 2008, a group of researchers found that a very common variation in the KIF6 gene seems to increase a person's chance for heart disease. The reason why isn't known.
Variations in our genes are normal. These variants make each of us unique. Researchers are working hard to find out which gene variants might help predict a person's risk for health problems, like heart disease. See What Is a Variant? for more information.
KIF6 and Heart Disease Risk
There are two common forms of the DNA code at a certain place in the KIF6 gene. The typical form is called "Trp". A different or variant form that predicts a higher risk for heart disease is called "Arg". Read the box below to find out why the variants are named this way.
KIF6: Trp and Arg Variants
The DNA code is read in groups of 3 letters at a time to tell the body what amino acid to put next in the protein it is making. A gene with the DNA letter "G" puts an arginine (or "Arg") into the protein. A gene with the DNA letter "A" puts a tryptophan (or "Trp") into the protein. This DNA variation affects the 719th amino acid, so the variants may also be called "719Arg" or "719Trp".
People have two copies of the KIF6 gene in each cell — one inherited from each parent. Having at least one copy of the Arg variant may raise the risk for heart disease a small amount. Researchers found that people with at least one Arg variant (called "Arg carriers") have a 1.2 to 1.5 times higher chance for heart disease than people who don't have an Arg variant. Recently, however, other researchers found that having an Arg variant makes no difference in risk for heart disease.
KIF6 Risk Example
The actual risk for heart disease depends on a combination of factors. This example uses a made up person as an example of how KIF6 test results may change heart disease risk.
Example starting risk for heart disease:
Heart disease risk if a KIF6 Arg carrier:
12% to 15%
If the first group of researchers is right, this amount of risk is similar to other things that we know affect heart disease risk — like diabetes, age, and cholesterol. The chart below shows how these risk factors compared to each other in one study. See What Are The Risk Factors For Heart Disease? to learn more about what causes heart disease.
Since the research on KIF6 is equally divided into studies that show a higher risk and studies that don’t, it’s not clear yet if KIF6 testing should be recommended. More research is in progress.
KIF6 and Statin Response
Having at least one Arg variant may mean that statin drugs will be more effective for you. In one study, Arg carriers who took statins lowered the risk for heart disease by 37% to 50%. People without the Arg variant only lowered their risk by 6% to 20%. Recent research, however, did not find any difference in how people respond to statins.
One of the challenges of the research so far is that is that none of the studies were originally designed to study the KIF6 gene. Instead, the KIF6 analysis was done after the studies were completed. This means that there could be issues that weren’t taken into account during the study that could have affected the KIF6 results. So, we don’t know for certain yet if the KIF6 variant predicts a person’s risk for heart disease and their response to statins, or exactly how this information can be used to prevent heart disease. More research is in progress.