High cholesterol can be genetic, and a DNA test may help
Familial Hypercholesterolemia—often known by its acronym, FH, is a condition where a person’s body processes cholesterol differently, leading to chronically elevated cholesterol levels. It is genetic, which is why you may have heard it described as “inherited high cholesterol.” So, why is it so important to know whether you or members of your family have FH?
Your body packages cholesterol into fat pods (doctors know these as lipids) that circulate through the body. When there is more cholesterol and less fat in those pods, they are called low-density lipoproteins (LDL-C)—also known as “bad cholesterol.” These LDL-C fat pods are normally pulled out of the bloodstream by your liver. But in individuals with FH, gene variants affect one or more of the proteins involved in collecting LDL-C from the blood. These variants limit the liver’s ability to remove LDL-C and can lead to heart conditions in both children and adults, including coronary heart disease and stroke.
FH is a genetic disorder, and there are various forms of it depending on which gene variant a person carries. (A gene variant is what we call a gene when there is a slight difference in its DNA sequence relative to other people, so there can be multiple variations, or variants, of a given gene.) The most common form of FH is when a person has one copy of an FH related gene variant that’s inherited from one of their parents, which is what we commonly refer to when talking about FH. (In this article we focus on this type, but great resources are available to learn about other types.)
Unfortunately, FH is underdiagnosed. In fact, in the US population, rates of FH may be as high as 1 in every 200-250 individuals. For those who have FH, the risk of heart attack is more than 20 times greater than someone without FH and with normal cholesterol.
How can you know if you have FH?
FH can be identified through genetic testing. Genetic testing reads your DNA in search of gene variants among four different genes that are known to be associated with FH. For individuals who have been diagnosed with FH, it is recommended that family members also get tested, because the condition can be inherited. For three of the four genes associated with FH, at least 50% of direct relatives (parents, children, and siblings) will have the disease-causing gene variant as well.
What can be done after an FH diagnosis?
It’s important to talk to your doctor, because both lifestyle changes and medication can be essential parts of FH management. Individuals with FH are often put on statin therapy, which helps to prevent dangerous cholesterol buildup in the blood. Because people with FH are exposed to high cholesterol levels from birth, early diagnosis and active treatment is important in reducing risk. Amazingly, a 2008 study showed that statin therapy could reduce the risk of heart disease by some 76% in those with FH.