High cholesterol is a common medical condition, but it's often the result of unhealthy lifestyle choices, and thus preventable and treatable. With familial hypercholesterolemia, a person's risk of high cholesterol is higher because a defect (mutation) in a gene changes how the body processes cholesterol. This mutation prevents the body from removing low-density lipoprotein (LDL) cholesterol, the "bad" cholesterol, from the blood. As a result, plaques can cause your arteries to narrow and harden, increasing the risk of heart disease. Genetic testing can reveal whether you have this mutation.

These gene mutations are passed from parent to child. To have the condition, children need to inherit an altered copy of the gene from one parent. Most people with familial hypercholesterolemia have one affected gene and one normal gene. In rare cases, a person inherits an affected copy from both parents, which can lead to a more severe form of the condition.

Familial hypercholesterolemia is caused by a gene that's passed down from one or both parents. People who have this condition are born with it. This defect prevents the body from ridding itself of the type of cholesterol that can build up in your arteries and cause heart disease. This type of cholesterol is called low-density lipoprotein but it's also commonly known as LDL or bad cholesterol. LDL cholesterol can cause your arteries to get hard and narrow. This increases your risk of a heart attack and heart disease.

The risk of familial hypercholesterolemia is higher if one or both of your parents have the gene defect that causes it. Most people who have the condition got one affected gene. But in rare cases, a child can get the affected gene from both parents. This can cause a more severe form of the condition.