About Familial Hypercholesterolemia

Key points

  • Familial hypercholesterolemia (FH) is an inherited condition that causes high blood levels of low-density lipoprotein (LDL) cholesterol.
  • People with FH are more likely to have coronary artery disease or a heart attack.
  • Finding and treating FH early, with medicines such as statins, is important to prevent coronary artery disease.
a heart shape

What it is

What is FH? FH is a genetic condition that causes high cholesterol. Left untreated, heart attacks happen in 30% of women by age 60 and 50% of men by age 50. Finding and treating FH early REDUCES coronary artery disease risk by about 80%.
If FH is left untreated, heart attacks happen in 30% of women with FH by age 60 and 50% of men with FH by age 50.

Familial hypercholesterolemia (FH) is a genetic disorder that affects about 1 in 250 people and increases the likelihood of having coronary artery disease at a younger age. People with FH have increased blood levels of low-density lipoprotein (LDL) cholesterol, sometimes called "bad cholesterol." Having too much LDL cholesterol in your blood increases your risk for developing coronary artery disease or having a heart attack. For people with FH, exercising and healthy eating habits are important, but often not enough to lower their cholesterol to a healthy level. Medicines, such as statins, are needed to help control cholesterol levels. If you have FH, finding the disorder early and treating it can reduce your risk of coronary artery disease by about 80%. If your child is diagnosed with FH, statin therapy in childhood may be required, often starting by age 8-10.

Signs and symptoms

How do you know if you have FH? Signs of FH include: LDL-cholesterol levels over 190 mg/dL in adults, Family health history of early heart attacks or heart disease, Swollen or painful Achilles tendons, and Bumps around the knuckles, elbows, or knees. Talk to your healthcare provider if you think you could have FH
There are a number of ways to know whether you have FH.

One of the main signs of FH is LDL cholesterol levels over 190 mg/dL in adults (and over 160 mg/dL in children). In addition, most people with FH have a family health history of early coronary artery disease or heart attacks. In some cases, elevated LDL levels are found through routine blood cholesterol screening. If you have a family health history of heart disease or FH and have not had your cholesterol screened, your healthcare provider may order lipid screening, which measures the amount of cholesterol and lipids (fats) in your blood.

Your healthcare provider may be able to detect physical signs of FH during a clinical exam, although not everyone with FH has these signs. These physical signs of FH occur when extra cholesterol builds up in different parts of the body:

  • Bumps or lumps around your knees, knuckles, or elbows
  • Swollen or painful Achilles tendon (the tendon at the back of your lower leg)
  • Yellowish areas around your eyes
  • A whitish gray color in the shape of a half-moon on the outside of your cornea (the clear outer layer at the front of your eye)

If your healthcare provider suspects you have FH, he or she may refer you for genetic counseling and testing for FH.


FH is mainly caused by inherited genetic changes (mutations) in the LDLR, APOB, and PCSK9 genes, which affect how your body regulates and removes cholesterol from your blood. About 60-80% of people with FH have a genetic change found in one of these genes. Genetic testing is available to check for these and other rarer genetic changes. However, there are likely more genes involved in FH that remain unknown.

You have two copies of each of the genes involved in FH, one from your mother and one from your father. A genetic change in only one copy of the LDLR, APOB, or PCSK9 genes is enough to cause FH. If either your mother or father has a genetic change in one of these genes that causes FH, they have a 50% chance of passing it on to you.

Most people with FH only have one FH-causing genetic change. In very rare cases, a person can have two FH-causing changes in both copies of the same gene, which results in a much more serious, rare form of FH called homozygous FH. There are two forms of homozygous FH:

  • Having two FH-causing changes in both copies of the LDLR, APOB, or PCSK9 gene
  • Having two FH-causing changes in both copies of the LDLRAP1 gene (People with genetic changes in only one copy of the LDLRAP1 gene do not have FH.)

People with homozygous FH have extremely high levels of cholesterol and can have heart attacks in childhood. People with homozygous FH need to find a healthcare provider knowledgeable about FH and start treatment right away.

Next steps

If you are concerned that you could have familial hypercholesterolemia or hereditary heart disease, the first step is to collect your family health history of heart disease and share this information with your healthcare provider.