Familial hypercholesterolemia (FH) is an inherited, or genetic, condition. The main risk factor is having a parent with the condition. This usually arises as a concern because a parent or aunts and uncles have had a cardiovascular event when they were young, usually before age 50.
In general, if one of your parents has FH, you have a 50/50 chance of having it. In the same way if you have FH, each of your children has a 50/50 chance of being born with it.
Detecting FH early and starting treatment is important to lower LDL cholesterol and prevent heart attacks, stroke and related death. That’s why it is important to find out who else in the family may have FH or be at risk for it.
Signs and Symptoms
What are the signs and symptoms of familial hypercholesterolemia (FH)?
The main red flags are having:
- Very high levels of LDL-cholesterol (over 190 mg/dL) that don’t improve much with exercise, healthy eating or certain medications
- A family history of very high cholesterol or family members who developed heart disease, had a heart attack or died at young ages
For some people with FH, a heart attack, stroke or dying suddenly and at a young age may be the first sign. That’s because high cholesterol itself typically doesn’t cause signs or symptoms. Over time, as more cholesterol builds in the blood vessels, it can narrow or block arteries limiting blood flow.
| Heterozygous FH (more common, one FH gene) | Homozygous FH (less common, two FH genes) | |
|---|---|---|
| Typical LDL Levels | Over 190 mg/dL for adults Over 160 mg/dL for children | Over 400 mg/dL |
Other signs of FH may include:
- Evidence of cholesterol buildup in the heart’s arteries, such as seen in a coronary artery calcium (CAC) scan or other early detection test.
- Peripheral artery disease, which is when cholesterol builds up in arteries in the legs, which may result in discomfort or pain upon walking that usually subsides when resting
- Carotid artery disease, which is a narrowing of the blood vessels in the neck that carry blood from the heart to the brain
- Nodules or raised bumps on your skin or tendons (called xanthomas)
- Bumps on your upper or lower eyelids (called xanthelasma)
- White, blueish or yellowish cholesterol deposits that form a ring around the cornea of the eye.
Exams and Tests
A diagnosis of familial hypercholesterolemia (FH) is usually based on:
- A simple blood test to measure the amount of cholesterol in your blood. LDL-cholesterol is much higher among people with FH. Heterozygous FH (more common, one FH gene)Homozygous FH (less common, two FH genes)Typical LDL LevelsOver 190 mg/dL for adults
Over 160 mg/dL for children Over 400 mg/dL - A thorough family history. FH runs in families. Your care team will want to know if a close relative has FH, very high LDL cholesterol, or has died from heart or blood vessel disease at an early age.
- A physical exam, to look for any physical signs, including cholesterol deposits or bumps under the skin or around the eyes.
- Genetic testing may be used to confirm that someone has FH. Testing looks for gene changes, or variants, that have been linked to FH.
If you have a gene variant, you can test to see if other family members also have the same one. In some cases, it’s not possible to find the variant that is causing FH because it hasn’t been discovered yet. A genetic counselor can help answer questions and give advice about testing.
If you have FH, you may be referred to a preventive cardiologist, endocrinologist or lipidologist — a doctor who specializes in treating high cholesterol or lipid disorders.
There are many imaging tests that can look for early development of atherosclerosis (plaque buildup in the arteries) including calcium scoring and CT scans that may help guide your diagnosis or plan.
When Should Screening for FH Begin?
Two types of screening approaches can be used to find FH: universal and cascade. The American Academy of Pediatrics, for example, recommends that all children have their cholesterol levels checked by ages 9 to 11 years old. This universal screening approach can identify children with high LDL cholesterol levels that are caused by genetics or lifestyle habits given the growing number of children who are overweight.
If you have FH, “family tracing” or “cascade screening” with lipid and/or genetic testing can help identify other first-degree family members who might be affected.
If there is suspected or confirmed FH in a parent, consider screening children starting at age 2. If both parents have FH, consider screening their children at birth.