Familial hypercholesterolemia (FH) is an inherited condition that results in high levels of total cholesterol and LDL (low-density lipoprotein) cholesterol. Cholesterol is a waxy substance found in cells that can be dangerous when it builds up on artery walls, causing atherosclerosis and the risk of heart attacks at an early age in those affected. Familial hypercholesterolemia is also known as Type II hyperlipoprotinemia.
As the most common form of inherited high cholesterol, FH affects about 1 in every 500 individuals. Compared to cases of non-genetic hypercholesterolemia, FH is much more severe. People who have the familial version will have much higher cholesterol levels.
This condition is a result of a genetic disorder that occurs on chromosome 19. Unlike recessive genetic disorders that require both sides of the family to have the condition, FH is autosomal dominant, meaning that a child may have the condition even if only one parent has the mutated gene.
In rare instances, both parents may be carriers of the gene. When this occurs, the condition is more severe because the offspring is born with two copies of the mutated gene.
FH is more common among certain ethnic groups such as the French Canadians, the Finnish, the Lebanese, and the Afrikaners in South Africa. However, anyone who has a parent with the disease is at risk.
High cholesterol often has no symptoms. Cholesterol is a silent killer, so the damage may be done long before you notice anything is wrong. Some of the signs and symptoms are:
- angina from heart disease
- xanthomas (fatty skin deposits) on the elbows, buttocks, knees, and tendons
- cholesterol deposits around the eyelids, also known as xanthelasmas
- cholesterol deposits around the corneas, also known as corneal arcus
Blood tests will reveal that your cholesterol levels—both total and LDL—are higher than normal.
A physical exam will be conducted by your physician. The exam helps identify any types of fatty deposits or lesions that have developed as a result of the elevated lipoproteins. Your physician will also ask about your personal medical history, as well as your family medical history.
Your physician will order blood tests, too. The blood tests are used to determine your cholesterol levels. The results may indicate that you have high levels of total cholesterol and LDL cholesterol. The results of the test will look like the following if you do in fact have FH:
- in children, it will be more than 250 mg/dL
- in adults, it will be more than 300 mg/dL
- in children, it will be more than 170-200 mg/dL
- in adults, it will be more than 220 mg/dL
The doctor will also test your triglycerides, another type of fatty acid. Triglyceride levels tend to be normal in patients with this genetic condition. Normal results are below 150 mg/dL.
Other tests may include:
- a genetic test that establishes whether you have the defective gene
- testing the fibroblasts (connective tissue cells) to see how cholesterol is absorbed
within the body
Like ordinary high cholesterol, FH is treated with diet or medication. Often, a combination of both is needed to successfully reduce cholesterol and delay the onset of heart disease or a heart attack. Your physician will usually ask you to modify your diet and increase exercise for several months before suggesting medication.
If you have FH, your physician will place you on a diet with less than 30 percent of total calories coming from fat. You will be asked to:
- limit meats like lamb, beef, chicken, and pork
- restrict coconut and palm oils
- switch from low-fat dairy to full-fat dairy products
Limiting or eliminating egg yolks will also contribute to lowering your cholesterol.
Diet and exercise are important to maintaining a healthy weight, which can help lower cholesterol levels.
If lifestyle modifications do not work, you may need medications to reduce your cholesterol.
Statins are the most common drugs used to reduce LDL cholesterol. Examples of statins include simvastatin (Zocor), lovastatin (Mevacor), atorvastatin (Lipitor) and rosuvastatin (Crestor).
Other drugs that lower cholesterol include bile acid-sequestering resins, ezetimibe, nicotinic acid and fibrates.
Possible complications of FH include:
- heart attack (at an early age)
- heart disease
The outcome depends on whether you make lifestyle modifications and take your prescribed medications. These changes can delay a heart attack significantly.
Individuals who inherit the mutated gene from both parents are at greater risk for heart attack and death before age 30. Men with FH tend to have heart attacks when they are in their 40s or 50s. In fact, 80 percent of men with this condition have a heart attack by the time they reach 60. Women with this condition tend to have heart attacks when they are in their 50s or 60s.
Since this disease is genetic, the only way to prevent it is to seek genetic counseling before conceiving. If you already have the disease, the key to living longer is to control cholesterol levels.