Familial Lipid Disorders
What are familial lipid disorders?
Familial lipid disorders are genetic forms of elevated lipids—or fats—in the blood. Blood lipids include cholesterol and triglycerides. There are subtypes of cholesterol, including HDL (high-density lipoprotein), LDL (low-density lipoprotein), and VLDL (very low-density lipoprotein). HDL is ‘good’ cholesterol. LDL and VLDL are ‘bad’ cholesterol. The medical term for high blood lipids is hyperlipidemia. It can lead to clogged arteries, which increases the risk of heart disease, heart attack, and stroke.
There are two main types of hyperlipidemia—primary and secondary. Familial lipid disorders are primary hyperlipidemias. The cause is genetic. Secondary hyperlipidemias are acquired. Causes include lifestyle factors, such as diet, and other medical conditions, such as diabetes. Secondary lipid disorders are the most common form. An example is high cholesterol or high triglycerides. Familial lipid disorders are rare.
There are several types of familial lipid disorders. The more common ones include:
Familial combined hyperlipidemia causes high levels of triglycerides, LDL and VLDL. It often results in early heart attack without treatment. It develops in teenagers and young adults.
Familial hypercholesterolemia causes very high levels of LDL cholesterol. It starts at birth and can cause early heart attack.
Familial hypertriglyceridemia causes high triglycerides and VLDL. It can cause coronary artery disease (CAD) at an early age.
Different genetic defects are responsible for each kind of disorder. Typically, none of the disorders cause any symptoms in the very early stages. CAD symptoms, such as chest pain, tend to develop at young ages. Doctors may suspect a familial lipid disorder if you have high lipids at an early age or if you have a family history of early CAD or heart attack.
Treatment of familial lipid disorders is similar to acquired high cholesterol. It involves lifestyle and dietary changes, along with medicines when necessary. Prognosis depends on how early you catch the disease and begin treatment. Left untreated, these disorders can cause serious and even life-threatening complications. Seek immediate medical care (call 911) for symptoms of a heart attack or stroke, such as chest pain, difficulty breathing, or sudden weakness, confusion, or trouble speaking.
What are the symptoms of familial lipid disorders?
Early on, there are typically no symptoms of familial lipid disorders. However, coronary artery disease (CAD) tends to develop early, in the teenage years or young adulthood. Symptoms of CAD include chest pain, fatigue, and shortness of breath with exertion. Even if you have no history of early heart disease or heart attack in your family, tell your doctor if you experience unusual symptoms.
When symptoms other than CAD develop, they can include:
Calf cramps with walking
Fatty deposits on the eyelids (xanthelasmas) and on other areas of the body (xanthomas)
Non-healing sores on the toes
Serious symptoms that might indicate a life-threatening condition
In some cases, familial lipid disorders can lead to heart attack or stroke. Seek immediate medical care (call 911) if you, or someone you are with, have any of these life-threatening symptoms including:
Chest pain, pressure or squeezing
Discomfort in the upper body, such as the neck, shoulders, arms, or upper back
Drooping of one side of the face
Trouble speaking or understanding speech
If you have a familial lipid disorder, regular medical care is vital. Your doctor will monitor your blood lipids regularly and screen for potential problems.
What causes familial lipid disorders?
Familial lipid disorders are genetic conditions. Families pass down genes that cause these conditions. For some disorders, it only takes one copy of the defective gene to cause disease. In this case, disease starts at birth. For most disorders, having the gene only makes people more susceptible to environmental factors, such as diet. It can take more time to see the disease develop to the point that you notice symptoms or that blood tests show higher-than-normal lipid levels.
What are the risk factors for familial lipid disorders?
Because familial lipid disorders are genetic, the main risk factor is having a family history. You may be more likely to have a familial lipid disorder if:
You have a family history of early CAD or heart attack.
You have abnormal blood lipids at an early age.
Reducing your risk of familial lipid disorders
You can’t control your genes, so there is no way to prevent a familial lipid disorder. However, you may be able to lower your risk of developing CAD, heart attack, and stroke by:
Eating more fiber, fresh fruits and vegetables, and healthy fats
Getting regular physical exercise
Maintaining a healthy weight
Reducing the amount of saturated fats, trans fats, and cholesterol in your diet
Treating high cholesterol as your doctor recommends
Seeing your doctor regularly can help identify problems early and start or adjust treatment as necessary.
How are familial lipid disorders treated?
Treating familial lipid disorders starts with lifestyle changes. This includes the same strategies for lowering your risk of high cholesterol. When these changes are not enough, your doctor may recommend medicines to lower your lipid levels. Medications that treat high lipids include:
Ezetimibe (Zetia), which blocks the absorption of cholesterol you eat
Bile acid resins or sequestrants, which help your body get rid of cholesterol in the blood. Examples include cholestyramine (Questran) and colesevelam (Welchol).
Niacin or nicotinic acid, which increases HDL and decreases LDL and triglycerides
Fibrates or fibric acid derivatives, which increase HDL and lower triglycerides. Examples include fenofibrate (Tricor) and gemfibrozil (Lopid).
PCSK9 inhibitors, which increase the amount of LDL your body clears from the blood. Examples include alirocumab (Praluent) and evolocumab (Repatha).
In very severe cases, a procedure called apheresis may be necessary. It’s similar to dialysis. It uses a machine to filter LDL out of the blood and returns the filtered blood to the body.
What are the potential complications of familial lipid disorders?
With familial lipid disorders, the outlook depends on how severe the disorder is, how early you catch it, and how closely you follow the treatment plan. Having other conditions, such as high blood pressure or diabetes, can contribute to the risk of complications.
Complications of familial lipid disorders are serious and can be life threatening. They include:
The risk of death is highest for people with familial hypercholesterolemia with two copies of the defective gene. This form of the disorder is resistant to treatment.