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| DiseaseID |
HGD39 |
| Genetic
Disorder |
HYPERCHOLESTEROLEMIA
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| Gene
Name |
LDLRAP1 gene |
| Description |
Hypercholesterolemia occurs when there is an elevated level of total cholesterol in the bloodstream. It is the result of high levels of low-density lipoprotein (LDL) as compared to high-density lipoprotein (HDL) cholesterol. These are the two major cholesterol groups.
LDL, the ‘bad’ cholesterol, leaves behind fatty deposits or plaques in the blood vessels. Accumulation of these plaques congests blood vessels and blocks blood supply to the organs. HDL, the ‘good’ cholesterol, cleans up excess cholesterol from the body, thus minimizing the amount of congestion and blockage.
Hypercholesterolemia hardens and narrows blood vessels in various parts of the body, leading to fatal diseases such as chest pains, heart attack and stroke. Blocked blood vessels in the limbs can cause pain, ulcers, infections and gangrene.
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| Symptoms |
Symptoms that may occur include:
Fatty, cholesterol-rich skin deposits (xanthomas)
Cholesterol deposits in the eyelids (xanthelasmas)
Chest pain (angina) associated with coronary artery disease
Obesity
Persons with two copies of the defective gene develop fatty skin deposits over their elbows, knees, buttocks, tendons, and around the cornea of the eye
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| Causes |
Familial hypercholesterolemia is caused by a gene defect on chromosome 19. The defect makes the body unable to remove LDL cholesterol from the bloodstream. This results in consistently high levels of LDL in the blood, which leads to atherosclerosis at an early age.
The condition is typically passed down through families in an autosomal dominant manner. That means you only need to get the abnormal gene from one parent in order to inherit the disease. An individual who inherits one copy of the gene is considered "heterozygous."
In rare cases, a child may inherit the gene from both parents. Individuals who inherit both genes are considered "homozygous." Homozygous familial hypercholesterolemia is much more severe. Cholesterol levels may exceed 600mg/dL, greatly increasing the risk for heart attacks and heart disease. |
| Diagnosis |
A physical examination may reveal fatty skin growths called xanthomas and cholesterol deposits in the eye (corneal arcus).
Other signs include:
A strong family history of familial hypercholesterolemia or early heart attacks
High levels of LDL that resist treatment in either or both parents
Individuals from families with a strong history of early heart attacks should have blood tests done to determine lipid levels. Blood tests may show:
High levels of total cholesterol
Greater than 300 mg/dL in adults
Greater than 250mg/dL in children
LDL greater than 200mg/dL
High level of triglycerides
Other tests that may be done include:
Heart function (stress) test
Studies of cells called fibroblasts to see how the body absorbs LDL cholesterol
Genetic test for the defect associated with this condition
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| Treatment |
Proper diet, exercise, and certain medications can bring lipids (fats in the blood) down to safer levels and reduce your risk of heart disease and heart attacks. Those who inherit only one copy of the defective gene may respond well to diet changes combined with statin drugs.
The first step is to change what you eat. You typically follow a modified diet for several months before your doctor adds on medications. You'll be told to decrease fat intake to less than 30% of the total calories you get each day.
You can reduce fat intake by:
Eating less beef, pork, and lamb
Choosing low-fat dairy products
Avoiding coconut and palm oil
Cholesterol intake is reduced by avoiding:
Egg yolks
Organ meats
Sources of animal-derived saturated fat
Further reductions in the percentage of fat in the diet may be recommended. For more information, see: Heart disease and diet.
Exercise, especially to induce weight loss, may also aid in lowering cholesterol levels.
Drug therapy may be started if diet, exercise, and weight-loss efforts have not lowered your cholesterol levels over time. Several cholesterol-lowering drugs are available, including:
Bile acid sequestrant resins (cholestyramine and colestipol)
Fenofibrate
Gemfibrozil
Nicotinic acid (niacin)
Statin drugs
In rare cases, persons who inherited two copies of the defective gene may need surgery such as a liver transplant. |
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