Having high cholesterol levels increases your risk of developing atherosclerosis and having a heart attack or a stroke. Many cases of high cholesterol are influenced by lifestyle factors such as your weight and diet. Your genes, however, also play a role in your blood cholesterol levels, and genetic conditions such as familial hypercholesterolemia can cause your cholesterol levels to be high even in the absence of other risk factors.
Signs
High blood cholesterol levels do not cause any symptoms until they result in atherosclerosis, a condition which makes arteries narrow and hard. Nonetheless, if you have multiple relatives who have high cholesterol levels or who have suffered a heart attack or stroke, you may have genetically high cholesterol levels. Another sign that your high cholesterol levels are caused by your genes is if your cholesterol is high early in life, particularly if you have a normal body weight, the Better Health Channel notes.
How Genes Affect Cholesterol
Your genes control the way that your organs function. Genetic causes of high cholesterol can result from mutations which occur in the LDL receptor, a protein which helps transport cholesterol out of the blood into organs, where it can be used to make bile, hormones and cell membranes. This kind of mutation causes your LDL or "bad" cholesterol levels to be chronically high, Medline Plus notes. Genes can also influence the quantity of different lipids which your liver synthesizes.
Types
High blood levels of lipids caused by genetic problems are called familial hyperlipidemias. One form, known as familial hypercholesteremia, typically affects only your LDL cholesterol levels. Another type of hyperlipidemia, known as familial combined hyperlipidemia, affects the levels of many different lipids, including your triglycerides, LDL cholesterol, HDL cholesterol and apolipoprotein B100, a protein involved in regulating lipid levels. Both of these conditions are autosomal dominant, which means you only need one mutated gene to develop the disorder. If you have two mutated genes, you may have even higher cholesterol levels and can develop deposits of cholesterol, known as xanthomas, in other parts of your body, the University of Maryland Medical Center explains.
Treatment
Although the familial hyperlipidemias are caused by genetic defects, they are still treatable. Most patients will need to take medications, such as statins, fibrates and niacin, to improve their cholesterol levels and reduce their risk of developing cardiovascular disease. Patients will also need to follow a healthy lifestyle, which includes maintaining a healthy weight and eating a diet low in saturated fat and cholesterol.
