Heredity is one of several factors that can affect individuals' blood cholesterol levels. Genetic disorders are relatively rare, but they can cause very high total and bad cholesterol levels and very low good cholesterol levels.
Fortunately, you can often overcome bad genes and improve bad cholesterol levels via a good diet, quitting smoking, more exercise, stress reduction and prescription drugs.
Two Bad Genes
About one in 500 people have familial hypercholesterolemia, the inheritance of an abnormal gene from their father or mother that causes a very high total cholesterol level. Inheriting an abnormal gene from both parents is very rare, but victims "may have a heart attack or angina by age 20," reports The Merck Manuals Online Medical Library. You are 30 times more likely to have a heart attack at an early age if you have hypercholesterolemia, reports "Controlling Cholesterol."
A Lack of Good Cholesterol
Heredity can also cause hypoalphalipoproteinemia, a condition that results in low good cholesterol, which is also known as high-density lipoproteins (HDL) cholesterol. The Merck Manuals Online Medical Library reports that low HDL cholesterol can be caused by several genetic defects. Some people are able to overcome this genetic abnormality via vigorous exercise, which often raises HDL.
Too Much Bad Cholesterol
Bad genes can also cause an excess of bad cholesterol, which is also known as low-density lipoproteins (LDL) cholesterol. About one in 500 people inherit only one parent's LDL receptors. These receptors remove LDL cholesterol so that people missing half of them are far more likely to have their LDL cholesterol form plaque that can cause heart attacks. People who don't inherit LDL receptors from either parent can die of heart attacks before age 20 if their condition is untreated, reports "Controlling Cholesterol."
Other Genetic Defects
Two other genetic diseases can cause high cholesterol levels--familial dysbetalipoproteinemia and familial combined hyperlipidemia. The former causes an increase in total and very-low-density lipoproteins (VLDL) cholesterol, a cholesterol that often becomes LDL cholesterol. The latter can result in either an increase in total cholesterol or an increase in triglycerides. You are at high risk of having atherosclerosis in your 30s if you inherit either condition, reports The Merck Manuals Online Medical Library.
Predicting The Future
There is a correlation between the cholesterol levels of six- to 16-year-olds and the heart disease histories of their much older relatives, according to a study of 98 healthy children conducted by the Mayo Clinic and the University of Michigan that was published in "Preventive Medicine" in 1986. In addition, the Mayo Clinic reports that you are at "greater than average" risk of heart disease if you inherit high cholesterol levels and a parent or sibling had heart disease before age 55.
References
- "Controlling Cholesterol;" Dr. Kenneth H. Cooper; 1989
- The Merck Manuals Online Medical Library: "Dyslipidemia"
- Mayo Clinic: "High Blood Cholesterol"
- University of Illinois McKinley Health Center: "Cholesterol Basics"
- Weill Cornell Medical College: "Obesity and Cardiovascular Disease"
