Why Does High Cholesterol Run In Families
Familial hypercholesterolemia (FH) is the term used for high blood cholesterol that is passed down in families. Let’s learn more about what it is and why it happens.
What is familial hypercholesterolemia?
It is an inherited condition that causes high blood cholesterol to run in families. It is basically a genetic defect that begins at birth and increases the risk of getting cardiovascular diseases at a very young age.
What causes familial hypercholesterolemia?
The familial tendency to high cholesterol is passed down due to a defect on the chromosome 19. This defect makes the body unable to remove the low density lipoprotein (LDL) cholesterol –the bad cholesterol-which gradually piles up. This trait is passed down in an autosomal dominant manner which means that the trait can be passed down in children even if one of the parents carries this defective gene.
As LDL cholesterol progressively surges in quantity, the likelihood of cholesterol plaques deposition in arteries increases. People with familial hypercholesterolemia are more prone to developing narrowing of vessels (atherosclerosis) from a very young age.
What is the morbidity risk for FH?
People with familial hypercholesterolemia are at higher risk of developing cardiovascular diseases like angina, heart attack and stroke as compared to the general population. If the trait is acquired from both the parents, the risk of these diseases is abnormally high and so is the mortality risk.
Men with familial hypercholesterolemia are at risk of developing cardiovascular diseases almost 20 years earlier than general male population and about 50% of them are at risk of having a second heart attack or stroke before they reach the age of 50.
In women, the risk is even higher. Women with familial hypercholesterolemia are at risk of developing cardiovascular abnormalities 30 years earlier than women of similar age and about 1/3rd of these women are prone to recurrence of these diseases before they reach the age of 60.
How to diagnose familial hypercholesterolemia?
The evaluation for FH should be done as soon as possible at very young age. FH may be diagnosed on the basis of
- Detailed history including family history
- Physical examination
- Lab testing including fasting lipid profile
- Imaging including coronary angiography and carotid Doppler to evaluate cardiovascular risk
- Molecular and genetic testing-for definitive diagnosis
How is familial hypercholesterolemia treated?
The condition cannot be controlled by lifestyle changes like diet and exercise alone.
- People with FH are started on statins (lipid lowering medications) very early on.
- People with abnormally high LDL cholesterol levels may be advised LDL apheresis– a procedure that removes cholesterol from blood in the same way dialysis removes toxins from blood.
- Injectable antibodies may be used to treat this condition. This treatment is practiced on a limited scale right now.
- Santos RD, Gidding SS, Hegele RA, Cuchel MA, Barter PJ, Watts GF, Baum SJ, Catapano AL, Chapman MJ, Defesche JC, Folco E. Defining severe familial hypercholesterolaemia and the implications for clinical management: a consensus statement from the International Atherosclerosis Society Severe Familial Hypercholesterolemia Panel. The lancet Diabetes & endocrinology. 2016 Oct 1;4(10):850-61.
- Soutar AK, Naoumova RP. Mechanisms of disease: genetic causes of familial hypercholesterolemia. Nature clinical practice Cardiovascular medicine. 2007 Apr;4(4):214-25.