Dear Doctors: Can you please do a column about familial hypercholesterolemia? It is my diagnosis, and I would like you to explain it. My LDL is over 500. It is my understanding that there are different kinds of LDL. Is that correct? Any information would be helpful.
Dear Reader: Familial hypercholesterolemia, often shortened to FH, is a condition that interferes with the mechanisms the body uses to manage blood cholesterol levels. In medical terminology, “hyper” means that something is above normal, and “emia” refers to the blood. The word “familial” indicates this condition has a genetic component. More specifically, FH results in very high levels of a type of cholesterol known as low-density lipoprotein, or LDL. This puts people living with FH at increased risk of developing heart disease and of having a heart attack at an early age. To understand how and why, we need a few more details.
Cholesterol is a fatty, waxy substance that is transported throughout the body in the blood. The liver produces about 80% of the cholesterol our bodies use, and 20% comes from our diet. Although the focus is often on cholesterol as a risk factor for heart disease, it is needed by every cell in the body. It is a crucial building block of our cell membranes; is essential for the production of certain hormones, including estrogen and testosterone; and is necessary for the manufacture of vitamin D. That said, high levels of cholesterol, particularly of LDL, can lead to a dangerous buildup of fatty deposits within the blood vessels. This significantly increases the risk of narrowing of the arteries.
Cholesterol is classified into two main types. High-density lipoprotein cholesterol, or HDL, helps move lipids from the blood and into the liver for disposal. This has led to HDL being referred to as “good cholesterol.” But low-density lipoprotein does the opposite. It transports lipids from the liver into the blood for delivery to the cells. You are correct that there are different types of LDL. It is broken down into several subclasses, each of which decreases in size and increases in density. It is those characteristics, the smaller size and higher density, that make an overabundance of LDL particularly dangerous. Some researchers have come to suspect that the subclasses of LDL behave differently from one another, and that each may have a unique role in cardiovascular disease.
The good news is that lifestyle choices, along with medical interventions, can have a positive effect on this condition. These include not just changes to diet and the use of medication, but also regular screenings to monitor blood lipid levels. Due to the genetic component, each case of FH is different and benefits from highly personalized treatment. That makes it important for anyone living with FH to seek out expert medical care. Genetic testing can also shed light on the condition and inform treatment choices. It is recommended that, when possible, someone with FH work with a cardiologist who has experience with the disorder.
(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)
