The invisible danger: When genes are to blame for high cholesterol levels

Good and bad cholesterol

In fact, cholesterol, an important substance in the body, was the culprit. It is found in every cell and is the basic substance of various hormones such as testosterone and estrogen. However, it may cause problems in the veins. It accumulates in the arteries and causes narrowing, which can cause problems, especially in the very thin vessels that feed the heart muscle.

Cholesterol is transported in the blood in two ways. HDL (“high density lipoprotein”) carries it to the liver where it is broken down. It is known as “good cholesterol” because it eliminates excess cholesterol (HDL mnemonic: “I love you”). “Anyone with too much HDL in their blood has a lower risk than the normal population,” says Nicolas Rodondi, chief physician of the outpatient clinic and lipid consultation at Inselspital and professor at the University of Bern. In contrast, LDL (“low-density lipoprotein”) brings cholesterol into the body from the liver, so it is colloquially known as “bad cholesterol” (LDL mnemonic: “Don’t do that”). “High LDL value increases the risk of heart disease and stroke,” says Rodondi.

Urs Müller’s LDL level increased significantly; How can this happen despite a healthy lifestyle? “Through lifestyle, bad cholesterol can usually be reduced by only 5 to 10 percent,” says Rodondi, who is also on the Education and Prevention Committee of the Swiss Heart Foundation. “If the diet was previously very poor, there will also be a greater reduction.”

So: There are people whose high LDL levels are genetically determined. This is called familial hypercholesterolemia (FHC). The gene for the receptor that removes LDL from the blood in the liver is defective. “Probably one in 200 Swiss has such a gene,” says David Nanchen, professor at the Department of Health Promotion and Prevention at the University of Lausanne. “Most people don’t know anything about it.” Only 15 percent of those affected are aware of the danger. David Nanchen is running a study to see how this can be changed.

Well tolerated medications

“You inherit this gene from your mother or father,” he says. “And if you have children, you have a 50 percent chance of passing it on to them.” In one study, scientists examined 160 people with one of three known genes for familial hypercholesterolemia and found that at least one family member was always also affected. “This is important because these people have an increased risk of heart disease and stroke,” says Nanchen. “And if you know that, you can prevent it very effectively.”

Various medications are available to lower LDL cholesterol. Statins, or injectable drugs called PCSK9 inhibitors for people who cannot tolerate them, greatly lower LDL levels. “All of these medications ensure that there are more receptors for LDL in the liver and therefore more LDL is removed from the blood,” explains Nanchen. “If you have genetically high cholesterol levels, you should take medication early.”

So how should you know if you are affected? The first step is to have your LDL level checked by your family doctor. “This is recommended for anyone over 40,” says David Nanchen. “However, if people under the age of 60 have a family history of heart disease, you should have your cholesterol checked starting from the age of 20.” An LDL value is considered high if it is above 3.5 millimoles per liter (mmol/l). In case of hereditary hypercholesterolemia it is above 5.

The lower the value, the better

For Urs Müller this rate was 6 mmol/l. He has been on statins since his heart attack; since then the LDL level has fallen to just under 3 mmol/l. The next check-up will be done soon, after which it will be decided whether to take additional medication. “People who already have heart disease should aim for a lower value than healthy people and take several medications if necessary,” says Nanchen. “The deeper it is, the better the chances of a long, healthy life.”

Genetic testing may be useful

Genetic testing was not done on Urs Müller; It is not paid by health insurance. This makes no difference to his treatment and Müller has no children. But many people who develop heart disease at a young age do not consider that their children or other blood relatives may be at risk. David Nanchen has identified 160 people at risk so far in his study. “We hope that with our study we can convince the Federal Public Health Agency that genetic testing and family screening will be adopted in the future,” he says.

Only 0.5 percent of Swiss people have familial hypercholesterolemia; One third of them have high cholesterol levels. The same goes for everyone: Changing your lifestyle reduces the risk of heart disease. “Mediterranean diets generally reduce LDL levels by only 5 to 10 percent,” says Nicolas Rodondi. “But the risk of heart attack can be reduced by a third.”