When high cholesterol runs in the family

High cholesterol is a common condition. They are often the result of an imbalanced diet, insufficient exercise and a lot of stress – in other words, an unhealthy lifestyle. However, there are also high cholesterol levels that run in families and increase the risk of heart attack and stroke. 

How often does this occur?

More frequently than you might think. It is estimated that as many as 1 in 200 people have elevated cholesterol levels that persist irrespective of environmental factors such as diet and lifestyle. Known as familial hypercholesterolaemia (FH), this is a metabolic disorder: cholesterol is deposited in various parts of the body – including the walls of blood vessels. Over time, this leads to a hardening of the arteries (arteriosclerosis). The result is an increased risk of heart attack, stroke and intermittent claudication, which can lead to circulatory problems in the legs and sometimes also the arms (peripheral arterial occlusive disease).

Could you describe a specific case?

Mr K. recently turned 40 and, following a discussion with his GP, decided to have a medical check-up. Mr K. is fit and healthy, rows and plays tennis regularly and has not yet suffered any serious illnesses. His tests also show consistently normal values except for an elevated LDL cholesterol value. These results come as a surprise to Mr K. because he maintains a healthy diet, takes plenty of exercise, does not smoke and only drinks alcohol in moderation. His doctor explains that, in addition to the known, lifestyle-induced increased cholesterol, there is also a genetic form that cannot be influenced much by diet and always requires treatment.

What did the doctor do next?

Based on the results of a simple score indicating a hereditary explanation for the elevated cholesterol levels, the GP referred his patient to me for a genetic consultation. I asked Mr K. about illnesses in his family. That's always the first step: We don't just test for the sake of it, but first look at what makes sense during a genetic consultation. It turned out that his maternal grandfather had died of a heart attack at the age of 54, his mother had suffered her first heart attack at the age of 58 and her second at the age of 62, and an uncle on his mother's side suffered from coronary heart disease (= narrowing of the major arteries). Based on his family’s medical history, I suspected that the high cholesterol levels could be family-related. We then had his blood tested. Genetic testing confirmed this suspicion. We immediately put him on a course of medication to lower his cholesterol. Even if Mr K. had continued to watch his diet and lifestyle for many years, his cholesterol levels would not have improved much and his risk of developing cardiovascular problems, including heart attacks and strokes, would have remained high.

When should a genetic test be carried out and for whom?

Several factors need to be considered. Of course, you should always be suspicious if high cholesterol levels are detected even if the patient leads a healthy lifestyle. However, alarm bells should go off if one or more people in the family have suffered a heart attack or stroke at a young age or suffer from coronary heart disease or high cholesterol levels. And naturally also if there is a family history of high cholesterol levels.

What exact information can a genetic test provide?

To date, we know of at least 13 genes that are involved in the metabolism of cholesterol. Detecting a pathogenic gene variant confirms the diagnosis, allows for a more exact prognosis of the course of the disease and enables treatment to begin at an early stage. In addition, genetic diagnosis makes it easier for patients to accept that they need lifelong treatment. People then know why they need to take medication and why maintaining a healthy lifestyle on its own is sadly not enough. It can also benefit other family members. This is because a genetic test makes it possible to determine other family members accurately, especially relatives in the first degree.

And if the results come back clear?

If no pathogenic gene variant can be identified, it is unlikely that the patient suffers from a hereditary lipometabolic disorder. However, this cannot be ruled out with complete certainty. If necessary, you may wish to take another look at the environmental factors before prescribing medication. However, this is a decision for a heart specialist to make.