Understanding Familial Hypercholesterolaemia (FH): A Common Inherited Cause of High Cholesterol

You might be surprised to learn that high cholesterol can run in families—and for some, it starts at birth. This inherited condition is called Familial Hypercholesterolaemia (FH), and it affects how your body handles cholesterol, specifically LDL cholesterol, often called the "bad cholesterol."

What is FH?

FH (pronounced hyper-cholesterol-ee-me-ah) is a genetic condition that leads to very high LDL cholesterol levels from birth. Because it's inherited, FH often affects multiple members of the same family across generations. It significantly increases the risk of early heart disease—particularly heart attacks and strokes—if left untreated.

In people without FH, cholesterol levels usually increase with age, and heart problems might not appear until later in life. But with FH, damage can begin in childhood, and serious events like heart attacks can occur as early as the 20s or 30s.

How Common is FH?

FH is surprisingly common—about 1 in 300 people have it. That means over 77,000 Australians may be affected, but more than 80% remain undiagnosed.

Some ethnic groups, including Afrikaner, Christian Lebanese, Tunisian, French-Canadian, and Ashkenazi Jewish populations, have even higher rates of FH.

Why Does FH Cause High Cholesterol?

In a healthy person, LDL cholesterol is removed from the blood by LDL receptors in the liver. Think of these receptors as “doors” that allow cholesterol to enter the liver and be cleared from the body.

In people with FH, one of the genes responsible for making these LDL receptors is faulty. This means that only about half of the receptors work properly, making it difficult for the body to remove LDL from the bloodstream. As a result, cholesterol builds up in the blood and starts to deposit in artery walls, leading to blockages and cardiovascular disease (see Figure below).

How is FH Inherited?

We all inherit one copy of the LDL receptor gene from each parent. In FH, one of these copies carries a mutation, which means that person produces fewer working LDL receptors. This form of FH is called heterozygous FH, and it's the most common type.

In rare cases, if both copies of the gene are affected, the condition is more severe and symptoms appear earlier in life.

Why Early Diagnosis Matters

Because FH starts affecting the body from such a young age, early diagnosis and treatment are crucial. With the right care—often including lifestyle changes and cholesterol-lowering medication—people with FH can significantly reduce their risk of heart attacks and live long, healthy lives.

If you have a family history of high cholesterol or early heart disease, consider speaking with your doctor about testing for FH. Identifying it early could save a life—maybe even your own.

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