Polygenic Hypercholesterolaemia

Polygenic hypercholesteroleamia is high cholesterol which is caused by problems with a number of different genes.

‘Hypercholesterolaemia’ simply means too much cholesterol in the blood. And ‘polygenic’ means there are many different genes involved. So, if you have polygenic hypercholesteroleamia this means your cholesterol is raised because of the small effects of many different genes all added together.

Without treatment, the cholesterol in your blood will be higher than the healthy levels. The cholesterol can collect in your arteries and lead to serious problems such as heart attacks and strokes. But there are treatments available to lower your cholesterol and a healthy lifestyle will help too.

Polygenic hypercholesterolaemia is different to familial hypercholesterolaemia (FH) which is caused by a problem with one gene, rather than many. 

How are genes involved in your cholesterol levels?

Our genes give instructions to our cells, allowing them to do their jobs. And our genes play a role in our cholesterol levels. They are involved in controlling the ways cholesterol is taken out of the blood by our cells, and how it’s broken down to be removed from the body.

A problem with these genes can mean that cholesterol isn’t taken out of the blood or broken down as it should be. So, it can collect in the arteries and clog them up.

Researchers have found 12 different genes which they think are involved in polygenic hypercholesterolaemia. When these genes are ‘altered’ or ‘faulty’, they can each raise your LDL cholesterol a little. If you inherit many of these genes, it can raise your cholesterol much higher.

Genetic conditions run in families

We inherit our genes from our parents and pass them on to our children. So, your parents might have high cholesterol and problems with their heart health.

You might also pass these genes onto your children, but by getting cholesterol tests, living a healthy lifestyle and getting treatment if they need it, there’s no reason why they can’t live a perfectly normal and healthy life.

How is Polygenic Hypercholesterolaemia diagnosed and treated?

Getting diagnosed

If you have a cholesterol test which shows your cholesterol is high, your doctor will want to find out what’s causing it – so they can give you the right treatment.

Sometimes doctors will come across people with high cholesterol and think it might be caused by familial hypercholesterolaemia (FH) – usually because the cholesterol levels are high enough to look like FH.

They can arrange for a genetic test to look for a faulty gene that’s causing FH, but can’t find one. If this happens, the most likely explanation is that you have smaller faults with a number of different genes which are all adding up together.

Finding out your risk of heart disease

As well as your cholesterol levels and genetic testing, your doctor will try to get an idea of your health and risk of heart disease overall. For example, they will ask whether you smoke and how much alcohol you drink and how active you. You will have your blood pressure measured and might be tested for diabetes.

Treatments

Your doctor will talk to you about bring your cholesterol levels down to prevent serious illness. This can be with medicines such as statins.

There are changes you can make to your lifestyle too. For example, stopping smoking if you smoke, drinking alcohol within the recommended limits, being physically active and eating a heart-healthy diet.

What are the differences between Polygenic High Cholesterol and FH?

Although polygenic hypercholesterolaemia can sometimes look like FH, these are separate conditions and there are some key differences.

Polygenic hypercholesterolaemia Familial hypercholesterolaemia
Polygenic hypercholesterolaemia is caused by several altered or faulty genes. FH is caused by one faulty gene.
Each faulty gene raises LDL cholesterol a little. The faulty gene raises LDL cholesterol to a very high level.
The faulty genes can be inherited from both parents. There is usually one faulty gene which is inherited from one parent.
Your parents might have healthy LDL cholesterol levels – as each parent might not have enough of the faulty genes to raise their cholesterol. The parent with the faulty gene is very likely to have high LDL cholesterol.
The risk of heart disease is thought to be lower than with FH. The risk of heart disease is thought to be higher than with FH.

Having Polygenic Hypercholesterolaemia and FH at the same time

It’s possible to have polygenic hypercholesterolaemia and FH at the same time. Around one in 250 people in the UK have FH, and some of these will also have one or more other genes which all raise their cholesterol a little higher.

There is some more detailed information on severe polygenic hypercholesterolaemia here.

 

 
Other cholesterol conditions