Familial combined hyperlipidaemia (FCH)
Familial combined hyperlipidaemia, or FCH for short, is an inherited condition where both your cholesterol and triglycerides are raised. You may also hear it referred to as Type IIb hyperlipidaemia.
FCH is quite common – around 1 in 100 to 1 in 200 people are thought to have it. It is a common cause of premature heart disease and heart attacks. As it runs in families, your doctor should ask you about any history of heart disease in your family to help make a diagnosis.
How does FCH raise your blood fats?
With FCH, your body makes too much cholesterol and removes triglycerides from the blood too slowly. This raises the cholesterol and triglycerides in your blood.
In particular, your body makes too much of the lipoprotein known as VLDL. These are parcels made of fats and protein which carry fats around your body. They’re very high in triglycerides but also carry cholesterol.
What causes FCH?
FCH is a very complex condition. It is caused by a combination of multiple genes and how these are affected by your diet and lifestyle.
How can FCH affect the body?
FCH starts to affect the body in adulthood, from around age 18 onwards, because it involves hormones which are not fully developed during childhood and adolescence.
People with FCH are more likely to develop type 2 diabetes and metabolic syndrome – and have similar patterns of blood fats where both cholesterol and triglycerides are raised – and heart disease.
The signs and long term effects of FCH can include:
Storing fat around your middle
Storing fat around your middle is linked to a higher risk of heart disease. It’s also linked to raised blood sugar and insulin resistance, which can lead to type 2 diabetes.
Type 2 diabetes
This is where your blood sugar is too high which can lead to health problems in the future.
Normally your body uses sugar for energy but with FCH it uses fat instead. This means your blood sugar will be raised and your body will make more of the hormone insulin to take the sugar out of your blood. Eventually, the body stops producing insulin or stops responding to it, and your blood sugar stays high.
The raised insulin also means that your blood sugar will be converted into fat, raising your blood fats further. This can lead to a build-up of fat in the liver.
You can have your blood sugar levels tested at your GP surgery to find out if you have type 2 diabetes or pre-diabetes.
Raised blood pressure
Having raised insulin means your body holds onto salt and water, raising your blood pressure. The only way to know your blood pressure is to have a blood pressure test. Visit your pharmacy or GP surgery for a quick, easy and painless test. They’re usually free.
Higher risk of gout
This is due to making too much uric acid which leads to crystals forming in your joints, causing pain.
Heart disease
Having raised blood fats and raised blood pressure can lead to fat being laid down in the walls of the blood vessels, clogging them up – a process known as atherosclerosis. This can affect the blood supply to the heart and around the body and raises the risk of blood clots, leading to diseases including heart attacks and strokes.
How is FCH diagnosed?
If your doctor thinks you might have FCH, they should refer you to a specialist at a lipid clinic for an assessment, especially if there is a history of cardiovascular disease (such as hearts attacks and strokes) in your family.
Your specialist can make a diagnosis using a combination of blood tests to check your blood fats and a protein called ApoB, along with your family history, to diagnose FCH.
Blood tests to check your blood fats
A blood test can help to diagnose FCH. Levels of blood fats vary for different people but:
• both triglycerides and LDL cholesterol are usually raised
• HDL cholesterol can be low.
This pattern is similar to type 2 diabetes and metabolic syndrome.
Triglyceride levels in the blood are usually two to three times higher than normal. This is what makes FCH different to another condition called Familial Hypercholesterolaemia (FH), where only LDL cholesterol is raised.
With FCH, both LDL cholesterol and triglyceride levels can be raised, even if you have a healthy lifestyle. See our HEART UK recommendations for healthy blood fats for those who are seen as low risk for diseases of the heart and blood vessels.
Blood tests for ApoB
Blood levels of a protein called Apolipoprotein B (ApoB) are sometimes raised in FCH. This can be looked into with a specific blood test.
Can genetic testing be used?
Multiple genes have been linked to FCH, but genetic testing is not yet available.
Checking for xanthelasmas
Some people with FCH and other inherited cholesterol and triglyceride (blood fat) disorders may have visible cholesterol deposits in the skin. The most form are xanthelasmas. These are yellowish deposits made up of cholesterol around the eye area, usually in upper or lower eyelids, or both.
Xanthelasmas are not only seen in people with inherited cholesterol and triglyceride conditions but and can occur for other reasons, and are more common in people who smoke.
As a starting point, people who are confirmed by their GP or specialist to have xanthelasmas should have their cholesterol and triglyceride levels measured and their cardiovascular risk factors assessed, particularly if they have early cardiovascular disease in their families.
How is FCH treated?
The best treatment for FCH is with statins, as these medicines lower the amount of cholesterol being made.
Medicines called fibrates can be used alongside statins to lower triglycerides (but not on their own). A fibrate called fenofibrate plus a statin is a good combination for FCH.
A healthy diet and lifestyle and staying a healthy weight are also essential, alongside medicines.