Diagnosing FH

Why get tested for FH?

Getting a diagnosis of FH means you can get treatment and make healthy lifestyle changes to lower your cholesterol and help prevent heart disease. It also means that members of your family can get tested and start treatment if they need it.

If you have children, they should get tested too so that they can start treatment early, before problems have time to develop.

How is FH diagnosed?

If you or your doctor think you might have FH, there are a number of tests they can do to get a better idea of what’s going on. Your doctor will:

 

Your family tree

FH is passed from parent to child in the genes and it’s usually possible to trace FH back through several generations.

Talk to your GP about illnesses in your family to see if your high cholesterol could be due to FH. If you go to a lipid clinic, you can also help your specialist draw a family tree.

Drawing a family tree helps your doctor to find out if your high cholesterol is caused by FH, and it means they can see if there is anyone else in your family who might have FH. The family tree is known as a pedigree.

If both parents have FH

It’s possible to have two altered genes – if you have two parents with FH and you inherit the altered gene from both parents. This is very rare. This is called compound heterozygous or homozygous FH.

To draw your family tree, your doctor will ask you:

  • if any of your blood relatives have high cholesterol
  • if they have had a heart attack or heart disease
  • how old they were when they were first diagnosed with heart disease
  • if they had angina, which is pain in the chest caused by heart disease, and how old they were when it started
  • how old they were when they had their first heart attack or needed treatment
  • if they died from heart disease and how old they were.

Blood tests

If your doctor thinks you have FH, you have probably already had a cholesterol test. You might have your cholesterol tested again, this time to look at all the different types of fats, known as lipids, in your blood. This is called a lipid profile, or a full fasting lipid profile.

Your doctor may also arrange for your blood to be tested for other things, such as blood sugar to check for diabetes, and signs of how well your liver and kidneys are working.

 

Physical signs of FH

There are a few physical signs and symptoms your doctor will look for if they think you might have FH. They are easy to miss, so you might have these signs and not notice.

If you don’t have these signs, it’s possible you still have FH, as not everyone with FH has them.

  • swollen tendons on the knuckles of your hands and your Achilles tendon at the back of your ankle (tendon xanthoma). These can look like small fatty lumps
  • raised, pale, yellowish patches around your eyes and on your eyelids (xanthelasma)
  • a white arc shape or ring around the edge of the iris, the coloured part of the eye (corneal arcus).

Getting a diagnosis

Once your doctor has worked through these questions and tests, they can make a clinical diagnosis using guidelines called the Simon Broome criteria or the Dutch Lipid Clinical Network criteria

Your doctor should then refer you to a specialist in a lipid clinic for tests and treatment and to confirm the diagnosis. These are centres run by specialists in blood fats and diseases of the heart and blood vessels.

You should be offered genetic testing if there is a very strong likelihood that you have FH. This is a specialist test to look for a gene alteration (mutation, or fault) that is causing your high cholesterol. 

Genetic testing

There are different types of FH, as FH can be caused by alterations in different genes. Genetic testing means your doctor can find out if you definitely have FH and which type you have – as the tests can find the specific gene involved.

Read about genetic testing

Read about the pilot screening service to find children with FH

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