Diagnosing HoFH

HoFH is diagnosed with a combination of cholesterol testing, checking for physical signs of HoFH, questions about your family’s and your own history of heart disease, and genetic testing.

Cholesterol tests

People with HoFH tend to have extremely high cholesterol levels, so it can often be diagnosed with a cholesterol test. As a guide:

  • In children under the age of 18 – LDL cholesterol levels will usually be above 11mmol/L. 
  • In adults – LDL cholesterol levels will usually be above 13mmol/L

If two parents have FH there is a high chance that any children they have will inherit FH or HoFH. Because the parents will probably already be under the care of a specialist, their child can be diagnosed very quickly with a cholesterol test.

If you have FH and you have children, get your child tested as early as possible so that they can start treatment from childhood.  

Physical signs of HoFH

Very high cholesterol can sometimes cause physical signs and symptoms which can be used to diagnose HoFH. 

  • Fatty lumps under the skin (cutaneous xanthoma) before the age of 10.
  • Swollen tendons caused by fatty deposits on the knuckles and backs of the ankles (tendon xanthoma), before the age of 10.
  • A white arc shape or ring around the edge of the iris which is the coloured part of the eye, (corneal arcus), before the age of 10.
  • Evidence of aortic valve disease ('aortic' refers to the aorta which is the main artery leaving the heart), before the age of five.

Your health and your family history

Sometimes cholesterol levels aren’t as high as expected for HoFH. In this case there are other things your health professional can consider to make a diagnosis. 

  • Tests to look for signs of early heart disease.
  • Family history – if you have close relatives with early heart disease this can be a sign that there is FH in your family.
  • Genetic testing – this gives more detail about the genes involved if both parents have FH. 

Genetic testing

Genetic testing is where scientists look in detail at your genes to see if there are any genetic faults which are causing disease. This can be very helpful for a number of reasons. It can:

  • confirm a diagnosis of HoFH
  • find out exactly which genes are involved, which means you can get the most targeted treatment. 

Read about genetic testing