Homozygous FH

Very high LDL cholesterol level in the blood caused by an inherited mutation from both parents. Where a person inherits exactly the same affected gene from both parents this is called truly “homozygous” FH. When the mutations in the LDL receptor gene (or equivalent) are different, this state is called “compound heterozygous”. In general the overall effect in both states is similar, in that LDL cholesterol concentrations are very high. Both groups of patients have the same clinical pattern and high risk of cardiovascular disease.

For clinical purposes both homozygous FH and compound heterozygous FH can be regarded as behaving in a similar manner. Therefore, for the purposes of this guideline the term “homozygous FH” is used to also encompass compound heterozygous FH.