Familial hypercholesterolemia (FH) is a dominant disorder, characterized by elevated circulating LDL levels beginning at birth and increased risk of coronary heart disease (CHD) and myocardial infarction. The prevalence of familial hypercholesterolaemia (FH) is estimated at 1 in 500 for the heterozygous dominantly inherited form, while the homozygous form is very rare (1/1 million).

Diagnosis of FH is based on the finding of severe LDLc elevations in the absence of secondary causes of hypercholesterolemia, it can be confirmed by molecular analysis. Treatments include proper diet, exercise, and certain medications to reduce the risk of CHD or risk of a CHD-equivalent condition. In some homozygous patients surgery, such as a liver transplant, might be needed.

Familial hypercholesterolemia (FH) is caused by mutations in the LDLR, APOB, or PCSK9 genes. Mutations in the proprotein convertase subtilisin/kexin type 9 (PCSK9) gene, associated with gain of function variants, cause a type of FH known as autosomal dominant hypercholesterolemia 3 (HCHOLA3).