Familial hypercholesterolaemia

Area of Science:

• Genetics
• Metabolic Disorders
• Cardiovascular Disease

Background:

• Familial hypercholesterolaemia (FH) is an inherited condition characterized by extremely high cholesterol levels, tendon xanthomas, and premature cardiovascular disease.
• It results from mutations in genes involved in low-density lipoprotein (LDL) metabolism, including the LDL receptor, apolipoprotein B (apoB), PCSK9, and the ARH adaptor protein.
• These genetic defects lead to impaired clearance of LDL cholesterol from the circulation.

Purpose of the Study:

• To review normal cholesterol and lipoprotein metabolism.
• To describe the genetic disorders causing FH, their metabolic disturbances, and clinical manifestations.
• To classify FH into distinct phenotypes based on metabolic derangement severity and discuss genetic diagnosis and population migration.

Main Methods:

• Review of literature on sterol and lipoprotein metabolism.
• Description of genetic defects in FH, including LDL receptor, apoB, PCSK9, and ARH pathways.
• Classification of FH into heterozygous and homozygous phenotypes based on genetic cause and metabolic severity.

Main Results:

• FH is caused by defects in at least four genes, with varying gene-dose effects impacting LDL clearance.
• Heterozygous FH involves defects in LDL receptor, apoB100, or NPC1L1, while homozygous FH involves LDL receptor or ARH mutations.
• Genetic diagnosis of FH enhances disease definition, detection, and provides insights into population migration patterns.

Conclusions:

• FH presents distinct phenotypes (heterozygous and homozygous) with significant atherosclerosis risk, particularly in homozygous individuals.
• Understanding the genetic basis and metabolic derangements is crucial for accurate diagnosis and management.
• Genetic diagnosis aids in identifying FH, understanding its population dynamics, and guiding treatment strategies.