Apolipoprotein E

Apolipoprotein E (ApoE) is a class of apolipoprotein found in the cholesterol transport system. The gene, APOE, that encodes for ApoE is polymorphic, with three major alleles: ε2, ε3, and ε4. Each of these alleles has a unique impact on lipoprotein metabolism.

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Function

ApoE is primarily produced by the liver, but has also been found in other tissues such as the brain, kidney, and adipose tissue. It is a component of several classes of lipoproteins, including chylomicrons, VLDL (Very Low-Density Lipoproteins), and HDL (High-Density Lipoproteins). ApoE plays a crucial role in the catabolism of triglyceride-rich lipoprotein constituents.

Clinical Significance

The ε4 allele of the APOE gene has been identified as a major genetic risk factor for Alzheimer's disease and cardiovascular disease. It has been associated with increased cholesterol and triglyceride levels, and thus increased risk for coronary heart disease. Conversely, the ε2 allele is associated with Type III Hyperlipoproteinemia and may provide some protection against Alzheimer's.

Research

Research into ApoE has focused on understanding its role in cardiovascular and neurological diseases. Studies have shown that ApoE plays a role in the deposition and clearance of amyloid-beta peptides in the brain, a key factor in Alzheimer's disease progression.

See Also

• Apolipoprotein
• Alzheimer's disease
• Cardiovascular disease
• Lipoprotein metabolism