ApoE exists in three major isoforms, E2, E3, and E4, which differ from one another by a single amino-acid substitution. Compared with E3 and E4, E2 exhibits the lowest receptor binding affinity. Defects in ApoE are a cause of hyperlipoproteinemia type III due to increased plasma cholesterol and triglycerides levels which are the consequence of impaired clearance of chylomicron and VLDL remnants. Alternative Names: ApoE-2 protein, ApoE-2, Apo-E2 protein, ApoE 2 protein, ApoE 2, ApoE2, Apo E2 protein, Apolipoprotein E2 protein