This gene encodes a member of the apolipoprotein A1/A4/E family of proteins. This protein is involved in the transport of lipoproteins in the blood. It binds to a specific liver and peripheral cell receptor, and is essential for the normal catabolism of triglyceride-rich lipoprotein constituents. Homozygous knockout mice for this gene accumulate high levels of cholesterol in the blood and develop atherosclerosis. Different alleles of this gene have been associated with either increased risk or a protective effect for Alzheimer's disease in human patients. This gene maps to chromosome 7 in a cluster with the related apolipoprotein C1, C2 and C4 genes. [provided by RefSeq, Apr 2015]