APOE and atherosclerosis: Mutations of human genes involved in lipoprotein metabolism, including low-density lipoprotein receptor (LDLR) and proprotein convertase subtilisin/kexin type 9 (PCSK9), can cause familial hypercholesterolaemia (FH) and atherosclerosis or, as in the case of apolipoprotein E (APOE), increase disease risk.