Compared with WT controls, Dscr-1−/− mice plasma did not show a significant increase in ApoB, whereas ApoE−/− mice plasma demonstrated an increase in remnant lipoprotein levels that were eventually reflected in ApoB increase (Fig. 3D), suggesting that increased hypercholesterolemia in Dscr1−/− and ApoE−/− double mutant mice is a result of exaggerated ApoE−/−-mediated impairment of cholesterol clearance. This evidence concerns the gene APOE and familial hypercholesterolemia.