Apolipoprotein E phenotypes and hyperlipidemia

Apolipoprotein E phenotypes were determined in 361 patients with hyperlipidemia and in controls. The E2 isoform was significantly more frequent in the group of hyperlipidemics (P P>0.005), ii) that isoform E4 was significantly more frequent in patients with hypercholesterolemia (0.01>P>0.005) and iii) that isoforms E2 (P>0.005) and E4 (0.05>P>0.025) were both more frequent in patients with mixed hyperlipidemia. Roughly 20% of patients with mixed hyperlipidemia had one of the rare phenotypes E-4/4,-4/2 or-2/2. We conclude that alleles e2 and e4 both contribute to the susceptibility for, and/or phenotypic expression of hyperlipidemia. Whereas the gene e2 seems to exert its influence on plasma lipoproteins by an abnormal gene product (E2) that has reduced binding activity to lipoprotein receptors, the mechanism underlying the association of the e4 gene with hyperlipidemia is presently unclear.