The apoE polymorphism studied by two-dimensional, high-resolution gel electrophoresis of serum.

The apoE polymorphism of human very low density lipoprotein (VLDL) was studied by the two-dimensional high-resolution gel electrophoresis technique of O'Farrell, which combines isoelectric focusing and SDA-polyacrylamide gel electrophoresis. With whole serum, six major patterns and two "sub-variants" of apoE were observed. A series of twin pairs (21 monozygotic (MZ) and 13 dizygotic (DZ) pairs) as well as unrelated people were analyzed. both members of MZ pairs always exhibited the same pattern, whereas DZ twins were often discordant. The patterns observed would be consistent with the hypothesis that three apoE isopeptides are coded for by three different alleles at one single locus. In this small series, all three postulated homozygous patterns, namely apoE-II, apoE-III and apoE-IV as well as the three heterozygous patterns apoE-II,III; apoE-III,IV and apoE-II,IV were seen.