There is agreement about the influence of the genetic apolipoprotein (apo E) 
polymorphism on plasma lipid and apoprotein levels in man. Whereas the 
association of the apo E2 isoform with primary dysbetalipoproteinemia and 
hyperlipoproteinemia type III is well established, the plasma- and 
LDL-cholesterol lowering effects of apo E2 and the phenomenon of apo E4 raising 
these parameters on the development of coronary heart disease is still a matter 
of controversial discussion. Despite these uncertainties the knowledge of an 
individual's apo E phenotype may provide additional information in future to 
judge its risk to develop atherosclerosis. From a variety of methods meanwhile 
described to analyze the polymorphism and evaluate the apo E phenotype the 
author has modified three procedures to apply to different questions concerning 
apo E isoform analysis. They concern the visualization of the apo E pattern in 
diluted solutions and those containing high salt concentrations, the apo E 
phenotyping on a large scale basis from whole plasma avoiding a possible 
misinterpretation by a thrombin fragment of apo E and finally the search for new 
apo E variants with a high resolution system on immobilized pH gradient gels.