Apolipoprotein E and coronary artery disease: the debate is still on

Apolipoprotein E (Apo E) is quite a fascinating lipoprotein. As reported by Zou et al.' in this issue of the Journal of Geriatric Cardiology, Apo E has three isoforms, e2, e3, and e4, differing from each other by the polymorphisms found in the amino acid residues at sites 112 and 158. Apo E and its three isoforms, with e3 being the most common, is like a Pandora's box of sorts, where upon investigation, interesting correlations to some very prominent modern diseases have been found. For example, there was evidence that the presence of one e4 allele in their Apo E gene increased the risk for type-2 Alzheimer's disease and two e4 alleles would increase further this risk. Also intriguing is the subject of this paper by Zou et al.: the relationship between Apo E isoform e2 and the pres-ence of coronary artery disease (CAD).