[Xanthoma and atherosclerosis in the presence of normal plasma lipids]

Normal plasma lipid levels do not prevent the infiltration of skin and arterial walls by cholesterol. This does not mean that lipoproteins do not play a role in tissue infiltration which takes place in subjects with normal lipids. Abnormal lipids, an abnormal distribution of atherogenic and non-atherogenic lipids in the blood, a latent hyperlipidemia, the relative proportions of apolipoproteins in circulation or an abnormal composition of the lipoproteins may contribute to this phenomenon. Our studies in subjects with normal lipid levels with xanthelasmata support the hypothesis that the apolipoprotein-B has atherogenic properties. In addition, they suggest that certain isomers of the apolipoprotein-E may also be involved. Preliminary studies in our laboratory using a simple technique of identifying the 6 phenotypes of the apolipoprotein-E suggest that the isomer E2 may favour the appearance of hyperlipidemia when another genetic or environmental factor is present.