- The importance of plasma apolipoprotein E concentration in addition to its common polymorphism on inter-individual variation in lipid levels: results from Apo Europe. Haddy, N., De Bacquer, D., Chemaly, M.M., Maurice, M., Ehnholm, C., Evans, A., Sans, S., Do Carmo Martins, M., De Backer, G., Siest, G., Visvikis, S. Eur. J. Hum. Genet. (2002)