APOE and Alzheimer disease: Consequently, APOE4 allele carriers have fewer omega-3 polyenoic fatty acids available for introduction into the membrane lipids, which may reduce the fluidity of the neuron plasma membrane and for the formation of eicosanoids (see “Eicosanoids and APOE4 in the Pathogenesis of AD”) and/or endocannabinoids (see “Endocannabinoids and APOE4 in the Pathogenesis of AD”).