Its isoform, APOE ε4, is the strongest genetic risk factor for Alzheimer’s disease.41 Though most studies focused on isoform-specific differences in structure and function, the main function of the ApoE protein, the redistribution of lipoproteins and cholesterol, is not sufficient to explain APOE’s detrimental effect in Alzheimer’s disease. This evidence concerns the gene APOE and early-onset autosomal dominant Alzheimer disease.