Nonetheless, an overall as well as an APOE genotype-specific comparison revealed, besides a high consistency between the overall SDG spectra patterns in AD CSF and the AD and control brain homogenates, certain qualitative differences in the distribution and levels of homomeric and heteromeric Aβ oligomeric forms among the AD APOE4+, the Ctrl APOE4+ and the Ctrl APOE4− groups. This evidence concerns the gene APOE and Alzheimer disease.