MAPT and Alzheimer disease: In addition to the expected AD markers (tau, β-amyloid and apolipoprotein E) and more recently AD-associated collagen type XXV [13], the heat map of extracted ion intensities (XIC, normalized protein intensities based on raw signal to noise ratio) [14,15] demonstrated significant enrichment of U1-70k and Sm-D2 in the FAD insoluble fraction (Figure 1).