As anticipated, several proteins associated with the 'core markers', 'metabolic', and 'synapse & membrane' clusters were selected for distinguishing between preclinical and prodromal AD (e.g., YWHAB, GDI1, SMOC1, UCHL1, NPTX2, DDAH1, ENO2; Supplementary Figure S12 A) and between prodromal AD and AD dementia (e.g., VGF, NPTXR, UCHL1, PCSK1, SPON1; Supplementary Figure S12 D). This evidence concerns the gene DDAH1 and Alzheimer disease.