Compared to AD patients, we observed down-regulation of CNTN2 (fold change (FC) = 0.77, CNTN4 (FC = 0.75) and CNTN5 (FC = 0.67) in bvFTD, and CNTN3 (FC = 0.72), CNTN4 (FC = 0.75) and CNTN5 (FC = 0.73) in PDD/DLB. This evidence concerns the gene CNTN5 and Alzheimer disease.