The proteins identified in this study to be differentially expressed and related to Alzheimer disease include: glyceraldehyde-3-phosphate dehydrogenase (GAPDH), cyclin-dependent kinase 5 (CDK5), ATP synthase-beta (ATPB), microtubule-associated protein tau (TAU) and protein phosphatase 3 – alpha (PPP3CA). Here, CDK5 is linked to Alzheimer disease.