Although these molecular mechanisms are recognised as fundamental to almost all aspects of AD pathogenesis [1], recently, various intracellular signaling molecules, such as cyclin-dependent kinase 5 (Cdk5, EC 2.7.11.22), glycogen synthase 3β, and mammalian target of rapamycin, have also been implicated in the development of AD [2–4]. This evidence concerns the gene CDK5 and Alzheimer disease.