An inducible CK-p25 mouse model for AD [77] leads to aberrant activation of cell cycle kinase Cdk5, generating a phenocopy of Alzheimer’s disease with hyperphosphorylated tau and neuronal loss in the cortex and hippocampus followed by an Alzheimer’s-disease-like forebrain atrophy, including intracellular Aβ accumulation. The gene discussed is CDK5; the disease is early-onset autosomal dominant Alzheimer disease.