CDK5 and Alzheimer disease: Furthermore, CDK5 is related to the pathogenesis of neurodegenerative diseases such as Alzheimer’s disease (AD), amyotrophic lateral sclerosis (ALS), and Niemann’s Pick type-C disease (NPD); its hyperactivation results in the deep remodeling of the nerve cytoskeleton, and the loss of synapses eventually leads to neurodegenerative changes [15,16,17].