Although the functioning of PP2A is not well understood, it is well established as a regulator of cell division, growth, and differentiation, and the functions of PP2A in cancer and various neurodegenerative disorders, such as Alzheimer’s disease, have been studied in detail; for PPP2R1A, the crucial mechanism is determined by an alteration in the dependent dephosphorylation dynamics [24]. The gene discussed is PPP2R1A; the disease is early-onset autosomal dominant Alzheimer disease.