The role of PP2A in neurodevelopmental disorders has been well described, and abnormal phosphorylation of tau is observed in AD.136 PP2A has been identified as a tau phosphatase137 and is responsible for approximately 71% of the total tau phosphatase activity in the human brain.138 However, patients with AD show lower PP2A activity in both gray and white matter.139. The gene discussed is MAPT; the disease is Alzheimer disease.