Studies of cells expressing the (APPswe) mutation, transgenic mice expressing both APPswe and presenilin mutations, and sections of hippocampus and entorhinal cortex from human AD patients, show that PP2A levels are decreased and Y307 levels (an inhibitor of PP2A) were increased [104] implying that the phosphatase affects the processing of APP and highlighting its importance in limiting AD pathology. The gene discussed is PTPA; the disease is Alzheimer disease.