MAPT and Alzheimer disease: In two recent articles published in Nature Neuroscience and Cell, Nelson et al.1 and Chen et al.2 have shown that a rare APOE3 Christchurch (APOE3Ch) variant, R136S, has protective effects on neurodegeneration in various Alzheimer’s disease (AD) model systems through attenuating tau pathology and regulating its related neuroimmune responses.