Given the close relationship between tau topographical distribution and clinical manifestations of AD,12,38,39 it is reasonable that PCA and lvPPA resemble the clinical extreme of posterior (S3) and lateral temporal (S4) tau subtypes.14,40 However, we could not find any significant association between the frequency of AD atypical variants and subtype assignment, likely because most of our patients with AD had a typical clinical profile. This evidence concerns the gene MAPT and Alzheimer disease.