Tau accumulation observed in molecular neuroimaging studies has significant clinical correlations: a greater accumulation of tau is related to the increased severity of cognitive decline115)-(117) and, in atypical AD, the regions with higher radiotracer retention are associated with symptoms related to these regions, such as occipital lobes in PCA, and to the pattern of glycolytic hypometabolism.118. This evidence concerns the gene MAPT and Alzheimer disease.