Consequently, it is probably that the CSF-first Aβ pathway may represent the typical evolution of Alzheimer's disease which shows Alzheimer's typical tau spreading pattern,38–43 whilst the PET-first Aβ pathway may have cortical Aβ-burden related hippocampal-sparing elevated tau in early amyloidosis stage of Alzheimer's disease. This evidence concerns the gene MAPT and early-onset autosomal dominant Alzheimer disease.