In post-mortem human brain samples from AD patients, the levels of SIRT1 in some brain regions (entorhinal, temporal, and frontal cortices, hippocampus, and white matter) were lower than those in the corresponding control group, and significant correlations were observed between SIRT1 levels and Braak stages of neurofibrillary degeneration in the same regions of the brain [34,114,115]. This evidence concerns the gene SIRT1 and Alzheimer disease.