Histone deacetylase protein Sirtuin 6 (SIRT6) has been implicated in DNA repair and neurodegeneration where the lack of SIRT6 correlates with increased phosphorylation of tau [12,219].Furthermore, SIRT6 depletion in the AD brain results in increased GSK-3β activity, tau hyperphosphorylation, and subsequent neurodegeneration [220]. This evidence concerns the gene GSK3B and Alzheimer disease.