HTT and early-onset autosomal dominant Alzheimer disease: Several mechanisms are associated with the neuroprotective effect of NMNATs, including the suppression of ROS production, mitochondrial stabilization [120], promotion of the clearance of hyperphosphorylated Tau protein oligomers [121], autophagic clearance of amyloid plaques in Alzheimer’s disease models [122], and reduced accumulation of mutant Huntingtin (Htt) aggregation [123].