From the first reports indicating alterations of tau in the brains of HD patients [55,56], there is appealing evidence of tau hyperphosphorylation, increased total levels, mis-splicing affecting the 4R-Tau/3R-Tau ratio, protein misfolding and aggregation, subcellular redistribution, neurofibrillary tangles and neuropil threads in the brains of HD patients [57,58] that appears to correlate with late cognitive deficits and dementia in HD patients [56,59], suggesting that HD may have a tauopathy component [60] that deserves further exploration. This evidence concerns the gene MAPT and Cognitive impairment.