Within this picture, the reduction of brain antioxidant capability and the impairment of protein synthesis/folding/clearance mechanisms represent major critical events, associated with trisomy 21, that initiate a self-sustained vicious cycle of degenerative processes, which may promote and contribute to the progression of APP- and tau-related pathological hallmarks and to the development of cognitive decline [7,10]. Here, MAPT is linked to Mental deterioration.