MAPT and Alzheimer disease: Alzheimer’s disease (AD), whichis the most frequently seenneurodegenerative disorder, is characterized by the accumulation ofhyperphosphorylated microtubule-associated tau protein as intraneuralneurofibrillary tangles and by the accumulation of amyloid-βpeptide as extracellular amyloid plaques in the brain.1 On the other hand, Parkinson’s disease (PD) is definedby Lewy bodies and Lewy neurites, which are dominantly composed ofα-synuclein (α-syn) protein.2,3 In both diseases,defects in energy metabolism due to mitochondrial dysfunctions occurduring the neurodegeneration process.