MT-ND6 and Alzheimer disease: Remarkably, both the somatic mtDNA mutations detected in AD brains (described above) and the AD-associated genetic polymorphism of the MEF2 loci, appear to target the same protein, the same complex, the same process, and the same organelle, namely the ND6 subunit, NADH dehydrogenase (Complex I), oxidative phosphorylation, and mitochondria, correspondingly [101, 129, 138], (Table 2).