This gene encodes the ND6 subunit that seems to be important for the assembly of Complex I [14]; in humans various point mutations of the MT-ND6 gene affect NADH dehydrogenase activity [15] and are associated with diseases such as Leber’s optic neuropathy, encephalomyopathy, and stroke-like episodes [16]. Here, MT-ND6 is linked to mitochondrial DNA depletion syndrome, encephalomyopathic form with methylmalonic aciduria.