[5] The ND6 protein is a subunit of NADH dehydrogenase (ubiquinone), which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain.

[6] The MT-ND6 product is a subunit of the respiratory chain Complex I that is believed to belong to the minimal assembly of core proteins required to catalyze NADH dehydrogenation and electron transfer to ubiquinone (coenzyme Q10).

[11] Initially, NADH binds to Complex I and transfers two electrons to the isoalloxazine ring of the flavin mononucleotide (FMN) prosthetic arm to form FMNH2.

The electrons are transferred through a series of iron-sulfur (Fe-S) clusters in the prosthetic arm and finally to coenzyme Q10 (CoQ), which is reduced to ubiquinol (CoQH2).

These genetic changes appear to prevent Complex I from interacting normally with ubiquinone, which may affect the generation of ATP and may also increase the production within mitochondria of potentially harmful molecules called reactive oxygen species (ROS).

[7] A G → A mutation at the 14459 base pair in the MT-ND6 gene also has been identified in a small number of people with Leigh's syndrome, a progressive brain disorder that typically appears in infancy or early childhood.