[6] Variants of the human MT-ND1 gene are associated with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS), Leigh's syndrome (LS), Leber's hereditary optic neuropathy (LHON) and increases in adult BMI.

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

Abnormalities in mitochondrial energy generation result in neurodegenerative disorders like Leigh syndrome, which is characterized by an onset of symptoms between 12 months and three years of age.

The symptoms frequently present themselves following a viral infection and include movement disorders and peripheral neuropathy, as well as hypotonia, spasticity and cerebellar ataxia.

[7] The m.4171C>A/MT-ND1 mutation also leads to a Leigh-like phenotype as well as bilateral brainstem lesions affecting the vestibular nuclei, resulting in vision loss, vomiting and vertigo.