In HD, this points towards possible impairments in mtDNA maintenance, with a consequent increase in mitochondrial biogenesis (TFAM) and amounts of VDAC2/3 and LonP as essential regulators of mtDNA copy number that might contribute to lower mtDNA levels and retention of deleterious mtDNA mutations.51,52 This was supported by Dimension 5, which distinguished cases and controls, explaining 8.5% of the variability. Here, VDAC2 is linked to Huntington disease.