SOD2 and Huntington disease: Dysregulated expression of peroxisome proliferator-activated receptor γ (PPARγ) co-activator 1α (PGC1), a regulator of mitochondrial biogenesis and oxidative stress, and superoxide dismutase 2 (SOD2), a mitochondrial enzyme that catalyzes superoxide radicals into hydrogen peroxide, have been reported in HD [38,39,40].