PPARGC1A and Huntington disease: One biologically compelling candidate thought to be involved in HD pathogenesis is PPARGC1A, localized at 4p15.1-2, which encodes peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), a transcriptional regulator of adaptive thermogenesis (Puigserver et al. 1998) and mitochondrial respiration and oxidative stress (Puigserver and Spiegelman 2003; St-Pierre et al. 2006).