The lack of PGC-1α expression produces an HD-like phenotype in mice (Lin et al. 2004; Leone et al. 2005) and mutant, but not wild type, huntingtin down-regulates the expression of PGC-1α and its target genes (Cui et al. 2006; Lin et al. 2004; Weydt et al. 2006). This evidence concerns the gene HTT and Huntington disease.