The corresponding set of evidence implicating a potential pathogenetic role of PGC-1α repression in mitochondrial dysfunction in HD as well as early observations of striatal alterations in PGC-1α-deficient mice [175, 176] suggested that such animals may serve as experimental models for HD; however, findings of a recent detailed neuropathological evaluation of mice lacking the expression of full-length PGC-1α has indicated that it might not indeed be the case and turned our attention to another group of diseases where systemic mitochondrial dysfunction is pathognomonic [122]. The gene discussed is PPARGC1A; the disease is Huntington disease.