Finally, we found that neurodegeneration induced by the mitochondrial complex II inhibitor 3-nitropropionic acid, which has been used to model HD (Beal et al., 1995), was exacerbated in Bmal1 hemizygous mice, which have intact systemic rhythms but only half the normal level of BMAL1 protein expression in the brain. The gene discussed is BMAL1; the disease is Huntington disease.