Studies where HSF1 null mice were crossbred with the R6/2 mice revealed that lack of HSF1 worsens neurodegeneration and disease progression (Hayashida et al., 2010) while HD transgenic mice overexpressing a constitutive active form of HSF1 significantly ameliorated HD symptoms (Fujimoto et al., 2005). Here, HSF1 is linked to Huntington disease.