Although the role of Sp1 in HD pathogenesis is still controversial, mHtt was shown to inhibit Sp1-dependent transcription in postmortem brain tissues of patients with HD even in the presymptomatic stage [244], while overexpression of Sp1 promotes the expression of wild-type Htt and diminishes the cellular toxic effects of aggregated mHtt [237]. Here, SP1 is linked to Huntington disease.