If several lines of evidence suggest that mHtt binds to Sp1 and causes a loss of Sp1 function on selective genes promoters [18], [19], [20], other studies reported that Sp1 protein level is increased in HD and that genetic or pharmacological approaches which decrease the level or activity of Sp1 have beneficial effect on HD mice [21], [22]. The gene discussed is SP1; the disease is Huntington disease.