In HD patients and animal models, aside from the N-terminal part of mHtt, ubiquitin, molecular chaperones including GRP78/BiP, HSP70, and HSP40, and the 20S, 19S, and 11S subunits of the 26S proteasome were also found ([37, 158], reviewed in [159]). This evidence concerns the gene HSPA5 and Huntington disease.