A neuropathological hallmark of HD is the presence of intracellular inclusion bodies composed of mutant Htt N-terminal fragments found in human postmortem brain, animal models, and cell culture models (DiFiglia et al., 1997; Gutekunst et al., 1999; Lunkes et al., 2002; Schilling et al., 2007; Juenemann et al., 2011). Here, HTT is linked to Huntington disease.