Inhibition of the proteasome increased the number of Htt aggregates in cells and in induced pluripotent stem cells (iPSCs) generated from HD-patients, which can be quantified by microscopy or filter retardation assays (Wyttenbach et al., 2000; Waelter et al., 2001; Koyuncu et al., 2018). Here, HTT is linked to Huntington disease.