TDP-43 pathology has also been linked to Huntington’s disease, although in this disease TDP-43 and the polyQ-expanded protein sometimes co-localize (Schwab et al., 2008; St-Amour et al., 2018)—a feature not seen in SCA2 (Toyoshima et al., 2011; Mori et al., 2014) or SCA3 (Tan et al., 2009; Seidel et al., 2010). This evidence concerns the gene ATXN3 and juvenile Huntington disease.