HTT and Huntington disease: Because the HD KI mouse brain displays more abundant cytoplasmic TDP‐43, the above findings also support the idea that cytoplasmic TDP‐43 binds aberrant Htt exon1‐intron1 transcripts and brings them to the cytoplasmic ribosome for translation, resulting in the increased level of mutant exon1 Htt (Figure 7).