The gene, absence of melanoma 2 (Aim2), another cytosolic DNA sensor (40), was also up-regulated in HD cells, but to a much smaller extent than observed for cGAS (the RPF/mRNA for cGAS was 14, whereas it was 2.2 for Aim2 in HD-homo cells) (Fig. 1D). Here, CGAS is linked to Huntington disease.