SMAD3 and Huntington disease: Example target gene tracks are shown in Fig 6G–I including differentially expressed genes Adcy5, Kcnt1, and Pde1b. By contrast, SMAD3 target genes were not overrepresented among genes that became upregulated in the striatum of HD mouse models (143 upregulated SMAD3 target genes, odds ratio = 0.92, P = 0.40).