The YAC128 mouse is a yeast artificial chromosome animal model of HD with the entire human HTT gene containing 128 CAG repeats.40 This mouse model of HD is well characterized, has been used previously for evaluating HTT mRNA and protein lowering, and exhibits age-dependent striatal neurodegeneration and progressive motor and cognitive deficits.40,52,53 We compared the 16 precandidate pri-amiRNAs in the YAC128 mouse, with bilateral intrastriatal injection at total doses of 2.65 × 1010 to 6.00 × 1010 VG per animal, which were the maximum possible doses given the stock concentrations of vector. Here, HTT is linked to Huntington disease.