Additionally, injecting AAV9-miRNA targeting human huntingtin (HTT) in the striatum of transgenic Huntington’s disease (HD) sheep so that these express the full-length HTT gene reduced the mRNA and protein of human HTT by 50–80% in the striatum at 1 and 6 months postinjection (Pfister et al., 2018). This evidence concerns the gene HTT and juvenile Huntington disease.