There are currently no disease-modifying therapies for Huntington’s disease and strategies that aim to lower the levels of the HTT protein hold great promise.22 Transcriptional and post-transcriptional approaches that include small interfering RNAs,23 microRNAs,24 antisense oligonucleotides,25 zinc-finger proteins26 and small molecule splicing modulators27 are in clinical development.28 These modalities either target the full-length HTT transcript or both HTT and HTT1a. This evidence concerns the gene HTT and juvenile Huntington disease.