Review contributors: Rachel J. Harding, Claudia Alvarez and Jacob McAuleyHuntington’s Disease Research Team, Structural Genomics Consortium, University of Toronto, CanadaNB: Review structure adapted from PreReview guidelines: https://prereview.org/users/164141/articles/200820-prereview-guidelines-how-to-write-a-preprint-reviewPreprint: https://www.biorxiv.org/content/10.1101/721191v1