CRISPR/Cas9 Editing of the Mutant Huntingtin Allele In Vitro and In Vivo

Mol Ther. 2017 Jan 4;25(1):12-23. doi: 10.1016/j.ymthe.2016.11.010. Epub 2017 Jan 4.


Huntington disease (HD) is a fatal dominantly inherited neurodegenerative disorder caused by CAG repeat expansion (>36 repeats) within the first exon of the huntingtin gene. Although mutant huntingtin (mHTT) is ubiquitously expressed, the brain shows robust and early degeneration. Current RNA interference-based approaches for lowering mHTT expression have been efficacious in mouse models, but basal mutant protein levels are still detected. To fully mitigate expression from the mutant allele, we hypothesize that allele-specific genome editing can occur via prevalent promoter-resident SNPs in heterozygosity with the mutant allele. Here, we identified SNPs that either cause or destroy PAM motifs critical for CRISPR-selective editing of one allele versus the other in cells from HD patients and in a transgenic HD model harboring the human allele.

Keywords: AAV; CRISPR/Cas9; Huntington’s disease; gene therapy; genome editing.

MeSH terms

  • Alleles*
  • Animals
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • CRISPR-Associated Protein 9
  • CRISPR-Cas Systems*
  • Clustered Regularly Interspaced Short Palindromic Repeats
  • Disease Models, Animal
  • Endonucleases / genetics
  • Endonucleases / metabolism
  • Exons
  • Fibroblasts
  • Gene Editing*
  • Gene Order
  • Gene Silencing
  • Humans
  • Huntingtin Protein / genetics*
  • Huntington Disease / genetics*
  • Mice
  • Mice, Transgenic
  • Mutation*
  • Nucleotide Motifs
  • Plasmids / genetics
  • Polymorphism, Single Nucleotide
  • Promoter Regions, Genetic
  • RNA, Guide, CRISPR-Cas Systems


  • Bacterial Proteins
  • Huntingtin Protein
  • RNA, Guide, CRISPR-Cas Systems
  • CRISPR-Associated Protein 9
  • Cas9 endonuclease Streptococcus pyogenes
  • Endonucleases