Meijboom, Katharina EAbdallah, AbbasFordham, Nicholas PNagase, HirokoRodriguez, TomásKraus, CarolynGendron, Tania FKrishnan, GopinathEsanov, RustamAndrade, Nadja SRybin, Matthew JRamic, MelinaStephens, Zachary DEdraki, AlirezaBlackwood, MeghanKahriman, AydanHenninger, NilsKocher, Jean-Pierre ABenatar, MichaelBrodsky, Michael HPetrucelli, LeonardGao, Fen-BiaoSontheimer, Erik JBrown, Robert HZeier, ZaneMueller, Christian2023-01-302023-01-302022-10-21Meijboom KE, Abdallah A, Fordham NP, Nagase H, Rodriguez T, Kraus C, Gendron TF, Krishnan G, Esanov R, Andrade NS, Rybin MJ, Ramic M, Stephens ZD, Edraki A, Blackwood MT, Kahriman A, Henninger N, Kocher JA, Benatar M, Brodsky MH, Petrucelli L, Gao FB, Sontheimer EJ, Brown RH, Zeier Z, Mueller C. CRISPR/Cas9-mediated excision of ALS/FTD-causing hexanucleotide repeat expansion in C9ORF72 rescues major disease mechanisms in vivo and in vitro. Nat Commun. 2022 Oct 21;13(1):6286. doi: 10.1038/s41467-022-33332-7. PMID: 36271076; PMCID: PMC9587249.2041-172310.1038/s41467-022-33332-736271076https://hdl.handle.net/20.500.14038/51610A GGGGCC24+ hexanucleotide repeat expansion (HRE) in the C9ORF72 gene is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), fatal neurodegenerative diseases with no cure or approved treatments that substantially slow disease progression or extend survival. Mechanistic underpinnings of neuronal death include C9ORF72 haploinsufficiency, sequestration of RNA-binding proteins in the nucleus, and production of dipeptide repeat proteins. Here, we used an adeno-associated viral vector system to deliver CRISPR/Cas9 gene-editing machineries to effectuate the removal of the HRE from the C9ORF72 genomic locus. We demonstrate successful excision of the HRE in primary cortical neurons and brains of three mouse models containing the expansion (500-600 repeats) as well as in patient-derived iPSC motor neurons and brain organoids (450 repeats). This resulted in a reduction of RNA foci, poly-dipeptides and haploinsufficiency, major hallmarks of C9-ALS/FTD, making this a promising therapeutic approach to these diseases.enOpen Access: This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/ licenses/by/4.0/. © The Author(s) 2022Attribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/Amyotrophic lateral sclerosisCRISPR-Cas9 genome editingJournal ArticleNature communications