Publications
Molecular therapy : the journal of the American Society of Gene TherapyJul 2025 DOI:
10.1016/j.ymthe.2025.07.038

Treatment of GATA2 deficiency by allele-specific CRISPR/Cas9-directed gene correction in hematopoietic stem cells

Skov, Thomas Wisbech; Wolff, Jonas Holst; Haslund, Didde; Revenfeld, Anne Louise; van de Venn, Lilly; Dorset, Sofie Rahbek; Ravendran, Sujan; Jørgensen, Sofie Eg; Thomsen, Martin Kristian; Holm, Mette; Corn, Jacob E; Møller, Bjarne Kuno; Mogensen, Trine H; Bak, Rasmus O; Mikkelsen, Jacob Giehm
Product Used
Genes
Abstract
GATA2 deficiency is a rare inborn error of immunity caused by monoallelic variants in the GATA2 gene, leading to dysfunction of hematopoietic stem and progenitor cells (HSPCs). Here, we investigate a potential therapeutic strategy for GATA2 deficiency based on CRISPR/Cas9-based gene correction, utilizing recombinant adeno-associated virus serotype 6 (rAAV6) as a template for homology-directed repair (HDR). For a 7-bp deletion giving rise to GATA2 deficiency, we identify a single guide RNA (sgRNA) supporting allele-specific cleavage in the disease allele. Initially, we observe high cytotoxicity in HSPCs upon Cas9/sgRNA ribonucleoprotein nucleofection and rAAV6 transduction, but this is mitigated by co-administering mRNA-based modulators of the DNA-damage response combined with a 10-fold reduction in rAAV6 dose. Using this protocol, we achieve efficient HDR (>80%) in HSPCs derived from a patient carrying the 7-bp deletion and show increased engraftment potential after GATA2 correction. Using DISCOVER-seq, we find limited off-target activity. However, with PCR-free long-read sequencing, we detect frequent large aberrations at the on-target site in HSPCs, primarily attributed to the integration of AAV concatemers identified in 15% of the targeted alleles. Our findings describe the effect of gene correction on GATA2 deficiency and highlight potential on-target aberrations following HDR-mediated gene correction.
Product Used
Genes

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