{"id":"doi:10.1186/s43556-026-00589-z","kind":"article","title":"Precision base-editing of the cryptic 3' acceptor site to correct the RNA splicing defect of β<sup>654</sup>-thalassemia","authors":["Lu D","Gong X","Guo X","Cai Q","Li W","Chen Y","Li D","Zeng F"],"author_count":8,"year":2026,"published":"2026-09-30","venue":"Molecular biomedicine","cited_by":0,"doi":"10.1186/s43556-026-00589-z","arxiv_id":null,"nct_id":null,"source_url":"https://doi.org/10.1186/s43556-026-00589-z","archive_url":"https://space-kitty.com/papers/doi:10.1186/s43556-026-00589-z","updated":null,"pmid":"42814316","pmcid":"PMC13627643","openalex_id":null,"pdf_url":"https://europepmc.org/articles/PMC13627643/pdf","abstract":"β-Thalassemia is one of the most common inherited disorders worldwide and is caused by mutations affecting β-globin production. β 654 mutation (IVS2-654, C > T) is one of the most frequently occurring β-thalassemia alleles in Han Chinese population, which activates a cryptic 3' splice site and leads to aberrant RNA splicing. Previous studies demonstrated that direct base editing of the IVS2-654 mutation is challenging because suitable single-guide RNAs (sgRNAs) cannot effectively target this site. Here we investigated an alternative therapeutic strategy by targeting the mutation-activated cryptic 3' splice acceptor site, rather than the disease-causing mutation itself. We first introduced base substitutions into the cryptic splice acceptor site in a β 654 -thalassemia mouse model using CRISPR-Cas9-mediated homology-directed repair, which restored normal RNA splicing and validated the therapeutic rationale of this approach. We then generated base-edited β 654 mice by microinjecting Td-CBEmax mRNA together with sgRNAs targeting the cryptic splice acceptor site into one-cell embryos. Base editing was successfully achieved in 78% of live-born β 654 mice, of which 86% produced correctly spliced β-globin transcripts. Restoration of normal RNA splicing was accompanied by marked improvement of hematological parameters and tissue pathology in most base-edited founder mice and their offspring compared with non-edited β 654 mice. Together, these findings demonstrate that mutation-activated cryptic splice sites are therapeutically actionable targets for precision base editing and provide proof of concept for a precise and effective strategy to correct aberrant RNA splicing in β 654 -thalassemia.","abstract_license":"CC-BY (article license as recorded by Europe PMC; abstract reproduced unmodified apart from markup removal)","license":"CC-BY","is_open_access":true,"retracted":false,"peer_reviewed":null,"categories":[],"details":null,"provenance":"europepmc","attribution":"Abstract of \"Precision base-editing of the cryptic 3' acceptor site to correct the RNA splicing defect of β<sup>654</sup>-thalassemia\" by Lu D, Gong X, Guo X et al., https://doi.org/10.1186/s43556-026-00589-z, used under its Creative Commons Attribution license (CC-BY); markup removed, otherwise unmodified.","topics":[{"slug":"gene-editing-therapies","name":"CRISPR & Gene-Editing Therapies","domain_slug":"medicine"}],"cited_in_dossiers":[]}