Correction of the Pathogenic Constant Spring Mutation for Alpha-Thalassemia Using a Cytosine Base Editor

This study aims to correct the pathogenic Constant Spring mutation (c.427T>C) in the HBA2 gene, which causes alpha-thalassemia, using a cytosine base editor (CBE) delivered via a dual-AAV system. In vitro experiments in HEK-293T cells demonstrated that the CBE, guided by specific sgRNAs, could efficiently convert the mutant TAA (Ter) codon back to the functional CAA (Gln) codon, restoring gene function. To validate the editing efficiency and specificity, we performed targeted deep sequencing (NGS) at both the on-target HBA2 locus and potential off-target sites predicted by Cas-OFFinder. The raw sequencing data (FASTQ files) generated in this study, which includes amplicon sequencing results from edited and control samples, are being submitted to support the findings of precise genome editing and off-target assessment presented in the manuscript.