Development of base (BE) and prime (PE) editors to correct the SBDS c.258+2T>C mutation. (A) Schematic of the designed BE and PE editors. The sequence of the sense and antisense DNA strands, with exon and intronic sequences in upper and lower case respectively, is reported. The cryptic 5′ss located 8 bp upstream of the SBDS exon 2 5′ss is underlined. The c.258+2T>C mutation, on both DNA strands, is in bold. The spacer RNA, and the PBS, RTT, and gRNA scaffold sequences are indicated in red, blue, green, and orange, respectively. (B) Evaluation of correctly spliced transcripts through the denaturing capillary electrophoresis of labeled mRNA transcripts. Histograms report the amount of correctly spliced transcripts. Results are presented as the mean ± SD of three independent experiments. CBE: evoAPEBEC1-BE4mac-NG (Addgene plasmid no. 125616), PE2-SpG (Addgene plasmid no. 159978), and PE2 (Addgene plasmid no. 132775).