CRISPR Gene Correction Approaches for CBS/PSP

SUMMARY

# CRISPR Gene Correction Approaches for CBS/PSP ## Background and Rationale CRISPR-Cas9 gene editing represents a transformative therapeutic modality for treating monogenic forms of neurodegeneration, offering unprecedented precision for correcting disease-causing mutations at their genomic source. Progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS) include several genetic variants caused by mutations in MAPT (microtubule-associated protein tau), GRN (granulin), and C9orf72 gene

METHODOLOGY NOTES

**Phase 1: Patient Recruitment and Screening (Months 1-6)** • Recruit 60 patients with genetically confirmed CBS/PSP (MAPT, GRN, or C9orf72 mutations) • Obtain informed consent for research participation and genetic analysis • Collect detailed clinical assessments using PSP Rating Scale and CBS severity measures • Extract peripheral blood mononuclear cells (PBMCs) and establish patient-specific iPSC lines • Perform whole genome sequencing to confirm pathogenic variants **Phase 2: CRISPR Design and Validation (Months 3-9)** • Design patient-specific guide RNAs targeting pathogenic mutations using CHOPCHOP and Benchling • Synthesize Cas9-RNP complexes with homology-directed repair (HDR) templates • Test editing efficiency in patient iPSCs using digital droplet PCR and Sanger sequencing • Validate off-target effects using GUIDE-seq and targeted amplicon sequencing • Optimize electroporation conditions for >70% editing efficiency **Phase 3: Neuronal Differentiation and Correction (Months