Exhibit 99.1 Taysha Gene Therapies Reports Full Year 2023 Financial Results and Provides Corporate and Clinical Updates Data from first adult patient in REVEAL Phase 1/2 trial showed TSHA-102 (low dose, 5.7x1014 total vg) was well-tolerated with no treatment-emergent SAEs as of 35-week assessment, with sustained improvement across key efficacy measures at decreased steroid levels and new improvement in RSBQ at month six Data from second adult patient showed TSHA-102 (low dose, 5.7x1014 total vg) was well-to ...