AAV9-Ctsa-Bici-Neu1

**AAV9-Ctsa-Bici-Neu1** is a preclinical bicistronic adeno-associated virus serotype 9 gene therapy designed to co-deliver functional **CTSA** and **NEU1** genes for the treatment of **galactosialidosis** and **sialidosis**. CTSA encodes protective protein cathepsin A, which is required for the stability, lysosomal trafficking, and enzymatic activity of neuraminidase 1 encoded by NEU1. By restoring both components, the vector is intended to reconstitute lysosomal neuraminidase activity, reduce pathological glycoconjugate accumulation, and address central nervous system and peripheral manifestations. UMass Chan Medical School has evaluated combined intracerebroventricular and intravenous administration in Neu1-knockout and Ctsa-knockout mouse models.