P134: Neuronal Pathways by Differential Tractography Correlate with Clinical Outcomes Following Gene Therapy for GM1 Gangliosidosis: New Biomarker for Neurodegenerative Diseases*

GM1 gangliosidosis, a lysosomal storage disorder caused by biallelic mutations in GLB1, results in progressive neurodegeneration, is uniformly fatal, and has no approved therapies. We compared GM1 Type II patients treated with AAV9GLB1 intravenous gene therapy (GT, N=9, NCT03952637) with untreated GM1 Type II patients from our natural history study (NHS, N=10, NCT00029965). We used differential tractography (DT) derived from magnetic resonance imaging (MRI) from a total of 49 scans to assess brain neuronal tract development in participants.