Although IDS protein was detected in the brain tissues of all treated mice, neither AAV8.TBG.eBT-IDS1 nor AAV8.TBG.eBT-IDS2 resulted in a significant increase in IDS enzyme activity in the brain of MPS II mice compared to AAV8.TBG.IDSco (Fig. S3c). The gene discussed is IDS; the disease is mucopolysaccharidosis type 2.