The lysosomal enzyme is secreted by cells and moves to other cells for integration into lysosomes to exert its effects.35 Therefore, many lysosomal storage diseases are treated by inducing genes in some cells in the brain, as confirmed by several studies on gene therapy for lysosomal diseases.36 However, as NPC1 is not secreted by cells,37 the NPC1 gene needed to be delivered to a larger proportion of cells. This evidence concerns the gene NPC1 and lysosomal storage disease.