Chronic lentivirus-mediated GLB1 overexpression in three infantile-onset GM1 gangliosidosis patient fibroblast lines (Fig. 8A; see Fig. 8E for patient genotypes) over a period of 8 days promotes a dose-dependent increase in the relative amounts of precursor nonlysosomal β-gal protein levels (Fig. 8A; see Fig. 8B for quantification), which coincides with a dose-dependent decrease in the relative amount of mature, lysosomal rhβ-gal protein levels (Fig. 8A; see Fig. 8C for quantification). Here, GLB1 is linked to GM1 gangliosidosis.