The increased expression of Grp78 in GM1 gangliosidosis patient fibroblasts in response to virus-mediated GLB1 overexpression also appears to be time-dependent, with increased Grp78 protein levels only becoming apparent 7 days following transduction with LV-CMV-GLB1 (Fig. S5). Here, HSPA5 is linked to GM1 gangliosidosis.