GLB1 and mucopolysaccharidosis type 4B: The treatment of GM1-gangliosidosis and MPS IVB patient fibroblasts with 20 to 500 μM DLHex-DGJ showed a 1.3- to 12.5-fold increase in GLB1 activity depending on the mutation, reaching values between 0.4% and 57.2% of those from wild-type fibroblasts (Table 2).