ARSA and metachromatic leukodystrophy: Deficiency of arylsulfatase A and B, that are associated with metachromatic leukodystrophy and Maroteaux-Lamy syndrome, respectively, increases sulfatides and sulfated chondroitin 4-sulfate in the CNS, attenuating oligodendrocyte differentiation and neural recovery (Zhang et al., 2014; Bhattacharyya et al., 2015; Pituch et al., 2015).