✓ Most lysosomal storage disorders are characterized by progressive central nervous system impairment, with or without systemic involvement. Affected individuals have an array of symptoms related to brain dysfunction, the most devastating of which is neurodegeneration following a period of normal development. The blood–brain barrier has represented a significant impediment to developing therapeutic approaches to treat brain disease, but novel approaches—including enzyme replacement, small-molecule, gene, and cell-based therapies—have given children afflicted by these conditions and those who care for them hope for the future.