Myelin lesions associated with lysosomal and peroxisomal disorders

Abnormalities of myelin are common in lysosomal and peroxisomal disorders. Most display a primary loss of myelin in which the myelin sheath and/or oligodendrocytes are selectively targeted by diverse pathogenetic processes. The most severe and, hence, clinically relevant are heritable diseases predominantly of infants and children, the leukodystrophies: metachromatic, globoid cell (Krabbe disease) and adreno-leukodystrophy. Our still limited understanding of these diseases has derived from multiple sources: originally, neurological-neuropathologic-neurochemical correlative studies of the natural disease in humans or other mammals, which has been enhanced by more sophisticated and contemporary techniques of cell and molecular biology. Transgenic mouse models seem to be the most promising methodology, allowing the examination of the cellular role of lysosomes and peroxisomes for formation and maintenance of both myelin and axons, and providing initial platforms to evaluate therapies. Treatment options are woefully inadequate and in their nascent stages, but still inspire some hope for the future.