Deep white matter lesion along with the involvement of thalamus suggests Krabbe's disease. The deficient lysosomal enzyme in Krabbe disease is galactocerebrosidase (GALC; also called galactosylceramide beta-galactosidase); it normally degrades galactocerebroside to ceramide and galactose. The deficiency results in the accumulation of galactocerebroside; a toxic metabolite, psychosine, leads to the early destruction of oligodendrocytes and depletion of lipids in the cerebral white matter. The EEG shows nonspecific slowing without spikes, and the CSF protein is usually elevated (70 to 450 mg/dL). CT scanning and MRI reveal symmetrical nonenhancing areas of increased density in the internal capsules and basal ganglia. C.T. shows diffuse symmetric attenuation of the cerebellar and cerebral white matter in Alexander's disease. The onset is in infancy with a failure to thrive, psychomotor retardation, spasticity of the craniospinal musculature, and seizures. An early and progressive macrocephaly has been a consistent feature.Pathologically, there are severe destructive changes in the cerebral white matter, most intense in the frontal lobes. Distinctive eosinophilic hyaline bodies, most prominent just below the pia and around blood vessels, are seen throughout the cerebral coex, brainstem, and spinal cord. These have been identified as Rosenthal fibers and probably represent glial degradation products. C.T. scan demonstrates degeneration of the white matter most prominent in the frontal lobes. Canavan's disease. C.T. scan shows diffuse white matter degeneration primarily in the cerebral hemispheres with less involvement in the cerebellum and brainstem in Metachromatic leukodystrophy. This is another of the lysosomal (sphingolipid) storage diseases. The abnormality is the mutation of the gene for enzyme arylsulfatase A, which prevents the conversion of sulfatide to cerebroside (a major component of myelin) and results in an accumulation of the former. The disease is transmitted as an autosomal recessive trait. Ref: Ropper A.H., Samuels M.A. (2009). Chapter 37. Inherited Metabolic Diseases of the Nervous System. In A.H. Ropper, M.A. Samuels (Eds), Adams and Victor's Principles of Neurology, 9e.