Selective corticospinal tract involvement in late-onset Krabbe disease.

A 4-year-old girl presented with increasing falls and progressive limb stiffness noticed for 2 months. There was no history of cognitive decline, seizures, or vision impairment. Examination revealed spastic quadriparesis, with no sensory or cerebellar abnormalities. A suggestive MRI scan of the brain (figure) and reduced galactocerebrosidase activity in leukocytes confirmed the diagnosis of late-onset Krabbe disease. MRI in late-onset Krabbe disease classically shows parieto-occipital periventricular white matter and posterior corpus callosal signal changes with sparing of subcortical U fibers and cerebellar white matter.1 Isolated corticospinal tract involvement is an unusual pattern described in adultand late-onset forms of Krabbe disease.1 In the setting of childhood neurodegeneration, similar changes have also been described in X-linked adrenoleukodystrophy, acyl– coenzyme A (CoA) oxidase deficiency, and 3-hydroxy-3-methylglutaryl–CoA lyase deficiency.2,3