ADULT-ONSET KRABBE-DISEASE WITH HOMOZYGOUS T1853C MUTATION IN THE GALACTOCEREBROSIDASE GENE - UNUSUAL MRI FINDINGS OF CORTICOSPINAL TRACT DEMYELINATION

A 51-year-old woman developed a slowly progressive spastic paraparesis and diminished vibration sense beginning at age 38. Intellectual capa city was normal. Krabbe disease was confirmed by markedly reduced leuk ocyte galactocerebrosidase (GALC) activity, typical inclusions in Schw ann cell cytoplasm, and an identification of the homozygous point muta tion T1835C (Leu(618)Ser) in the GALC gene. T2-weighted MRI of the bra in showed symmetric higg-signal-intensity lesions in the bilateral fro ntoparietal white matter, the centrum semiovale, and the posterior Lim b of the internal capsule with sparing of the periventricular white ma tter. This case is unusual because of the late onset, protracted clini cal course, and MRI findings of demyelination confined to the corticos pinal tracts.