A 40-year-old woman presented with bilateral juvenile cataract, tendinous xanthomas, intellectual deterioration, spastic tetraparesis, proprioceptive deficit and parkinsonian syndrome. A younger sister's clinical picture differed by the absence of xanthomas and the presence of a cerebellar syndrome. The diagnosis of cerebrotendinous xanthomatosis was confirmed by a high concentration of plasma cholestanol and by urinary chromatography. Magnetic resonance imaging displayed some abnormalities in the hemispheric and cerebellar white matter. Under chenodesoxycholic therapy the biological abnormalities decreased while the clinical disturbances were unchanged.