Neuropathology of dentatorubropallidoluysian atrophy

We examined 12 autopsy cases of dentatorubropallidoluysian atrophy (DRPLA). We confirmed the commonly or often recognized neuropathological findings in DRPLA as follows: 1, thickening of the skull bone; 2, atrophy of the brain; 3, degeneration of the dentate nucleus and its afferent fibers; 4, degeneration of the globus pallidus‐subthalamic nucleus system; 5, atrophy of the tegmentum of the brain stem especially in the pons; 6, symmetrical necrotic small foci of the ventro‐lateral portion of the pontine tegmentum; 7, degeneration of the striatum; 8, degeneration of the superior colliculus; 9, degeneration of the gracile nucleus; 10, degeneration of the pyramidal tract; 11, mild degeneration of the cerebellar cortex; 12, mild degeneration of the cerebral cortex; and 13, degeneration of the cerebral white matter. From the histopathological point of view, DRPLA is clearly distinguished from Machado‐Joseph disease and myoclonus epilepsy associated with ragged‐red fibers. We also examined the clinico‐pathological correlations in three clinical groups which were classified as juvenile type, early adult type and late adult type. We noted that in juvenile type presenting with progressive myoclonus epilepsy syndromes as the main clinical features of DRPLA, degeneration of the globus pallidus was more severe than that of the dentate nucleus, and atrophy of the brain stem and spinal cord was mild. We also noted that in late adult type presenting with cerebellar ataxia and choreoathetoid involuntary movements without myoclonus or epilepsy or either, degeneration of the dentate nucleus was more severe than that of the globus pallidus, and severe atrophy of the brain stem and spinal cord.