Rapidly progressive sporadic dentatorubral pallidoluysian atrophy with intracytoplasmic inclusions and no CAG repeat expansion.

A 48-year-old man developed progressive hemidystonia and postural impairment with falls, followed by choreoathetosis, hyporeflexia, ataxia, supranuclear vertical gaze palsy, and dementia, lasting only 3.5 years from symptom onset to death. Family history and genetic testing were unrevealing. Neuropathology showed findings identical to genetic dentatorubral pallidoluysian atrophy (DRPLA), except for the absence of intranuclear inclusions and the presence of intracytoplasmic inclusions in the pons, striatum, thalamus, and subthalamic nucleus. This case expands the clinical and neuropathological spectrum of DRPLA and supports the hypothesis that aggregates may not be intrinsically pathogenic.