| Atrophin-1 protein accumulation | Intranuclear inclusions containing mutant ATN1 protein with expanded polyQ tracts, most abundant in neurons of the striatum and cerebellum |
| White matter degeneration | Involvement of cerebellar white matter and pontocerebellar tracts |
| Cerebral atrophy | Progressive cortical and subcortical brain atrophy, particularly in later stages 9 |
| Dentate nucleus and red nucleus | Degeneration underlies progressive cerebellar ataxia |
| Globus pallidus (external segment) | Choreoathetosis and dystonia |
| Subthalamic nucleus | Movement disorder manifestations |
| Brainstem | Various neurological symptoms including dysphagia and dysarthria 10 |
| Progressive myoclonus epilepsy (PME) | Intractable myoclonic seizures, often with generalized tonic-clonic seizures |
| Severe intellectual disability | Progressive cognitive decline leading to profound dementia |
| Myoclonus | Less prominent than in juvenile form |
| Ataxia | Progressive cerebellar ataxia with gait instability |
| Chorea and athetosis | Involuntary choreiform movements, often beginning in the face and extremities |
| Databases | OMIMOrphanetClinicalTrialsPubMed |