SCA2 family presenting as typical Parkinson's disease: 34 year follow up.
We describe a Korean family in SCA2 with long-duration levodopa-responsive parkinsonism without cerebellar ataxia. Clinical evaluation, genetic testing, and extensive imaging studies were done. All family members showed a typical Parkinson's disease phenotype without cerebellar ataxia for a long disease duration (up to 34 years). Genetic testing showed 40 CAG repeats and 4 CAA interruptions which is the longest repeat number among the families or patients manifesting with a parkinsonian phenotype without ataxia. Structural imaging (7T MRI and brain CT) showed a normal cerebellum and functional images showed nigrostriatal dopaminergic degeneration and normal D2 receptor binding activity, in agreement with the clinical phenotype. SCA2 should be considered as a cause of typical Parkinson's disease phenotype even in the absence of cerebellar ataxia.