Reduced striatal [123 I]FP-CIT binding in SCA2 patients without parkinsonism.

Degeneration of substantia nigra has been described in spinocerebellar ataxia type 2 (SCA2). In this study, dopamine transporter (DAT) density with [I-123]FP-CIT SPECT was studied in six SCA2 patients with no Parkinsonian signs, six Parkinson's disease (PD) patients, and six controls. Marked striatal DAT loss was found in both SCA2 and PD patients. However, a more severe reduction in the caudate and a higher putamen to caudate ratio distinguished SCA2 from PD patients, suggesting a more uniform nigrostriatal impairment in SCA2. Striatal DAT density of SCA2 patients correlated with the severity of cerebellar ataxia.