Parkinsonism and nigrostriatal dysfunction are associated with spinocerebellar ataxia type 6 (SCA6)

SCA6 is a slowly progressive, late-onset cerebellar ataxia due to a trinucleotide expansion in the CACNA1A gene. We describe two unrelated cases that presented with Parkinsonism and cerebellar ataxia. One case was L-dopa-responsive with a pattern of (18)F-dopa uptake similar to Parkinson's disease, and the second case was not L-dopa-responsive and had an atypical pattern of nigrostriatal dysfunction. We suggest that SCA6, in common with SCA2 and SCA3, may be associated with Parkinsonism attributable to nigral loss and dopaminergic dysfunction. Moreover, isolated cases may be confused with multiple system atrophy.