Late Emergence of Parkinsonian Phenotype and Abnormal Dopamine Transporter Scan in Chorea-Acanthocytosis.

Chorea-acanthocytosis (ChAc) is a neurodegenerative condition predominantly manifesting with chorea and often acanthocytes on peripheral blood film. Abnormal appearances with ¹²³I-FP-CIT single-photon emission computed tomography (SPECT) have not previously been reported in ChAc. We describe 2 cases with typical presentations of ChAc and late development of parkinsonism with asymmetric reduction in presynaptic striatal uptake on ¹²³I-FP-CIT SPECT. Case 1, a 50-year-old male, developed micrographia and limb bradykinesia 14 years after initial presentation at the age of 30. Case 2, a 42-year-old female presenting with vocal tics and generalized dystonia at the age of 25, developed tremor, bradykinesia, and rigidity 11 years into the disease course. These cases represent the best description to date of the natural history of ChAc, in which the early hyperkinetic clinical syndromes give way to a parkinsonian phenotype. This is consistent with a gradual deterioration of presynaptic nigrostriatal projections, reflected in the clinical parkinsonism and abnormal ¹²³I FP-CIT SPECT.