123I-FP-CIT SPECT [(123) I-2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl) nortropane single photon emission computed tomography] Imaging in a p.A53T α-synuclein Parkinson's disease cohort versus Parkinson's disease.

BACKGROUND

The p.A53T point mutation in the α-synuclein gene (SNCA) is a rare but highly relevant cause of autosomal dominant Parkinson's disease (PD).

OBJECTIVES

The objective of this study was to assess striatal dopaminergic denervation in a cohort of symptomatic carriers of the p.A53T SNCA mutation as compared to PD patients.

METHODS

Data from the Parkinson's Progression Markers Initiative database of 11 symptomatic p.A53T SNCA mutation carriers who underwent 123I-FP-CIT SPECT [(123) I-2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl) nortropane single photon emission computed tomography] imaging at our site were compared with those of 33 age-, sex-, and disease duration-matched PD patients.

RESULTS

The p.A53T mutation carriers had significantly lower caudate nucleus binding ratio both contralaterally and ipsilaterally to the most affected side (P = .002 and P = .006) and a decreased contralateral caudate/putamen signal ratio (P = .007) as compared to PD. A similar degree of striatal asymmetry was observed in both subgroups. No correlation between scores in neuropsychological tests and caudate nucleus dopaminergic denervation could be demonstrated.

CONCLUSIONS

PD patients harboring the p.A53T SNCA mutation show evidence of a more severe nigrostriatal denervation, especially evident in the caudate nucleus. The lack of significant differences in the putaminal binding ratios may reflect a floor effect or a true preferential targeting of the caudate terminals in p.A53T SNCA-associated PD. © 2018 International Parkinson and Movement Disorder Society.