Objective: To investigate whether the presence of parkin gene mutations is associated with different nigrostriatal impairment than other early-onset parkinsonism.
Methods: Eighteen consecutive early-onset Parkinson disease (PD) patients (nine parkin and nine nonparkin patients) and six controls were studied with [123I]FP-CIT SPECT.
Results: Parkin patients had longer disease duration (15 +/- 9 vs 6 +/- 2 years, p = 0.008) and higher Unified Parkinson's Disease Rating Scale (UPDRS) motor score (35.8 +/- 13.7 vs 22.8 +/- 7.9, p = 0.025) than nonparkin patients. Caudate and putamen DAT density were reduced by 60% and 79% in parkin and by 43% and 70% in nonparkin patients. Multiple regression analysis showed that the UPDRS and the presence of parkin gene mutations, but not the disease duration, were significantly correlated with the striatal DAT density. Parkin patients showed a more symmetric DAT loss in both caudate and putamen as compared with nonparkin patients.
Conclusions: Parkin-related disease may be associated with a higher degree of nigrostriatal impairment, independently of the clinical severity of the disease, and a more symmetric involvement as compared with non-parkin early-onset disease.