Differentiating symptomatic Parkin mutations carriers from patients with idiopathic Parkinson's disease: contribution of automated segmentation neuroimaging method.

BACKGROUND

Parkin (PARK2) gene mutations are the predominant cause of autosomal recessive parkinsonism. Characteristic features include: early onset symptoms with slow clinical course, good response to low doses of levodopa, and frequently treatment-induced dyskinesia. Studies using a voxel-based morphometry approach showed a decrease in the gray matter volume of the basal ganglia in mutation carriers during the symptomatic stages. A bilateral, presumably compensatory increase of basal ganglia gray matter value was recently demonstrated in asymptomatic Parkin mutation carriers. Behavioral disorders including: anxiety, psychosis, panic attacks, depression, disturbed sexual, behavioral and obsessive-compulsive disorders have been reported in these patients.

METHOD

A total of 28 Parkinson's Disease (PD) patients consisting of 10 Young-Onset without Parkin mutations (YOPD), 9 Young-Onset with Parkin mutations (YOPD-p), 9 Late-Onset without Parkin mutations (LOPD) and 32 healthy control subjects were studied with an automated volumetric assessment method to quantify subcortical atrophy. Patients but not controls also underwent a neuropsychological and neuropsychiatric assessment.

RESULTS

Results revealed a reduction of bilateral caudate nuclei volumes in YOPD-p patients compared to the YOPD patients while there were no statistically significant differences between other groups. YOPD-p patients showed similar results to other patient groups on neuropsychiatric and neuropsychological evaluation measures.

CONCLUSION

YOPD-p and YOPD patients showed a different pattern of volume changes in basal ganglia. Despite its relatively benign clinical course, carrying the Parkin mutation seems to be associated with greater atrophy in subcortical structures. Failure of compensatory mechanisms, different mutation types and pathophysiologic processes may underlie this diverse pattern of subcortical brain changes.