Motor and nonmotor heterogeneity of LRRK2-related and idiopathic Parkinson's disease.

Background: Parkinson's disease (PD) associated with LRRK2 mutations has been described as similar to idiopathic PD with minor clinical differences. No study has compared the clinical features of LRRK2-associated PD due to different mutations. The objective of this study was to compare LRRK2-associated PD due to G2019S and G2385R mutations and to compare each to idiopathic PD.

Methods: Sites within the international LRRK2 Cohort Consortium undertook family-based, community-based, or clinic-based studies to gather clinical data on manifesting carriers and patients with idiopathic PD.

Results: Five hundred sixteen PD patients with the G2019S mutation, 199 with the G2385R mutation, and 790 patients with idiopathic PD were included in the data set. Adjusted for age, sex, disease duration, and levodopa-equivalent daily dose, mean MDS-UPDRS part II or III scores and the frequency of motor fluctuations were higher in the G2385R mutation carriers than in either the G2019S mutation carriers or idiopathic PD patients. G2019S mutation carriers had significantly lower UPDRS part III scores than idiopathic PD patients. Both G2019S and G2385R mutation carriers had a higher proportion of the postural instability gait disorder phenotype compared with idiopathic PD patients. LRRK2 G2019S PD patients had better UPSIT scores and lower Geriatric Depression Scale scores than idiopathic PD patients in adjusted analyses.

Conclusions: G2385R and G2019S PD appear to have motor differences that may be explained by contrasting local treatment or measurement practices or differences in the biology of the disease. Longitudinal studies should evaluate whether progression is faster in G2385R mutation carriers compared with G2019S PD or idiopathic PD. © 2016 International Parkinson and Movement Disorder Society.