LRRK2 and Parkinson disease: Interestingly, PD patients with GBA (N370S) mutations may exhibit a faster decline in striatal DAT availability during the premotor phase compared to patients with LRRK2 mutation or idiopathic PD using DAT SPECT in the PPMI cohort [15], while 18-FDOPA rate of change in GBA1 mutation carriers was similar to controls [29].