1.Available evidence confirms that the LRRK2 variant rs34637584 is associated with less cognitive impairment in people with PD.2.GBA variants rs76763715 and rs421016 are associated with more severe cognitive impairment in people with PD.3.The GBA variants rs76763715, rs421016, rs387906315 and rs80356773 have been significantly associated with the onset of depressive symptoms in PD.
Contrastingly, high levels of human LRRK2 cause locomotor alterations and cognitive deficits accompanied by reduced striatal dopamine levels, with the latter also observed in G2019S mutant mice.
PD in AJ LRRK2 G2019S mutation carriers is similar to idiopathic PD but is characterized by more frequent lower extremity involvement at onset and PIGD without the associated cognitive impairment.
These results demonstrate biochemical abnormalities of alpha-synuclein, and increased oxidative stress damage and oxidative stress responses in the frontal cortex in PD linked with G2019S LRRK2 mutation not related with the presence of cortical LBs and in the absence of apparent cognitive deficits.