Congruent with the notion that increased LRRK2 activity contributes to PD pathogenesis, Cho et al. demonstrated that normal LRRK2 levels are higher in the frontal cortex of sporadic PD and PD with dementia (PDD) patients compared to non-pathological controls (NPC) (Cho et al., 2013). Here, LRRK2 is linked to dementia.