LRRK2 and Parkinson disease: Furthermore, it is worth noting that two of the genes linked to genetic PD, i.e., Parkin and LRRK2, encode for proteins involved in the regulation of microglia activity; in particular, Parkin mutation is associated with a more severe damage of DA neurons and increased production of M1 cytokines [91], while LRRK2 is expressed in activated microglia and takes part in the modulation of inflammation in response of pathological stimuli [92].