Evidence suggests that crosstalk occurs between microglial leucine-rich repeat kinase 2 (LRRK2)—a regulator of neuroinflammation—and neuron-released α-synuclein (αSyn)—a promoter of microglial activation and neuroinflammatory responses—in neuroinflammation-mediated Parkinson’s disease (PD) progression. This evidence concerns the gene LRRK2 and Parkinson disease.