Taken together with the involvement of LRRK2 in a number of immune cell-relevant signalling pathways, which we expand upon below, the GWAS implication of LRRK2 in the pathogenesis of three separate chronic inflammatory conditions creates a powerful body of work arguing for an essential function of LRRK2 in inflammatory responses that have potential implications for PD. This evidence concerns the gene LRRK2 and Parkinson disease.