LRRK2 and Parkinson disease: In addition, genome-wide association studies (GWAS) have identified genomic variants at the LRRK2 locus that confer risk for sporadic PD, suggesting that this gene is involved in the pathogenesis of a large portion of PD cases (Satake et al., 2009; Simón-Sánchez et al., 2009; Nalls et al., 2014, 2019).