LRRK2 and Parkinson disease: Moreover, most familial PD genes such as PINK1, PARK, DJ-1, and LRRK2 have at least one C. elegans homolog (Sakaguchi-Nakashima et al., 2007; Sämann et al., 2009; Chege and Mccoll, 2014; Lee and Cannon, 2015).