For example, the LRRK2 G2019S mutation increases the inflammatory response to paraquat in mice; DAT variants and herbicide exposure can jointly influence PD risk; and CYP2D6 variants are associated with altered DNAm and PD risk (Elbaz et al., 2004; Ritz et al., 2009; Tiili et al., 2015; Rudyk et al., 2019). This evidence concerns the gene SLC6A3 and Parkinson disease.