In support of a complex disease model for typical PD, we find it tantalizing that variants of another PD gene, LRRK2, have recently been found to alter the course of microbial infections in select paradigms from experimental investigations; these were conducted in immune cells, mice, and humans to better understand its association with three complex diseases (i.e., PD, Crohn’s and leprosy) (Hakimi et al. 2011; Ness et al. 2013; Liu et al. 2011; Fava et al. 2016; Dzamko et al. 2016). This evidence concerns the gene LRRK2 and Parkinson disease.