LRRK2 and Parkinson disease: A substitution of serine for glycine at position 2019 (G2019S) in the kinase domain of leucine-rich repeat kinase 2 (LRRK2, [MIM: 609007]) represents the most prevalent genetic mutation in PD (Zimprich et al., 2004; Di Fonzo et al., 2005; Gilks et al., 2005; Nichols et al., 2005).