Subsequently, three different groups identified in parallel the mutation G2019S at the kinase domain of LRRK2 as the most common pathogenic variant of LRRK2-associated PD (Di Fonzo et al., 2005; Hernandez et al., 2005; Kachergus et al., 2005) that remarkably it is found not only in monogenic but also in sPD cases lacking mendelian segregation. The gene discussed is LRRK2; the disease is Parkinson disease.