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. This evidence concerns the gene LRRK2 and Platelet storage pool disease.