Genetic linkage studies of Parkinson's Disease (PD) have identified susceptibility loci in five genes which include SNCA [1] (PARK1), Parkin [2] (PARK2), PTEN-induced putative kinase [3] (PINK1;PARK6), DJ-1 [4] (PARK7) and Leucine rich repeat kinase 2 [5] (LRRK2; PARK8). Here, LRRK2 is linked to Parkinson disease.