The causes of PD are unknown, but mutations in several genes have now been identified in rare cases of inherited PD, including the genes SNCA (alpha-synuclein), PARK2 (parkin), PTEN induced Putative Kinase 1 (PINK1), PARK7 (DJ-1), Leucine Rich Repeat Kinase 2 (LRRK2) and ATP13A2 (Yang et al., 2009). Here, PINK1 is linked to Parkinson disease.