Only 10% of all PD cases are caused by genetic mutations, and animal models of these mutations (α-synuclein and LRRK2, autosomal dominant PD) and (PINK1/Parkin and DJ-1, autosomal recessive PD) are important since they represent a possible therapeutic target (Dauer and Przedborski, 2003). Here, PRKN is linked to Parkinson disease.