PRKN and autosomal recessive disease: Mutations in PARKIN (PARK2) coding for an E3 ubiquitin ligase enzyme called Parkin, and PINK1 (PARK6) coding for a protein kinase called phosphatase and tensin homolog (PTEN)-induced protein kinase 1 cause autosomal recessive disease accounting for the majority of familial PD cases, while mutations in DJ-1 (PARK7) are seen in rare forms of familial PD with autosomal recessive inheritance (Pankratz and Foroud, 2007; Klein and Westenberger, 2012).