Recessive, early-onset forms of PD are linked to loss of function mutations in three gene products that are directly involved in mitochondrial biology, i.e., PINK1, encoding a mitochondria-targeted kinase, and Parkin/PARK2, encoding an E3 ubiquitin ligase, both involved in mitophagy and mitochondrial biogenesis and DJ-1, encoding a redox-regulated chaperone essential for oxidant defenses [2]. The gene discussed is PRKN; the disease is Parkinson disease.