Many of the proteins encoded by genes causing recessive, atypical forms of PD, such as parkin, PINK1, and DJ-1, are involved in mitochondrial homeostatic processes (Lin and Beal, 2006; McCoy and Cookson, 2012; Kalia and Lang, 2015; Bose and Beal, 2016). Here, PRKN is linked to Parkinson disease.