The mitochondrial quality-control pathways that evolved to maintain the integrity of mitochondria therefore have key roles in the normal function of cells.1, 2 The pathogenesis of a large number of inherited diseases in humans, including Parkinson's disease, has been linked to mitochondrial dysfunction.3, 4, 5 The pink1 and parkin genes encode a mitochondrially targeted protein kinase and an E3 ubiquitin ligase, respectively. Here, PINK1 is linked to Parkinson disease.