Autosomal recessive mutations of genes encoding the mitochondrial protein kinase PTEN-induced kinase 1 (PINK1) and RING-IBR-RING (RBR) ubiquitin (Ub) E3 ligase Parkin are causal for familial early-onset Parkinson’s disease (PD) (1, 2). The gene discussed is PINK1; the disease is Parkinson disease.