Because of the lack of in vivo phenotypes in PINK1 and Parkin mutant mice, it is hard to evaluate the impact of PINK1/Parkin-mediated mitophagy deficiency on PD pathology in vivo (Goldberg et al., 2003; Perez and Palmiter, 2005; Kitada et al., 2009). The gene discussed is PINK1; the disease is Parkinson disease.