Zhou et al. (2015) reported on Pink1/Parkin double knockout pigs generated using CRISPR/Cas9 in a one-step transfection and cloning. The brains of cloned knockin pigs lost the expression of Pink1 and Parkin, but no PD-associated phenotypic changes were found (Zhou et al., 2015). This evidence concerns the gene PRKN and Parkinson disease.