In the 2019 publication ‘To be or not to be pink (1): contradictory findings in an animal model for Parkinson disease’ by de Haas et al.,1 the authors presented important data with regard to the discrepancies in the number of substantia nigra dopamine neurons and extracellular striatal dopamine concentrations reported by their laboratory and others in the Pink1−/− rat model of Parkinson disease. This evidence concerns the gene PINK1 and Parkinson disease.