CYP2D6, an important drug metabolizer (Tyndale et al., 1991; Rendic and Guengerich, 2015), as well as CYP2E1 (Vaglini et al., 2004) were found to convert the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) which was shown to induce PD-like symptoms in mouse models of PD. Here, CYP2E1 is linked to Parkinson disease.