We observed statistically significant changes in patients suffering from IPD versus healthy controls (HC) and in patients with a genetic predisposition (mutations of the LRRK2, SNCA, PRKN and other genes) for PD (GPD) versus HC and identified several P450s displaying a significant over-representation of selected SNPs in PD patients compared with the HC. The gene discussed is PRKN; the disease is Parkinson disease.