We performed mass spectrometric metabolomics of plasma from: i, patients with idiopathic PD; ii, PD patients with the p.G2019S or p.R1441G mutations of the LRRK2 gene (Figure 1A and Supplementary Table 1); and iii, from a PD mouse model (Supplementary Table 2). The gene discussed is LRRK2; the disease is Parkinson disease.