Plasma gpNMB concentrations were lower in patients with IPD and GBA heterozygous IPD patients from the Biopark Cohort compared with patients with GD1, GD3 and GD1 with PD (p<0.001, p<0.001, p<0.001) from the GAUCHERITE Cohort, respectively. Here, GPNMB is linked to Parkinson disease.