Although only 7 patients with a diagnosis of Gaucher disease had PD at the time of sampling, it is perhaps not surprising that plasma gpNMB concentrations were significantly elevated in patients affected by Gaucher disease and PD when compared with patients suffering from either idiopathic Parkinson’s disease or Parkinson’s disease associated with heterozygous GBA1 mutations. This evidence concerns the gene GPNMB and Parkinson disease.