In addition, the immunoblotting detection of GPR37 in PD SN revealed upregulation of a prominent 52-kDa receptor form, which correlated with the increased CSF density of upstream N-terminal peptides, especially the EEQGAAFLAGPSWDLPAAPGRDPAAGR and GRDAWGPGNSAR peptides. This evidence concerns the gene GPR37 and Parkinson disease.