According to the Human Protein Atlas (https://www.proteinatlas.org (accessed on 9 September 2021)), the top of DEGs in GBA-PD patients compared to controls, JUNB, EGR1, NR4A2, and potential biomarkers of GBA-PD (DUSP1, COLEC12, TRIM13, BCL6, ARL4C) express not only in the blood, but in brain tissues. This evidence concerns the gene EGR1 and Parkinson disease.