RAB39B and Parkinson disease: The remaining 20 genes were assessed for co-expression with known Mendelian PD genes (ATP13A2, FBXO7, LRRK2, PARK2, PARK7, PINK1, RAB39B, SNCA, and VPS35) using the UKBEC GCN (Additional file 1: Table S11 and Additional file 2: Figure S7).