we used information from a global interactome for Homo sapiens in order to identify high confidence interactors of DLGAP1 and GRIK2 (confidence threshold > 0.95) 34. No sub-network reduction was applied and only genes representing first neighbors of DLGAP1 and/or GRIK2 in the global interactome were considered for this analysis. We used gene-based results in order to identify an enrichment of association with OCD in interaction partners of DLGAP1 and the ionotropic kainate 2 glutamate receptor (GRIK2). This analysis was motivated by the assumption that biologically closely related genes of these previously described OCD risk genes would make reasonable candidates for hypothesis driven downstream analyses. Based on an assumed similarity between these genes with regards to an involvement in common biological processes and provided that, on a broader level, these biological processes themselves are associated with the phenotype under study it seems reasonable to hypothesize that focusing on biologically closely related genes (see above) helps to identify new disease genes (through reduction of some of the multiple testing burden in standard GWAS). More information on the usage of the interactome data and the visualization of the resulting networks are found in the supplementary material and methods. In brief, we would
