Consistent with prior studies of the brain transcriptome15,47–50, we find gene co-expression to be organized into modules of distinct cellular and functional categories (Supplementary data file 7). In particular, the M2c module is enriched for multiple categories, including axon guidance, postsynaptic membrane, transmission across chemical synapses, and voltage-gated potassium channel complexes (Fig. 6C). Gene sets identified in prior genetic studies that highlighted certain neurobiological functions are also enriched in the M2c module, including the activity-regulated cytoskeleton-associated (ARC) protein complex, targets of fragile X mental retardation protein (FMRP), neuronal markers, post-synaptic density (PSD) proteins, and NMDA receptors (Fig. 6A). Overall, our results point to the M2c module of ~1400 genes that possess functions related to synaptic transmission as being enriched for differential expression, overlapping SCZ genetic signal, and with some genes having less dense co-expression in SCZ cases.
