Of the 596 unique genes differentially expressed in our SCZD hiPSC neurons (>1.30-fold, p<0.05), 25% have been previously implicated in SCZD (SI Table 3). While our gene expression profiles of SCZD hiPSC neurons confirm and extend the major hypotheses generated by pharmacological and GWAS studies of SCZD, they also identify some pathways not before linked to SCZD, such as NOTCH signaling, SLIT/ROBO axon guidance, EFNA mediated axon growth, cell adhesion and transcriptional silencing (SI Table 4). Many of the genes most affected in SCZD hiPSC neurons belong to pathways previously associated with SCZD, though they have not yet been singled out as SCZD genes. For example, while PDE4B is a well-characterized SCZD gene, we observed significant misexpression of PDE1C, PDE3A, PDE4D, PDE4DIP, PDE7B, ADCY7 and ADCY8. Additionally, though some key SCZD/BD genes, including NRG1 and ANK3, were misexpressed in all of our SCZD hiPSC neurons, many others, including ZNF804A, GABRB1, ERBB4, DISC1 and PDE4B, were aberrantly expressed in some but not all patients. Our data support the “watershed model”23 of SCZD whereby many different combinations of gene misfunction may disrupt
