First of all, we reasoned that the 782 DEGs or a subset of them would form co-expressed network(s), and that perturbation of the network(s) could contribute to functional disruptions in SZ patients with 22q11.2 deletion, as co-expressed genes are often functionally associated. To address this, we obtained gene expression data from the Brainspan project and separated the Brainspan samples (n = 398) into 16 groups according to brain regions and developmental stages (see Methods for details) (Table 1). Within each group, we computed the correlation coefficient of expression between every pair of our DEGs and connected a pair of genes if the coefficient was > 0.9 (or < −0.9), resulting in a co-expression network. In analyzing the networks, we found, remarkably, that the DEGs from our study showed high levels of connections in brain regions of two developmental stages, the embryonic and the adolescence stages (Fig. 5a). Moreover, the numbers of edges in the networks for all four embryonic brain regions and three of the four adolescence regions (except subcortex) were significantly greater than those of the networks derived from
