Intracellular signaling pathways in the developing cortex also likely contribute to the progenitor regulatory network that includes 22q11.2 genes. It is known that the integrity of FGF signaling pathways is critical in the generation, proliferation and maintenance of neural progenitors [132, 133]. Distal deletion in the 22q11.2 region has been associated with basal progenitor defects via ERK/FGF signaling [121]. Therefore, we speculate that there may be a group of genes in the 22q11.2 region whose dosage is critical for intracellular signaling linked to cell proliferation. Indeed, function analysis of genes most co-expressed with the DEGs in embryonic brains fully supports this (Fig. 6). Also, several components (i.e. MAPK, APK3, FGFR2) from ERK/FGF signaling were among the top co-expressed DEGs in the embryonic stage (Table 3).
