PCDH19 and autism: In the Mef2c cKO DEGs, we identified a significant overrepresentation of ASD-risk genes (p=0.0007, hypergeometric test, perm=0.001) and synapse-linked genes (p=0.0004, hypergeometric test, perm=0.001), (Figure 4B), including the autism-linked genes Ntng1, Nlgn1, Nrxn1, Nrxn3, Pcdh19, Shank2, Shank3, Pten and Htr1b. We also detected a significant enrichment for FMRP-associated RNAs (p=3x10−07, hypergeometric test, perm=0.001), which is interesting since FMRP is required for MEF2C-VP16-induced excitatory synapse elimination (Pfeiffer et al., 2010).