TRIO and schizophrenia: The recent PGC GWAS (16) included fine-mapping of schizophrenia-associated single nucleotide polymorphisms to several individual genes with known roles in neurite outgrowth and synapse formation, including ZNF804A (49), in which schizophrenia risk variation may act specifically during fetal brain development (50,51); CNTN4 (52); LRRC4B (53); and DCC (54), the last encoding a Netrin-1 receptor known to interact with TRIO (46).