Numerous genes are associated with autism spectrum disorder (ASD); however, it remains unclear how most ASD risk genes influence neurodevelopment and result in similar traits. Recent genetic models of complex traits suggest non-tissue-specific genes converge on core disease genes; so we analyzed ASD genetics in this context. We found ASD risk genes partition cleanly into broadly-expressed and brain-specific genes. The two groups show sequential roles during neurodevelopment with broadly-expressed genes modulating chromatin remodeling, proliferation, and cell fate, while brain-specific risk genes are involved in neural maturation and synapse functioning. Broadly-expressed risk genes converge onto brain-specific risk genes and core neurodevelopmental genes through regulatory networks including PI3K/AKT, RAS/ERK, and WNT/ -catenin signaling pathways. Broadly-expressed and brain-specific risk genes show unique properties, wherein the broadly-expressed risk gene network is expressed prenatally and conserved in non-neuronal cells like microglia. However, the brain-specific gene network expression is limited to excitatory and inhibitory neurons, spanning prenatal to adulthood. Furthermore, the two groups are linked differently to comorbidities associated with ASD. Collectively, we describe here the organization of the genetic architecture of ASD as a hierarchy of broadlyexpressed and brain-specific genes that disrupt successive stages of core neurodevelopmental processes.Recent studies present an alternate model of complex traits where the functional impact of genetic aberrations propagates through gene regulatory networks to converge on downstream core processes related to the trait (Boyle et al., 2017;Califano and Alvarez, 2017;Courchesne et al., 2020;Gazestani et al., 2019;Iakoucheva et al., 2019;Liu et al., 2019). In contrast to the single-group rASD network model, if the polygenic and omnigenic models are relevant to ASD, they would suggest that many risk genes are not necessarily part of underlying neural mechanisms in ASD. Rather many rASD genes would be broadly-expressed across many tissues, but regulate core neurodevelopmental processes underlying ASD (Boyle et al., 2017;Califano and Alvarez, 2017;Courchesne et al., 2020;Gazestani et al., 2019). Moreover, by emphasizing the gene regulatory networks, these alternative models suggest that, to the extent that the gene regulatory networks are preserved, the dysregulation could also be reflected in non-neuronal cells . Supporting these ideas, many rASD genes are broadly-expressed across tissues and strongly enriched for gene expression regulators such as chromatin remodelers, transcription factors, and modulators of signaling pathways (Courchesne et al., 2020;Courchesne et al., 2019;Werling et al., 2020). Similarly, genome wide association studies (GWAS) and whole genome sequencing both highlight the important role of broadly functional eQTLs and gene regulatory networks in ASD liability (Brandler et al., 2018;Courchesne et al., 2020;Grove et al., 2019).The fundamen...