Substantial progress has been made to understand the genetic causes of ASDs. Genes implicated in syndromic forms of autism were first identified in the 1990s. Subsequent genomic copy number variant (CNV) analysis in the 2000s generated a list of rare but highly penetrant CNVs associated with ASDs. Pathogenic CNVs are estimated to account for ~10% of non-syndromic ASDs (Devlin and Scherer, 2012). Most recently, whole exome and whole genome sequencing techniques have been utilized to identify rare de novo and inherited sequence variants in hundreds of genes from ASD subjects. Despite the inability to establish a causal role for the majority of these sequence variants, a subset of new genes have emerged as strongly causal because de novo loss-of-function and likely-gene-disrupting mutations are found in multiple affected patients and are absent in a large number of controls (Table 1). In other cases, mutations that likely disrupt protein function are found in genes that are implicated in other neuropsychiatric disorders. Functional annotation of these genes immediately suggests the following molecular features: 1) neuronal ion channels and receptors; 2) synapse-related cytoskeleton and
