Autism, the prototypic pervasive developmental disorder (PDD), is usually apparent by 3 years of age. It is characterized by a triad of limited or absent verbal communication, a lack of reciprocal social interaction or responsiveness, and restricted, stereotypic, and ritualized patterns of interests and behavior (Bailey et al., 1996, pubmed:8655659; Risch et al., 1999, pubmed:10417292). 'Autism spectrum disorder,' sometimes referred to as ASD, is a broader phenotype encompassing the less severe disorders Asperger syndrome (MIM:608638) and pervasive developmental disorder, not otherwise specified (PDD-NOS). 'Broad autism phenotype' includes individuals with some symptoms of autism, but who do not meet the full criteria for autism or other disorders. Mental retardation coexists in approximately two-thirds of individuals with ASD, except for Asperger syndrome, in which mental retardation is conspicuously absent (Jones et al., 2008; pubmed:18698615). [from MIM:209850; 2017.03.18]

CHD8 encodes a member of the chromodomain-helicase-DNA binding protein family, which is characterized by a SNF2-like domain and two chromatin organization modifier domain; members of this family have been shown to function in several processes that include transcriptional regulation, epigenetic remodeling, promotion of cell proliferation, and regulation of RNA synthesis. [Gene Cards, CHD8; 2020.11.03]

Many to one: 4 human genes to 1 Drosophila gene; the human genes are CHD6, CHD7, CHD8, and CHD9.