Autism Spectrum Disorder: Integrating Genetic and Environmental Risk.

Autism spectrum disorder is a common neurodevelopmental condition, defined by persistent deficits in social interaction and communication, as well as restricted repetitive patterns of behavior, interests, or activities. Autism spectrum disorder is highly heterogeneous, encompassing a broad range of clinical presentations and suggesting it includes multiple etiological subtypes. Although no unified cause has been established, accumulating evidence indicates that genetic susceptibility interacts with environmental and developmental factors to shape diverse phenotypic outcomes. This review summarizes epidemiological findings and discusses major proposed etiological mechanisms, integrating evidence from human studies and animal models. Although animal models are not directly translatable to humans, their findings provide mechanistic insights that bridge epidemiological observations with neurobiological hypotheses.