This document provides an overview of autism spectrum disorder (ASD). It describes ASD as a neural development disorder characterized by impaired social interaction and communication, as well as restricted and repetitive behaviors. Key points include: ASD is defined by social and communication deficits without general language delays; it includes conditions like autism, Asperger's, and childhood disintegrative disorder; prevalence is about 2 in 1000 people; intelligence levels vary greatly in ASD from below 50 IQ to above average. The document also outlines common signs and symptoms seen at different developmental stages that are used for screening and diagnosing ASD.