Abstract Autism spectrum disorders (ASD) encompass a group of lifelong neurodevelopmental conditions that are characterized by a triad of symptoms in impaired social communication, social reciprocity, and repetitive/ stereotypic behavior. While the behavioral phenotype of ASD is well described, the search for autism biomarkers continues. Biomarker development has so far been hampered by the large degree of phenotypic complexity associated with ASD, and no “biological tests” yet exist that could facilitate case identication, or predict response to treatment.

Contents Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 6.2 Gold-standard diagnostic assessment tools for ASD and