Identifying the distinct biological mechanisms at play in autism spectrum disorder (ASD) may help to better understand the heterogeneous manifestations of this complex condition. Jessica Ann Lasky-Su and Rachel Kelly contend that utilizing the metabolome as a composite measure of both genetic and environmental influences in a biofluid such as plasma will identify distinct subgroups groups of ASD individuals with common underlying biological mechanisms. Findings from this project may lead to the development of metabo-endotype approaches to optimize treatment.