Identifying essential cell types and circuits in autism spectrum disorders.

Autism spectrum disorder (ASD) is highly genetic in its etiology, with potentially hundreds of genes contributing to risk. Despite this heterogeneity, these disparate genetic lesions may result in the disruption of a limited number of key cell types or circuits-information which could be leveraged for the design of therapeutic interventions. While hypotheses for cellular disruptions can be identified by postmortem anatomical analysis and expression studies of ASD risk genes, testing these hypotheses requires the use of animal models. In this review, we explore the existing evidence supporting the contribution of different cell types to ASD, specifically focusing on rodent studies disrupting serotonergic, GABAergic, cerebellar, and striatal cell types, with particular attention to studies of the sufficiency of specific cellular disruptions to generate ASD-related behavioral abnormalities. This evidence suggests multiple cellular routes can create features of the disorder, though it is currently unclear if these cell types converge on a final common circuit. We hope that in the future, systematic studies of cellular sufficiency and genetic interaction will help to classify patients into groups by type of cellular disruptions which suggest tractable therapeutic targets.