Gastrointestinal Issues in Autism Spectrum Disorder

Hsiao, Elaine Y PhD

doi: 10.1097/HRP.0000000000000029

While autism spectrum disorder (ASD) is characterized by communication impairments, social abnormalities, and stereotypic behaviors, several medical comorbidities are observed in autistic individuals. Of these, gastrointestinal (GI) abnormalities are of particular interest given their reported prevalence and correlation with the severity of core autism-related behavioral abnormalities. This review discusses the GI pathologies seen in ASD individuals and the association of particular GI conditions with known genetic and environmental risk factors for autism. It further addresses how GI abnormalities can affect the neuropathological and behavioral features of ASD, as well as the development of autism-related endophenotypes such as immune dysregulation, hyperserotonemia, and metabolic dysfunction. Finally, it presents emerging evidence for a gut-brain connection in autism, wherein GI dysfunction may contribute to the pathogenesis or severity of ASD symptoms.

From the Divisions of Biology and of Chemistry and Chemical Engineering, California Institute of Technology.

Original manuscript received 16 February 2013, accepted for publication subject to revision 8 April 2013; revised manuscript received 15 May 2013.

Correspondence: Elaine Y. Hsiao, PhD, 1200 E. California Blvd., M/C 216-76, Pasadena, CA 91125. Email:

© 2014 President and Fellows of Harvard College