A Microbial Association with Autism

Autism is a heterogeneous group of complex developmental disabilities that result from a number of possible etiologies. There are a well-known number of comorbidities associated with autism spectrum disorders (ASD), including, commonly, gastrointestinal (GI) pathology, which can include variable combinations of constipation, diarrhea, abdominal pain, gastroesophageal reflux, and vomiting. An American Academy of Pediatrics consensus panel has recommended that prospective studies be carried out to determine the prevalence of GI disorders in ASD and their pathophysiologic basis. In a recent article, Williams et al. [B. L. Williams, M. Hornig, T. Parekh, and W. I. Lipkin, mBio 3(1):e00261-11, 2012] have provided one such study of autism with GI comorbidities by presenting evidence of Sutterella species in ileal mucosal biopsy specimens from patients diagnosed with ASD but not in control children with GI symptoms, suggesting a specific role for Sutterella in ASD. Sutterella sequences represented similar to 1 to 7% of the total bacterial sequences, and this is a very large effect size on the ileal mucosal composition of the autism phenotype, rivaling or perhaps exceeding the effect size of the ileal Crohn's disease phenotype. This study opens a new field of investigation to study the etiology or consequences of GI comorbidities in ASD.