A major challenge in addressing the relationship between autism spectrum disorders and gastrointestinal symptoms is that the tools used to assess the symptoms in children with autism differ from the ROME III questionnaire typically used to assess similar symptoms in other children. Ellen Li and her colleagues at the State University of New York at Stony Brook are aiming to characterize fecal microbiota and gastrointestinal symptoms in roughly 300 children with autism and their unaffected siblings within the Simons Simplex Collection (SSC). The SSC is a rigorously characterized set of genetic, anatomic and behavioral data drawn from 2,700 families that include one child with autism and unaffected parents and siblings. Li and her team propose to use the same questionnaires, including the ROME III, for both affected and unaffected siblings. They plan to analyze results from the fecal bacteria DNA analysis (using 16S rRNA gene sequencing) in conjunction with data concerning autism symptoms and gastrointestinal problems. Li’s group aims to determine whether individuals with autism show an increased prevalence of gastrointestinal complaints compared with their unaffected siblings and, if so, whether changes in the fecal microbial composition are associated with these complaints. The researchers plan to link these data with existing genetic data from SSC families. They plan to add the results obtained from this study, including the clinical and 16S rRNA sequence data, to the SSC database so that they can be made available to other investigators.