Kamhout, Sarah; Eddington, Hyrum; Orr, Taylor; Gilliat, Stephen; Hayward, Tyler (Brigham Young University)
Faculty Advisor: Lundwall, Rebecca (Family Home and Social Sciences, Psychology Department and Neuroscience Center)
Human stool contains microbiota that impact brain development and behavior through neuroendocrine and neuroimmune systems. Prior studies on adults with autism show differences in microbiota between autistic and control subjects. Since microbiota are normally established early in life, we wanted to know if infants with older siblings with autism had different microbiotal abundance and variety than infants with no first-, second-, or third-degree relatives with autism. We were also interested in sex differences as historically autism spectrum disorder (ASD) has been diagnosed more often in boys.
We collected fecal samples from 36 children ages 3-24 months. 18 control samples (no first-, second-, or third-degree relatives with ASD) were matched for age and sex with 18 samples from children with an older sibling diagnosed with ASD. Following triplicate PCR amplification of a single DNA extraction, QIIME software was used to assign operational taxonomic units to each strain. PCoA and PERMANOVA were completed in R. These tests showed gut flora of high-risk individuals was significantly different than controls (p = .008). PCoA showed segregation of experimental from control samples (p = .037), most pronounced in female sub-population (p = .006). A differential abundance test was done with ANCOM. Levels of B. fragilis were significantly lower in the at-risk females (W = 560). One of the taxa groups with the most abundance, Lachnospiraceae, was also significantly lower in the at-risk group (W = 48).
This suggests that microbial markers, including B. fragilis, may help identify individuals at risk for ASD, particularly girls. This is consistent with other research on B. fragilis and ASD. Further study is necessary to determine the predictive accuracy of ASD diagnosis based on biomarkers including B. fragilis. More detailed understanding of the microbiome of at risk individuals may lead to earlier detection, intervention, and ultimately improved outcomes for ASD patients.