Diagnoses for individuals with autism spectrum disorder have risen over the past decade, and researchers still have far too many questions about the disorder. While multiple genes possessing the potential to cause some types of autism have been identified, putting together the pieces of the puzzle has proven complicated. The range within the autism spectrum is quite vast, from the milder end where some might’ve received a diagnosis for Asperger’s syndrome in the past, to the more severe end, where individuals struggle with both physical and cognitive disabilities. These extremes within this spectrum have further complicated the world of autism research.
It’s also worth noting that the severe end of the autism spectrum is significantly underrepresented in clinical research data. For example, brain imaging studies that require a child to remain still for a significant period of time would be near impossible to achieve for a child with severe autism. Similarly, caregivers commonly decline to participate in research studies requiring more invasive testing, even a simple blood draw, because they don’t want to cause additional stress for their child.
This means many of the studies evaluating a specific intervention across the wide autism spectrum (e.g. specialized diets, medications, behavioral therapies, etc.) might lack statistical legitimacy, but could potentially be highly beneficial to a subset of individuals within the spectrum. We need larger, more effective studies composed of individuals who will allow us to evaluate potential treatments and begin teasing out potential subtypes of autism. This will require the merging of multiple evaluated characteristics, including gastrointestinal (GI) symptoms, behavior, genetics and laboratory testing results (including the microbiome and metabolome) to name a few.
So, how can we conduct meaningful, more inclusive research for the entire spectrum? Our approach involves using something most people are more than willing to hand over … poop! GI issues are very common within the autism spectrum, and we know our gut microbiome is closely connected to our behavior and mood. We call this the microbiome-gut-brain axis, and thanks to research funding from Autism Speaks, we’ve spent the past three years collecting stool from children all over the country and across the autism spectrum. What we hold in our hands (or in our freezers, to be exact) is the largest autism study of the gut microbiome to date. We’re in the process of analyzing the microbes and small molecules from these samples in order to identify distinct profiles within the larger autism spectrum sharing common GI symptoms, behavioral patterns and of course, bacteria.
Interest in this area started well over 20 years ago, when parents began reporting improvements in their autistic children while on a typical course of antibiotics. These anecdotal success stories were met equally with stories of observed regression in other children. Both scenarios obviously pointed to the same hypothesis, though, that microbial shifts were often associated with shifts in behavior. We’ve seen this phenomenon reproduced in various animal models of autism, and with support from N of One: Autism Research Foundation, we’re continuing to recruit autistic children who are prescribed antibiotics to evaluate changes in the gut microbiome in parallel with changes in behavior.
Many of the most promising avenues for autism research are based on shared parental observation, and as a mother to a 9-year-old son with severe autism, I’m able to contribute a parental perspective with our research in the Texas Children’s Microbiome Center. Since this month signifies National Autism Awareness Month, I’d like to extend a “thank you" to all of the families who’ve participated in our research so far. Your efforts will change this field and will help us get the answers all of our loved ones with autism deserve.