Mute and truculent, the boy sat across from Dr. Alessio Fasano. His parents had brought the 5-year-old to see the pediatric gastroenterologist at the University of Maryland because of he suffered from bloating and other gastrointestinal problems. But the child had autism spectrum disorder and the only way he could express the discomfort he felt was through violence, through throwing things and pounding his little fists.

It was the mid-1990s. Fasano, who’d recently moved to Baltimore from Italy, gently drew the boy’s blood to test for antibodies linked to celiac disease, an autoimmune condition in which the body virulently rejects gluten, a protein in wheat, barley and rye products. When the test, and later an endoscopy, both proved positive, he prescribed the only treatment for the disease: a gluten-free diet.

Over the next six months, the boy transformed in such dramatic fashion that his speech therapist was spurred to write Fasano a letter. “What did you do?” she asked. “I’ve been treating him for three years and couldn’t get two words out of him. Now, he doesn’t stop talking!”

For Fasano, now head of the university’s Celiac Disease Center and a star in the world of celiac research, the solution had been simple.

“It was like this boy was living in a parallel world, trying to communicate with others through a thick veil,” he says. “He did not have to make up developmental milestones so much as have that veil lifted. Once it was gone, there was no stopping him.”

While few turnarounds are as extreme as this boy’s, the case does demonstrate how the body can react to gluten in severe and unexpected ways, far beyond common symptoms such as diarrhea, constipation and stomach bloat.

His interest piqued, Fasano reviewed small studies of gluten’s association with autism and keenly observed his own patients for patterns. This led him to the preliminary observation that a gluten-free diet may help about 20 per cent of the children with autism spectrum disorder or ASD. This is the catch-all term used for mysterious developmental conditions that range in severity and are characterized by varying degrees of social deficits and repetitive behaviors.

Not that the kids with a response to gluten have undiagnosed cases of celiac disease; rather, Fasano suspects gluten sensitivity. This is a relatively new medical diagnosis with a wide range of symptoms similar to those seen in celiac disease, but without untreated celiac’s association with osteoporosis, infertility and other serious health issues.

“We can’t help all kids with autism,” Fasano cautions of the gluten and ASD research. “But that help, when it comes, can be pretty dramatic, not just for the child but for the whole family.”

Next page: Investigating the ‘leaky gut’

“There is tremendous confusion when it comes to these disorders,” explains Dr. Alessio Fasano, the head of the Celiac Disease Center at the University of Maryland and one of the authors of a new guide on how to define them, published in the journal BMC Medicine.

Like wheat allergy and celiac disease, gluten sensitivity occurs in reaction to a protein found in wheat, barley and rye. Unlike celiac disease, the reaction is not an autoimmune response, in which one’s immune system sees gluten protein as intruder and will initiate a protective response that damages the small intestine.

Nor does it lead to the development of osteoporosis, neurological issues or other autoimmune diseases – as celiac disease can. But gluten sensitivity can still be horribly uncomfortable and painful. It’s a condition that Fasano says is related to “the older, innate” immune system that is not as sophisticated, modern as the adaptive immune system, which is the one linked to the other conditions on the spectrum.

To add to the confusion, symptoms of gluten sensitivity may start and stop without warning.

The new recognition of this condition should lead to speedier diagnoses for patients who complain of symptoms but test negative for celiac disease and wheat allergy. It also helps to explain why such patients who eliminate gluten from their diets despite the negative test findings do feel better.

“We’re at the same place with gluten sensitivity that we were almost 20 years ago with celiac disease,” Fasano says. “We’re just beginning to understand how it affects certain individuals.”