UM Doctors Find First Clear Link Between Autism and Gastrointestinal Disorder
For immediate release: December 12, 1999
Children with autism have a much higher rate of gastrointestinal disorders than other children, according to a study conducted by doctors at the University of Maryland School of Medicine in Baltimore. The study, led by Karoly Horvath, M.D., Ph.D, further suggests that gastrointestinal disorders may contribute to some of the behavioral problems associated with autistic children and may be caused by low levels of the hormone secretin in the body.
The discovery of a link between autism and gastrointestinal disorders is published in the November issue of the Journal of Pediatrics. An accompanying editorial said that the study provided further support for a physiological cause of autism.
Researchers examined 36 children with severe cases of autism who suffered from gastrointestinal symptoms such as abdominal pain, chronic diarrhea, bloating, nighttime awakening, and unexplained irritability. Each child was given an extensive gastrointestinal examination, including an upper gastrointestinal endoscopy. All routine causes for the problems, such as infections and other diseases were ruled out. The findings were compared with those of non-autistic children in a control group.
The most frequently detected abnormalities among the autistic children were a high prevalence of esophageal reflux, which affected nearly 70 percent, and chronic inflammation of the stomach and duodenum. Only two percent of children without autism suffered from reflux. Fifty-eight percent of the examined children with autism suffered from chronic diarrhea caused by malabsorption of carbohydrates.
"Many of the autistic children cannot express themselves, so they often suffer without treatment from these chronic gastrointestinal problems," says Karoly Horvath, M.D., Ph.D., lead author of the study and associate professor of pediatrics at the University of Maryland School of Medicine. "Of the autistic children with reflux esophagitis, 88 percent could not sleep through the night. The interrupted sleep pattern and discomfort caused by these underlying gastrointestinal problems may contribute to the sudden unexplained irritability, mood changes and aggressive behaviors often attributed to brain dysfunction," explains Horvath.
The evaluation of the autistic children also included intravenous injection of secretin to assess pancreatic function during an edoscopic examination. Secretin is a naturally occurring hormone produced during the digestion of food. It is approved by the Food and Drug Administration for use in the diagnosis of certain gastrointestinal conditions. Test results showed that 75 percent of the 36 children had a significantly higher pancreatico-biliary fluid secretion in response to secretin than the control group of non-autistic children. Horvath says this may be due to a defect in secretin production or release among autistic children.
"I think our research shows there is a clear link between gastrointestinal disorders and autism, but more research is needed. Hopefully these findings will lead to a better understanding of autism and treatment of these children," adds Horvath.
The study was funded by an internal grant from the University of Maryland School of Medicine. Since the study, the Repligen Corporation of Needham, Mass. has entered into a clinical research agreement with the University of Maryland School of Medicine to support further research and clinical studies of secretin and autism. The Repligen Corporation develops drugs for autism, organ transplant and cancer treatment.
"We plan to continue our rigorous research effort to confirm and better understand this linkage between secretin and autism," says Jay Perman, M.D., chairman of the Department of Pediatrics at the University of Maryland School of Medicine.
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