Brain Cells That Fail To Mature In Utero Responsible For Autism
By Liisa Vexler
The roots of autism begin in the womb when specific brain cells do not mature fully, say researchers who have ascertained that the “scattered pattern” of underdeveloped cells may provide an explanation for the wide array of symptoms found in children with the condition.
While studying cadaver brain tissue taken from children, the scientists discovered that cells from those with an autism diagnosis were missing key genetic markers for brain cells that normally develop in utero. The irregularities were present in areas that are responsible for emotion, communication, language and social comprehension, all tasks impaired in individuals with autism, the study authors reported.
The results, published in the New England Journal of Medicine, offer another hint to hasten diagnosis of the disorder, when the treatment effectiveness is at its peak. To date, the cause of autism is not known. It affects 1 in 50 children in the United States, most of whom are diagnosed between three and five years of age as a result of behavior changes noticed by parents, caregivers or teachers.
“We found a novel aspect of cortical development never seen before that provides clues to the potential cause of autism and when it began,” said study author Eric Courchesne, the University of California at San Diego’s director for the Autism Center of Excellence. “The type of defect we found points directly and clearly to autism beginning during pregnancy.”
Up to this point, most studies on autism have been conducted using MRI or other imaging technology. A few have been done on brain tissue taken from adults. This study looked at tissue samples from 22 children, 2 to 15 years of age, half with an autism diagnosis prior to death. Though the sample size was small, it is considered larger than any previous postmortem studies conducted to date, with more than 12,000 slides painstakingly analyzed. The results indicate that the disruption of cell development in the brain probably occurred in the second and third trimesters, Courchesne said in a telephone interview.The next step for these researchers is looking into the cause of the irregularly developed cells.
Autism has no cure. Treatment for kids with the condition includes behavioral therapy and medication to treat symptoms in some cases.