Though it has been confirmed that autism is not caused by vaccines, health researchers are still unclear on exactly what does cause the condition. Research is continuing on the topic and this week a new study has shown that the origins of autism may actually start in the womb.

The study, published today in the New England Journal of Medicine, shows that patches of abnormal neurons seen in the brains of autistic people can be traced all the way back to early brain development in the womb. Extra neurons in the prefrontal cortex have been linked to autism in children.

The study looked at children with autism between the ages of two and 15. By analyzing the genes associated with the brain’s cortical layers and those associated with autism, researchers found that genetic markers for some layers of the prefrontal cortex were missing in 91% of autistic children. The same markers were missing from only 9% of children not diagnosed with autism.

“While autism is generally considered a developmental brain disorder, research has not identified a consistent or causative lesion,” said Dr. Thomas Insel, director of National Institutes of Mental Health, which partially funded the study. “If this new report of disorganized architecture in the brains of some children with autism is replicated, we can presume this reflects a process occurring long before birth. This reinforces the importance of early identification and intervention.”

The disorganized neurons in the brains of autistic children were found in patches throughout the frontal and temporal lobes of the cortex. The patches are five to seven millimeters in length and go through multiple layers of the cortex. These regions of the brain are associated with social, emotional, communication, and language functions, suggesting that the patches could be associated with common autism symptoms.

The nature of the patches could also help explain why early interventions in children with autism can help mitigate symptoms of the disorder. The study’s authors hypothesize that children’s brains, which are still developing, could lean to bypass the patches with healthier neurons in other areas of the brain.

Image via NIH