Researchers found that the abnormalities appeared in the prefrontal cortex, a portion of the brain that is key to complex thoughts and behaviors.
"The genes that control the number of brain cells did not have the normal functional expression and the level of gene expression that governs the pattern of neural organization across the prefrontal cortex is turned down," Eric Courchesne, director of UCSD's Autism Center for Excellence, said in a news release.
According to Courchesne, who led the study, the abnormal numbers and patterns lead to too many brain cells in some locations, such as the prefrontal cortex, and not enough brain cells in other regions of the cortex.
Furthermore, only a few previous studies were able to investigate gene expression in the brains of young autism patients.
"Our results indicate that gene expression abnormalities change across the lifespan in autism," Courchesne said. "The dysregulated genetic pathways we found at young ages in autism may underlie the excess of neurons - and early brain overgrowth - associated with this disorder."
Researchers stated that the findings from this new study can help explain previous studies which found that the brains of young children with autism are larger, particularly in the prefrontal cortex.
These new findings could lead to discoveries as well as new prevention strategies and treatment for autism.