Autism Spectrum Disorder (ASD) is characterized by developmental defects in three specific areas: social skills, language skills and behavior. Genetics play a role in the development of autism, but environmental factors are involved as well. Signs of autism usually become apparent by the age of 18 months, but a diagnosis is not always confirmed until the age of 2 or 3, when language skills are more easily assessed.
Because autism is most often detected in early childhood, the assumption has been that it originates during these early months and years of life.
Early diagnosis and intervention have made an impact on affected children -- but so much about autism is still unknown.
A study done at the University of California, San Diego, published in The Journal of the American Medical Association, suggests that autism begins much earlier than suspected. Lead researcher Dr. Eric Courchesne and his team discovered an excess number of nerve cells (67 percent more) in the brains of autistic children, with the greatest area of enlargement being in the prefrontal cortex. This is the area of the brain that controls expression of personality, prediction of outcomes and appropriate social behavior -- classic areas of defect in autism. The overabundance of nerve cells occurs in utero, during early development of the fetus, not after birth.
"Several years ago, we discovered that in early life the brain grows too large, too fast in many children with autism," says Dr. Courchesne. "That finding led us to look more carefully with MRI scanning to determine just what part of the brain is most affected." Researchers studied the brains of seven autistic boys who died between the ages of 2 and 16 and compared them to the brains of children the same ages who were unaffected by autism.
Focus for future research
Now that scientists have discovered this correlation between autism and increased brain neurons, how does this affect future research? "The focus for research can target genetic systems that regulate the number of neurons that are generated and survive," says Dr. Courchesne. Determining why an excess number of neurons would be disruptive to the brain is interesting to researchers as well.
Each new study provides another piece of the puzzle for parents of autistic children, and gives hope for children who are diagnosed in the future.
allParenting's Dr. Mom says...
allParenting's resident Pediatrician, Melissa Arca, M.D., had this to say about the study: "First word of caution is that this study is very small, so more studies are definitely needed, especially to elucidate whether children with autism actually generate more neurons in utero or if there is a failure to prune them.
"But it does reinforce what several other recent studies have been finding: Exposure in utero to specific conditions can increase risk of autism, and that genes and/or genetic mutations play a huge role as well. For instance, recent studies have indicated that moms exposed to an increase in environmental pollution (living near a highway) had a higher incidence of having children with autism. While other studies show an increase in autism amongst children whose mothers took antidepressants or a seizure medication during pregnancy. Furthermore, we know that 15-20 percent of autistic children have a genetic mutation causing their autism. So, autism is a puzzle indeed and every study that unlocks one more piece of that puzzle is helpful and aids researchers in their future studies."