Small head circumference at birth followed by an accelerated increase in head size by the age of 1 has been linked to the development of autism, a finding that may give doctors their first early indicator of the disorder, according to a study by UC San Diego researchers.
The finding raises hopes that doctors will be able to begin therapies for autistic children at a much earlier age to lessen the effects of the disorder, which seems to be sharply increasing in California and elsewhere.
The study also strengthens the contention that autism is a genetic or biological disorder, and is not caused by later environmental factors, such as various childhood vaccines that used to contain a mercury compound.
While the study does not rule out these factors, it indicates that abnormal signs already exist before the age when vaccines are typically administered.
"Because these abnormalities are present at birth, it further supports all the previous work that shows a significant biological-genetic component to this disorder," said Dr. Daniel Geschwind, director of the neurogenetics program at UCLA.
Eric Courchesne, a professor of neuroscience at the UC San Diego School of Medicine and the lead author of the study appearing today in the Journal of the American Medical Assn., said: "There is little doubt that genes are a major factor in autism -- what is unclear is the extent to which the genetic factors relate to other factors."
For example, genes may not directly cause autism, but instead could make patients more susceptible to certain environmental pollutants, vaccines or foods that could trigger its onset, Courchesne said.
Autism refers to a spectrum of related neurological disorders that tend to result in severe social withdrawal. Children often appear socially cut off from the world and often have profound handicaps in areas such as speech.
No widespread test has been developed to diagnose children with autism before they begin showing symptoms, which include impaired speech, lack of eye contact and extreme passivity.
Rick Rollens, who is the parent of an autistic child and was instrumental in creating the MIND Institute for researching autism at UC Davis, said the best way to detect autism is "to go with your instincts."
"If you feel something might not be quite right with your child, you should immediately point these symptoms out to your pediatrician," he said.
