Autism Linked to Head Size at Birth, 1st Year
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.
“It’s better to know as early as possible that something might be wrong.”
Autistic children are being reported to the California Department of Developmental Services at record rates. On Tuesday the department announced that 831 people in California were diagnosed with autism in the last three months, bringing California’s total to 22,040 recorded cases -- the fourth largest quarterly increase since DDS began monitoring the trend a decade ago.
The cause of the increase is still unclear, but a large study presented last year did rule out some possible causes, such as changes in diagnostic criteria, improvements in diagnosis and immigration.
The department sees the sudden increase as a sign that more research needs to be done to find early diagnostic techniques and therapies.
“The increase that we’re seeing now has been going on for probably eight or nine years, if not longer,” said Ron Huff, a senior psychologist at DDS.
The UC San Diego study was relatively small, and its findings cannot be used alone to diagnose autism in an otherwise normal child.
By examining the medical records of a group of 48 children diagnosed with autism, the UC San Diego researchers found that, on average, the children were born with head circumferences that were smaller than 75% of other newborns. However, the autistic infants experienced a rapid growth in head size during the first year of their lives, shooting them into the upper percentiles -- with an average head circumference larger than 84% of typical 1-year-olds.
“It was surprising because the degree of change seems to occur rapidly at such a young age,” said Natacha Akshoomoff, an assistant professor of psychiatry at UC San Diego and co-author of the JAMA article.
“We know that pattern is very rare among most kids who are typical in their development.”
The study also showed that “children with the more severe form [of autism] showed the biggest increase in growth,” said Courchesne, who is also the director of the Center for Autism Research at Children’s Hospital and Health Center in San Diego. “This suggests a strong relationship between what developmental changes the brain is undergoing and how severe the autistic symptoms are later.”
Triggers for the rapid overgrowth remain undetermined, and there is no cure for autism.
But other studies lend support to the idea that early detection and treatment -- through various language and behavioral therapies -- may lessen its effects.
“Children with autism are responsive to treatment,” said Sally Rogers, a professor of psychiatry at UC Davis. “They show reduced symptoms of autism and increasing skills.”
